Does it make sense? An $1800 Full frame DSLR from Canon [Archive]

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Benjamin

03-28-2009, 11:37 PM

Dallasphotog

03-29-2009, 12:26 AM

I think you have interesting ideas, but I'm not sure what drives Canon. There was a thread on this Forum about what photographers wanted in the future and it went all over the map. Canon probably just thinks we are all crazy.

It seems like full frame cameras aren't much of a priority as Canon only has two selections. However, maybe the long waits for the 5DMKII will send a message that there are a lot of photographers who value full frame bodies.

I'm stuck in the middle. I have a 1DMKII which was pretty good for sports and weddings. Now, the best sports camera seems to be the 1DMKIII, but the 5DMKII looks like a great wedding machine. I really can't justify both or worse buying both of the MKIII models.

I'll probably end up with the 1DMKIII and bet that it will be a good enough wedding camera.

Jon Ruyle

03-29-2009, 12:32 AM

Well, it would be cool. I'm not holding my breath, though. To make it cheaper, you'd have to do more than lower the resolution, and I'm not sure there would be much market for a "bare bones" ff dslr. Not sure what they would have get rid of to bring the price down that much.

Do you really think the D700 does a much better job at high iso than the 5DII? From comparisons I've seen, they look pretty close. I would even give the 5DII the edge for black and white (it seems to me to have more chroma noise but less lumanance noise... I say "seems to me" because I haven't done anything scientific... just looked at samples taken by other people)

Keith B

03-29-2009, 01:00 AM

I'd say for 21MP compared to a 12MP, the 5Dmk2 is far more impressive. It really isn't an oranges to oranges.

From the sounds of it, the only thing I'm envious of is the Nikon focusing abilities.

The lack of focus points really bites me in the rear often when shooting wide angle portraits when I want the subject of to the side. Recomposing is obviously not going to give me a well focused image.

Off topic I know.

ShutterbugJohan

03-29-2009, 01:35 AM

I don't know if it makes sense, but I hope you're right. It would be a very pleasant surprise to have a more affordable FF D-SLR on the market.

Sinh Nhut Nguyen

03-29-2009, 02:47 AM

Sure why not an entry level FF camera around $1500-1800? I was hoping that Canon would keep the 5D and give it some new features and facelift.

Mark Elberson

03-29-2009, 09:29 AM

Sure why not an entry level FF camera around $1500-1800? I was hoping that Canon would keep the 5D and give it some new features and facelift.
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Providing I could convince my wife that I "need it", I would be 1st in line to purchase it! I would be fine with the 5D's 12MP Full Frame Sensor. I would love it to have Digic IV processing and extended ISO range along with the new 3'' VGA LCD.

Daniel Browning

03-29-2009, 02:26 PM

Would it make sense to bring the full frame DSLR’s price down once again? Such as a FF DSLR with 16MP or so like a downgraded 5D II that comes @ $1800.

It would be nice, but the cost of the full frame sensor is not going down any time soon.

First of all, the cost of a sensor rises exponentially with area.

Image sensors don't follow Moore's Law. Most other silicon wafer electronics, such as computers, can double performance every 18 months for the same price level. Or they can halve the price every 18 months for the same performance level. The reason this is possible is that transistors shrink: so you can do the same thing in less area or more things with the same area.

Image sensors don't get much benefit from shrinking, because the total size of the sensor *must* remain the same.

The 5D2 has a $1,500 premium over the 50D, despite the fact that the 50D is more advanced in many ways (gapless microlenses, autofocus, smaller pixels, etc.). In fact, some of the 5D2 features, such as autofocus, are more in line with the $800 500D, not the $1200 50D.

The price difference is due to the large sensor. The 5D1 had a similar price premium over the most comparable APS-C camera of its time: the 20D. This price premium has shrunk very little since the 5D1.

Back to 2005 Canon was the first one to offer a full frame 5D at $3000 and that triggered a revolution.

This might be a different breakthrough than you think. The largest semiconductor mask (reticle) only goes up to APS-C sizes (1.6X). Up to that size, cost rises exponentially with area.

For larger-than-APS-C, it's a whole different ball game: two or more reticles must be stitched together. Stitching accelerates the costs even faster than the already-exponential rate of increase. Canon's 1.3X format (1D-series) is a single stitch of two reticles, and full frame is two stitches of three reticles.

With a single stitch, manufacturing yields drop to less than 25% (!) of normal yields, so imagine how low the yield drops with two stiches: on top fo the yeilds for three reticles. The breakthrough of the 5D1 was that Canon found a way to increase stitching-related yields enough to get the price premium as low as $1,500. It's still massively expensive compared to 1.6X, but at least now the difference is a little more down to earth (depending on your perspective it might still be astronomical).

Research and development is another factor, but it must be considered in the context of the amortization over the number of cameras sold. The R&D budget for APS-C can be higher than full frame because sales are in the millions. I believe that's why the 5D2 just re-hashed the same old autofocus as the 5D1: they saved money by reusing the same old design and same old parts rather than adapting the newer, more expensive autofocus like they did in the 50D.

Cost is not related to the number of megapixels. A 1 MP sensor costs just as much as a 21 MP sensor because they have the same area. Higher research and development can cause a difference, unless it also has higher sales, in which case the amorization comes out the same per camera.

When it comes to full frame cameras, everyone seems to wonder the same thing: Why can't someone build the *cheapest* full frame camera possible. No frills like high MP, FPS, autofocus, build quality, etc. Just a cheap full frame camera.

But that's exactly what Canon, Nikon, and Sony have done. The "extras" they put in are so inexpensive that they add very little to the cost of the camera, compared to the sensor size. If Canon ripped out the cheap "extras", such as 6 MP, 1 FPS, no video, small LCD, etc., they might save $200 per camera, but then sales would be so much lower that amorization would eat the difference and then some: it'd be a higher price.

The cost of full frame is not going down any time soon. I don't like it any more than anyone else, but it's the reality of semiconductor manufacturing. Our only choices are to buy a used 5D ($1200), even though a similarly-equipped APS-C, the 20D, is much less (~$250).

Benjamin

03-29-2009, 03:07 PM

Thanks everyone for the thoughts! Especially Daniel: wow, what a wonderful analysis - that answers my big question in mind!

I now have hadthe 50D for 2 months and I think I will stick to it for at least 3 more years, it's a great camera in my opinion dispite those critical comments and reviews on the internet. I probably will save my digital FF plan for later, maybe after Canon comes up with a FF 1D or a 5D III with better focus system and speed - I guess that will not happen in a short while either.

I'm happy withmyAPS-C, robust, fast, advanced50D, at least now.[:)]

Jon Ruyle

03-29-2009, 06:55 PM

I'm actually inclined to think in the other direction. That is, I'd pay more for a full frame camera that had a 45-point autofocus. Yeah, I know that camera exists and its called the 1DsIII. But it just doesn't seem right that the fancier af and the weather sealing almost triple the cost of the camera. Somethin' ain' right there. I'd pay $1000 more for a 1D-like autofocus, but not $4300 more.

Obviously, Canon is better at making money than I am, though... they must know what they're doing.

Maybe one day camera components will be interchangable the way computer components are. Then you could buy whatever sensor, autofocus, body, features, etc you needed, and not pay for what you don't want.

Daniel Browning

03-29-2009, 07:25 PM

You're very welcome, Benjamin.

[The 50D is] a great
camera in my opinion dispite those critical comments and reviews on the
internet.

Agreed. Even after you do go full frame, it's nice to keep a second APS-C body around for telephoto and macro situations where the reach is a big advantage.

Maybe one day camera components will be interchangable the way computer components are.

RED is proposing an interchangable system in their upcoming Scarlet and EPIC digital cinema cameras ("http://red.com/).

Brain (sensor and electronics).
Lens mount (Nikon, Canon, RED, PL, etc.: take your pick).
I/O module (video/audio stuff)
Multiple battery options (between 1 and 140 batteries).
Wireless remote
Electronic Viewfinder
Handles
Recording modules (solide state, compact flash, hdd, etc.)
LCD and tons of other accessories

The idea is to mix and match whatever features are needed for a given camera.

ShutterbugJohan

03-30-2009, 12:57 PM

Daniel: Wow! You know a lot of info. Do you work for Canon? :-) Sorry about my ignorance, but what is a semiconductor mask (reticle)? Thanks!

UK_Scotty

03-30-2009, 02:14 PM

Keith B

03-30-2009, 03:16 PM

1.3 crop xxD probably won't happen. It will eliminate use of EF-S lenses.

UK_Scotty

03-30-2009, 03:35 PM

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"]<span style="font-family: Times New Roman; font-size: small;"]So no downside then!<span style="mso-spacerun: yes;"] The cropped lenses from any manufacturer rate along side betamax, hd-dvd, and French cars, just another con to get people to buy and then be forced to buy again!

Colin

03-30-2009, 05:29 PM

I don't know....

Practically speaking, I think most DSLR buyers are not photographers truly demanding the highest image quality to the detriment of convenience. What a smaller sensor allows you to do is carry less glass for the task, make the body smaller, etc. Don't get me wrong. I have no intention of giving up a full frame, but then again if you flip things around, I'm not looking to ditch my 1.6 crop body that has an edge on pixel density (over my arcane 5D) and a higher frame rate. Nor do I have any real interest to invest in even larger medium format systems and try to replicate my EF lens collection along that venue.

Smaller sensors simply allow smaller cameras, and the glass is more cost effective from a functional standpoint. There is an advantage in that.

But, still, as much as I admire the 50D, I wouldn't trade my 5D. However, if I could swap out my 30D for a 50D, or a 1DmkII/III, I'd be way happy [:)]

alexniedra

03-30-2009, 07:25 PM

I think Canon's long term plans consist of making all cameras full-frame - the advantages of this sensor size are many.

Daniel - Awesome info here. I wish I knew more about the manufacturing process myself.

The next step for Canon is to lower the production costs of these big - and expensive - imagers.

wolf

03-31-2009, 04:22 PM

You have to realize that sensor size and not pixels is at the root
of high camera cost for FF. The silicon cost wouldn't change much if
you had less pixels (you'd have a slightly larger yield with lower MP
sensors, which would reduce the cost).

If you have larger pixels (i.e. less MP for the same area) you're
going to have lower noise, which is why the original 5D was so good
(compared to the crop sensors at the time) and why the Nikon 700 is
less noisy at high ISOs (noise processing also helps). Less MP also
reduces lens aberrations, which is why people say the 40D has better
picture quality than the 50D.

The only way to reduce the price of FF cameras is to sell more of
them, then the cost per sensor die is reduced (the reason why Pentium
chips can be sold for the prices they do since they're produced in
hundreds of thousands).

Daniel Browning

03-31-2009, 06:27 PM

Daniel: Wow! You know a lot of info. Do you work for Canon? :-) Sorry about my ignorance, but what is a semiconductor mask (reticle)? Thanks!

Thanks, Johan. Photography is just my hobby, but I enjoy getting deep into it.

The reticle is the quartz "master" image of the sensor. A laser is shined through the reticle, focused onto the much smaller silicon wafer. For further reading, I suggest the following "white paper" from Canon:

http://forums.dpreview.com/forums/read.asp?forum=1000&message=30412083 (http://www.usa.canon.com/uploadedimages/FCK/Image/White%20Papers/Canon_CMOS_WP.pdf ]http://www.usa.canon.com/uploadedimages/FCK/Image/White%20Papers/Canon_CMOS_WP.pdf [/url]

It's mostly just marketing, but there is some good information in there described in simple terms with some illustrations.

From an engineering point I would say that the 50D is a step [too] far

I disagree.

A 1.6X sensor at 15mp is going to give problems that are not worth the extra resolution.

Aside from larger files, resolution has not caused the 50D any problems. Compared to the 40D, the 50D has slightly higher sensitivity, slightly less noise, and a lot more resolution:

http://luminous-landscape.com/forum/index.php?showtopic=29801&view=findpost&p=241562

[URL="http://forums.dpreview.com/forums/read.asp?forum=1000&message=30412083)

http://www.pbase.com/jkurkjia/50d_vs_40d_resolution_and_noise ("http://www.pbase.com/jkurkjia/50d_vs_40d_resolution_and_noise)

I think (hope) that the next mid range body [60D?] would have to have a larger sensor.

It does not "have to have" a larger sensor at all. Resolution can and will continue to improve in APS-C cameras. A larger size would not only increase cost greatly, but would not benefit the use of EF-S lenses.

A different sensor size would be a completely different product line.

One would hope for full frame

There is already a full frame option: the 5D series.

but suspect that a 1.3x sensor would be canons preferred option if forced down that route

It's possible that Canon could remove some features from the 1D 1.3X series, but the increased sensor size alone is still going to make them more expensive than APS-C.

Larger sensors are not going to get cheaper because you want it. Nor because you believe Canon reached some sort of "limit" in APS-C. Even if they had reached any kind of limit, that's not going to make larger sensors any cheaper.

but I think that all of the manufactures will try desperately to keep the 1.6 and 1.5X sensors.

Your position is indefensible.

The cropped lenses from any manufacturer rate along side betamax, hd-dvd, and French cars, just another con to get people to buy and then be forced to buy again!

If you're serious, then I think you're incorrect. If you're trying to be funny, then I fail to see the humor.

you'd have a slightly larger yield with lower MP
sensors, which would reduce the cost

Interesting. I haven't heard that before, but I do know that dead pixels on higher MP sensors affect the total image much less than the same number of dead pixels on a lower MP sensor.

If you have larger pixels (i.e. less MP for the same area) you're going to have lower noise, which is why the original 5D was so good (compared to the crop sensors at the time)

I disagree. If you have a larger *sensor*, you're going to have lower noise: pixel size is almost irrelevent. A digicam with a teensy, tiny sensor will never have less noise than a full frame senosr. Even if the digicam has large 200-square-micron pixels and the full frame sensor has tiny 16 um^2 pixels, the DSLR will still have less noise.

The 5D proves my point. If you compare "for the same area", as you said, then you take away the advantage of the large sensor size, and it's plainly worse than even the 20D. For example, for a given fixed exposure (f-number and shutter speed), the 20D collects 0.76 photoelectrons per ADU per square micron, whereas the 5D only records 0.61 e-/ADU/um^2. The smaller 20D is 20% more efficient. The difference in read noise is even more disparate.

So the "large pixels" of the 5D are plainly worse than the "small pixels" of the 20D. It's only the *sensor size* that makes the 5D better, not the larger pixels. Another example is the 1Ds3, which has smaller pixels than the 5D, but much higher quality (sensitivity and read noise).

And why the Nikon 700 is less noisy at high ISOs.

That's true. However, the Sony-built D3X has much less noise at low ISO, and far more dynamic range than the D700, despite much smaller pixels.

Less MP also reduces lens aberrations

I disagree. The aberrations are there no matter what size pixel you have. Smaller pixels just allow the photographer to see them if he so desires, whereas large pixels are so blurry that they can't resolve the aberrations.

Choosing to use large pixels for the purpose of "reducing lens aberrations" is sticking one's head in the sand. They're still there, you just can't see them. One may still stick their head in the sand with a 50D, just resize the image down to the spatial resolution of the 40D.

The wrong question is "what resolution is low enough and blurry enough to hide all the optical imperfections in my lens?".

The right question is "what resolution is high enough and detailed enough to to extract every last drop of information from my lens?".

I already know that much of my glass has useful information at extremely high resolutions, because I've used them with teleconverters. I'm looking forward to 200 MP, 500 MP, and 1 GP sensors in the future.

wolf

03-31-2009, 06:53 PM

You're right in the sense that lower MP hide lens aberrations which is what I meant by "reducing lens aberrations".

It's not just pixel size that reduces noise, it's the on-chip (or software) noise reduction algorithms. If you took the raw data (without noise reduction being applied) of two chips (with same physical size), the one with larger pixels will appear to be less noisy.

There is always a tradeoff when changing a single parameter. Smaller pixels (higher MP count): bigger enlargements but more noise at high ISOs. More noise reduction: less noise but you lose detail.

When comparing sensors of the same size, like the Nikon D700 and Sony A900, the one with less pixels will typically appear less noisy (without considering noise reduction). But there are always limits and if you push the number of MPs past a certain limit you loose the benefit and other factors come into play such as lens aberrations and noise issues.

Daniel Browning

03-31-2009, 08:52 PM

It's not just pixel size that reduces noise, it's the on-chip (or software) noise reduction algorithms.

I'm aware of when and where noise reduction occurs.

If you took the raw data (without noise reduction being applied) of two chips (with same physical size), the one with larger pixels will appear to be less noisy.

I disagree.

There is always a tradeoff when changing a single parameter.

Yes, there is always a trade off, but noise is not one of them. The trade off for smaller pixels is stronger in-camera processing power, more storage space, slower demosiac and post processsing, etc.

Smaller pixels (higher MP count): bigger enlargements but more noise at
high ISOs.

I think that is a common misconception. For a given sensor size the "noise per detail" (i.e. noise power per spatial frequency) stays the same no matter what the pixel size. The only difference is that smaller pixels allow one to use higher spatial frequencies. This is illustrated in the link I provded above for the 50D/40D.

http://luminous-landscape.com/forum/index.php?showtopic=29801&view=findpost&p=241562 ("http://luminous-landscape.com/forum/index.php?showtopic=29801&view=findpost&p=241562)

When you compare them at different spatial frequencies (detail) by using 100% crop, the 50D appears to have more noise. But when you compare them at the same spatial frequency (amount of detail) by resampling both to the same resolution, it becomes clear that their noise is in fact the same.

ShutterbugJohan

03-31-2009, 10:53 PM

Daniel Browning said:

"Interesting. I haven't heard that before, but I do know that dead
pixels on higher MP sensors affect the total image much less than the
same number of dead pixels on a lower MP sensor."

Thanks for the responce, Daniel. That White Paper is very informative. What is the purpose of dead pixels? I believe that my Canon 10D has 6.5MP, but is only uses 6.3MP. Thanks.

--Johan

Daniel Browning

04-01-2009, 12:23 AM

What is the purpose of dead pixels?

Every sensor has a number of dead pixels and/or hot pixels, where they are full brightness even in the absence of light. They can be caused by impurities in the silicon. Most of them are "mapped out" at the factory. Mapped-out pixels are interpolated from the surrounding pixels. New ones often develop after the camera is shipped, resulting is a surprised customer, until the user learns how to map out the bad pixels themselves, like so:

http://community.the-digital-picture.com/forums/t/673.aspx ("/forums/t/673.aspx\)

HiFiGuy1

04-01-2009, 12:33 AM

<p class="MsoNormal"]<span style="font-size: small; font-family: Times New Roman;"]So no downside then!<span style="mso-spacerun: yes"] The cropped lenses from any manufacturer rate along side betamax, hd-dvd, and French cars, just another con to get people to buy and then be forced to buy again!
<div style="CLEAR: both"]</div>

Scotty,

I don't know if I can agree with you on the comparison of EF-S lenses with HD DVD and Betamax. Generally speaking, EF-S lenses are considered to be slightly (or more) inferior when compared with L lenses. In those two examples, the productswere arguable superior to their competition, but lost in the marketplace. French cars, OTOH, I can't speak for, though I'd like to find a really low mileage, clean Renault R5 one day, even if just for a test drive.

Jon Ruyle

04-01-2009, 01:24 AM

I disagree. If you have a larger *sensor*, you're going to have lower noise: pixel size is almost irrelevent.

I would have guessed read noise would be larger when you have more pixles (so high pixel density would hurt snr). Are you saying that isn't true? Or that it is true and isn't a significant factor?

Colin

04-01-2009, 01:48 AM

He's saying that if you look at signal to noise per pixel, it is true. However, if you look at noise per sensor area,the pixel size is irrelevant. If you look at noise per image area, the larger sensor willl have an advantage regardless of the pixel size.

At least, that's what I retained from a previous related post [:)]

quick example. Half the pixel dimension, 4 small pixels for every 1 big pixel. 1 Big pixel has 4 times the signal to noise as 1 small pixel, because it's got 4 times the signal (4 times as much light). HOWEVER, 4 small pixels, same area, have the same signal to noise ratio as the 1 big pixel, because they get the SAME amount of light, total. If yousum the output of the four small pixels, and average, the signal sums, and the noise cancels out. You lose detail, you increase signal to noise. What more pixels allows you to do is filter more selectively, after the fact, as opposed to filtering mechanically by larger pixel size.

Daniel Browning

04-01-2009, 02:02 AM

I would have guessed read noise would be larger when you have more pixles (so high pixel density would hurt snr).

You're in good company. That's the commonly accepted viewpoint among most photographers, web sites, magazines, and just about anywhere you look. But I still think it's incorrect, and it persists due to a fundamental misunderstanding of scale: chiefly, that pixels are compared at 100% crop, where smaller pixels are unfairly examined at higher magnifications and higher spatial frequencies. If all pixel sizes were examined at the same magnification, same print size, same resolution, and same spatial frequency, the bias against small pixels would never have gotten off the ground.

Generally, I think read noise is not correlated to pixel size. For example, the Panasonic LX3 has a read noise of 5.6 electrons per pixel (2.55 ADU), compared to 23.5 electrons in the 5D2, both at base ISO. But that's comparing very different spatial frequencies. After resampling the small LX3 pixels to the much larger 5D2 pixels, read noise per output pixel goes down significantly, because random noise adds in quadrature, so the LX3 is even better. This can be tested by measuring noise on any raw image, then resampling with a good algorithm (e.g. lanczos; not the poorly implemented algorithms in photoshop), and measure the read noise again.

Daniel Browning

04-01-2009, 02:12 AM

If yousum the output of the four small pixels, and average, the signal sums, and the noise cancels out. You lose detail, you increase signal to noise. What more pixels allows you to do is filter more selectively, after the fact, as opposed to filtering mechanically by larger pixel size.

Excellent summarization, Colin.

For an example, take a comparison between pixel sizes of 4 microns and 2 microns:

If the 2um pixel has read noise that is twice as bad, then the final image has the same read noise.
If the 2um pixel has read noise that is the same, then the final image has much less read noise.
If the 2um pixel has more than twice as much read noise, then the final image has more read noise.

So smaller pixels can be noisier per pixel (by an amount equal to the square root of the difference in size) to achieve the same amount of noise as larger pixels. My position is that, all other things being equal, smaller pixels do tend to be just about that much noisier, and so the final image is just about the same.

George Slusher

04-01-2009, 06:02 PM

The "cropped" (EF-S) lenses are necessary to give the "cropped" bodies similar performance to full-frame bodies at wide angles. Seen many 10-22mm zooms for full-frame bodies? The 16-35mm gives the same field-of-view on a full-frame body. The EF-S lenses are also probably less expensive to make for similar performance (smaller sensor size means that it's easier to control distortion, vignetting, etc.). Compare the EF-S 17-55mm f/2.8 IS ($1030 at B&H) vs the 16-35mm f/2.8L ($1450). (Read Bryan's review ("http://www.the-digital-picture.com/Reviews/Canon-EF-S-17-55mm-f-2.8-IS-USM-Lens-Review.aspx) to find out that the 17-55mm lens "matches or exceeds the optical performance of my L-series zooms in this similar focal length range," plus it has IS.)

The "cropped" bodies are not going away, so it's not like Betamax or HD-DVD. I have no data, but I would expect that the 1.6x FOV cameras from Canon outsell the full-frame cameras by at least 10-to-1, probably a lot more.

Sinh Nhut Nguyen

04-01-2009, 08:51 PM

Guys, I think we need to give this up and go shoot some photos yeah?[:)]

Jon Ruyle

04-02-2009, 02:09 AM

Thanks for taking the time to explain this, Daniel.

For an example, take a comparison between pixel sizes of 4 microns and 2 microns:

* If the 2um pixel has read noise that is twice as bad, then the final image has the same read noise.
* If the 2um pixel has read noise that is the same, then the final image has much less read noise.
* If the 2um pixel has more than twice as much read noise, then the final image has more read noise.

I agree with all of this, assuming by “twice as bad” you mean snr is twice as bad, not absolute noise is twice as big (ie, you don't mean sd of a Gaussian distribution of number of electrons of read noise is twice as big for the smaller pixel)

So smaller pixels can be noisier per pixel (by an amount equal to the square root of the difference in size) to achieve the same amount of noise as larger pixels. My position is that, all other things being equal, smaller pixels do tend to be just about that much noisier, and so the final image is just about the same.

Okay, so you're asserting that other things being equal, read noise is inversely proportional to the square root of the size of the pixel? That this is true for photon noise is clearly true, and requires very little knowledge of how the camera works. That it is true for read noise seems less obvious to me (as I said, I would have thought reading a pixel would have caused the same amount of noise no matter how big the pixel is) but I believe you [:)]

Colin

04-02-2009, 02:11 AM

Why, do you know where we can find some amorously violent birds, perhaps? [:)]

Jon Ruyle

04-02-2009, 02:12 AM

Guys, I think we need to give this up and go shoot some photos yeah

Yeah. But it's dark. Can't even do astrophotography until the moon goes down. [:)]

jblaschke

04-02-2009, 12:51 PM

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"]<span style="font-size: small;"]<span style="font-family: Times New Roman;"]From an engineering point I would say that the 50D is a step to far, a 1.6X sensor at 15mp is going to give problems that are not worth the extra resolution.<span> I think (hope) that the next mid range body 60D??? would have to have a larger sensor.<span> One would hope for full frame but suspect that a 1.3x sensor would be canons preferred option if forced down that route, but I think that all of the manufactures will try desperately to keep the 1.6 and 1.5X sensors.<span> So a 1.3x or FF sensor at £1200 (proper money) may not be too far away… <span>What is really needed now is a totally new type of sensor.<span>
<div style="clear: both;"]</div>

Never going to happen. Canon won't change sensor size on the crop-body cameras any time soon. They're not going to orphan the EF-S lenses and the cash inflow those generate. That's the entry-level to semi-pro market, and they've invested a lot of time and effort into convincing the public this is going to remain viable for a long time. Dumping the platform now would revisit the FD rancor of years past. The 5D II is too popular, and the Mark Is are commanding a comparable price to the 50D on the secondary market. I suspect Canon's happy with that.

I could see Canon expanding the 1.3x with a line of mid-pro cameras, but in all honesty, I suspect that chip is an evolutionary dead end. I'd expect Canon to develop a "new" 1.6 APS-C chip that's able to sidestep some of the current limitations while retaining the current size. Remember, Canon was criticized for cramming too many megapixels onto the D60 chip way back when, and they've long since worked around those issues.

Daniel Browning

04-03-2009, 02:44 AM

You're welcome, Jon.

I agree with all of this, assuming by “twice as bad” you mean snr is twice as bad, not absolute noise is twice as big

Yes, that's what I meant; I'm glad you saw through the obtuse writing.

One would naturally think that read noise must shrink in linear proportion to the area decrease in order to keep the same read noise. But the fact that noise adds in quadrature is what makes it possible for read noise to shrink at a slower rate while retaining the same "image level" noise (i.e. noise power for any given spatial frequency).

Okay, so you're asserting that other things being equal, read noise is inversely proportional to the square root of the size of the pixel?

How about "read noise is directly proportional to the square area"? (e- / um^2.) I think that works.

That this is true for photon noise is clearly true, and requires very little knowledge of how the camera works. That it is true for read noise seems less obvious to me, but I believe you

Read noise is indeed the much more complicated, inconsistant, and difficult to generalize. However, I think the rule is a pretty close fit to the cameras at hand. It's more often true for cameras of a similar sensor size and budget from the same manufacturer (e.g. 40D and 1D3), but not always. Unlike photon shot noise, read noise varies significantly from model to model, manufacturer to manufacturer, and even unit to unit of the same model. Generally, though, one of the exceptions seems to be that when comparing tiny inexpensive digicams to large, pricey DSLR, the DSLR has less read noise at high ISO, while the very tiny pixels in the cheap digicam have less read noise at low ISO. And yet high ISO read noise has dropped with each new and smaller pixel, and other DSLR seem to also indicate that it isn't something inherent to pixel size specifically, but another factor (design tradeoff?).

If we look at the example of the LX3 vs 5D2 at low ISO again:

5D2 6.4 microns vs LX3 2 microns using signal of 1 * N.
6.4um S/N = 23.5:23.5 (1:1)
2um scale factor = (6.4/2.0)^2 = 10.24
2um S = 23.5/10.24 = 2.2949
2um N = 5.6
2um S/N = 2.2949:5.6
2um resampled S = 2.30*10.24 = 23.5
2um resampled N = sqrt(5.6^2 * 10.24) = 17.92
2um resampled S/N = 23.5:17.92 = 1.31:1
31% better S/N.

Here's a visual example of a base ISO comparison that contains quite a bit of read noise (pushed from ISO 100 to ISO 13,000 in post).

http://forums.dpreview.com/forums/read.asp?forum=1018&message=28607494 ("http://forums.dpreview.com/forums/read.asp?forum=1018&message=28607494)

Pattern noise is another important factor to consider. The 5D2, for example, has very strong and objectionable pattern noise. Yet even the inexpensive Canon digicams have no pattern noise. So while the RMS read noise number may indicate the 5D2 has a certain amount of read noise, it's actually worse than the indicated number because the pattern noise makes it objectionable to the eye.

It's also worth mentioning that the OLPF means that when the small pixels are resampled to the same pixel size as the large pixels, they will have more detail. In other words, for comparisons near the Nyquist frequency of the large pixels, small pixels have a big advantage in resolution and contrast. But if the desired spatial frequency is below the strongest effect of the AA filter, this difference is not relevant.

We have a lot to look forward to in the future.

dmckinny

04-03-2009, 11:40 AM

Daniel,

Thank you for all the excellent information. I think you hinted at a couple of impacts in your last post, things that I was thinking about while reading through the entire thread. I thought one of the 'hidden' assumptions was that all pixels were designed the same way. By this I mean the circuitry of the pixel itself. If that is true then you can compare the relative performance of pixels of different size. However, I think that both the circuit design and the manufacturing processes are constantly improving. With these improvements we are seeing smaller pixels, and higher densities on the sensors, while at the same time seeing either no degradation or sometimes actual improvement in performance. Throw in micolens design changes and it becomes very difficult to compare various sensors and/or their pixels to each other.

Now I'm going to lay down for a while and get ready to shoot some soccer this weekend. [:D]

Jon Ruyle

04-03-2009, 01:59 PM

Hi Daniel,

Thanks again. Things are clearing up for me a bit.

Okay, so you're asserting that other things being equal, read noise is inversely proportional to the square root of the size of the pixel?

How about "read noise is directly proportional to the square area"? (e- / um^2.) I think that works.

How embarrassing. I meant "read noise (in absolute terms) is directly proportional to square root of area". If read noise was directly proportional to area, high pixel density would be better (because noise adds "in quadrature", as you say... so 4 times as many pixels 1/4 the size and 1/4 the noise gives half the noise when you add it all up... 4 times as many pixels 1/4 the size but with half the noise, though, is the same.) I *think* that's right [:)]

Read noise is indeed the much more complicated, inconsistant, and difficult to generalize. However, I think the rule is a pretty close fit to the cameras at hand.

This makes sense. I was a little baffled by the idea that there may be some reasoning with which one could come up with "read noise is proportional to square root of area".

Generally, though, one of the exceptions seems to be that when comparing tiny inexpensive digicams to large, pricey DSLR, the DSLR has less read noise at high ISO, while the very tiny pixels in the cheap digicam have less read noise at low ISO.

I'll take low read noise at high iso any day :)

I measured the read noise of my 5DII (not numerically, just by taking a picure and looking at it) and, as far as I can tell, it is extremely low anyway until iso is high.

The reason I measured it was that for a long time I thought there was no point in very long exposure photography: I reasoned it is better to take many images and stack (equivalent signal and noise, but far easier for a number of reasons). But then I realized read noise is worse when you stack. But after taking my dark pictures, I concluded that at iso3200 and below, read noise is pretty much negligible unless your signal size is minute.

The 5D2, for example, has very strong and objectionable pattern noise.

True, though only regularly visible by me above iso6400. At iso3200, I can't see it (in real pictures, that is). But IMO pattern noise is the worst part of very high iso images on the 5d2.

We have a lot to look forward to in the future.

Agreed. I'm very happy with my 5D2, but I think I should start saving for the 1DsX now. [:)]

Daniel Browning

04-03-2009, 02:25 PM

I'll take low read noise at high iso any day :)

Me too.

I measured the read noise of my 5DII (not numerically, just by taking a picure and looking at it) and, as far as I can tell, it is extremely low anyway until iso is high.

For a typical tone curve, that's normal. When 50,000 photoelectrons are flooding the camera, such as the bright exposure zones in a low ISO shot, the 23 electrons of read noise seem like nothing.

It's only when you try to maximize the dynamic range of the camera that you run into the limitations of the read noise, because it's in the extreme shadows where the number of photons gets closer to the number of electrons.

ISO 1600 has 10 times less read noise than ISO 100. If Canon could get ISO 100 down to the same level as ISO 1600, dynamic range would increase greatly and 14-bits would no longer be sufficient.

True, though [pattern noise is] only regularly visible by me above iso6400. At iso3200, I can't see it (in real pictures, that is

This is another low ISO dynamic range thing. Typical tone curves don't show it because they crush the blacks and don't exploit the full dynamic range of the camera.

If it weren't for pattern noise, I would be able to use another 2 stops of dynamic range (say, 12 instead of 10) at ISO 100. But I can't because the pattern noise ruins it. I can see into the promised land, but I can't enter.

Jon Ruyle

04-04-2009, 08:24 PM

If it weren't for pattern noise, I would be able to use another 2 stops of dynamic range (say, 12 instead of 10) at ISO 100. But I can't because the pattern noise ruins it.

Pattern noise at iso 100? The darks must be *dark*. I mean, I can't see anything if I take a total black picture at iso 100 (by total black I mean lens cap on, shutter speed 1/8000 and f/22.) If I then adjust the exposure upward, I see a few spots, but I don't recall anything I would call a pattern.

I can see into the promised land, but I can't enter.

I laughed when I read this. Did someone promise you a land of 12 stops of dynamic range? [:)]

Daniel Browning

04-06-2009, 10:38 PM

Pattern noise at iso 100? The darks must be *dark*. I mean, I can't see anything if I take a total black picture at iso 100 (by total black I mean lens cap on, shutter speed 1/8000 and f/22.) If I then adjust the exposure upward, I see a few spots, but I don't recall anything I would call a pattern.

Your raw converter is not set for high dynamic range. There is no such thing as black in a raw file. It just goes from white to noise. The point which is chosen as "black" is entirely a creative choice, though some raw conversion software does not allow the photographer to choose the true raw black point.

Strong contrast and little noise is the most pleasing conversion for most photographs and matches the taste of the most photographers, so the default settings on most raw conversion software are tuned to provide that by setting the black point far above the noise floor and using a tone curve that crushes the shadows.

In other words, the most common conversion is tuned for high contrast and low dynamic range.

If one is interested in utilizing more dynamic range than the typical "high contrast/crushed blacks" conversion, and the photographer chooses their own black point, gamma, and tone curve, it becomes possible to see down to the point where there is nothing but random noise. On some cameras, such as Canon DSLR, the pattern noise becomes a problem long before random noise is reached. Pattern tends to get magnified even further in most raw converters, perhaps because of how it interacts with the edge detection algorithms.

In Lightroom, for example, you can set a "linear" tone curve, "0" blacks, then set shadows to "100" and you should be able to see down into the pattern noise.

IRIS is an exmaple of a raw converter that allows the photographer to have complete control over the black point and true linear exposure compensation. 5.57 is the latest version and it can read 5D2 files. Here's how to do a simple conversion:

File->Open Raw
On the toolbar, find the little icon of the camera, and set it to your model (e.g. 5D2).
Processing->Subtract (enter 1024 for 14-bit Canon cameras such as 5D2, 128 for the 12-bit cameras).
Digital photo->convert a CFA image
To white balance, find a portion of the image that is white, drag a square in it,
Open the console (also an icon on the tool bar) and enter "white"
View->Logarithmic
File->Save (Tiff)

Then open the tiff in Photoshop and analyze the deep, deep shadows. You should see noise (and pattern noise): nothing should be black.

Most people think high ISO has more noise than low ISO, but in the most literal sense that's untrue. It only seems true because photographers tend to reduce light for high ISO and increase light for low ISO. The noise is not caused by the increase in ISO, but the *decrease* in the amount of light. Read noise is reduced at high ISO.

For example, one chooses the f-number for a certain depth of field and shutter speed based on the desired amount of motion blur. The next setting to choose is ISO. Lower ISO for more highlight headroom and more shadow noise. High ISO for less shadow noise and less highlight headroom. In Canon DSLR cameras, that shadow noise includes pattern noise. If, at ISO 100, important highlights are *almost* about to clip, it would be unwise to increase ISO because they would be lost. But if the shadows were more important, then ISO 1600 might be chosen: sacrificing four stops of highlight detail in order to get less noise in the shadows.

Did someone promise you a land of 12 stops of dynamic range?

We hold these truths to be self-evident, that all photographs are created equal, that they are endowed by their Photographer with certain unalienable Qualities, that among these are Color, Contrast and 12 stops of dynamic range.

That to secure these rights, Raw Converters are instituted among Men, deriving their just powers from the consent of the users, That whenever any Form of Software becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new raw conversion, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Dynamic Range and Contrast. Prudence, indeed, will dictate that Raw Conversions long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the software to which they are accustomed.

[;)]

Keith B

04-06-2009, 11:24 PM

Seriously, who is this Daniel Browning?

Is no one else frightened.

Like Doc Brown from Back to the Future.

SRPHOTO

04-07-2009, 01:13 AM

Daniel Browning is the-digital-picture forum GOD ahaha. good stuff

Colin

04-07-2009, 02:59 AM

I'm not frightened, because Jon keeps his attention. When Daniel goes Tech postal, I won't be the one in front of him [:)]

Jon Ruyle

04-07-2009, 12:19 PM

I dunno. Daniel seems pretty reasonable to me (except that stuff about "Raw Conversions long established should not be changed for light and transient causes"... that was a little dogmatic. As for me, I'll ditch DPP at the drop of a hat.)

You know who I'm scared of? The guys at dpreview who wrote that article about how downsampling doesn't help reduce snr. That was pure madness. Not to mention their 50D review:

Cons:

1) High resolution sensor means you have to have high quality lenses

2) You'll have to use high shutter speeds to take advantage of the high resolution

3) High resolution sensor means smaller pixels and thus more noise and worse dynamic range

4) It has a high resolution sensor. You'll get big files and they won't fit on your hard drive

5) Per-pixel detail not as good as in a camera with fewer pixels

6) You don't really need 15mp to get a good picure. 12mp is enough.

Whoa man. I don't want to be anywhere near them when *they* snap.

alexniedra

04-07-2009, 01:01 PM

I can't begin to say what's wrong with the 50D generalisations from dpreview...

I bet for any money they went ooo-ahh at the 21 MP of the 5D II, yet with the 50D, "they won't fit on your hardrive"?

What gives?

ShutterbugJohan

04-07-2009, 01:28 PM

ShutterbugJohan

04-07-2009, 01:32 PM

We hold these truths to be self-evident, that all photographs are created equal, that they are endowed by their Photographer with certain unalienable Qualities, that among these are Color, Contrast and 12 stops of dynamic range.

That to secure these rights, Raw Converters are instituted among Men, deriving their just powers from the consent of the users, That whenever any Form of Software becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new raw conversion, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Dynamic Range and Contrast. Prudence, indeed, will dictate that Raw Conversions long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the software to which they are accustomed.

LOL! :-) I currently shoot JPEG (because I have a very slow computer and lousy software; when I get a faster computer and better software, I will switch to RAW).

A question: Most of this thread has been a discussion of APS-C vs. FF sensor size noise and signal-to-noise ratio. (At least, that's how I understood it.) :-) How about the same thing with CMOS vs. CCD?

Jon Ruyle

04-07-2009, 01:36 PM

Okay, I may have been paraphrasing. They might not have actually said "it won't fit on your hard drive." [;)]

But I just looked at it, and some of the stuff I meant in jest actually in the review. (They really did list "less per-pixel sharpness than cameras with 10 or 12 megapixles" as a con)

Jon Ruyle

04-07-2009, 02:01 PM

ISO 1600 has 10 times less read noise than ISO 100. If Canon could get ISO 100 down to the same level as ISO 1600, dynamic range would increase greatly and 14-bits would no longer be sufficient.

What? I don't understand that... Wouldn't it be the other way around? :-)

Pictures *look* less noisy at low iso- not because noise is less, but because there is more light, and high signal/noise ratio is what makes a picture look noisy. Even if read noise is 10 times as great at iso 100, snr from read noise is usually less because typically you're letting 16 times as much light hit the ccd as compared to iso1600.

I have no understanding of why read noise would be different at different iso's. I guess the component coming from the adc (if any) is greater, because that comes after amplification (I think). So if you amplify the signal then add noise (as you do at high iso), your noise (translated back to electrons) counts less. Maybe that is why.

Anyhow, if Daniel says the read noise is 10 times as great at iso 100, I believe him :)

Keep in mind, though, at iso 1600 and below photon noise is in most cases more important than read noise. Photon noise is independant of iso (and goes like the square root of the signal strength) so your snr will in general be much lower at iso100 than 1600.

Daniel Browning

04-07-2009, 02:55 PM

I agree with Jon.

I guess the component coming from the adc (if any) is greater, because that comes after amplification (I think).

I think that's correct too. The Sony A900 has on-chip ADC and the read noise is the same at almost all ISO, so compared to Canon it has an extreme range of highlight headroom in low light. For example, if you shoot them both at ISO 1600, the Canon will have less shadow noise, but the Sony has over four stops more highlight headroom. I hope some day Canon can bring its ISO 1600 noise level to all ISO settings, in which case it would blow away the Sony for dynamic range in low light.