Who needs the mirror?

[piiooo]

I was recently wondering if Canon comes up with a Panasonic Lumix G type of camera any time soon. Theycould replace the pentaprism/mirror complex with a high resolution viewfinderbutkeep everything elseas it isina DSLR,maintainingcompatibility with EF and EF-s Lenses.


I think the advantages among many would be: 1)no hassle live view 2)less moving parts - less things to brake3) less dust on sensor 4)lesser weight 5)ability to display more informationinviewfinder, or customize the viewfinder 6)100% viewfinder coverage


A potential disadvantage would be AF speed, I guess


What isyour take on the concept?

[Daniel Browning]

I was recently wondering if Canon comes up with a Panasonic Lumix G type of camera any time soon. They could replace the pentaprism/mirror complex with a high resolution viewfinder but keep everything else as it is in a DSLR, maintaining compatibility with EF and EF-s Lenses.

I would love that.



I think the advantages among many would be: 1)no hassle live view 2)less moving parts - less things to brake 3) less dust on sensor 4)lesser weight 5)ability to display more information in viewfinder, or customize the viewfinder 6)100% viewfinder coverage

Here are a few more advantages:

Zooming to any part of the image for critical focus
View the actual captured image, including white balance, black and white, etc;
Tilt/swivel.
Movie mode.
Live zebras, histograms, false color "raw" mode, guide lines, overlays, etc.
Accurate DOF (typical viewfinder screens show f/1.2 as if it were f/3.5, making critical manual focus impossible).
Accurate rendition of the bokeh
Usable in much darker situations, including effective f/32 for macro, etc.
Contrast detect autofocus with movable focus points
Allows the entirety of the primary mirror to be used for phase detect autofocus
The possibility of reducing lag from 40ms to 0ms or even negative lag



Disadvantages compared to an optical viewfinder:

Battery usage
Heat generation (in rare circumstances can cause thermal noise to rise above the read noise floor).
Dynamic range limited by the sensor instead of the eye/brain.
More expensive
Slow frame rate
Low resolution
Bulky



These will improve as technology progresses.



A potential disadvantage would be AF speed, I guess

Not necessarily. They could leave the mirror in (just remove the pentaprism and viewfinder), and use the entire mirror for autofocus. Right now the autofocus can only use a tiny central portion of the light from the partially transparent area of the main mirror. This limits the coverage of autofocus on full frame sensors, and the amount of light for low light autofocus.

If autofocus didn't have to play second fiddle to viewfinder, then all the light from the main mirror could be used for autofocus, with coverage over the full frame entire sensor, and better performance in low light.



Who needs the mirror?


There are many photographers for whom the current technology is too expensive or insufficient, even if it were built into the camera they need.

A $50 million feature film was shot with a $3k EVF using manual focus and thin DOF ("Knowing"; it grossed about $93 mil so far). They will only get better, smaller, and cheaper with time.

I think its inevitable that they appear in more and more cameras.

[piiooo]

A potential disadvantage would be AF speed, I guess

Not necessarily. They could leave the mirror in (just remove the pentaprism and viewfinder), and use the entire mirror for autofocus. Right now the autofocus can only use a tiny central portion of the light from the partially transparent area of the main mirror. This limits the coverage of autofocus on full frame sensors, and the amount of light for low light autofocus.

If autofocus didn't have to play second fiddle to viewfinder, then all the light from the main mirror could be used for autofocus, with coverage over the full frame entire sensor, and better performance in low light.




The video (link below) shows that fast AF is perfectly doable in this type of configuration


http://www.youtube.com/watch?v=HuPxftjjFHQ ("http://www.youtube.com/watch?v=HuPxftjjFHQ)

[dmckinny]

OK, I'm obviously missing something here, EVF is electronic view finder (right?). So what is the difference between what you are talking about and the EVF on my old Canon Powershot S1 IS? Is it the same basic concept? Or are you talking about something completely different?





Just curious,


David McKinny

[piiooo]

OK, I'm obviously missing something here, EVF is electronic view finder (right?). So what is the difference between what you are talking about and the EVF on my old Canon Powershot S1 IS? Is it the same basic concept? Or are you talking about something completely different?





Just curious,


David McKinny
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The major differences wouldinclude APS-C or FF sensor and interchargeable, preferably EF/EF-S lenses.

[alexniedra]

1. "No Hassle Live View"


- Are you saying Live View in a DSLR is a hassle?


2. "Less Moving Parts - Less things to brake"


- Yes, shutters give out after tens, or hundreds of thousands of exposures, but I don't see this has a big shortcoming of DSLR's. My 40D will be obsolete before I take 100,000 shots.


3. "Less dust on sensor"


- With a shutter covering the sensor most of the time, wouldn't a DSLR have less dust? With the sensor constantly exposed, I wouldn't expect less dust on the sensor.


Also, the sensor would most likely have the tendancy to heat up more quickly. We can see this in DSLR's equipped with Live View. Live View will stop after a certain period of time beceause the sensor has to cool down.

[Daniel Browning]

Thanks for the response.



shutters give out after tens, or hundreds of thousands of exposures


Some photographers, like me, take 10,000 photos in a month. I'll do 5,000 in one weekend if I'm shooting timelapse. But I think we're a small minority.






- With a shutter covering the sensor most of the time, wouldn't a DSLR have less dust? With the sensor constantly exposed, I wouldn't expect less dust on the sensor.





I'm not sure. I've read that the air turbulence caused by a swinging mirror is what causes most of the dust. I don't think the sensor is "exposed" with liveview any more than with a mirror. The shutter can cover the sensor for lens changes just as well in both cases IMHO.

[Tim]

A digital viewfinder sounds like anawfulidea to me. when your eyes gets too close to a digital screen, its very easy to see pixels, and it might actually hurt your eye after a while. besides, I like mechanical devises way more than electrical ones.

[piiooo]

1. "No Hassle Live View"


- Are you saying Live View in a DSLR is a hassle?



Yeah, when you focus in live view/quick mode the mirror flips to focus. Disadvantage: noise and interrupted image. When you use contrast based AF, there is no flipping, but it takes sometimes a few seconds to get the image sharp. Plus - the overheating issue, i addressed it below.






2. "Less Moving Parts - Less things to brake"


- Yes, shutters give out after tens, or hundreds of thousands of exposures, but I don't see this has a big shortcoming of DSLR's. My 40D will be obsolete before I take 100,000 shots.



Just google for example: "canon 5d mirror recall"


I hope it won't turn into " canon XX markX vievfinder recall" in the future[;)]






3. "Less dust on sensor"


- With a shutter covering the sensor most of the time, wouldn't a DSLR have less dust? With the sensor constantly exposed, I wouldn't expect less dust on the sensor.



Like Daniel said, aflipping mirror produces turbulences inside camera whichstirs exogenous and endogenous dust in the camera.Because it usually happensjust beforethe shutter opens, the dustmay wind up on the sensor.






Also, the sensor would most likely have the tendancy to heat up more quickly. We can see this in DSLR's equipped with Live View. Live View will stop after a certain period of time beceause the sensor has to cool down.



Canon have been making camcorders including professional ones for quite a while, I hope they will use their camcorder technologies in their perspective cameras, just like Panasonic did.

[piiooo]

A digital viewfinder sounds like anawfulidea to me. when your eyes gets too close to a digital screen, its very easy to see pixels, and it might actually hurt your eye after a while. besides, I like mechanical devises way more than electrical ones.
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Each, mirror/pentaprism and electronic viewfinder have their pros and cons. IMHO, traditional setup will work better for sports/action/wildlife shooters, and the new one may appeal to still/landscape photographers. I hope to see both types of cameras available for a long time, although my prediction is that the electronic viewfinder will eventually take over.


As far as eye strain, if a good quality/resolution vewfinder is used, it is not worse than eye strain from using a traditional veiwfinder.

[ShutterbugJohan]

I hope to see both types of cameras available for a long time, although my prediction is that the electronic viewfinder will eventually take over.


I'm not against EVF interchangeable-lens cameras, but the day they take over and there are no more Canon pentaprisms, I'm switching to Nikon! [:)]

[alexniedra]

Hold on! What are we doing? Taking the SLR out of DSLR?

[ShutterbugJohan]

Hold on! What are we doing? Taking the SLR out of DSLR?


Technically, they're taking the "R" out of "SLR". It is still a "single-lens" camera, but the "reflex" (mirror) is gone. I still prefer the mirror. :-)

[ShutterbugJohan]

A digital viewfinder sounds like anawfulidea to me. when your eyes gets too close to a digital screen, its very easy to see pixels, and it might actually hurt your eye after a while. besides, I like mechanical devises way more than electrical ones.


I agree. Absolutely!

[alexniedra]

Yep. That would be it...


My mistake [:)]

[piiooo]

OK, I think I see light at the end of the tunnel:


Canon to launch smaller high-quality camera -executive ("http://www.reuters.com/article/idUSTOE66J04U20100720)

[scalesusa]

Prior to SLR cameras, we had viewfinder cameras, and twin lens reflex, and cameras with ground glass backs. The viewfinder cameras gave the photographer problems framing the image, and focusing the image.


The twin lens reflex cameras solved that to a great extent, but imposed other limitations, like the requirement for two identical lenses.


Cameras with ground glass backs were difficult to view in bright light, but, you could compose and focus accurately. With the larger film formats in use, results are still stunning when viewed 100 years later.


The SLR provided a better solution for smaller format film, but it required a mirror. There were variations on the theme, pellix mirrors that did not move, etc, but the advantages stayed the same.


Electronic viewfinders with the ability to display the actual image from the sensor have a lot of promise, but so far, the resolution is too low. Its just a matter of time until the point is reached where photographers decide the technology is ready for the big time.

[clemmb]

I like the idea of no mirror bringing the lens closer to the sensor. Then they can make an adapter for any manufacturers lens and have the entire focus range available and you can use Nikon, Canon, etc... which lens do you like the most?...


Also having the lens closer to the sensor allows for less glass/lens groups. I have always been told this is one of the reason a Rangefinder was so sharp.


Mark

[Manofmayo]

Back in the film days, didn't Canon or Nikon come out with a pro camera where the mirror didn't raise for each shot?

[wickerprints]

Bringing a lens closer to the sensor is only useful for wide-angle designs (e.g., &lt; 50mm). But even so, for very wide angle lenses, there will be much stronger vignetting due to the increased angle of light rays emerging from the rear element and striking the image periphery. So while less extreme retrofocus designs would be an advantage, this does not come without its own disadvantages as well.

[Daniel Browning]

Back in the film days, didn't Canon or Nikon come out with a pro camera where the mirror didn't raise for each shot?






The Canon EOS RT and EOS 1N RS are two such cameras. They used pellicle mirrors as someone mentioned earlier in the thread.



So while less extreme retrofocus designs would be an advantage, this does not come without its own disadvantages as well.


You bring up a good point. Another potential downside is that certain microlens designs cause sensors to have a low angle of response, so that non-telecentric designs reduce the amount of light gathered. This was one of the claims that Four Thirds marketed about their telecentric designs (though I'm not sure it was ever real since they've silently abandoned it and they're dramatically reversing their lens designs). I've read that modern microlenses are much better now (more so than than bare silicon and better than film too).


Personally, I think I'd much prefer the non-retro-focal (rangefinder) designs, because I can live with the dramatically increased vignetting in order to get better distortion, flare, C.A., and contrast. But I don't think Canon will come out with such designs for a very long time, because they could only market the lenses to owners of the new cameras (if and when they come out).

[clemmb]

Bringing a lens closer to the sensor is only useful for wide-angle
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What I am talking about is when you use an adapter to mount a nikon lens to a canon camera, the adapter moves the lens farther away from the sensor and you loose the full range of focus. With these cameras where their lense is closer to the sensor and you adapt a canon or nikon lens and the adapter moves the lens out it will be the right distance.


Mark

[clemmb]

Bringing a lens closer to the sensor is only useful for wide-angle
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What I am talking about is when you use an adapter to mount a nikon lens to a canon camera, the adapter moves the lens farther away from the sensor and you loose the full range of focus. With these cameras where their lense is closer to the sensor and you adapt a canon or nikon lens and the adapter moves the lens out it will be the right distance.


Mark
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I found the article that explains it much better then I.


Adapters have been around for years, but they never worked well. The
extra length they added to a lens meant that it would be mounted too far
off the body, and couldn&rsquo;t focus at infinity. But because these new
cameras don&rsquo;t have mirror boxes, their native lenses sit much closer to
the sensor. Adapters, then, have to move DSLR lenses further away. This is why they work so well with these little cameras.
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