5D Mark II - First Shots

[Jon Ruyle]

ISO 2000 for example looks lower than ISO 3200 and so you might expect lower noise levels, but that isn't true.

I'm not sure this is correct, Jan. Photon noise is a function of sensitivity and the amount of light hitting the camera. When you set your camera to ISO 2000, it uses a slower shutter speed and thus lets more light in than it would have if you had used ISO 3200.


The problem with fake ISO's isn't that you get too much noise, but rather, you lose range (see below)

ISO 2000 for example is a picture taken with ISO 3200 and processed 2/3 stop underexposed in camera-processing.

The camera also "overexposes" the picture by 2/3 of a stop as compared to an ISO 3200 shot. Thus you lose highlight headroom.

[Dave Johnston]

Congrats on your purchase, Alex.


I really want to go full frame. Just waiting to graduate. After 8 years of post high-school studies, I think I deserve it. Ha!


Keep shooting! Then post.


Dave.

[alexniedra]

Congrats on your purchase, Alex.


I really want to go full frame. Just waiting to graduate. After 8
years of post high-school studies, I think I deserve it. Ha!


Keep shooting! Then post.


Dave.

Thanks alot, Dave.


I say go for it. You have worked hard, and you certainly deserve it!


Now I feel weird about this whole thing - I'm in my final year of high school. Just saying. [H]

[alexniedra]

Here's one more from the other day... I grabbed this shot as I rode past the scene of a car accident (I believe everyone was OK), where some firefighters were leaning on the guard rail and seemed to be exhausted after a long day of hard work.


Check it out:





5D Mark II, EF 70-200mm f/2.8 L IS, 1/1000 sec., f/2.8, ISO 200 @ 200mm. Minor sharpening and lowered saturation in Lightroom 2.0. I kind of like the fact that you can see the "TORONTO" embroidered into the back of their jackets - Sort of cool.



C&C welcome.





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[Tom Wertman]

Ah the Gardner Expressway! Living in Rochester NY we get to Toronto often. I love the city. Great shot. Judging your work and comments you made regarding your technical prowess of the camera I would say you have a nice future ahead of you as a photog if you decide to pursue it.


Tom

[Daniel Browning]

The camera also "overexposes" the picture by 2/3 of a stop as compared to an ISO 3200 shot. Thus you lose highlight headroom.

To be clear, here is the whole story behind ISO 2000:

• Sets the camera to ISO 1600 (but displays "2000")
• Adds a hidden -1/3 stop EC to the autoexposure meter.
• After the photo is taken, it increases brightness of the raw file by 1/3 stop (with a linear digital push)

<div>The net result is that you lose 1/3 stop of highlight headroom, just as you said. You can simulate ISO 2000 by setting ISO 1600, -1/3 EC, and then increasing brightness in post. The only difference is that when you do it yourself, you can increase brightness in a way that doesn't clip highlights.</div>
<div></div>
<div>It's the same story with all the "plus 1/3" ISO settings: 125, 250, 500, 1000, 2000, 4000.</div>

[Jon Ruyle]

To be clear, here is the whole story behind ISO 2000:

• Sets the camera to ISO 1600 (but displays "2000")
• Adds a hidden -1/3 stop EC to the autoexposure meter.
• After the photo is taken, it increases brightness of the raw file by 1/3 stop (with a linear digital push)

So it is the opposite direction from what Jan and I were saying...


But then, don't you lose 1/3 stop in the darks instead of in the highlights? Doesn't doing a linear digital push leave you with no data at the low end of the raw file? Or do you mean you lose 1/3 stop of highlight headroom as compared to iso1600 underexposed by 1/3 stop (but not as compared to a "correctly" exposed picture?


Anyway, it bad.


If canon would just leave the raw alone, the world would be a better place.

[Daniel Browning]

But then, don't you lose 1/3 stop in the darks instead of in the highlights?

Normally it would mean you lose 1/3 in the highlights *and* some in the shadows, but in this case it's only highlights because two of Canon's flaws cancel each other out in the shadows. I'll explain:


If Canon allowed their engineers to design the camera, then they would choose the correct design design where raw files have a bit depth appropriate for the noise level. In that case, mucking about with the raw data like this would have negative consequences in the deep shadows by causing quantization error. Such posterization would probably cause the loss of even more than 1/3 stop, but that's in shadows much darker and deeper than most photographers ever go, so in practice most people wouldn't notice even if it caused the loss of a full stop. Of course, if you were going to choose a sensible design you wouldn't allow this sort of mucking about in the first place.


In any case, the reality of the situation is that Canon cameras are clearly not designed by the engineering department, but the Marketing department. So instead of a sensible raw file design (11 or 12 bits), they use 14-bits. At normal ISO settings, all those extra bits go to waste. But on the 1/3 stop ISO settings, where Canon mucks about with the raw data for no reason, the extra bits prevent quantization error. So the two flaws cancel each other out. Of course it would be better if we had neither flaw, but oh well.


If Canon had a *really* good design, like Nikon's compressed NEF, then mucking with the raw would have *really* bad effects, because then it would affect *all* tonal levels instead of just shadows. That's precisely what Nikon does and there are some NEF files floating around that show the damage (posterized skies, etc.). Nikon seems to combine brilliance with stupidity, while Canon is more of mediocrity with mediocrity. At least we have variety. []

Doesn't doing a linear digital push leave you with no data at the low end of the raw file?

Technically, no. That's because raw files don't go from white to black, they go from white to noise. You just put black wherever you want (most people choose a spot that is far away from the noise). Because of this, the net effect is that it basically just decreases the resolution that it can quantize with throughout all the tonal levels. In Canon cameras, photon shot noise will completely hide the loss in resolution at all tonal levels except for the deepest shadows, so that's the only place where the negative effect could be seen (if it had a more appropriate bit depth).

Or do you mean you lose 1/3 stop of highlight headroom as compared to iso1600 underexposed by 1/3 stop (but not as compared to a "correctly" exposed picture?

On these ISO settings, Canon literally takes the top 1/3 stop of values and deletes them.

Anyway, it bad.


If canon would just leave the raw alone, the world would be a better place.

Agreed. And if the engineers could somehow find a way to trick the Marketing department into thinking they were designing the cameras one way, but secretly do it the correct way. Oh, I can dream...

[bouwy]

Nice shots Alex. Keep them coming.


Wally