Anyone tried looking at ISO noise levels at their camera's 1/3 stop increments?

I used to have mine on full stop increments in manual settings (ie 100/200/400/800/1600...) Then someone pointed me at this...


Of course that is just for a Canon 7D and your camera might be totally different. I'm not even convinced about the 7D. I am going to do my own test . I'm not sure about the guy's technique of just going up through the ISOs in video capture with the lens cap on. I think I will shoot against a defocused green background - it seems to be a good colour for showing ISO noise. Useful if it is true tho' - if 160 is less noisy than 100 you may as well have 160 as your default and get the 2/3 stop extra speed for free.

Col

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I always thought it was the blue channel that had the most noise Col. I had a look and found this which says the same and makes interesting reading

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Sandy
Carried it in full, then carry it out empty.

Each sensor will have a "native" or "base" ISO - not necessarily 100. Intermediate ISOs are often derived simply by using a higher or lower "real" ISO and applying an exposure adjustment. You will know the digital rule of "expose to the right" to collect the maximum signal versus noise. Intermediate ISOs can be problematic because they push exposure to the left. It all depends on the manufacturer's implementation of ISO for that particular camera. I generally just avoid intermediate ISOs.

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Go here, click on measurements and then dynamic range and run your cursor over each point.

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Hi Steve/

I'm guessing the base ISO here might be 80, as the low noise ones in the test are all multiples thereof??? I didn't make much out of the diagram you pointed me at - remember you are talking to someone who last sat a physics test in 1976 .

So, when you are talking about intermediates ISOs, are you meaning those intermediate between 80, 160, 320, 640 and so on? It's a pain to stick to those on the dial, as to get them I have to be in 1/3 increments - full increments only offer 100, 200, 400 and so on. On top of that, I am these days adapting to there never being any usable light this far north by doing a lot on shutter priority... which fairly much demands auto ISO. And when in Auto ISO, it is your complete Donald Duck as to whether it picks 640, 800, 1000, 1250 or whatever...

Col

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Intermediate ISOs are those between 100, 200 and so on. Less than 1 stop increments. How they are handled depends on your camera.

"Native" ISO is the natural (unamplified sensitivity of your sensor).

The sweet spot of your camera is that setting which generates the best SNR.

Have a read here noting the points from Guillermo and EJ Martin (including the discussion he links to). (BTW "Schewe" is Jeff Schewe who is a bit of an Adobe guru - you may well have heard of him.) I can't be bothered getting my head around the effective versus real ISO discussion.

In any event, I think you will quite quickly understand why intermediate ISOs can be worse than their higher real ISO cousins.

I generally have my camera set to ISO 100 and move off it reluctantly. Newer versions of my camera have extended the range of acceptable SNR to much greater ISOs.

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Yep - the noisy ones in that test are 100, 200, 400, 800 and so on, while the less noisy ones are 160, 320, 640, 1250 and so on, which was why I was asking. I was also interested in this because I have had to grasp the nettle of high ISO since going over to shutter priority. Learning to live with it...


First one has a bit noise reduction applied in ACR6. Second one is just as it comes. Better noisy than blurry...

Col

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To be honest I'm not sure. Here's where the discussion between effective and real ISO becomes important. My presumption is that the ISOs indicated in the video are the camera settings (which presumably equate to "manufacturer ISO"). It certainly suggests that ISOs with multiples of 80 are cleaner analogue amplifications. But note the measured ISO in the DXO grids. I would need to read the threads again.

At least the noise in the second image isn't distracting. I like it. Likely better than what my 1Ds II would produce.

Did you ever run the ACR calibrator for your camera?


EDIT:

From EJMartin in the other thread I linked you to:

"The ISO's that are purely analog gain on the 7D are 100-200-400-800-1600-3200-6400; all others are obtained by digital multiplication from the nearest of these (eg 160 is 200 pulled 1/3 stop, 250 is 200 pushed 1/3 stop)."

When you run your tests you will need to ensure consistent exposure. Gray card target and light meter using 1/3 increments?

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I have a 450D and really struggle to produce anything worth looking at.

It appears to be on permenant lone to my lover at them moment, which suits me fine as I've gone back to using my father's Nikon FTN.

Only use on ISO on that too - 400 Tri-X B&W. I'm allowed to cover for my bad photography by saying "the grain was intentional -dharling it's arrrrrrt not science,"

Johnny

What do you put that down to?

Col

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