Michael Jardine
Senior Member
I'm ok at lower ISO, less so at higher ISO. JPG is better suited for a sports photography workflow, at least for me. I have a cousin who is a RAW purist and says I should never shoot JPG.
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Photons to Photos
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Michael Jardine
Senior Member
Sure. And in some modes, when you change the aperture, the ISO will change the exposure to compensate. And there are other permutations as well, for example ISO range as determined by minimum shutter speed. All of this compensating is being done by the onboard computer in order to achieve the same
See above.
bclaff
Forum Pro
Usually this means digital scaling rather than using only analog amplification.Yes I saw that. And my question still remains, what does 'values outside the normal analog range' mean? I think Jim answered but am still not clear what to do with this information.The legenda of symbols used are just above the graphJust saw references to this in another post. I'm trying to understand the differences between my old Nikon D800 and my new Sony A1.
What is the purpose of measuring the relationship between photo dynamic range and iso? In layman's terms I think this means that the higher the ISO, the less 'room for error' or the lesser the ability of the sensor to distinguish between ranges of light and dark, this increasing the requirement for light sources to be even and level?
1. Why do the graphs jump upwards at ISO 100? Does that mean, anything below ISO 100 is 'not real'? I guess I don't understand what 'outside the normal analog range' means.
2. What is happening to my old D800 above ISO 3200? Does that mean, the limit of the sensor is at ISO 3200? What happens above that?
3. Likewise, what is happening on my A1 sensor above ISO 20000?
Thanks in advance!
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Bill ( Your trusted source for independent sensor data at PhotonsToPhotos )
Michael Jardine
Senior Member
OK so it looks like analog amplification on the A1 stops at 12800 whereas on the A9 it stops at 51200. In practical terms, what does that mean to me as a photographer?Usually this means digital scaling rather than using only analog amplification.Yes I saw that. And my question still remains, what does 'values outside the normal analog range' mean? I think Jim answered but am still not clear what to do with this information.The legenda of symbols used are just above the graphJust saw references to this in another post. I'm trying to understand the differences between my old Nikon D800 and my new Sony A1.
What is the purpose of measuring the relationship between photo dynamic range and iso? In layman's terms I think this means that the higher the ISO, the less 'room for error' or the lesser the ability of the sensor to distinguish between ranges of light and dark, this increasing the requirement for light sources to be even and level?
1. Why do the graphs jump upwards at ISO 100? Does that mean, anything below ISO 100 is 'not real'? I guess I don't understand what 'outside the normal analog range' means.
2. What is happening to my old D800 above ISO 3200? Does that mean, the limit of the sensor is at ISO 3200? What happens above that?
3. Likewise, what is happening on my A1 sensor above ISO 20000?
Thanks in advance!
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Michael
www.Qamera.com
IG my.qamera
bclaff
Forum Pro
Nothing. Perhaps it informs you where to limit ISO Auto since you can scale digitally just as easily later.
It depends on the camera. Some sources of noise can be lower in the final result if analog amplification is used than if the digital data is scaled arithmetically. On the other hand, the amplifier could introduce its own noise. Probably best is to do some tests with your own camera and compare the results for the type of subject you plan to shoot.
I use a Canon 5DS and doing adjust the ISO higher than 3200 for the most part. I will sometimes underexpose at ISO 3200 and compensate in post. I find I get similar results that way for subject matter that's not clipped in the highlights. Using ISO 3200 instead of, say ISO 6400 then means I have more headroom. A typical scenario where I shoot with this setting is a dark jazz club with spotlights. If a spotlight or something close to the spotlight is in frame, its color is more likely to be true if I used ISO 3200 than ISO 6400. On the other hand, I don't often try to include such elements in frame, although sometimes I do. Sometimes it's a moot point, since I may treat them as B&W or sepia images.
Michael Jardine
Senior Member
Thanks. In my case I'm shooting in pretty extreme lighting conditions but I'm not alone that matter. If I could shoot at as low as 6400 I wouldn't have any problem. But we're all shooting at 12800 and 16000.
You could but to what benefit? If the in-camera JPEG is too dark, it's impossible to review to determine the quality of the composition, focus or depth of field. Setting ISO to make an image that's within a stop or less of where you'll set lightness in processing makes the review of photos in the field much more doable. You may even decide to change the exposure settings to put more light on the sensor and reduce the visibility of shot noise.So if I follow you, I can set the ISO at, say, 100 and just leave it there and shoot away in the dark at 1/2000 sec and not worry about underexposure in A mode, even though the camera is telling that the ISO needs to be at 10000?Yes. But so do Adobe.
When you adjust the exposure slider, you're really not changing exposure at all. You're adjusting the amplification of the exposure. But the slider is called exposure.
But it's really just the total amount of light falling on the film or sensor. So it's determined by shutter speed, aperture, and transmissivity of the lens. ISO does not enter into it.
With many cameras, there is a benefit to using an ISO other than base:
The plateaued plots are where the camera is ISO invariant. The D800 is invariant throughout its ISO range. Both the Sony A1 and A9 are invariant at ISO 620 and higher. The A1 is invariant from ISO 500 on up.
The A1's read noise is at its lowest from ISO 500 on up. The A9's read noise is lowest from ISO 620 and up.
So depending on the camera one is using, read noise can be reduced by shooting at a higher ISO. The lighter image will make the in-field review and evaluation of images much more doable. There are benefits and no significant disadvantages to using an ISO in the field that will result in a photo having a lightness within a stop or less of what the final image lightness will be.
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Bill Ferris Photography
Flagstaff, AZ
Headroom.
When you're shooting raw the lightness relationships throughout the final image are not usually the same -- and often wildly different -- than the relationships in the JPEG preview image.
It's trivial to manage lightness to avoid blowing out important highlights in a single exposure and image review can be a useful step in that process provided the image has enough lightness to be evaluated.
Photographers review in-camera JPEGs every day many times a day and to their benefit. But only if the image has enough lightness to make it reviewable.
JohnMoyer
Leading Member
I also find it difficult to understand. It does not make sense to me that "Photographic Dynamic Range versus ISO Setting" would be changed by cropping the image which is what I see in the EOS R5 graph. I think that I understand ISO and I think I understand what happens when cropping, so what is the definition of "Photographic Dynamic Range"? Is it photons per sensor total area used instead of photons per photosite? How does it relate to "Exposure Value" which is log 2 ( F-number squared / time ) with no area units?Just saw references to this in another post. I'm trying to understand the differences between my old Nikon D800 and my new Sony A1.
What is the purpose of measuring the relationship between photo dynamic range and iso? In layman's terms I think this means that the higher the ISO, the less 'room for error' or the lesser the ability of the sensor to distinguish between ranges of light and dark, this increasing the requirement for light sources to be even and level?
1. Why do the graphs jump upwards at ISO 100? Does that mean, anything below ISO 100 is 'not real'? I guess I don't understand what 'outside the normal analog range' means.
2. What is happening to my old D800 above ISO 3200? Does that mean, the limit of the sensor is at ISO 3200? What happens above that?
3. Likewise, what is happening on my A1 sensor above ISO 20000?
Thanks in advance!
Link to EOS R5 graph showing both crop and not crop: https://www.photonstophotos.net/Cha...S R5(APS-C),Canon EOS R5(ES),Canon EOS R5(HS)
Thanks.
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John Moyer
Full scale over signal level which produces a SNR of 16000 over picture height in pixels.
Normalizes for viewing a same-sized print.
I'd interpret that as the effect of using a cropped area of the sensor, which reduces the total light used to make the image and the resulting dynamic range of the image at any ISO in comparison with a photo made using the full sensor area at the same ISO.
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Bill Ferris Photography
Flagstaff, AZ
http://www.billferris.photoshelter.com
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