Why are my photos noisy - discussion

I do not believe those sensors are fully invariant, and so raising ISO speed still gives you more image quality compared to raising image brightness in post.

You will have slightly better shadow noise at the ISO point where the conversion gain increases than just below that point. There is little improvement in input referred read noise above that point.

Most raw converters and most color profiles have difficulty with more than a five-stop push, and the finder will be pretty dark by then, too.

Right, through some of the ISO range.

The GFX 100S shares its pixel architecture with the Sony a7RIV and a7RV.

(Counting on my fingers) 5 stop push is equivalent to ISO 3200? Very unusual for me to shoot that high. So Ok to using this strategy to, say, ISO 1600, then boost ISO for those emergency situations? I'm not bothered by optimising perfectly, if it's a stop more noise than when optimised, I'm fine with that, primarily interested in keeping it so simple I can remember it in the field.

My current strategy is auto-iso.

My previous strategy was base ISO only, resulting in lots of shots ruined by camera shake. Then one day I awoke and realised that noise is better than blur.

Should be OK.

Here's what you're leaving on the table:

blog.kasson.com/a7riii/a7riii-shadow-noise-isos-500-640-4-stop-push/

Thanks, Jim. It's probably obvious, but I haven't worked out the lesson from your post. Setting ISO 640 leads to less noise than shooting at ISO500 and pushing? For anything higher than 640, set 640 and push? What about the lower values of 200,400?

I read your other post on strategy. Does the A7rii behave the same as the Riii?

You get slightly less deep shadow noise at ISO 640, but it's not a big deal. I think your plan to keep it simple and keep the ISO low will get you the kind of images you want without the complexity that you don't appear to want. I tend to treat the camera as if it had two base ISO settings.

Yes, I got that from your strategy post.

If you expect trouble from highlight clipping, shoot a set of images with auto exposure bracketing. (I assume most cameras allow this.)

Don

Two base settings makes sense. ISO 100 for tripod or flash. ISO 800 for hand held and general walkabout.

Don

I also prefer to treat the camera as it has two base ISO settings. However, that approach can make the EVF too dark, which makes it harder to see details. At least with Nikons, a darker image in EVF also degrades AF.

It also depends on the light. If you can shoot handheld at ISO 100, you should do it.

Same with my Canon R5 and R7. If "exposure simulation" is enabled, and low light results in a dark image at max ISO, AF becomes hopeless. Turn off "exposure simulation" so that you get "auto-ISO" for the EVF, and the camera can easily focus.

It is very convenient if a camera supports a one-button switch for exposure simulation. DSLRs don't have that issue :).

I last took a physics class in 1968 and likely have forgotten much. I think I understood all that you wrote until

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I might have guessed that a warmer sensor chip would produce photons from black body radiation and some of those photons would be far enough from the peak in energy level or frequency to produce an electron in a photosite. Is that what you are talking about, or something I do not understand?

Thanks in advance.

Maybe warm electronics just free electrons directly? It'd be mildly interesting to know.

I mean the effect of thermally generated electron-hole pairs.

Dark (leakage) current doubles every 10 degrees C or so, and needs no photons to generate the excess electrons resulting from the leakage.