ISO vs. Image Quality

Started Feb 21, 2014 | Discussions thread
Brandon birder Veteran Member • Posts: 4,106
Re: ISO vs. Image Quality

Inky22 wrote:


I'm the OP and first off I want to thank everyone for their input. I was hoping I could stir the pot a bit with this topic and I'm not at all disappointed. I did not mention in my original post that this camera and lens are new to me. I used to do a lot of film photography, but then everything pretty much switch to digital and I was pretty disappointed with the results unless I wanted to spend a gazillion dollars. But now that DSLR have come down so much in price it was time to jump back in. So I'm currently on a pretty steep learning curve and it's nice to have this group of advisers.

Today I set up a test for ISO, shooting the same subject using a tripod starting at ISO 100 and stepping up to about ISO 2000. The subject had both smooth and textured surfaces. From this test and from what others have said and shown in this thread I'd have to say I can expand my tolerance for noise and IQ quite a bit, and rely on Lightroom to help me out. One thing I did notice is that noise is much easier to detect and more bothersome the smoother the surface is, so the details of a birds feathers suffers much less than say a stalk of bamboo that he might be perched on. That being said, there is a point where the loss of detail in the feathers is not tolerable, I just haven't quite determined just where that point is for me. Right now I'm thinking it's around 800, though I have to say I was very impressed with the detail of the blackbird that one of the respondents shared. I live near a wetlands that I visit daily to learn my camera and to dial in my tolerances, so I think I'll just set the ISO at 800 for a few days and see what I get.

Thanks again to you all,


The first part is true. Noise is more noticeable in plain areas like skies and plain background objects.

The second part about a point being related to a specific iso doesn't work, unless you relate it to the size of the output frame. If you don't crop iso3200 is often fine, especially in print. If you crop a lot as I do, noise will show through at a lower iso. On my D7100 I often crop down to 1/6th the frame size. I don't use noise reduction at those crop levels upto iso 1000 or thereabouts. Above that I use varying degrees of noise reduction, mainly to the background and only touch the feathers if they are very noisy.

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