in Old Film era - the suggested speed limit was at 1/30 ...as slowest you can go. I tried this, and yes - it was the line for hand held shoting with 50 mm lens ( let's say ) .
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Why is pixel peep relevant here ? Because of noise in high iso. You cannot get even decent pic without tack sharpness. Every imperfection would delivery - really unusable results.
Speaking about technique - let's say this - it's far better to increase your Iso - even at 10.000, then get blurry, mushy, underexposed pic with 6400 or 3200 . (k3 can handle even 12800 with this technique )
And I was't aware of that for a long time... because of that I was always trying to do stuff below 3200 ,
and that's wrong. Wrong for sharpness, and wrong for noise. Yes, you get correct reading about this statement. But it's true. I learned that.
explanation is because - if you do your pics below proper exposure - and specially if you do that in dark somewhere, on concert or some people occasion indoor,
for example - your decision is to go with 3200 - but let's say it's still insufficient lightning for 1/45;1/60 and 6,7 apperture - and you think you would quite easy compensate that with exposure in LR you'll be WRONG.
You will be getting the worse pic,
then you was go with different approach - iso - 9000, and 1/60 at f-6,7 .
Every single photographer - almost 99 % of us - is telling the one single story - and I was also one of them - use lower Iso as you can. So we think that 0,5-1 Ev underexposed pic in some darker room would do the job, and will be getting tack sharp image without noise, just beacuse we want lower Iso.
True is opposite in that darker area - I'm not telling this about good lighting - it'r reserved for darker spaces.
In darker area you have to choose to little overexposed white bright areas, and proper exposure shadows. Shadows from lower ISo shot would not be properly exposed just because you put it in LR after that - and raised exposure to proper value, and it would be look mushier, and with more artifacts .
Second factor here is SR, and high Iso offer better choice for shutter to be at least 1/30 - or 1/60 .
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try this advice for yourself. You will be shocked that 3200 post processed in LR is not good as 9000 unprocessed - if the enviroment was in darker room, and 3200 was insufficient for 1/30 speed for at least 6.7 apperture
I know low Iso technique is little off topic here - but when we talk about conditions I must bring it up here.