| Joined: | Thu Apr 19th, 2012 |
| Location: | United Kingdom |
| Posts: | 4424 |
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I have been critical of sensor manufacturers failure to improve medium iso noise levels whilst giving us hugely high, infrequent use capability like 250,000iso.
Well yesterday I was photographing Redpolls in my garden.... in very poor light.
I grabbed the camera when the first bird appeared and fired off a couple of shots before checking the camera settings.
The camera was set to +0.3 exposure compensation from the day before. I needed -0.3 for this particular bird/background.
With the camera set to Manual and auto iso, the first two shots were recorded at 8,000iso! The third shot, having adjusted the exp comp to -0.3, was down to 5000iso. The former had unacceptable noise (for my taste) the latter was ok.
So a shift in 0.6 of a stop was all that was needed to go from acceptable to unacceptable noise. I suppose that shouldn't have been a surprise. A whole stop change in iso at lower levels (say 400 > 800) has a barely noticeable noise change. But a change from 4000 > 8000 does.
It made me realise that when having to use high iso, exposure is especially critical to better control noise generation.
In fact, when working at these high iso, it may even be worth countering conventional wisdom and deliberately reducing exposure slightly in camera (using iso setting) to specifically generate less noise. The underexposed raw image can then be lifted to the required exposure in PS without affecting captured noise level. (Obv while managing shadow areas that may suffer )
I am finding that the Sony noise level is well controlled up to 4000iso...which anyway should be good enough on dull days.
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Eric