ISOless sensors, read noise and photography - many questions!

Started 6 months ago | Discussions thread
bobn2
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Re: ISOless sensors, read noise and photography - many questions!
In reply to boardsy, 6 months ago

boardsy wrote:

bobn2 wrote:

boardsy wrote:

bobn2 wrote:

Yes, I think that's true. The D7000 above is better at 200 for instance.

But it has less DR & Sat Cap and equal read noise at 200 vs 100?

Sur, but saturation capacity and DR are only of interest if you're going to use them. If your scene and chosen exposure doesn't include anything that will blow out at 200, then 200 is as good as 100, and maybe a bit better in some cases.

A bit better how, in what cases - you're getting lower DR and equal read noise at 200?

Well, the case that you're not using the extra DR, in which case it's loss is not a loss and where the quality of the noise, rather than just the amount, makes a difference. Quite often, for instance with the D7000, the noise just looks nicer at 200.

- how do us non-scientists interpret these sensor graphs? E.g. for the Sony NEX C3 (probably the same sensor as my F3, maybe, lol), read noise actually drops down to ISO800 ...but so does DR! Is ISO400 the best compromise here, or should best DR (at ISO200) trump lower read noise (at ISO800)? And could this non-base ISO be valid for all shooting, or just low-light where optimal exposure becomes problematic?

DR trumps lower read noise if you need it, which is one of those judgements based on experience. A rule of thumb which covers most cameras pretty well is go with ISO but stop about 2 stops faster than base (3 for an APS-C Canon, 4 for a FF one).

You mean raise ISO in-camera as required, up to 2 (APS-C), 3 (APS-C Canon), or 4 (FF) stops?

the 4 stops for FF was Canon only. Yes, essentially use that as your fixed working ISO, lowere it if you need more highlight headroom.

You mean not just as required by low light, to choose lowest read noise despite lower DR? Interesting, I wouldn't have expected that - so DR would only trump read noise in high DR scenes e.g. midday sun & dark shadows?

Exactly, if you aren't using the DR, it doesn't give you any advantage. When you do need it (which is actually typical with low light scenes, because they often have light sources included in the scene, which are very much brighter than a reflective 'white' at the ambient illumination.

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Bob

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