non-standard ISOs increase noise?

barry13

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Hi, I came across an article today (http://www.lightstalking.com/digital-image-noise) which says:

Here is one ISO tip that many photographers aren’t aware of: keep your ISO setting to the industry standard numbers – 100, 200, 400, 800, 1600, 3200, etc. All digital cameras offer ISO settings between these numbers (such as ISO 250). But, what is really happening (with many camera models) is that the camera has electronically boosted the sensitivity of the sensor to ISO 400, then cut it back to ISO 250 using an algorithm, and this will increase the noise beyond what you might expect for that particular ISO setting.
Does this apply to any/all mu-43 cameras?

I notice on my E-M1 (fw 1.4) that if I change the "ISO Step" option to '1 EV', then it only offers the 'standard' ISOs when choosing manually, but if ISO is set to Auto, it'll still choose non-standard ISOs such as 640.

Thanks,
Barry
 

Robstar1963

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Hi
I think the 'low' ISO setting made available on latest firmware on OM- D EM-5s (and also as standard on EM-1s ?) is equivalent to 100 ISO but is I believe artificially generated by the camera and is only a 'pseudo' 100 ISO and apparently subject to a lower dynamic range
I don't know if there is any effect on image noise on this setting ?
Regards
Rob
 

biomed

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Rob,
Panasonic does the same with the "low" ISO setting. I haven't seen any advantage to using this over the normal Low ISO setting of 200. I believe you are correct about the lower dynamic range.
 

b_rubenstein

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From what I read several years ago, Canon did what was described in your quote. No idea if other makers used the same technique.

FWIW, Kent DuFault (the person who was quoted) based on what I read on his site is just a photographer and not particularly technical. Professional photographers virtually never have a solid technical background.
 
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Rather than me make a poor attempt to try to explain the concept here, if you research the term "ISO-less sensor" you will find that for cameras which use type of sensor, every ISO other than the base value requires a push to the exposure so there is no great distinction between, say, a 2 stop push and a 1 2/3 stop push. Sensors such those made by Canon don't use this type of design and I do remember watching a demonstration a few years ago that showed how the "uneven" ISO values could produce more noise than the "even" values.
 

fortwodriver

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Um...this was a Canon thing... I don't think it applies to m43... I remember this mostly coming about around the time of the Canon 7D and the 5D mkii in 2009. I remember people making WAY too much of a big deal about it.
 

MajorMagee

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It was years ago that I tested it on an E-PL2, but I couldn't see that it mattered on that sensor.
 
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