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08-03-2011, 05:30 AM   #1
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645d iso100

advantages and disadvantages. what can you say?

08-03-2011, 06:12 AM   #2
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QuoteOriginally posted by spacevoid8 Quote
advantages and disadvantages. what can you say?
i always try and shoot at the lowest ISO possible so have enabled the more gradual increase intervals in ISO through the menu. I use ISO 100 pretty often, and even though I always shoot RAW, it's still easier to put more light in than to take it away. I find that the metering of the 645D is not as accurate as that of my Canon 5DmkII, but I try to shoot in manual as often as I can although I am often in Aperture priority
08-03-2011, 07:03 AM   #3
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Look at measurements: DxOMark - Pentax 645D
Lower noise, more dynamic range and so on. No idea if you can notice the small difference between iso 100 and iso 200 in your work.
08-03-2011, 10:01 PM   #4
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i`ve heard that when shooting at LOW iso values you are narrowing dynamic range of camera.. is that true?

08-04-2011, 11:44 AM   #5
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QuoteOriginally posted by spacevoid8 Quote
i`ve heard that when shooting at low iso values you are narrowing dynamic range of camera.. Is that true?
no not true
08-04-2011, 04:54 PM   #6
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QuoteOriginally posted by spacevoid8 Quote
i`ve heard that when shooting at LOW iso values you are narrowing dynamic range of camera.. is that true?
Look the DXO charts linked to in the earlier post, that tells you all you need to know about the impact of shooting 100 ISO vs 200 ISO
08-05-2011, 06:40 AM   #7
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not so fast - while shooting the lowest "native" ISO will result in the best IQ for your particular camera, if you shoot an artificially lowed ISO (such as 50 ISO on a Canon) then you will have a reduced dynamic range.

the DXO measurements however indicate that the camera they tested had a "genuine" ISO of 100 to test. (not pushed or pulled, up or down)

do our cameras have the same native ISO of 100 as the DXO test camera?

The answer is, we do not know for certain; however, I do generally use the ISO of 100 and am very happy with the results.

It seems to me that if the native ISO was 100 however, you would not have to 'expand' the ISO range to reach it - but this is just a presumption on my part.

(So why would the "native" ISO of our camera be set for ISO 200? Obviously as a compromise in order to get such an excellent response at ISO 800. The same sensor of the 645d when placed in a H4D is tuned-down to a native ISO of 50. Obviously in an effort to maximum total potential dynamic range, tones, and decrease noise at the expense of higher ISO exposures. As the Hasselblad is a tethered studio camera (in practice) the native 50 ISO is the best tuning for that sensor. As the 645d is multi-purposed, Pentax elected to expand to the higher ISO - but that obviously comes at a price to IQ as it is a zero sum technology.)
08-08-2011, 04:16 PM   #8
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THe K-5 has the lowest noise and the most DR at ISO80, yet that is not it's native ISO. The old wisdom of a camera sensor offering the best IQ at it's native ISO is dead, whatever magic the current engineers have managed to weave in the image processing engine has killed it.

08-12-2011, 08:33 AM   #9
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then there is a meaning to use iso 100, but wisely..
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