My own A99-D600 ISO test

Started Jan 9, 2013 | Discussions thread
tex
tex
Veteran MemberPosts: 6,202Gear list
Like?
Well, imaginary or otherwise, I have questions
In reply to TrojMacReady, Jan 10, 2013

TrojMacReady wrote:

Giant Tsunami wrote:

tex wrote:

I did read the exif. yes, the exposures were the same in terms of fstops and speed. Nevertheless they came out different, probably function of the iso difference (even though they both show the "same"), because in digital cameras that's a processing difference, really.

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tex_andrews
"Photography is the product of complete alienation" Marcel Proust
"I would like to see photography make people despise painting until something else will make photography unbearable." Marcel Duchamp

Exactly, now if you could match up the exposure perfectly by raising a99 iso, you would end up with the same discrepency that DXO shows. Why did we need to go through all this to get to the truth?

Imaginary because the A99 ISO 1600 crop is brighter on average and the differences are smaller than 1/6th of a stop. Neither of which translates to the DXO measurements. Unsurprisingly because the DXO measurements do not represent visual brightness of exposures or metering.

First, it seems like a lot more than 1/6 of a stop to me. I'm not sure I can infallibly tell the difference of 1/6 of a stop.  Looked like at least 1/3 of a stop to me, and really more like something between 1/3 and 1/2.  I thought it looked like a pretty pronounced difference.

Second, could you elaborate on your last sentence?  I want to make sure i understand correctly.

Also, are all identical fstops really identical?  Identical shutter speeds really identical (probably here differences are too minor for us to tell a difference...)?  Since lens coatings can have a marked effect on color rendition, can they also on light transmission? How does the metering work into all of this? Who is measuring/taking account of all these variables? Since the ISO bit in digital is really a processing thing, what do we make of two similar sensors with different processing?  What does this processing really mean in terms of the camera's sensitivity?  And don't the manufacturers all have a different ideas on what the precise exposure response of their cameras should be?  They certainly seem to have different ideas about everything else! Finally, is it so wrong to simply dial in a touch of exposure compensation to "zero-out" a camera?

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tex_andrews
"Photography is the product of complete alienation" Marcel Proust
"I would like to see photography make people despise painting until something else will make photography unbearable." Marcel Duchamp

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