DP1, DP2 & DP3 color rendition: same or different? The truth revealed :)

Started Mar 29, 2013 | Discussions thread
(unknown member) Contributing Member • Posts: 659
Just a couple (or more) points

vbd70 wrote:

mroy wrote:


'To sum things up, it is clear to me that Sigma changed the colour output of the DP3 Merrill noticeably when using IN CAMERA WB and WB presets. When using CUSTOM WB in Sigma Photo Pro 5.5.1, on the other hand, the output of the three Merrills is much closer to one other: so much so that most users wouldn't notice any differences at all, and that whatever differences there are can be fixed easily enough in post-processing if one so wish.'

Not so. Your test shows the AWB behaviour of the three DPM under one defined and rather narrow condition - flash, studio, same shutter speed / aperture etc.

AWB is basically an algorithm which tries to determine the correct WB by identifying a 'neutral or white' reference point under a very large range of lighting conditions.

You can't really conclude anything from your controlled tests using flash light for other (and much more common) 'natural' lighting conditions , I'm afraid.

You mention it yourself:

'while I only tested Flash WB preset under controlled conditions, casual use of the Merrills today leads me to assume this to be a general behaviour for all presets'.

Framkly, that's a bit too much 'casual' and 'assume' for my taste - most definitely not what I would dare call the truth.

By the way:  I very much applaud the effort you have put into your tests and I actually very much like your photography - but coming from a scientific background I'm very careful when it comes to truth.

Personally, I'm looking forward to the next firmware upate of the DP2M


indeed, the truth about the assumption I set out to prove.

My test was aimed at seeing if there were any differences between the DP1, DP2 and DP3 Merrill, not at proving anything absolute about the colour rendition of any of these three cameras.

As a scientist, you should know that one way to prove an assumption is to build a test case; I did so using Auto WB, Flash WB and Custom WB, which IMHO were enough to see whether there were in fact differences or not between the rendition of these three cameras. There are.

Indeed there are: between your three DPM and in this particular test.

Of course, it is possible that - say - under incandescent WB there are NO differences at all between the cameras, but something tells me that this is not very likely. As a scientist, you are familiar with Ockham's razor of course.

Ockham's razor, or in short: 'amongst competing hypotheses to explain a certain fact, one should favour the hypothesis which makes the fewest assumptions' is not a valid principle to determine scientific truth.

So: I proved that there are in fact differences under three different WB; my eyes (even without a thorough test), tells me that there are differences even under other WB in casual shooting - where casual means "real world", no charts - so I assume that these differences that I proved true under three particular conditions, if seen under the naked eye under other conditions, would be there under these conditions as well. More, one of the WB I used is CUSTOM WB, which should theoretically output the best results (and it does, though there are still differences).

Custom WB does not automatically output the best result - all it does is adjust WB to match the white / grey of the referent.

Not perfect science, but close enough for me; especially seeing the argument we are talking about - are the cameras in fact different - which is trivial compared to, say, the rigour one needs to test nuclear fission Relax, the colour output of the cameras IS different; I accept this, after my little experiment, and will do so unless you prove me otherwise... you, of curse, can believe whatever you want, not a problem for me.

Fair enough - especially since I only have the DP2M.

And my experience with the DP2M, since August last year and hundreds and hundreds of pictures: colours with the DP2M are not an issue at all for me.

H Bowman for instance will disagree - but that's fine. I don't claim that what I see has to be true for everybody, especially when it comes to colour.

Oh by the way, you are of course aware that it would be practically impossible to prove my starting assumption under ALL possible lights and WB combination ever present anywhere on Earth, don't you agree...? Unless you have infinite time and resources, that is.

Exactly - which is why I was pointing out the rather bold use of truth (as in 'the truth revealed').



All in the spirit of that most elusive goal: truth

And, although I'm in danger of repeating myself: I enjoy your photography!

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