Re: Media Testing for maclife.de
Re: Media Testing for maclife.de
- Subject: Re: Media Testing for maclife.de
- From: Bob Marchant <email@hidden>
- Date: Thu, 11 Sep 2008 00:07:03 +0100
On 10 Sep 2008, at 17:18, Fleisher, Ken wrote:
Developers of the commercial products go to great
lengths to achieve pleasing color, not accurate color.
Hi Ken.
Although there is always a certain amount of smoke and mirrors with
proprietary software , but some manufacturers do attempt to tip the
balance towards accuracy over pleasing colour . The Sinar system
that we use employs a system of camera profile + calibration , and
has proved to be a great system for advertising photography (BTW
there are no options for "looks "in the Sinar software). I believe
that Hasselblad and Lightphase in addition to looks have the option
of "accuracy". These systems ( CCDs as opposed to the mostly CMOS
chips used in the smaller DSLRs ) are used by photographers who do
prize accuracy over looks in the areas of colour critical advertising
photography , catalogue fashion photography , catalogue product
photography , beauty etc .
I appreciate that the Canon's , Nikons etc appeal more to a wider
market , and that for many , the look is more important than
accuracy , but I feel that it's too broad a brush to say that all
digital camera systems are geared towards prettiness at the expense
of everything else.
One additional aspect of camera calibration that has not been
discussed here
(Uli, perhaps you can tell us if you included this step for your
testing) is
flat-fielding. This is the process of correcting for spatial
non-uniformities in the lighting, lens falloff, etc. This is a
critical step
for camera calibration and can become very problematic if not done
(and done
correctly). The only stand-alone application that I know of for
this purpose
is Robin Myers' Equalight
Sinar have ( or should I say had as one has been removed from the
present software version ) systems in place . The first is a
diffuser placed over the lens at the working aperture that enables
the production of a white reference file which then takes into
account any difference in lens fall off due to camera movements /
vignetting.. The second is a two part calibration procedure where
the macbeth chart is captured followed by a white card capture
( this is the feature that has been removed , but hopefully will be
replaced on the next software release ).
In reality though , in order to get any substantial uneveness in the
first instance you would have to be shooting with either a wide angle
lens , loads of camera movement ( read tilt and shift lens on small
DSLR ) or some problem with the shutter.
Would it be possible to explain what you mean by spatial non-
uniformities in the lighting ?
Bob Marchant.
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