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standardized color test for lenses
#1
Nobody is doing it for lenses, Dpreview is doing it for cameras. Could it be fone at PZ, a standardized test for color accuracy for lenses shooting a color chart under a very specific lighting, plenty of tools available for this.

I know it is of little importance for most, it is Costy and would take a lot of time, and will make lens testing more difficult and time consuming, but nobody's doing it and it's good to be pioneering in lens testing domain
#2
I agree, would be nice indeed if possible.

 

Of course, just to make things more complex, I'd liek to se the difference between standard (in-body) processed jpegs and raws which are processed entirely netrally i fat all possible, i.e, some processign for any raw file, whatevr themake is. That would make for soem interestign comparisons I'd think. I do hope what will show in that case is what I always thought, considering Pentax, Fuji and Canon lenses, amongst others, and see what rendering differences there are caused by glass and coatings.

 

Kind regards, WIm

Gear: Canon EOS R with 3 primes and 1 zoom, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, extension tubes, an accessory plague, and an Olympus OM-D 1 Mk II and Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ...
#3
With people using AWB 90% of time time ... what is this good for? The film era is over ...
#4
To see what the effect of lens design and coating is on image rendering. Regardless of AWB or processing, different lens coatings f.e. still give a different look.

 

F.e. Fuji glass used to be good at green, Pentax was quite neural be it a bit bluish, Canon a little reddish, etc. I'd love to know how the different lenses render in this regard.

 

If it cannot be done, or too much work, I obviously understand Smile.

 

Kind regards, Wim

Gear: Canon EOS R with 3 primes and 1 zoom, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, extension tubes, an accessory plague, and an Olympus OM-D 1 Mk II and Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ...
#5
I'm still wondering whether we are talking about colors. AWB corrects color temperature and tint. What is left?

I strongly suspect that we are talking about contrast here.

Of course, each lens has its slightly different color rendition but IMHO this is overridden by the camera.


If we are going to introduce a new chapter it'll be glare. I'd love to do that one ... time permitting ...
#6
Things like AWB are crude adjustments and don't really account for the transmission spectrum.

 

I did a low tech setup to measure the transmission characteristics of assorted filters before, to try to verify the performance of low cost IR filters and other astronomical use ones. I used an old torch so this would provide a wide emission spectrum well into the IR region. Shine it through a slit, through the filter, a diffraction grating and capture the resulting spectrum with a IR-cut removed camera. You can then feed this into inexpensive spectroscopy software which can then work out the amplitudes of the spectrum. Compare it to the case without filter, and you have a response. In my case I got a toy diffraction grating with no specification, not blazed. I had to work back with known narrowband sources to get the line spacing and thus an absolute wavelength scale. If they replace the low pressure sodium light outside my house with an LED one I'll lose my reference!

<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.
#7
I agree that AWB is crude but the question remains whether this isn't so good enough that the remaining differences are irrelevant for normal photographic purposes.  During the good ol film times I got annoyed by some lenses in this respect but during the recent years I can't remember an obvious color tint caused by a lens.

 

Of course, AWB isn't everything. If you select florescent light WB, the values are static and then the differences can pop up again. However, if you go for such a setting you got way bigger problems regarding color accuracy than the lens.

 

In any case - I will not test this because most readers won't understand what I am talking about there. Ghosting/glare would be of much higher priority since that's immediately something people can relate to.

#8
I understand the original request, but I agree with Klaus that it's not the most useful thing to test... I agree that AWB is crude and there's a remaining little impact of lens quality to colour rendering, but at this point the measurement should be so precise that would probably cost too much. I'd be personally more interested in ghosting and glare, since this is probably the most disappointing area of my lenses after the mirrorless switch... I suppose because I've mostly zooms and in my previous life mostly primes; but the last zooms I had in the previous system seemed to perform better in this respect.

stoppingdown.net

 

Sony a6300, Sony a6000, Sony NEX-6, Sony E 10-18mm F4 OSS, Sony Zeiss Vario-Tessar T* E 16-70mm F4 ZA OSS, Sony FE 70-200mm F4 G OSS, Sigma 150-600mm Æ’/5-6.3 DG OS HSM Contemporary, Samyang 12mm Æ’/2, Sigma 30mm F2.8 DN | A, Meyer Gorlitz Trioplan 100mm Æ’/2.8, Samyang 8mm Æ’/3.5 fish-eye II | Zenit Helios 44-2 58mm Æ’/2 
Plus some legacy Nikkor lenses.
#9
Significant colour rendering can exist between lenses and it my experience is not resolved well by post-processing of white or colour balance. A notorious personal examples for me was the Sigma 18-125mm (first version) which I used in the dawn of DSLR days. That lens had a very unattractive yellow/green tint which I could not correct. The replacement Pentax 18-250mm had no such colour issues.

 

A more recent example is the Mitakon 85mm 1.2 which although a sharp lens with nice build, suffers from a noticeably yellow tint in colour rendering. I have now replaced it with the Sony 85mm 1.5 G master, a truly wonderful lens by all metrics save focusing speed. 

 

Also I believe optyczne.pl used to test colour transmission characteristics in their older tests - these could be used as an indication of colour rendering. 

#10
Think about the setup: To really compare lenses, this should be done with only one sensor - how many different ones are on the market, each with it's own characteristic / colour profile? How many of them are only for one mount type? Fuji-modified, Sony, Nikon modified sensors, not to mention Foveon with it's own characteristic - what good is it to have a reference of a Fuji lens if you cannot mount it on a Canon?

 

In theory it could be equalized with colour profiles (to a certain limit), yes, but, Toni-A, you seem to believe there are no factory tolerances? If you want to profile a certain combination, do so, but don't expect you could just take the measured profile of one lens /sensor combination and transfer it to your needs.

 

Think also about the test equipment : who would calibrate it, what would be the costs and what would be the benefit for most of us. After all, color rendition is only one of a lot of other factors and only needed for high fideltity reproductions of existing pictures. Which is basically forbidden if not explicit permitted. Each other set-up, sunlight, monlight, etc. has no standard-lighting but lots of colour reflections. I can't see a real reason to take and pay this effort.
  


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