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Camera colors: Sony A900/A7 vs Fuji GFX
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PostPosted: Mon Mar 13, 2023 12:12 am    Post subject: Reply with quote
cbass wrote:
D1N0 wrote:


The portraits of the test scene at dpreview have deteriorated. Those are probably printed by a inkjet photo printer. It doesn't take very long to fade under the influence of light. The reds have gone. Red is always the first color to fade.


Sadly, I don't think this is the case. This is not the first time I have seen a Sony go Simpsons. This guy's channel has nothing to do with cameras. Here is a test he did long ago to try to decide which camera to use for his channel.

https://youtu.be/C21w0Ogxh8U

Look at his skin tones with the Sony. Unless Josh faded also, but he was a live human being at the time of filming and not printed by an inkjet.


They have admitted this is in the comments. Just look at the other colours. They don't show such major discrepancies as the portraits.

Here is a comparison with the first 4 sony a7r (1 to 4) five is better again because they reprinted the portraits.

Here The Panasonic DC-S1 and the later DC-s1H and the A7-R IV and V The earliers models show yellow skin. Fixed in the later model because the portraits were reprinted. Panasonic doesn't use the Sony sensor.


PostPosted: Mon Mar 13, 2023 12:35 pm    Post subject: Reply with quote
My angle on this is not scientific but rather subjective from using the camera and looking at the pictures on a computer screen.

This is probably way off but the way I would describe the issue is that there is not enough color separation. And not enough shades of green in a scene with different types of foliage, while the browns of tree trunks and ground has the right tones. At the same time the sky is the wrong kind of blue.

When using film like Provia and Ektachrome the balance of colors can look beautiful and better than my digital cameras even though the digital cameras superior in every way on paper.

When converting my Sony a7 RAW files in Adobe Camera Raw the files are often too yellow and I have to go into the calibration tab and increase the green primary slider. There is no point in saving a preset because the amount subjectively need is not the same from shot to shot.

This makes it better but it only makes me about 80-90% satisfied with the colors.

The Photo Ninja converter can do interesting things and sometimes make better colors with a lot of fiddling.


PostPosted: Mon Mar 13, 2023 12:42 pm    Post subject: Reply with quote
Oh and an interesting anecdote. Taking apart an old CCD camera and removing the IR blocking filter and looking through it made me realize how different cameras sees the world and how much magic needs to be done to get good colors out of it. The filter blocks much more the IR and UV, well into the visible range.


PostPosted: Mon Mar 13, 2023 6:43 pm    Post subject: Reply with quote
Strange that the point of my post above was entirely missed~
That a Sony made sensor can be made to give proper skin tones.

And for those of you wondering, a sensor made by Sony, is still a Sony- especially if it bears Sony markings. Let's have a little common sense in here. Wink

-D.S.


PostPosted: Mon Mar 13, 2023 7:13 pm    Post subject: Reply with quote
Doc Sharptail wrote:
Strange that the point of my post above was entirely missed~
That a Sony made sensor can be made to give proper skin tones.

And for those of you wondering, a sensor made by Sony, is still a Sony- especially if it bears Sony markings. Let's have a little common sense in here. Wink

-D.S.

I only have experience with the SONY A7S and SONY A7RII. Both cameras don't give me any issues with skin tones.

Caveat: I don't shoot RAW and I rarely use auto white-balance.


PostPosted: Mon Mar 13, 2023 9:21 pm    Post subject: Reply with quote
There's nothing wrong with Sony cameras and colour, it's that age old case of the bad workman blaming his tools...

Learn to use your tools to the best of their ability, modern digital postprocessing means you can adjust colours almost ad infinitum.

I always shoot RAW (if the camera allows it) and handle colour as partof the PP process, I just leave the camera on AWB and then tweak the colours as I seef it in post.


PostPosted: Mon Mar 13, 2023 10:34 pm    Post subject: Reply with quote
If I understand the problem lies in the in-camera algorithms converting raw sensor data to jpegs.

Computer raw converters have more comprehensive and complex algorithms.

If I'm that concerned about color balance I'll photograph a white card in the same light for reference in pp.

If I'm really really really wanting to get it right I'll use GretagMacbeth system.


PostPosted: Mon Mar 13, 2023 10:46 pm    Post subject: Reply with quote
calvin83 wrote:
This paper may be useful to this topic: Use of commercial off-the-shelf digital cameras for scientific data acquisition and scene-specific color calibration https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4028365/ .


Like 1 Like 1 Thank you!


PostPosted: Mon Mar 13, 2023 11:37 pm    Post subject: Reply with quote
visualopsins wrote:
If I'm that concerned about color balance I'll photograph a white card in the same light for reference in pp.


That is how we were taught to do it in film school


PostPosted: Tue Mar 14, 2023 6:00 pm    Post subject: Reply with quote
visualopsins wrote:

If I'm that concerned about color balance I'll photograph a white card in the same light for reference in pp.


Yep, that's what I'm doing often as well. However, if the white card (grey card?) has a slightly glossy surface, you may see nasty surprises if light sources of different color are contributing to the "average light" (e. g. in churches with colored windows). Depending on the angle between the light sources, the grey card and the sensor the measured color temperature may vary wildly.

S


PostPosted: Tue Mar 14, 2023 6:23 pm    Post subject: Reply with quote
stevemark wrote:
visualopsins wrote:

If I'm that concerned about color balance I'll photograph a white card in the same light for reference in pp.


Yep, that's what I'm doing often as well. However, if the white card (grey card?) has a slightly glossy surface, you may see nasty surprises if light sources of different color are contributing to the "average light" (e. g. in churches with colored windows). Depending on the angle between the light sources, the grey card and the sensor the measured color temperature may vary wildly.

S


A caveat to avoid, yes; thanks for adding that. I suppose in those lighting cases pp white balance must be manually adjusted?


PostPosted: Tue Mar 14, 2023 7:07 pm    Post subject: Reply with quote
visualopsins wrote:
stevemark wrote:
visualopsins wrote:

If I'm that concerned about color balance I'll photograph a white card in the same light for reference in pp.


Yep, that's what I'm doing often as well. However, if the white card (grey card?) has a slightly glossy surface, you may see nasty surprises if light sources of different color are contributing to the "average light" (e. g. in churches with colored windows). Depending on the angle between the light sources, the grey card and the sensor the measured color temperature may vary wildly.

S


A caveat to avoid, yes; thanks for adding that. I suppose in those lighting cases pp white balance must be manually adjusted?


Church interiors can be difficult in any case, grey card or not; different light sources from different directions: extreme contrast, direct sunlight through some windows, indirect blue sky light through other windows, stained glass windows, and additional artificial lighting which may be any random combination of tungsten, legacy fluorescent, and modern LED, purposeful dim lighting near sensitive paintings & frescos etc. I often have to adjust to a best compromise as whilst I can control the natural lighting to some extent (choice of weather & time of day), as a tourist I can't control the choice and mix of artificial lighting they turn on inside.

I guess professionals working on commission may be given more control of artificial lighting & can bring their own fill-in lighting (+tripods, a big no-no for tourists in many churches here).


PostPosted: Tue Mar 14, 2023 9:59 pm    Post subject: Reply with quote
RokkorDoctor wrote:

I guess professionals working on commission may be given more control of artificial lighting & can bring their own fill-in lighting (+tripods, a big no-no for tourists in many churches here).


Depends very much on the importance of a given religious building. When I'm doing such work in a local church, I usually can play with light system of the church myself. Often I prefer the natural light, though.

More important churches such as the S. Maria dell'Anima in Rome are more tricky. I was allowed to work at any time and whenever I wanted, but the available time without tourist visiting (=without artificial light) usually was limited to about 13:30-14:45. Not that much time indeed ...

At really important places - e. g. the Duomo and the Baptistery in Florence, or St. Peters in Rome - I had to work with the given artificial light. Occasionally you get lucky, and the responsible person / monk is a photographer himself. That happened to me at the monastery of St. Francis in Assisi.

S


PostPosted: Tue Mar 14, 2023 10:06 pm    Post subject: Reply with quote
Your average church interior will be no more complec]x, light wise, then your average film or TV stage.


PostPosted: Wed Mar 15, 2023 3:55 am    Post subject: Reply with quote
iangreenhalgh1 wrote:

I always shoot RAW (if the camera allows it) and handle colour as partof the PP process, I just leave the camera on AWB and then tweak the colours as I seef it in post.


In theory this works. In practice this can make your life miserable. If you have one picture and can spend hours on it making it perfect no problem. If you shoot an event and have to go through hundreds of pictures with color cast issues, then it's time to get some rope to hang yourself. Some casts correct relatively quickly and painlessly, but I am sure most of us at some point bought some cheap filter with a cast and you can end up in a painful place quickly. Way beyond just correcting the WB.

The more the camera and lens combination produces the colors I want and the more I only have to focus on composition the happier I am.


PostPosted: Wed Mar 15, 2023 9:50 am    Post subject: Reply with quote
iangreenhalgh1 wrote:
Your average church interior will be no more complec]x, light wise, then your average film or TV stage.


Sure, but I was observing this from the perspective of a tourist. You already get told not to use any tripod or flash inside a church, never mind what they would say if you turned up with additional lighting stands & units, or ask for access to the existing lighting control panel... Wink

Location shoots for film & TV are by agreement (& likely legal contract) with the site's proprietor; I imagine lighting issues can be discussed as required as part of setting up that agreement.


PostPosted: Wed Mar 15, 2023 10:06 am    Post subject: Reply with quote
cbass wrote:
iangreenhalgh1 wrote:

I always shoot RAW (if the camera allows it) and handle colour as partof the PP process, I just leave the camera on AWB and then tweak the colours as I seef it in post.


In theory this works. In practice this can make your life miserable. If you have one picture and can spend hours on it making it perfect no problem. If you shoot an event and have to go through hundreds of pictures with color cast issues, then it's time to get some rope to hang yourself. Some casts correct relatively quickly and painlessly, but I am sure most of us at some point bought some cheap filter with a cast and you can end up in a painful place quickly. Way beyond just correcting the WB.

The more the camera and lens combination produces the colors I want and the more I only have to focus on composition the happier I am.


That's one reason why I rarely use AWB. When shooting a lot of images under the same lighting conditions (incl. relatively stable natural lighting outdoors), using a fixed WB setting gives me both predictability and consistency of colour; if an adjustment is required afterwards it is likely to be the same for most of those images.

Worst case of AWB un-helpfulness is when you shoot the same subject twice under the exact same lighting, one in landscape format, one in portrait format, and get completely different colour rendering for both images. The standard Camera App on the iPhone is one of the worst offenders I have seen there (only has AWB setting and can'y turn it off); hence I only use the Halide App on that which at least offers a few fixed WB settings.


PostPosted: Wed Mar 15, 2023 12:09 pm    Post subject: Reply with quote
iangreenhalgh1 wrote:
visualopsins wrote:
If I'm that concerned about color balance I'll photograph a white card in the same light for reference in pp.


That is how we were taught to do it in film school


Though it should be a neutral light gray surface to have some play in the image data for the white balancing. Third gray patch of the Color Checker Passport for example. I have some gray plastic cards stored in the bags, measured with a spectrometer on neutrality. That one measures a bit into UV as well.

For a neutral white material in reprographic work I went for plumber's Teflon tape more than a decade ago, roll cut to the core of the reel and folded to at least a thickness of 6mm. From time to time peeling off a layer to get a clean surface again. Or made into a thick knot to create some shady parts too to measure. Anyway now always with an extra grey card next to it.

https://www.dpreview.com/forums/thread/4052278

For vintage lenses just the white balance correction is probably not sufficient, though I did not make much work of that either. An ICC profile for Capture One's LCC tool, not more than one lens. Some kind of a spectral filter in the software might work better for landscapes though. Measured through the lens only with a monochromator like it should be done?


PostPosted: Wed Mar 15, 2023 6:46 pm    Post subject: Reply with quote
Ernst Dinkla wrote:


Though it should be a neutral light gray surface to have some play in the image data for the white balancing. Third gray patch of the Color Checker Passport for example. I have some gray plastic cards stored in the bags, measured with a spectrometer on neutrality. That one measures a bit into UV as well.


My Kodak 18% reflectance gray card is still accurate enough for use today, better than 40 years after it was purchased. It still resides in the heavy plastic sleeve it was sold in.
It came as part of a set with an 8" X 10" resolution test chart that fell apart long ago.
I haven't seen that particular item in circulation for quite some time now.
Inquiries at photo shops usually generate lengthy drawn out blank stares...

-D.S.


PostPosted: Wed Mar 15, 2023 7:31 pm    Post subject: Reply with quote
For film & video work, we did both white and black balance, no 18% gray.

At the end of the day, if you want to do it properly, AWB and in-camera JPEG processing is just not good enough, you need to colour grade everything during the RAW development process. Not that time consuming if you have your workflows properly organised.


PostPosted: Wed Mar 15, 2023 7:51 pm    Post subject: Reply with quote
Ernst Dinkla wrote:
iangreenhalgh1 wrote:
visualopsins wrote:
If I'm that concerned about color balance I'll photograph a white card in the same light for reference in pp.


That is how we were taught to do it in film school


Though it should be a neutral light gray surface to have some play in the image data for the white balancing.

...


Afaik the ratios between R, G, & B values are used for balancing the image colors. I don't think grey offers any advantages. Of course the image of the white card should be properly exposed -- a white reference in that light. Overexposure can result in worst case a 1:1:1 ratio which balances nothing.


PostPosted: Wed Mar 15, 2023 8:25 pm    Post subject: Reply with quote
visualopsins wrote:


Afaik the ratios between R, G, & B values are used for balancing the image colors. I don't think grey offers any advantages. Of course the image of the white card should be properly exposed -- a white reference in that light. Overexposure can result in worst case a 1:1:1 ratio which balances nothing.


I guess that’s the main ‘problem’ with a white card. When overexposed it will always be white, no matter the WB of the image.


PostPosted: Wed Mar 15, 2023 8:33 pm    Post subject: Reply with quote
visualopsins wrote:
Ernst Dinkla wrote:
iangreenhalgh1 wrote:
visualopsins wrote:
If I'm that concerned about color balance I'll photograph a white card in the same light for reference in pp.


That is how we were taught to do it in film school


Though it should be a neutral light gray surface to have some play in the image data for the white balancing.

...


Afaik the ratios between R, G, & B values are used for balancing the image colors. I don't think grey offers any advantages. Of course the image of the white card should be properly exposed -- a white reference in that light. Overexposure can result in worst case a 1:1:1 ratio which balances nothing.


Depends on the algorithm used; some use linear R, G, B scaling factors like the simplest implementation of the "Grey World" AWB method and the "White Patch" AWB method (see below), some other methods use a more complex quadratic mapping (again, see below); none are perfect as a single method. The below treatise will probably tell you more than you ever want to know:

https://courses.cs.washington.edu/courses/cse467/08au/labs/l5/whiteBalance.pdf

By using a grey card you are effectively forcing the "Grey World" AWB method and the "White Patch" AWB method to generate the same (or at least a somewhat consistent) result if unsure what AWB method the camera actually uses; this may then obviously violate the "Grey World" paradigm for a normal scene that isn't a grey card.

I guess that's a longwinded way of saying that using a grey card may not necessarily give the same AWB results as using a white card; it depends on the algorithm used in the camera.

EDIT: just noticed you guys were talking about photographing a grey (or white) card for reference in PP. Obviously the same applies, but then with reference to the algorithms used in the PP software, which may use different sampling methods and parameterisations for the algorithm used (e.g. black point, grey point, white point).
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