I have conducted a small non-scientific test of the manual color balance with my DP2M and the CBL color balance lens.
You can find the images in this flickr album
WB settings with appended "n" have been neutralized by setting the white point with the eyedropper tool in SPP.LED with adjustable color temperature at 5600 K:
This LED light is difficult to judge. It seems to fit "incandescent-n" best as the colors look more vivid and the table is less green. I think that the manual WB is more desaturated than the presets in SPP in almost all cases of artificial and mixed light as a continuous spectrum is probably achieved by muting the spikes of the histogram. Therefore it's maybe good to overexpose or expose for the shadows. I still elaborate on this.LED with adjustable color temperature at 4400 K:
Strange spectrum. Greens seem to be well saturated. Other colors look good with magenta desaturated or underexposed. sunlight-n has better contrast. The wooden desktop looks more natural due to exaggerated warm colors.LED with adjustable color temperature at 3200 K:
Manual looks better than auto. Both are terrible. Magenta looks orange. I would choose manual or tungsten-n with further adjustments in SPP. auto-n looks wrong.Night scenes with many different lights:
I have included two night photos in the test as they are almost impossible to guess on location. These images look best with Custom WB. Look at the skin tone of the candy shop seller or the almost neutral pavement in the other shop compared to the other color balances. AWB doesn't work for this shots. Manual WB with the CBL even can reduce the yellow of the churches in the background. Most presets give either a color cast which cannot be neutralized in SPP or they exaggerate colors to a point there they become posterized/oversaturated. Even pink/magenta lights look good. This is different in the color target shots where those colors are skewed to orange or desaturated to a mild dusky pink.Overcast daylight (cloud symbol):
Not bad with all WB-modes. Optimal light quality. No need for manual WB. Still a grey card or CBL is useful for finding a neutral grey.Tungsten light +
incandescent fluorescent light:
The results don't differ much from the pure tungsten examples as this was the main light. Tungsten-n looks best, is more vivid but is in fact oversaturated. Magenta shifts to orange. I have to rethink how to hold this CBL to reflect the situation I want to depict.Tungsten light:
Manual WB looks better than AWB. Both look desaturated (or underexposed). Oversaturated red in tungsten-WB. Magenta looks orange. I would choose manual or auto-n with some saturation and exposure adjustments or vivid color mode in SPP or tungsten-n with neutral color mode.On the CBL color balance lens (for those who asked):
It's not a lens but a white balance target which you can use like a grey card. I have done all the color target shots you can see on flickr with both - the CBL and a 20 year old greycard and I decided to post only the former as the differences were marginally.
Nethertheless the CBL seems to work for the night shots I did as it better reflects the overall lighting situation with it's built in prisms and mirrors. Additionally one can use the CBL as an neutral grey target. For mixed light or to balance color reflections from objects one can use the cone shaped rim of the white side. Depending on where you click with the eyedropper in SPP you can adjust color balance to colored light falling from one side or from another. Don't forget to do the real shot without the device ;
The 110mm CBL comes with a strap, a box and a even more beautiful pouch. There is a manual included but you better skip it
I don't use the strap and the box but the pouch perfectly fits a DP2M with the RRS handgrip. You can even put a DP3M in it.
The CBL cannot improve the physics of your camera. Look at the tungsten light results to get an idea of what is impossible. You need a certain amount of blue light for the Merrill cameras to work. If you want to have color in your subject look the same color in your photos you need to have light with this color falling on your subject. Otherwise colors come out quite differently.
I hope I'm not boring you.