so i've spent a bit experimenting and trying to devise a test scene to compare the Heliopan #5 light yellow Digital ES versus the BW's, but I havent really come to any shocking findings.
At first I began testing for the UV/IR transmissibility of all of my colored filters and then stacking on a BW UV/IR cut.
I began by "verifying" that my UV/IR cut filter was working as I was able to notice a small bit of difference on the 240 in my test scene. I used some materials I know to be highly reflective to both UV and IR, and while some differences could be noted on the IR reflective material, I cant say i noticed any difference on the UV materials. The largest difference I saw, while still relatively small, was in color rendering. This really isnt a surprise, but just doing my part to make sure my cut filter is cutting.
My next step was to test the UV/IR sensitivity of the 246 in the same manner, but I struggled to see any difference between no filter and just the uv\ir filter on the 246 other than a very very slight shift in the histogram to the left. My guess is that the UV/IR filter also cuts out about .05 or less of a stop of light.
Beyond repeating the test using a UV flashlight and IR flashtrigger light sources right in my test scene, I'm not sure anyone will really notice anything significant. Which was honestly surprising to me, especially since I could see a difference in the color comparison. So surprising, that I just went back and looked at the files while typing this sentence.
Moving on, I compared the filters directly, while also stacking the UV/IR Cut. The results basically showed, at least in near field distances, that all of these filters behaved nearly identically, except for the obvious difference in color filtration. In other words, due to the lack of impact in the final image of uv/ir on the 246, feel free to use the filter color you want without regard if it has the digital moniker on it.
Furthermore, since this really turned into a color vs color filter I will say that I think I can see why the Heliopan light yellow is somewhat favored. It probably does about ~75% of the contrast adjustment as the BW022, but with a about half as much light absorption/filter factor. It seems to help keep the highlights from a bright blue sky in-check just as well without overly darkening or altering the midtones as much as the 022. And since there's less light being absorbed by the filter, more of that light is making its way onto the sensor to help with lifting shadows in post. Really, I think this is all due to the color difference. I have to do some more shooting to be 100% certain, but I am fairly confident that I'm not too far off from having made a fairly reasonable and accurate conclusion.
I could provide some comparison pictures of my incredible stupid test scene, but I'll spare you all the bunch of pictures that look identical except for the difference in contrast due to the filter color.
Having said all that now; Back to the thread!
