Cadmium Posted January 31, 2020 Share Posted January 31, 2020 This topic is related to a previous discussion/topic:https://www.ultravioletphotography.com/content/index.php/topic/3634-some-ideas/page__st__40 Quick test of Hoya 8mm thick filter, and compared to Baader U.This is not a stack it is just U-340 alone (see graph).Weather = all clouds. These are full frame marquee white balanced in CNX2.Much more testing ahead.D7000 UV/IR, UV-Nikkor 105mm. Hoya U-340 8mm (no suppression) Baader U Schott UG11 8mm (no suppression), and Hoya U-340 8mm (no suppression)Here is another graph: https://www.ultravio...dpost__p__19190 Link to comment
Andrea B. Posted January 31, 2020 Share Posted January 31, 2020 Wow, an 8mm thick filter. How long was the exposure? Interestingly (or not?), when diff-stacked the tonality of the two photos is very nearly identical. Link to comment
Cadmium Posted January 31, 2020 Author Share Posted January 31, 2020 ISO 200, f/8, Aperture Priority, Matrix.Exposure U-340 8mm = 8sExposure Baader U = 1.6s At peak (~85%), the Baader U is much stronger and obviously (violet/blue) has stronger 320nm-400nm content exposing much faster. Link to comment
Cadmium Posted January 31, 2020 Author Share Posted January 31, 2020 U-340 8mm, WB in CNX2 from RAW (full frame marquee WB) This version below was white balanced from RAW in Photo Ninja (full frame WB). Link to comment
Andy Perrin Posted January 31, 2020 Share Posted January 31, 2020 When I try white balancing the 8mm one in PN, it looks pretty much like the Baader. Link to comment
Cadmium Posted January 31, 2020 Author Share Posted January 31, 2020 Full frame WB from RAW in CNX2 and Ninja look a little different. I WB in CNX2.Full frame WB from the JPG above in Ninja looks much different, and much more lavender, not yellow like from RAW.I think the big difference for you is you are WB from the JPG. I tried both, and it is dramatically different from RAW or from JPG. Link to comment
Andy Perrin Posted January 31, 2020 Share Posted January 31, 2020 Ideally from RAW, yes, but I don't have the RAW, so I did the best I could. By clicking around rather than doing full frame (which is pretty arbitrary, as you mentioned...) I can make the colors look quite similar to the Baader. Link to comment
Cadmium Posted January 31, 2020 Author Share Posted January 31, 2020 The first U-340 8mm JPG photo at top, re-WB from JPG in Photo Ninja. U-340 8mm RAW file WB in Photo Ninja. Link to comment
Andy Perrin Posted January 31, 2020 Share Posted January 31, 2020 The bottom does not look white balanced. If you want to do this rigorously, put some PTFE in there and white balance the RAW off that. Link to comment
Cadmium Posted January 31, 2020 Author Share Posted January 31, 2020 I prefer the bottom one myself, has more differentiation in it than the first one at the top of the topic.I will try some PYFE at some point, this was just a quick test. It looks promising to me.It reminds me a little of the PrimaLuceLab U that Enrico posted about some time back on his page.http://www.savazzi.net/photography/images/P1030193s.JPGhttp://www.savazzi.n...alucelab_u.html(about half way down the page)https://www.primaluc...ltraviolet.htmlUnfortunately the PrimaLuceLab U has a pretty bad IR leak, and some of its color may be the result of the IR.This U-340 8mm seems to have a similar mix of colors. Link to comment
dabateman Posted January 31, 2020 Share Posted January 31, 2020 That looks like what I would expect, green. You really have a 340nm filter there. The amount of higher UV wavelengths is really low. A Baader venus filter allows in much more of the 380nm than your U340. Link to comment
Cadmium Posted January 31, 2020 Author Share Posted January 31, 2020 Indeed, and that is why most people with lenses that are not capable of a lower UV reach should stick with UV filters that cut off at 400nm rather than 380nmThis has a different color mix, which I find interesting. It is not suppose to look like a Baader or a U-360 stack, I don't want it to.When white balanced in Photo Ninja, it takes on a much more variegated color palette. Wait till I shoot the dandelions that I found late today. Yep, dandelions in January. Link to comment
Cadmium Posted January 31, 2020 Author Share Posted January 31, 2020 I forgot to include these links.First off, this thick U-340 filter was inspired and discussed here previously:https://www.ultravioletphotography.com/content/index.php/topic/3634-some-ideas/page__st__40 And here are Jonathan's scans of various thicknesses of thick U-340 which should be the best. Thanks Jonathan.https://www.ultravioletphotography.com/content/index.php/topic/2383-good-practice-and-setup-for-spectrometer-measurements/page__view__findpost__p__19186 Link to comment
Stefano Posted January 31, 2020 Share Posted January 31, 2020 Oh, nice! You did it! So it is simply a lower cut off filter than the usual UV-pass filters, which renders differently some things (I made a recent topic about the differences between these two kinds of filters). It suppresses IR to OD 5+, which I think is required in deeper UV. Link to comment
Stefano Posted January 31, 2020 Share Posted January 31, 2020 Schott UG11 8mm (no suppression), and Hoya U-340 8mm (no suppression)Here is another graph: https://www.ultravioletphotography.com/content/index.php/topic/2383-good-practice-and-setup-for-spectrometer-measurements/page__view__findpost__p__19190As I previously said, the U-340 is better than the UG-11, both in UV transmission and in IR rejection. Link to comment
Cadmium Posted January 31, 2020 Author Share Posted January 31, 2020 Oh, nice! You did it! So it is simply a lower cut off filter than the usual UV-pass filters, which renders differently some things (I made a recent topic about the differences between these two kinds of filters). It suppresses IR to OD 5+, which I think is required in deeper UV. Yes, it suppresses to OD5, and I think it probably has a 55% peak UV, like Jonathan's graph shows for 8mm. I probably don't have the correct reflection factor entered for the U-340 in my calculation, so I trust his scan.https://www.ultravioletphotography.com/content/index.php/topic/2383-good-practice-and-setup-for-spectrometer-measurements/page__p__19186#entry19186 Link to comment
Cadmium Posted January 31, 2020 Author Share Posted January 31, 2020 As I previously said, the U-340 is better than the UG-11, both in UV transmission and in IR rejection. Unless you are using thinner U-340, like under 2mm or especially under 1.5mm, then it can leak more than UG11 in the 500nm range. Link to comment
Cadmium Posted February 10, 2020 Author Share Posted February 10, 2020 Hoya U-340 8mm thick non-glued air-gaped stack from today, actual sunshine.Late afternoon sun, this shot is pointed west by northwest.Nikon D-7000 UV/IR, UV-Nikkor 105mm. ISO 200, f/8, 2s.White balanced using Spectralon in Photo Ninja.My neighbor moved his truck. Link to comment
Cadmium Posted February 10, 2020 Author Share Posted February 10, 2020 Here is the U-360 2mm + S8612 2mm version of the same scene, also individual Specralon WB/PN. Link to comment
colinbm Posted February 10, 2020 Share Posted February 10, 2020 Much more nice Steve....;-) Link to comment
dabateman Posted February 10, 2020 Share Posted February 10, 2020 Interesting, the dry grass and the side of the TV seem to have a slight blue or purple in the U340 shot to my eyes. But the dry grass not at all in the U360+S8612 shot.However that Winnebago is clearly most purplish in the 360. Also did you blur out the license plate or is that a cover? Link to comment
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