ulf Posted August 19, 2019 Share Posted August 19, 2019 I found the rare KV418 filter in stock at an Italian site:https://www.adrianololli.com/articolo.asp?ID=6033https://www.adrianololli.com/articolo.asp?ID=6464It is a sharp cut laminated long pass filter that do not show any fluorescence like the normal long pass glass types like GG420... Link to comment
Cadmium Posted August 19, 2019 Share Posted August 19, 2019 That guy! :-/Good find, if it is really KV418 and all, but that is the guy who posted a really bad negative YouTube about fake U-360 years back, simply because he thought U-360 was suppose to pass only UV alone... He is scary if you ask me. Link to comment
ulf Posted August 19, 2019 Author Share Posted August 19, 2019 Well, the transmission graphs on "that guy's" web site do not agree with other more reliable sites: https://www.itos.de/en/schott-optical-filters/interference-and-special-filters/kv-filters/A KV418 here is below OD5 at 400nm, where at www.adrianololli.com the graph show 30% transmittance! Link to comment
Cadmium Posted August 19, 2019 Share Posted August 19, 2019 KV418 is definitely something to get if you are doing a lot of UVIVF, for sure.I got mine via ITOS, they were the only place I found that still had the KV418 in stock. It is a discontinued Schott product. I think because that glass didn't comply with RoHS guidelines, was what I was told.ITOS had some left, I don't know if they still have some or not, but Schott doesn't make it anymore.Because it is a laminated glass, I don't know how easy it is to cut and shape, I have never tried.It actually looks very much like the Tiffen edge (like you discovered a while back, being a laminated glass also), and as I remember you said the Tiffen doesn't fluoresce either.My KV418 from ITOS was about $250 for a 49mm circle.Where someone would be finding such stock glass is a question...? No idea, and also at a price that would make it affordable enough to cut and sell. Yes, comparing those graphs, the Schott graph at ITOS shows complete cutoff above 400nm, where as the graph shown on "that guy's" site shows 10%, 20% transmission below 400nm, and like you say, 30% at 400nm.If that is true, then not good, and not what we want, and therefore would not be true KV418.Best to email ITOS first, see if they even still have the glass available, ask their price... Link to comment
ulf Posted August 20, 2019 Author Share Posted August 20, 2019 A Tiffen Haze 2A might be a more accessible and less costly alternative. Link to comment
Cadmium Posted August 20, 2019 Share Posted August 20, 2019 Hmm, yeah, I don't know if I have one of those in particular, so I don't know if that is also a laminated build, but probably I am guessing. Does Tiffen make a 2E? Link to comment
dabateman Posted August 21, 2019 Share Posted August 21, 2019 Cadmium,We had a post a while ago about the tiffen filters. Yes they are some filter, polyester or gelatin sandwiched between glass. A 2A is currently being made, but the 2E has been discontinued. However, there is still one left at B&H 77mm for a high price.https://www.bhphotovideo.com/c/product/808131-REG/Tiffen_77HZE2E_77mm_2E_Pale_Yellow.html Link to comment
Cadmium Posted August 21, 2019 Share Posted August 21, 2019 Ulf caught this, and definitely whatever glass is being shown in the video is absolutely not Schott KV418.The video shows a very uniform edge color, fairly noticeable yellow in color, with no center layer or color.True KV418 has a very faint yellow center layer, sandwiched between two layers of clear glass. Remember, the yellow color of 418nm is very faint and hard to see.Below is comparison of Tiffen #12 glass on the right and Schott KV418 on the left.Both are laminated with a thin layer of colored non-glass material in the center.The center of the KV418 is about 0.75mm thick, and the center of the Tiffen #12 is very thin, similar to gel filters or Lee/Rosco polyester filters.I would point out once again that Schott discontinued the KV line, some places still have it, but I think even ITOS only has some of that line left.Regardless of what is shown in the video, the actual product may be something different, but the video doesn't show KV418, that is something else, and the graph they have is not KV418 either.So it may not be what it says it is, and most importantly it may not cut cleanly above 400nm, their graph look like it leaks a fair amount below 400nm. Link to comment
Andy Perrin Posted August 21, 2019 Share Posted August 21, 2019 Wow, this keeps getting shadier. Link to comment
ulf Posted August 21, 2019 Author Share Posted August 21, 2019 Ulf caught this, and definitely whatever glass is being shown in the video is absolutely not Schott KV418.The video shows a very uniform edge color, fairly noticeable yellow in color, with no center layer or color. The video:https://youtu.be/x2vlxRMY-1s Link to comment
Cadmium Posted August 21, 2019 Share Posted August 21, 2019 I also came across a Tiffen UV HAZE 1 filter in my collection, which if I shine a U-340 2mm thick filtered Convoy S2+ Nichia 365nm through the Tiffen UV HAZE, completely blocks any fluorescence at all on anything.So that filter seems to work rather well for a UVIVF lens UV barrier filter, and it should be fairly common on eBay and such.Someone would probably want to test one with a spectrometer, but nothing that passes through the U-340 2mm is getting through mine.So if you have one of those around, give it a try.By the way, I took it out of the ring to check, and it also is a laminated design with a sandwiched middle like the rest of the Tiffen filters. Link to comment
ulf Posted August 21, 2019 Author Share Posted August 21, 2019 Cadmium,We had a post a while ago about the tiffen filters. Yes they are some filter, polyester or gelatin sandwiched between glass. A 2A is currently being made, but the 2E has been discontinued. However, there is still one left at B&H 77mm for a high price.https://www.bhphotov...ale_Yellow.html I think the 2E is overkill and losing some interesting parts of the fluorescence-spectrum. (10nm)A 2A might be better.https://alanwatsonfo...rple/curves.png Link to comment
dabateman Posted August 21, 2019 Share Posted August 21, 2019 Cadmium,This is the spectra I have for Tiffen UV filters. The Haze-1 looks to be a Wratten 2B filter. Link to comment
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now