vla Posted June 18, 2009 Share #1 Posted June 18, 2009 Advertisement (gone after registration) good evening, i recently bought a nice second hand 135 tele-elmar from my favorite leica store in berlin. i also ordered the indispensable ir-filter. i did not specify the brand and - coincidentally or not - they sent me a b+w filter. since i have the 'original' leica filter on my 35 'cron i decided to compare the two filters. enclosed three shots of some randomly picked books from my bookshelf - #1 without any filter, #2 with the leica filter, #3 with the b+w filter. all shots were taken at f4, iso 160 and with lens-detection on+uv/ir. no post-processing was applied. as expected, colors without any filter were quite awful. as mentioned many times before, the ir-issue not only turns black into magenta, but distorts the entire color spectrum. next step was to compare the two filters. as far as i can tell differences between them are minimal. on my monitor b+w colors appear a tiny little bit warmer, but that might be an artifact. one thing surprised me - auto-exposure without filter was 1/25. with filter exposure increased to 1/16 - both for the b+w and the leica filter. i was not aware that filters take away that much light! clearly, this is a serious drawback, especially since the ir-filtering is mostly needed for available light photography where one definitely does not want to waste any of that precious light ... high time for leica to straighten out their awkward ir-issue!! markus ps - i'm quite pleased with the tele-elmar ... Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/88368-comparing-bw-with-leica-uvir-cut-filters/?do=findComment&comment=936892'>More sharing options...
Advertisement Posted June 18, 2009 Posted June 18, 2009 Hi vla, Take a look here comparing b+w with leica uv/ir-cut filters . I'm sure you'll find what you were looking for!
efftee Posted June 19, 2009 Share #2 Posted June 19, 2009 Hi, was your M8's lens detection + uv/ir set to ON without any filter mounted? good evening,i recently bought a nice second hand 135 tele-elmar from my favorite leica store in berlin. i also ordered the indispensable ir-filter. i did not specify the brand and - coincidentally or not - they sent me a b+w filter. since i have the 'original' leica filter on my 35 'cron i decided to compare the two filters. enclosed three shots of some randomly picked books from my bookshelf - #1 without any filter, #2 with the leica filter, #3 with the b+w filter. all shots were taken at f4, iso 160 and with lens-detection on+uv/ir. no post-processing was applied. as expected, colors without any filter were quite awful. as mentioned many times before, the ir-issue not only turns black into magenta, but distorts the entire color spectrum. next step was to compare the two filters. as far as i can tell differences between them are minimal. on my monitor b+w colors appear a tiny little bit warmer, but that might be an artifact. one thing surprised me - auto-exposure without filter was 1/25. with filter exposure increased to 1/16 - both for the b+w and the leica filter. i was not aware that filters take away that much light! clearly, this is a serious drawback, especially since the ir-filtering is mostly needed for available light photography where one definitely does not want to waste any of that precious light ... high time for leica to straighten out their awkward ir-issue!! markus ps - i'm quite pleased with the tele-elmar ... Link to post Share on other sites More sharing options...
Bo_Lorentzen Posted June 19, 2009 Share #3 Posted June 19, 2009 Markus, Interesting comparison. About the exposure issue. If Leica move the IR filter back in front of the chip... the filter will still cause the same light loss. So the light loss is going to be in the optical system one way or another. . Link to post Share on other sites More sharing options...
vla Posted June 20, 2009 Author Share #4 Posted June 20, 2009 @ aftee - setting was on lens detection + uv/ir for all three shots @ bo - you are absolutely right, it seems that with current filters some loss of available light is inevitable - what a pitty ... markus Link to post Share on other sites More sharing options...
sean_reid Posted June 21, 2009 Share #5 Posted June 21, 2009 The filters don't take away any light at all. Cheers, Link to post Share on other sites More sharing options...
adan Posted June 21, 2009 Share #6 Posted June 21, 2009 Well - to be pedantic, they obviously take away IR light. And at a slant angle (the cyan drift region) they take away some visible red - not a factor with the 135, though. Are silicon blue meter cells sensitive to IR - and is that what the M8 uses for metering? Link to post Share on other sites More sharing options...
efftee Posted June 21, 2009 Share #7 Posted June 21, 2009 Advertisement (gone after registration) @ aftee - setting was on lens detection + uv/ir for all three shots You may just want to set Lens Detection to ON, instead of ON + UV/IR, if/when you are not using a filter. Link to post Share on other sites More sharing options...
AlanG Posted June 21, 2009 Share #8 Posted June 21, 2009 Well - to be pedantic, they obviously take away IR light. No offense as IR light is a common term here and elsewhere. But when I was in college, we instructed to never refer to IR or UV radiation as "light." Light is defined as the "visible" part of the electro-magnetic spectrum. Link to post Share on other sites More sharing options...
stunsworth Posted June 21, 2009 Share #9 Posted June 21, 2009 Are silicon blue meter cells sensitive to IR - and is that what the M8 uses for metering? I don't know what type of cells they are, but they're sensitive to IR - albeit several stops below the sensitivity of visible light. Link to post Share on other sites More sharing options...
giordano Posted June 21, 2009 Share #10 Posted June 21, 2009 I don't know what type of cells they are, but they're sensitive to IR - albeit several stops below the sensitivity of visible light. Almost certainly they're "silicon blue". These are silicon photodiodes (whose native sensitivity peaks at about 900nm in the near infrared), with an integrated correction filter that attenuates the red and infrared to give a sensitivity peaking at about 550nm, comfortably within the visible spectrum. Link to post Share on other sites More sharing options...
chris_livsey Posted June 21, 2009 Share #11 Posted June 21, 2009 Firstly, as has been noted, it was not "fair" to leave +UV/IR on the shot without the filter. On my system, Mac and Safari which I am told is aware of and respects the embedded colour profiles of images, I see significant differences in colour saturation and in "sharpness"/"contrast". If you look at the palm trees in the book cover they appear "best" in the unfiltered shot then the Leica then the B+W. This could be because the angle is showing flare which is not handled well by the filters. Thanks for posting, nice lens looks really good in the corners as well. Link to post Share on other sites More sharing options...
jaapv Posted June 21, 2009 Share #12 Posted June 21, 2009 On the exposure difference : The filters have a filter factor of 1 for visible light. i.e. no light lost. The filter factor for IR light is maybe 50. i.e. (nearly) blocked That means that you measure the amount of IR light in the image by the change in exposure between a lens without filter and a lens with filter. Link to post Share on other sites More sharing options...
vla Posted June 21, 2009 Author Share #13 Posted June 21, 2009 thank you everybody, for your comments, this is very educational! couple of remarks - i am aware that without filter one should change camera settings. i did not do this on purpose to isolate the effect of a missing filter from image post-processing congrats to chris lively for superior monitor and/or eyesight - i can't detect any difference in palm tree resolution on my imac ... . btw, accdg. to serial number the lens is from 1972, it's really a nice piece from the other comments i'd conclude that there is some 'unsharpness' in the interaction between filters and photodiodes. either, as jaapv and other suggest, the photodiodes are sensitive to ir-radiation and measure the effect of the filter. or - diodes are insensitive to ir-radiation (that's what i would expect) and filters take a away a certain amount of the non-ir spectrum. anyone to resolve this ... ? best, markus Link to post Share on other sites More sharing options...
jaapv Posted June 21, 2009 Share #14 Posted June 21, 2009 Yes. They are IR sensitive - you can take IR shots with an 092 or 093 filter on (black filter IR pass) and use AE without problem. Link to post Share on other sites More sharing options...
vla Posted June 21, 2009 Author Share #15 Posted June 21, 2009 jaapv, thank you very much for the explanation, good to know. and i always thought that silicon let's ir-radiation pass by. at least, in our wafering-fab we us ir-radiation to inspect silicon bricks. guess i need to have a closer look at absorption properties of photodiodes ... markus Link to post Share on other sites More sharing options...
sbelyaev Posted June 21, 2009 Share #16 Posted June 21, 2009 I hope the author of this thread would not mind my experiment. I converted all images to B&W using preset Lightroom low contrast settings. The results are below. The images are in the original order. Please draw your own conclusions. Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/88368-comparing-bw-with-leica-uvir-cut-filters/?do=findComment&comment=939573'>More sharing options...
vla Posted June 21, 2009 Author Share #17 Posted June 21, 2009 stanislav, excellent idea, i don't mind at all. before anything else your conversions show that there is too much clarity on the color jpeg files. on my monitor it also seems that the shot without any filter is crisper than the other ones. so i went back to my originals and converted them to b&w using aperture and silver efex. then i looked at them at 100% size. a couple of observations - - the structure of the synthetic fabric in the background appears crisper in the filterless picture than in those taken with filters. this is probably due to the fact that the color shift exaggerates the contrast in that fabric - looking at fine details (have a look at the small 'a' where it says 50th edition) i cannot detect any deterioriation between image 1 (i.e. without filter) and image 2 (with leica filter). however, the third shot (i.e. the one with the b+w filter) has significantly lower resolution of fine details. i am not sure whether this is attributable to the filter. i could be that there was some minimal movement of the camera body. i used my tripod for the shot, but maybe i hit the release button a bit too hard on the third shot. i will have to repeat the test sometime ... best, markus Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/88368-comparing-bw-with-leica-uvir-cut-filters/?do=findComment&comment=939709'>More sharing options...
microview Posted June 21, 2009 Share #18 Posted June 21, 2009 I went back to my originals and converted them to b&w using aperture and silver efex. then i looked at them at 100% size. a couple of observations - - the structure of the synthetic fabric in the background appears crisper in the filterless picture than in those taken with filters. this is probably due to the fact that the color shift exaggerates the contrast in that fabric - looking at fine details (have a look at the small 'a' where it says 50th edition) i cannot detect any deterioriation between image 1 (i.e. without filter) and image 2 (with leica filter). however, the third shot (i.e. the one with the b+w filter) has significantly lower resolution of fine details. i am not sure whether this is attributable to the filter. i could be that there was some minimal movement of the camera body. i used my tripod for the shot, but maybe i hit the release button a bit too hard on the third shot. The top left – at least on screen – displays a marked moirée pattern barely discernible in the second. As to the three b/w shots posted above by Stanislav: the one with the Leica filter I thought the best (and that was a 'blind' response as I had not checked back over your original sequencing). Link to post Share on other sites More sharing options...
jaapv Posted June 21, 2009 Share #19 Posted June 21, 2009 I am wondering which RAW converter was used, That makes a lot of difference. ACR has a kind of "one size fits all" profile for the M8, whereas C1 lets you choose between M8 generic and M8 Generic UV/IR. That makes quite a lot of difference. It will also allow you to use many third party (or your own) profiles, including Jamie Roberts' IR contamination reducing profile. And it will show finer detail. In that sense this test makes little sense, because the files should be developed correctly. Link to post Share on other sites More sharing options...
vla Posted June 21, 2009 Author Share #20 Posted June 21, 2009 jaapv, as said before, i've used aperture for raw conversion and silver efex for b&w white treatment. what do you mean by saying that the files should have been developed correctly? any suggestions for improved conversion in aperture would be highly welcome ... markus Link to post Share on other sites More sharing options...
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