Archived posting to the Leica Users Group, 2009/03/26
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]On Mar 25, 2009, at 11:57 PM, Peter Klein wrote: > Sue: I can corroborate pretty much everything Henning said. IR cut > filters are necessary for best quality, even in black and white. > Without them, you get a slight smearing effect, and less contrast. > Some people may like this effect--I prefer otherwise. > > In color, you get unpredictable color shifts in many things--flesh > tones, green plants, and clothing of all kinds. Sometimes it > doesn't matter much, other times it does. The Jamie Roberts > profiles available for Capture One help with these issues, but they > do not eliminate them. And since you're dealing with the effect of > light you can't see, you never know when you're going to be lucky or > not. > > Check out this comparison under tungsten light, which is rich in IR: > http://users.2alpha.com/~pklein/temp/IRNofiltVsFilt.jpg > > The good news is that lenses longer than 35mm don't really need to > be coded. And even the 35mm lens can live without coding much of > the time--there's a little cyan shift in the corners, but it's often > not noticeable unless you look for it. So the priority should be > to get the filters for your most-used lenses first. Get a Milich > adapter for the 21 VC and code that. And then add additional > filters as you can. > > FWIW, I use IR cut filters on all my lenses. My 28 and 35mm lenses > are coded, either permanently, or using the M-Coder and a Sharpie > marking pen. A 50 Summicron I have holds a Sharpie mark well, so I > hand-coded that just to have the focal length in the pictures' EXIF > data. I have not coded my other 50s or my 90s, and there's no > problem. fwiw Peter is my good friend, a scientist, and I respect him. Me, I personaly stay away from direct lens/filter testing etc, but I respect people like Peter who do this well, explain how, and report the results to the group. While all of the above is likely true, if one is to do testing, more than two observations must be compared to draw conclusions... I'd like to see each done at least half a half dozen times... then I would believe the differences shown are not due to sample error/variation/movement etc.... However, my obsevation is that one must take photos, have fun, and remember that small differences, of the sort that may ! exist, plus and minus a filter, won't convert a great image into a so-so one, and I believe the reverse is also likely to be true... Steve > > --Peter > > At 09:26 PM 3/25/2009 -0700, Sue asked, and Henning answered: >> >I'm sure this has been discussed ad nauseum before, but I never paid >> >much attention because it wasn't relevant to me at the time. I >> >currently have a 50mm Summicron, 35mm Summilux, a Nocti, a 90mm >> >Summicron, and a CV21mm. If I buy a used M8, will I realistically >> >be able to use my lenses without coding or IR filters? I'm thinking >> >about taking the plunge but the catch-22 is that my bank account >> >will be so broken I wouldn't be able to send my lenses in for coding >> >for awhile, and I don't know firsthand how severe the IR problem is >> >going to be. I could try a coding kit or the "do it yourself" method >> >and I know those are my only options for the CV but I don't know how >> >worthwhile those options are. If anyone is happily shooting uncoded >> >and unfiltered I'd like to hear from you. Off list response is fine >> >with me - apologies in advance for boring 99% of the list. >> > >> >Sue >> >> >> >> Hi Sue, >> >> I'm sure you'll hear from a lot of people that IR cut filters aren't >> really necessary. >> >> Unfortunately, for the best quality they are. Even outdoors on sunny >> days they are as IR reflection off leaves is quite intense and makes >> the colours murky. The only time that the IR filters are not >> necessary is when there is no IR radiation, as on very overcast days >> or under bad flourescents. The 'synthetic clothing' thing is a bit of >> a red herring, pun unintended. You'll find black cotton and black >> wool, black cars and black furniture that all gets various funky >> magenta hues. It can be subdued with clever Photoshop work, but not >> eradicated, and it doesn't solve the following problem. >> >> IR also causes some degradation of sharpness, as the IR doesn't focus >> at the same plane as the visible light. This will generally be more >> noticeable with older lens designs. >> >> So - best plan on getting IR filters at some time. I assume the 35 >> Summilux is the non-ASPH that uses the series 7 filters? If so, and >> if your 90 Summicron is an older one that uses 48mm filters, or >> somewhat later that uses 49mm filters, you're in luck, as the 48 or >> 49mm filters can be reversed in the hood of the Summilux where the >> series 7 filters reside. Then get a step down ring from 48 (or 49) to >> 39 and you can use the filter on the 50 Summicron and the 21CV as >> well. Switching lenses (and filters) can be a pain, though. >> >> The 21CV should be coded, as should all lenses below 35mm. Best is to >> either get an adapter ring (Leica thread to M bayonet) from John >> Milich which has the pits in the correct locations, or buy a 'type 2' >> Cosina adapter from cameraquest and send it to John Milich to get the >> pits engraved. Then just paint in the dots to code the lens as a 21 >> Elmarit. Works great; no cyan corners and even illumination. >> >> Your other lenses don't need to get coded as the cyan corners are >> barely noticeable (35mm lens) to non-existent (50 and 90mm). >> >> That leaves the Nocti. You can try to live without a filter for a >> while, and you can compare the results from the Summicron to see if >> it's worth it. I eventually did get a filter for it. >> >> So, budget about $200 for filter, adapter rings and John Milich, and >> you should be set to start. >> >> A short term solution for the 21 is the Cornerfix program, but it's a >> bit of a pain and the quality can drop a bit erratically. >> >> If you have any further questions, fell free to ask. >> >> Regards, >> >> Henning > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information