stephengilbert Posted July 24, 2007 Share #1 Posted July 24, 2007 Advertisement (gone after registration) Did you know this? According to the Leica instructions for use of the WATE, "The LEICA UV/IR filter combined with lenses from 16-28mm focal length should not be used for shots under fluorescent light (fluorescent tubes). As fluorescent tubes emit light with a very uneven spectrum, this could result in incorrect color correction." Quote Link to post Share on other sites More sharing options...
Advertisement Posted July 24, 2007 Posted July 24, 2007 Hi stephengilbert, Take a look here UV/IR Filters in Fluorescent Light. I'm sure you'll find what you were looking for!
fotografr Posted July 24, 2007 Share #2 Posted July 24, 2007 Did you know this? According to the Leica instructions for use of the WATE, "The LEICA UV/IR filter combined with lenses from 16-28mm focal length should not be used for shots under fluorescent light (fluorescent tubes). As fluorescent tubes emit light with a very uneven spectrum, this could result in incorrect color correction." This makes no sense to me. I've used my 24 with the UV/IR filter quite a number of times under fluorescent lighting and have gotten very good results. The option, it seems, would be to not use the filter and have synthetic blacks rendered magenta. Quote Link to post Share on other sites More sharing options...
jaapv Posted July 24, 2007 Share #3 Posted July 24, 2007 Brent is right - if light is so uneven that it won't balance with filters on, it won't balance with filters off either. Quote Link to post Share on other sites More sharing options...
Shootist Posted July 24, 2007 Share #4 Posted July 24, 2007 Did you know this? According to the Leica instructions for use of the WATE, "The LEICA UV/IR filter combined with lenses from 16-28mm focal length should not be used for shots under fluorescent light (fluorescent tubes). As fluorescent tubes emit light with a very uneven spectrum, this could result in incorrect color correction." And where exactly did you read this? Quote Link to post Share on other sites More sharing options...
stephengilbert Posted July 25, 2007 Author Share #5 Posted July 25, 2007 "And where exactly did you read this?" On the Leica Download page (http://www.leica-camera.us/service/downloads/rangefinder_cameras/m8/), the PDF for "Using M + Tri-Elmar M etc" download. Quote Link to post Share on other sites More sharing options...
Jack_Flesher Posted July 25, 2007 Share #6 Posted July 25, 2007 Brent is right - if light is so uneven that it won't balance with filters on, it won't balance with filters off either. Actually guys, this is NOT correct. Has to do with the source light being full spectrum and fluorescents aint full spectrum, lots of spikes. The way the IR cut filters work, some wavelengths can bleed through more than others and this could (not always) create color balance issues under certain types of lighting... Quote Link to post Share on other sites More sharing options...
erl Posted July 25, 2007 Share #7 Posted July 25, 2007 Advertisement (gone after registration) Jack, With respect, I think Jaap is right, or at very least, not entirely wrong. I'm definitely no expert but I have a lot of experience which tells me that under fluorescent lights, which vary widely, The IR cut filter (on the M8) has always improved what is basically a bad lighting scenario regardless of synthetic black or otherwise. Either way, accurate colour balance will not happen, but I believe, based only on experience, that the IR cut filter is way better than none. This I find true regardless of fluoro or tungsten lighting. YMMV, but I can't see how. Quote Link to post Share on other sites More sharing options...
ho_co Posted July 25, 2007 Share #8 Posted July 25, 2007 I'll go with Jack on this one: The pdf refers specifically to the M8 and firmware. So what they're saying here is simply that they won't guarantee a better quality image with the filters under fluorescents. In other words, the firmware isn't likely to give better results in that case with the filters than without. A better wording from them would probably be "Pay your money and take your choice." --HC Quote Link to post Share on other sites More sharing options...
erl Posted July 25, 2007 Share #9 Posted July 25, 2007 Howard, You are certainly right when you refer to "pay your money & take your choice". That's exactly what most of us have done! My point is that there is no way of knowing about IR sensitive fabrics or substances before shooting, so IR cut filter is the only sensible way to go IMHO. Regardless of that, fluor lights are going to muck up your colour balance anyway, for exactly the reason Jack explained. ie. intermittent specrtum emission. One thing I think we will all agree on, it ain't boring figuring one's way round all this. Quote Link to post Share on other sites More sharing options...
ho_co Posted July 25, 2007 Share #10 Posted July 25, 2007 Erl-- I agree completely. I originally even had a paragraph in the post that I later deleted pointing out that you need the filters to fix the IR problems, even though the filters introduce their own problems. Actually, I only posted a response because I'm avoiding doing some Things That Must Be Done. As you say, there's no way to know ahead of time whether the picture would be better with or without filters; you can argue it both ways. And indeed, the Leica instructions say using the filters "_could_ result in incorrect color correction." Or maybe not... It's funny that we've all paid our money, and now every day there's a new choice to be made. Maybe when the firmware gets a little more settled, Leica should publish a flowchart on the decision sequence for using the camera-- shooting monochrome? do X otherwise do Y lens coded? do X otherwise do Y lens = WATE? do X otherwise do Y etc. It's good, though, that we're devoting time to deciding whether to use filters in fluorescent lighting, instead of debating the merits of going back to our dSLRs! --HC Quote Link to post Share on other sites More sharing options...
sandymc Posted July 25, 2007 Share #11 Posted July 25, 2007 The firmware's correction is a "one size fits all" solution that works fairly well for average lighting situations - basically daylight and incad lamps. But not for anything more exotic, and many fluorescents qualify as more exotic. But the key distinction here is that without an IR filter, you can and will get color casts that cannot be effectively corrected in post processing, because the M8 has "translated" invisible light into visible light. If you use an IR filter, you may still get color casts/vignetting, but those color casts/vignetting can usually be corrected quite well in post processing, because all the light that the M8 is responding to is at least in the visible spectrum. Specifically, as regards post processing, if you need better correction, you can use CornerFix, and generate a profile specifically for the light source that you are dealing with. That will give far better correction than the firmware, but of course the trade-off is that its lots more work that the firmware approach.......... Regards, Sandy Quote Link to post Share on other sites More sharing options...
Jamie Roberts Posted July 25, 2007 Share #12 Posted July 25, 2007 Am I the only one to notice a relatively recent big difference between the new mini-fluourescents (the energy efficient things), which seem very stable and actually don't need a filter because they emit not much IR anyway---and the old ones with the transformers, where getting a white balance is near impossible with or without filter (because the temperature quality of the light is changing per cycle?)... Am I dreaming, or is this the case? Back with film, I just filtered and shot on...Now I see photo floods being made with high-quality fluourescents.. so something is different! Quote Link to post Share on other sites More sharing options...
Jack_Flesher Posted July 25, 2007 Share #13 Posted July 25, 2007 Am I the only one to notice a relatively recent big difference between the new mini-fluourescents (the energy efficient things), which seem very stable and actually don't need a filter because they emit not much IR anyway---and the old ones with the transformers, where getting a white balance is near impossible with or without filter (because the temperature quality of the light is changing per cycle?)... Am I dreaming, or is this the case? Back with film, I just filtered and shot on...Now I see photo floods being made with high-quality fluourescents.. so something is different! Hi Jamie: Nope, you're not dreaming! I have noticed the same behavior. WIth cheap fluorescents, I get yellow, green or sometimes even brownish-magenta casts -- and on occasion what looks normal. WIth quality fluorescents, I almost always get clean results using AWB on my Canons. (FWIW to M8 shooters, Canon's AWB is FAR superior to Leica's -- By way of comparison M8 WB basically just sucks... Like comparing a model T technology to that in a Z-07 Corvette... Maybe the next firmware will have something for us on this front.) Cheers, Quote Link to post Share on other sites More sharing options...
Guest tummydoc Posted July 25, 2007 Share #14 Posted July 25, 2007 The firmware's correction is a "one size fits all" solution Specifically, as regards post processing, if you need better correction, you can use CornerFix, and generate a profile specifically for the light source that you are dealing with. That will give far better correction than the firmware, but of course the trade-off is that its lots more work that the firmware approach.......... Regards, Sandy Exactly what I found, not only with different light sources but different apertures too. Other than the one lens I bought already coded, I will not waste my money coding any others. Yes CornerFix (or in my case, PanoTools) is an added step but one that I found necessary more than half the time in addition to the firmware with my coded lens. Quote Link to post Share on other sites More sharing options...
jaapv Posted July 25, 2007 Share #15 Posted July 25, 2007 Actually the problem here is not the colour balance - that is a simple matter of sliders in raw conversion, the trouble is a discontinuous spectrum of visible light. Adding IR by removing the filter is not going to help you on that. In fact, it is liable to add to your troubles. Quote Link to post Share on other sites More sharing options...
gravastar Posted July 25, 2007 Share #16 Posted July 25, 2007 I've found that it's necessary to use the filters with fluorescent lights, at least with the small energy efficient bulbs. Without the filter not only is there the unpredictable magenta colour of some materials but an overall pink cast which doesn't always seem to be uniformly eliminated with custom white balance. With filters I find custom white balance always works well with those bulbs. Bob. Quote Link to post Share on other sites More sharing options...
pklein Posted July 25, 2007 Share #17 Posted July 25, 2007 When the color temperature starts to resemble a comic opera plot, I find a reason why B&W would be far superior, aesthetically, for the subject. Pro shooters may not have this luxury, of course. In that case, shoot close-in with an extreme wide angle, and argue how the wonky colors contribute to the photograph's "edginess" and appeal to the sought-after younger demographic. --Peter Quote Link to post Share on other sites More sharing options...
ho_co Posted July 25, 2007 Share #18 Posted July 25, 2007 The firmware's correction is a "one size fits all" solution that works fairly well for average lighting situations - basically daylight and incad lamps. Didn't I read somewhere (LFI? Reid Reviews?), though, that the firmware has a stronger correction in general use? That is, when "lens detection on + IR" is set, the firmware applies a lesser correction than generally. Certainly, one's own experience trumps all our logic! Sandy, you're not yet offering CornerFix for Mac, am I right? --HC Quote Link to post Share on other sites More sharing options...
luigi bertolotti Posted July 25, 2007 Share #19 Posted July 25, 2007 I add myself to people who affirm that Leica statement is rather misleading and undetailed... better they wouldn't have written it, for fluorescent lights can have very broad variations in spectrum one from each other... a general advice has little value.. and I think that instances in which th UVIR deteriorates the color balance are very rare... the truth is that under that kind of light ... BW is better. Quote Link to post Share on other sites More sharing options...
sandymc Posted July 26, 2007 Share #20 Posted July 26, 2007 Didn't I read somewhere (LFI? Reid Reviews?), though, that the firmware has a stronger correction in general use? That is, when "lens detection on + IR" is set, the firmware applies a lesser correction than generally. Certainly, one's own experience trumps all our logic! Sandy, you're not yet offering CornerFix for Mac, am I right? --HC Broadly, the firmware correction of luminance vignetting is stronger when "lens detection on + IR" is off, and less strong when it's on. However, the chroma (angle dependent color cast) correction is of course far stronger when "lens detection on + IR" is on. A Mac version of CornerFix is in progress. No dates....... Sandy Quote Link to post Share on other sites More sharing options...
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