dspeltz Posted July 20, 2013 Share #1 Posted July 20, 2013 Advertisement (gone after registration) This is curious. I have two Monochrom bodies and today shot through an IR filter (93) using exactly the same settings, lens, etc etc, just changing bodies. Both were processed in Lightroom syncing the settings. The difference between the results was revealing. Although it is not apparent shooting normally, the IR filter shows what may well be a serious problem on one of the bodies. Yet I cannot see a difference when the filter is not used. I repeated the test several times in different scenes and got the same thing. I sent the two images to Leica to see if they can explain what is happening. Anyone seen this before? 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/209238-ir-filter-reveals-an-issue/?do=findComment&comment=2378915'>More sharing options...
Advertisement Posted July 20, 2013 Posted July 20, 2013 Hi dspeltz, Take a look here IR filter reveals an issue. I'm sure you'll find what you were looking for!
doolittle Posted July 20, 2013 Share #2 Posted July 20, 2013 Point of view is slightly different in each of the pictures, so comparison is impossible. You would need to repeat the experiment on a tripod. Link to post Share on other sites More sharing options...
dspeltz Posted July 20, 2013 Author Share #3 Posted July 20, 2013 I actually used a tripod for most of the tests. Same result. The point of view difference is minimal and not the issue. But thanks for looking. If Solms wanted me to re-do it for them I would, of course, but as I said, no matter what way I turn, or where, tripod or no, same thing, same location. Link to post Share on other sites More sharing options...
doolittle Posted July 21, 2013 Share #4 Posted July 21, 2013 With IR a small change in camera position could have a major impact on IR reaching the sensor, which wouldn't be obvious to the human eye. Plus you want to rule out reflection from the IR filter having an effect, so camera really needs to be in exactly the same position and angle. Link to post Share on other sites More sharing options...
msap7222 Posted July 21, 2013 Share #5 Posted July 21, 2013 Obvious I know ... But Is it possible ISO on both bodies mis-matched? Definitely looks like an exposure issue. Love the detail in image 1. How much of that effect is direct out of camera and how much is in post? Sent from my iPad using Tapatalk HD Link to post Share on other sites More sharing options...
jffielde Posted July 21, 2013 Share #6 Posted July 21, 2013 If the OP could post samples from each different location tested with the same phenomenon in the same location, it hard for to me to imagine that is a slight angle difference. Am I reading the OP right to say he could do that? Link to post Share on other sites More sharing options...
enboe Posted July 21, 2013 Share #7 Posted July 21, 2013 Advertisement (gone after registration) I'll throw a couple of forensically-derived guesses into the mix: 1) Examining the shadows on the birdbath and from the tree line, it appears that the sun was high and to the right. The second photo is canted right by several degrees, enough to allow some spillage, perhaps? 2) Were the two bodies at the same physical temperature, or was one sun-baking while you were shooting with the first? The easy way to resolve the issue will be by sending the body you do not prefer to Leica for assessment and repair, but some more, tightly-controlled experiments might provide entertainment. It's up to you and your curiosity. Link to post Share on other sites More sharing options...
kdriceman Posted July 21, 2013 Share #8 Posted July 21, 2013 Long exposures I presume? My M9 as well as my MM will exhibit light leak on long exposures when the camera is in direct sunlight - this shows up as overexposure in the lower right part of frame (others on the LUF have experienced this also). This corresponds to the upper left part of the lens/body interface. I use a thick rubber band placed around the lens/body to ensure a better light seal on long daylight exposures. You might try this to see if that makes a difference. Link to post Share on other sites More sharing options...
dspeltz Posted July 21, 2013 Author Share #9 Posted July 21, 2013 The light leak idea makes sense. OK, to satisfy all of us, I cam going to redo these with and without IR filter, on a tripod. And with the wrap around the body as well. It will take me a couple days to do this. Oh, and the post processing will be none. I will do jpeg versions and upload as taken rather than raw. Any other ideas before I put this all together. Body light leak ..... makes sense. We will find out.... Link to post Share on other sites More sharing options...
farnz Posted July 21, 2013 Share #10 Posted July 21, 2013 I agree that this looks like a light leak. I suspect that the culprit may be where the lens's six-bit coding meets the body. If the lens is on a LTM to M adaptor or one of the third party replacement flanges that have the coding pits then I'd advise looking at that owing to the potential for non-flatness. It should be straightforward to check by applying tape at that point (but it needs to be impenetrable to IR of course). Pete. Link to post Share on other sites More sharing options...
vanhulsenbeek Posted July 21, 2013 Share #11 Posted July 21, 2013 Simple: reflection of the lens-lettering on the filter. Happened on the WATE with me:.blacked out the lettering. Long exposure is the give--away. Sales value reduced but won't sell the lens anyway:) Link to post Share on other sites More sharing options...
dspeltz Posted July 24, 2013 Author Share #12 Posted July 24, 2013 It appears the body has a light leak. Here are three images: One with no filter, one with IR filter, and one with same IR filter and the body covered in a dark cloth. It calls for a trip to Leica. 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/209238-ir-filter-reveals-an-issue/?do=findComment&comment=2381415'>More sharing options...
Your Old Dog Posted July 25, 2013 Share #13 Posted July 25, 2013 Do you shoot with lens shades? Link to post Share on other sites More sharing options...
kdriceman Posted July 25, 2013 Share #14 Posted July 25, 2013 What are the exposure times? Link to post Share on other sites More sharing options...
250swb Posted July 25, 2013 Share #15 Posted July 25, 2013 I'm sure there will be a light seal where the focusing arm comes into the shutter chamber. But you could reduce the variables by making three or four equally long exposures and blanking off various potential leak points one by one to see which may be the culprit. The leak seems to be coming from above, so first the viewfinder window, then the eyepiece, etc. But don't forget the lens mounting flange as has already been suggested. Some lenses like early Zeiss ZM have been known to have screws on the lens flange that coincide with a screw or coding sensor on the Leica mounting ring, and this can cause a leak over the extended time of a long exposure, as can LTM adapters that have the usual cut outs around the circumference of the adapter. If this is the case it isn't the body at fault so it might save a trip back to Solms. That it is OK on one body and not the other may be that the bayonet seal is just a fraction tighter on one. The problem then might be it's the good tight one that is out of adjustment, which creates a conundrum over what should be 'repaired'. Steve Link to post Share on other sites More sharing options...
dspeltz Posted July 25, 2013 Author Share #16 Posted July 25, 2013 I'm sure there will be a light seal where the focusing arm comes into the shutter chamber. But you could reduce the variables by making three or four equally long exposures and blanking off various potential leak points one by one to see which may be the culprit. The leak seems to be coming from above, so first the viewfinder window, then the eyepiece, etc. But don't forget the lens mounting flange as has already been suggested. Some lenses like early Zeiss ZM have been known to have screws on the lens flange that coincide with a screw or coding sensor on the Leica mounting ring, and this can cause a leak over the extended time of a long exposure, as can LTM adapters that have the usual cut outs around the circumference of the adapter. If this is the case it isn't the body at fault so it might save a trip back to Solms. That it is OK on one body and not the other may be that the bayonet seal is just a fraction tighter on one. The problem then might be it's the good tight one that is out of adjustment, which creates a conundrum over what should be 'repaired'. Steve It must be in the body as I have two bodies, and this is the bad one. The lens is the new Summicron 50mm AA and it shows up in a Summicron 35mm as well. It could be the flange, but whatever, it needs a look by Leica. I notice a small amount of IR flare in the other body, but not much. I assume that the IR leak decreases contrast in the normal non-IR picture. Anyhow, it is time for a trip to New Jersey or Germany. Thanks all for the advice. When it returns, I will let you know how it went. Now I will check my other Ms for light leaks using the magic IR filter. Link to post Share on other sites More sharing options...
dspeltz Posted July 25, 2013 Author Share #17 Posted July 25, 2013 Do you shoot with lens shades? Yes Link to post Share on other sites More sharing options...
dspeltz Posted July 25, 2013 Author Share #18 Posted July 25, 2013 What are the exposure times? 8 seconds on these. I have opened it up to f/2.8 with 2 seconds. Same issue. Link to post Share on other sites More sharing options...
kdriceman Posted July 25, 2013 Share #19 Posted July 25, 2013 8 seconds on these. I have opened it up to f/2.8 with 2 seconds. Same issue. It is worse than what I experience with even longer exposures with my flange leak. I'm interested to see what Leica says about it. Link to post Share on other sites More sharing options...
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