MarkP Posted September 17, 2013 Share #41 Posted September 17, 2013 (edited) Advertisement (gone after registration) Both these types of flare could also be caused by filters in front of your lens? Is it an nd or ir? Remove them & reshoot. They can cause internal reflections. Probably from the shutter box or lens throat combined with a light source, however slight, just out of your frame, heightened by the long exposures. There's nothing wrong with your camera. Although I initially thought this was due to internal reflections between the ND filter and sensor this is NOT the case - haven't you read how we have just tested this My testing in post #22 above was done WITHOUT filters and with a black cloth covering the end of the lens with the cap in place and the aperture shut down to 16 just to minimise any potential light leak, and the torch directly against the lens flange. Edited September 17, 2013 by MarkP Quote Link to post Share on other sites More sharing options...
Advertisement Posted September 17, 2013 Posted September 17, 2013 Hi MarkP, Take a look here Monochrom Long Exposure Issue. I'm sure you'll find what you were looking for!
kdriceman Posted September 18, 2013 Share #42 Posted September 18, 2013 I would be interested to know if the M240 has this issue. Although it is weather sealed I have been under the impression that there is no additional sealing on the flange. And, of course, the lenses are the same, so unless the flange has been modified vs the MM and M9 it would seem likely to have the same issue. But, I haven't heard of this issue arising on the M240. Quote Link to post Share on other sites More sharing options...
MarkP Posted September 18, 2013 Share #43 Posted September 18, 2013 I would be interested to know if the M240 has this issue. Although it is weather sealed I have been under the impression that there is no additional sealing on the flange. And, of course, the lenses are the same, so unless the flange has been modified vs the MM and M9 it would seem likely to have the same issue. But, I haven't heard of this issue arising on the M240. Read my post, #22. Yes I can reproduce the finding on the M240 but to a much lesser extent. However this was using a very powerful directed light source for an extended period to the same area on the lens mount(but none to other quadrants) so it may not be relevant in real life situations especially as the M240 does not allow such long exposures as does the M9/Monochrom. 1 Quote Link to post Share on other sites More sharing options...
kdriceman Posted September 18, 2013 Share #44 Posted September 18, 2013 Read my post, #22. Yes I can reproduce the finding on the M240 but to a much lesser extent. However this was using a very powerful directed light source for an extended period to the same area on the lens mount(but none to other quadrants) so it may not be relevant in real life situations especially as the M240 does not allow such long exposures as does the M9/Monochrom. What is the maximum exposure time allowed on M240? Quote Link to post Share on other sites More sharing options...
fotografr Posted September 27, 2013 Author Share #45 Posted September 27, 2013 What is the maximum exposure time allowed on M240? As long as your thumb can hold down the cable release button. Quote Link to post Share on other sites More sharing options...
fotografr Posted September 27, 2013 Author Share #46 Posted September 27, 2013 I think we can agree here that the problem is light leaking in around the flange where the lens mounts to the camera body. My tests confirmed that was the problem with my light leaks. The one remaining question, which I have not heard back from the Leica technicians about, is whether this is repairable. If there is a fix, I'd send my camera in and have it done. But I don't want to send the camera in for lengthy testing if this is a design flaw that can't be dealt with. I was promised an answer after the technicians in New Jersey finish their intensive training on the M 240, and when I hear from someone I'll pass the news along. Quote Link to post Share on other sites More sharing options...
kdriceman Posted September 27, 2013 Share #47 Posted September 27, 2013 Advertisement (gone after registration) As long as your thumb can hold down the cable release button. I think this may not be true. When I first asked the question I did not own a M240, but I have since received one. In B mode I could not get an exposure longer than 60s without the shutter closing automatically and, in fact, then checked the technical specifications sheet which states that 60s is the longest exposure - and, of course, that is only possible in Bulb. Quote Link to post Share on other sites More sharing options...
ymc226 Posted September 28, 2013 Share #48 Posted September 28, 2013 Thanks kdriceman for working out a fix. I thought my Lee Big Stopper or filter holder was defective. The only thing I can't explain is why the problem isn't more consistent. I'll guess it occurs in about a third of sequential long exposure shots done back to back. Quote Link to post Share on other sites More sharing options...
trastevere Posted November 6, 2013 Share #49 Posted November 6, 2013 Is there any more news on this problem? Quote Link to post Share on other sites More sharing options...
250swb Posted November 6, 2013 Share #50 Posted November 6, 2013 Is there any more news on this problem? What more news can there be? The solution is simple, use something to stop the light entering around the top of the lens flange if the exposures get above 20 seconds or if there is a close bright light source. Most photographers carry enough things in their camera bag to achieve this even if they don't carry a specific solution. You can use a lens cleaning cloth wrapped around or draped over, I use a specific solution, a stretchy neoprene gaiter with Velcro ends, designed to protect mountain bike headsets, it can be fitted and removed in a second. Steve Quote Link to post Share on other sites More sharing options...
250swb Posted November 6, 2013 Share #51 Posted November 6, 2013 Thanks kdriceman for working out a fix. I thought my Lee Big Stopper or filter holder was defective. The only thing I can't explain is why the problem isn't more consistent. I'll guess it occurs in about a third of sequential long exposure shots done back to back. I agree it is inconsistent, one shot OK, the next with the flare, but the light hasn't changed enough for me to notice. I had considered it may be an accumulative effect caused by the size of the image circle, the 'excess' reflecting off something inside the camera for the length of the exposure, and perhaps equally lens dependent as some lenses are shinier on their inner faces than others. What I don't understand is why there is no gradual trace of the 'flare' increasing as you increase exposure, it is either on or off. Another thought regarding light leaking in is that it would be doing it where the focusing cam is, so does focus affect the leak, either the position of the cam or the position of the rear barrel? Steve Quote Link to post Share on other sites More sharing options...
MarkP Posted November 6, 2013 Share #52 Posted November 6, 2013 I had considered it may be an accumulative effect caused by the size of the image circle, the 'excess' reflecting off something inside the camera for the length of the exposure, and perhaps equally lens dependent as some lenses are shinier on their inner faces than others. No, it's definately a light leak at about 2-3 o'clock at the lens mount, obviously with further internal reflections. When I discussed this recently with someone from Leica Australia he was aware of it and had actually described it before in the RFF. I wonder whether the leak occurs near the screw hole in the mount ring, perhaps made worse if there is a similar screw hole in the lens mount. What I don't understand is why there is no gradual trace of the 'flare' increasing as you increase exposure, it is either on or off.Steve With different ambient light and exposure times, or testing with a strong torch, the intensity, duration, and angle of the light source affects the degree of this flare in the image. It's just that in normal daylight and exposure times the amount of light entering does not vary much. Test it yourself with a high intensity focussed light source as I did. It takes only a few minutes to reproduce the problem. Another thought regarding light leaking in is that it would be doing it where the focusing cam is, so does focus affect the leak, either the position of the cam or the position of the rear barrel? No. Quote Link to post Share on other sites More sharing options...
250swb Posted November 6, 2013 Share #53 Posted November 6, 2013 (edited) No. Except the consistent theme is a curve shape to the flare patch, which matches the shape of the cut out in the lens flange for the cam to clear. It also means this is the thinnest part of the mount with the least amount of light baffling in exactly the same place as the light is leaking in. As the rear barrel of the lens moves in an out to operate the cam when focusing it covers the cut out in varying amounts, at infinity it fills the space or blanks off the cam cut out, near focusing the space is fully open and unbaffled. I don't really feel I need to re-produce the problem because I have seen it often enough in real life. But if it appears at 30 seconds at f/16 and disappears without trace with a 25 seconds exposure this is what I mean about it being either 'on' or 'off'. Steve Edited November 6, 2013 by 250swb 1 Quote Link to post Share on other sites More sharing options...
Guest NEIL-D-WILLIAMS Posted November 9, 2013 Share #54 Posted November 9, 2013 OK well I have been doing my own testing and this is what I found. All shots with a 30 sec exposure With the 21mm Lux I got no light getting past the mount with both the lens supported or not supported With the Noctilux I got a bunch of light getting onto the sensor via the lens mount with the lens not supported (like you would if you had the camera mounted on a tripod) but with the lens supported i.e sat on the bed I got no light on the sensor…………..the M mount doesn't like the fat bastard Noctilux Not bad for a 7K camera:mad: Picture below 1/. 21mm supported 2/. 21mm not supported 3/. Noctilux not supported 4/. Noctilux supported 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! Quote 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/212964-monochrom-long-exposure-issue/?do=findComment&comment=2461197'>More sharing options...
DirkR440 Posted August 30, 2014 Share #55 Posted August 30, 2014 I discovered the same issue recently. I took two pictures with long exposure (240 sec) at sunset time. One with a hair band attached and one without. It works, but it is still a bit frustrating. 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! 1 Quote 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/212964-monochrom-long-exposure-issue/?do=findComment&comment=2660466'>More sharing options...
MarkP Posted August 30, 2014 Share #56 Posted August 30, 2014 OK well I have been doing my own testing and this is what I found. All shots with a 30 sec exposureWith the 21mm Lux I got no light getting past the mount with both the lens supported or not supported With the Noctilux I got a bunch of light getting onto the sensor via the lens mount with the lens not supported (like you would if you had the camera mounted on a tripod) but with the lens supported i.e sat on the bed I got no light on the sensor…………..the M mount doesn't like the fat bastard Noctilux Not bad for a 7K camera:mad: Picture below 1/. 21mm supported 2/. 21mm not supported 3/. Noctilux not supported 4/. Noctilux supported Why don't you send the lens and these photos to Leica. We know it's a problem but perhaps there is a subtle abnormality with the Noctilux lens mount. However, I can demonstrate light leaks with other much lighter lenses. Quote Link to post Share on other sites More sharing options...
Guest NEIL-D-WILLIAMS Posted August 30, 2014 Share #57 Posted August 30, 2014 Why don't you send the lens and these photos to Leica. We know it's a problem but perhaps there is a subtle abnormality with the Noctilux lens mount. However, I can demonstrate light leaks with other much lighter lenses. No need Marc The scrunches are a permanent fixture on my M when the Noctilux is attached and depending on whether I have the red case or the blue case depends what color bow I use with the scrunches:D:D 1 Quote Link to post Share on other sites More sharing options...
250swb Posted August 31, 2014 Share #58 Posted August 31, 2014 If light gets in it also depends on the lens design and focus of the lens. Because light creeps in around the cutout for the focusing cam in the lens flange the position and design of the rear barrel section of the lens can either fill the gap, or open it up at certain focus points. So while the weight of the lens may make a difference focusing close or to infinity may also make a difference. And some lenses have a fatter rear end than others, and this also helps act as a baffle. But ever since this thread started I've had a hair band in my camera bag and it has never let me down, and because it is only used for long exposures anyway the extra second or two fitting it makes no difference at all to the job. Steve Quote Link to post Share on other sites More sharing options...
wilfredo Posted September 1, 2014 Share #59 Posted September 1, 2014 This reminds me of the UVIR filter issue with the M8, and finally Leica supplied us with free filters. I think Leica will now need to manufacture a nice little black hair band with a Red Dot for all MM and M9 camera users. I'm glad I read about this here before it became an issue. I will alert my wife, I'm sure she won't mind me using one of her hair bands on my $8000. camera. I better put one in my camera bag. LOL!!! Quote Link to post Share on other sites More sharing options...
MarkP Posted September 1, 2014 Share #60 Posted September 1, 2014 My daughter has these fantastic black scrunchies that are just perfect - I stole two but got caught 1 Quote Link to post Share on other sites More sharing options...
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