Guest redge Posted January 30, 2014 Share #21 Posted January 30, 2014 Advertisement (gone after registration) Star trails can appear in any nighttime photo with visible sky. You can't turn off dark frame subtraction on the M, so exposure stacking gives you a series of 1 minute exposures with 1 minute gaps between them, making your star trails into dotted lines. Yuck. The star trail in the 13th photo in Wilson's link looks pretty good (100 shots, each 30 sec): Long Exposure Photography: 15 Stunning Examples - Digital Photography School But the procedure is kinda complicated: Racing Stars | Flickr - Photo Sharing! Link to post Share on other sites More sharing options...
Advertisement Posted January 30, 2014 Posted January 30, 2014 Hi Guest redge, Take a look here Long exposures on the M240. I'm sure you'll find what you were looking for!
earleygallery Posted January 30, 2014 Share #22 Posted January 30, 2014 Peter, I don’t see how that would work. If you have a number of dark exposures which are all under-exposed, how does adding them together in merge, improve the situation? Sure if you want to get movement, like a stream of car lights, I can see how it would work but not for very dark conditions. Wilson Wilson, you mentioned star scenes in your OP, and in fact one of the images you linked to is a starscape made with multiple images. It's a potential solution. Maybe not if you're trying to shoot a black cat in a coal mine though! (I expect it would have to be a dead cat too, to avoid blur) Film remains the better option for some applications. Link to post Share on other sites More sharing options...
Guest redge Posted January 30, 2014 Share #23 Posted January 30, 2014 Wilson, you mentioned star scenes in your OP, and in fact one of the images you linked to is a starscape made with multiple images. It's a potential solution. Maybe not if you're trying to shoot a black cat in a coal mine though! (I expect it would have to be a dead cat too, to avoid blur) Film remains the better option for some applications. Looks like we noticed the same photo at the same time. Have a look at the guy's process (linked in my post). It's an educational read. If you click on the photos in Wilson's link, you're taken to the photographer's page. In several cases there's discussion about how the photo was done. Link to post Share on other sites More sharing options...
Jeff S Posted January 30, 2014 Share #24 Posted January 30, 2014 I would think there's no overheating or damage issue - after all, the camera can record 30mins of video and AFAIK there is no limit on the live view time. Both video recording and live view are more likely to generate heat due to the continuos sensor read and reset cycles than one long exposure (essentially most of the power consumption in CMOS circuits is during state transitions). Michael explains differences between video and long exposure here. The rest of the thread covers other issues discussed here as well. Jeff Link to post Share on other sites More sharing options...
mirekti Posted January 30, 2014 Share #25 Posted January 30, 2014 Does this mean Leica wanted to keep the image quality above some threshold, and decided exposures longer than 60 seconds would deteriorate the IQ above mentioned threshold? If so, it makes a lot of sense to me. I believe same could be applied to the ISO. They could have put one or two more stops of ISO, but why bother when the IQ would be useless. Link to post Share on other sites More sharing options...
Bobitybob Posted January 30, 2014 Share #26 Posted January 30, 2014 I would think there's no overheating or damage issue - after all, the camera can record 30mins of video Jonathan I don't know a lot about video, but if you can take this amount of video at 25 or so frames per second, why not take a video for up to 30 minutes and then extract the individual frames and stack them as required. I'm sure I've seen software that allows you to extract individual frames, but I can't recall what it was Link to post Share on other sites More sharing options...
Guest redge Posted January 30, 2014 Share #27 Posted January 30, 2014 Advertisement (gone after registration) I don't know a lot about video, but if you can take this amount of video at 25 or so frames per second, why not take a video for up to 30 minutes and then extract the individual frames and stack them as required. I'm sure I've seen software that allows you to extract individual frames, but I can't recall what it was It won't give you DNG. The video format is Motion JPEG. Link to post Share on other sites More sharing options...
brill64 Posted January 30, 2014 Share #28 Posted January 30, 2014 Dark current generation...the stuff of nightmares. Multiple composite exposures could be a very controllable workaround in many situations but if this is something you really must do long term, a back up Canon camera body with liveview mated to your favorite Leica lens via EOS-LM (or is it LM-EOS?) adaptor, which might work quite favorably (I mean that respectfully & as a helpful idea, not as a sarcastic swipe). Long exposures, especially at night time can be bitterly cold, soaking wet, lonely affairs after all. I do think messing about with scripts & codes could open a whole new undesirable can of worms for you unless you're very experienced in that field. Great fun, though.. Link to post Share on other sites More sharing options...
wlaidlaw Posted January 30, 2014 Author Share #29 Posted January 30, 2014 Wilson, you mentioned star scenes in your OP, and in fact one of the images you linked to is a starscape made with multiple images. It's a potential solution. Maybe not if you're trying to shoot a black cat in a coal mine though! (I expect it would have to be a dead cat too, to avoid blur) Film remains the better option for some applications. James, Dotted lines on starscapes is something I dislike and one of the things I wanted to avoid. As I am not taking a laptop with me, even if circumventing the 60 secs limitation could be done in Image Capture, I would not be able to do it in India. I also did not realise until someone pointed it out in this thread that the 60 seconds is only available in 200 ISO. I wonder if this does point to some sort of thermal issue but as Michael says, there is only a single data dump and process from the CMOS sensor, irrespective of the length of exposure, which should cause no more heat than 1/4000 second. If there is no danger of damage to the camera, I would rather Leica had let us make up our own minds about what is acceptable image quality and what isn’t. Wilson Link to post Share on other sites More sharing options...
jaapv Posted January 30, 2014 Share #30 Posted January 30, 2014 Film remains the better option for some applications. Reciprocity failure, anybody? Link to post Share on other sites More sharing options...
honcho Posted January 30, 2014 Share #31 Posted January 30, 2014 Quite. Try bracketing RVP 50 at a metered reading of 2.5 minutes. The best option for the OP's application is a camera that can handle long exposures. Leica should take note. Link to post Share on other sites More sharing options...
pico Posted January 30, 2014 Share #32 Posted January 30, 2014 [...] I do think messing about with scripts & codes could open a whole new undesirable can of worms for you unless you're very experienced in that field. Great fun, though.. Stacks in Photoshop are very useful. Photoshop Help | Image Stacks (Photoshop Extended) Link to post Share on other sites More sharing options...
jaapv Posted January 30, 2014 Share #33 Posted January 30, 2014 CMOS sensors are supposed to be lower noise than CCD due to lower thermal stress. I have certainly taken images with the M9 longer than one minute (4 minutes) and they worked just fine. I think a number of us are puzzled by this limitation. Wilson That is incorrect. CMOS sensors are more noisy than CCD sensors, especially on long exposures, but the pixel variation is corrected by on-sensor circuitry, which, however takes up space that cannot be used for the photo-sensitive area of the pixel.I am sure that Leica and CMOSIS biased the compromise towards photosensitive area to avoid the plastic “CMOS-look”. Which means the on-sensor circuitry cannot handle extreme noise. An image over 60 secs would probably not meet quality standards. Disclaimer: just my supposition. Astrophysical sensors for large telescopes are normally CCD, nitrogen-cooled. Link to post Share on other sites More sharing options...
thighslapper Posted January 30, 2014 Share #34 Posted January 30, 2014 The Sony A7r seems to have no limit ..... you can use 'b' for what appears to be an unlimited amount of time (if you can be bothered to keep the shutter button manually depressed and keep it steady).... .... but the manual does states that image quality may deteriorate with risnig temperature and it may trigger the temperature auto-cut off and shut the camera down..... .... which nicely brings us back to a known issue with the M ...... and I suspect this is the real cause of the limits imposed by Leica ..... Link to post Share on other sites More sharing options...
colonel Posted January 30, 2014 Share #35 Posted January 30, 2014 That is incorrect. CMOS sensors are more noisy than CCD sensors, especially on long exposures, but the pixel variation is corrected by on-sensor circuitry, which, however takes up space that cannot be used for the photo-sensitive area of the pixel.I am sure that Leica and CMOSIS biased the compromise towards photosensitive area to avoid the plastic “CMOS-look”. Which means the on-sensor circuitry cannot handle extreme noise. An image over 60 secs would probably not meet quality standards. Disclaimer: just my supposition. Astrophysical sensors for large telescopes are normally CCD, nitrogen-cooled. CCD only theoretically has less noise. The technology has not been developed as much as CMOS which now has lower noise. Theoretically if CCD had been developed as much over the years it would be better with the same investment, but it hasn't and CMOS has overtaken it. The big argument for CMOS when it came out was simply power consumption Link to post Share on other sites More sharing options...
wlaidlaw Posted January 30, 2014 Author Share #36 Posted January 30, 2014 CCD only theoretically has less noise. The technology has not been developed as much as CMOS which now has lower noise. Theoretically if CCD had been developed as much over the years it would be better with the same investment, but it hasn't and CMOS has overtaken it. The big argument for CMOS when it came out was simply power consumption Just been playing with my Olympus EP-5. It does long exposures with no problems on its CMOS sensor but it is a slow process. I have only done up to 90 seconds so far and it seems to take an equal length black subtractive frame. I have not discovered the correct menu setting to show the real time histogram but it is showing a digital timer (the EP-5 has the densest, most convoluted menu system I have ever come across - I think it must have been written by an IBM mainframe programmer). So it looks like the Nocti on the Olympus for long exposures. Wilson Link to post Share on other sites More sharing options...
david strachan Posted January 30, 2014 Share #37 Posted January 30, 2014 I love shooting star trails in Outback Australia. Film does remain the best medium. I tried on my M8 and got very dotty trails...no good. Many of the Japanese cameras do reasonable star trails for long periods. Unfortunately another limitation by Leica, and to its camera system as a whole. Dave S Link to post Share on other sites More sharing options...
dasjak Posted February 6, 2014 Share #38 Posted February 6, 2014 I think it is very embarrassing for Leica to limit long exposures to 30seconds on iso200?! I mean COME ON! what is it on iso800? 8seconds, wtf? I love my M but this is just ridiculous and really makes me angry. Every other digital camera is able to do long exposures except one of the priciest of them... Link to post Share on other sites More sharing options...
bideford Posted February 6, 2014 Share #39 Posted February 6, 2014 Hopefully not too off topic, but having used a 10 stop filter previously on my Canon 5D2 (for exposures much longer than 60 seconds) and since on the M (within the 60 second parameter) - I have come to the conclusion that using any interchangeable lens camera requires an absolutely spotless sensor. Long exposures will find dust particles that are not even remotely evident in normal use. If sensor cleaning is not in your repertoire (and using a rocket blower will not suffice here) then you will spend sometime removing dust marks in post processing. My M is also currently at Solms for a hot pixel remap that was only evident on long exposures. I have now stated to use my X100 (with it's fixed lens) and my long exposure tool of choice (focal length permitting, of course). Dust is never a problem. I'm also going to try with film "new sensor every time", however I do envisage the recognize the possibility of dust particles/scratches being introduced during the developing and scanning process (I develop b&w at home) - although to be fair I can usually produce pretty clean images. James Link to post Share on other sites More sharing options...
Gary Clennan Posted February 6, 2014 Share #40 Posted February 6, 2014 I think it is very embarrassing for Leica to limit long exposures to 30seconds on iso200?! I mean COME ON! what is it on iso800? 8seconds, wtf? I love my M but this is just ridiculous and really makes me angry. Every other digital camera is able to do long exposures except one of the priciest of them... I thought it was 60s at ISO200? Link to post Share on other sites More sharing options...
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