Timmyjoe Posted March 17, 2011 Share #1 Posted March 17, 2011 Advertisement (gone after registration) Having an issue with exposure with my old M6 TTL and a new 35mm Summicron Asph lens. Using both new Tri-X and some left over old AgfaPan 100. No matter what I do, about half the time the images are coming out underexposed. Tried rating the Tri-X at 200, tried adding 1/2 stop more exposure to each shot, even calibrated the meter in the M6 with a gray card and my Sekonic light meter, and checked the shutter speeds on the M6, everything seems to be fine, but the images still keep coming out on the underexposed side. Am I missing something here? Has anyone experienced this before? The only thing different is the new 35 Summicron. Do they generally underexpose? It doesn't make any sense to me. I have never used this M6 with any lens other than a 50mm Summilux (which is what it came with), does the 35mm Summicron require a different metering style since it's wide angle? Link to post Share on other sites More sharing options...
Advertisement Posted March 17, 2011 Posted March 17, 2011 Hi Timmyjoe, Take a look here UnderExposure w/M6 & 35 cron. I'm sure you'll find what you were looking for!
pico Posted March 17, 2011 Share #2 Posted March 17, 2011 Tim, could it be a processsing error? I'd try 1/2 the roll with each lens to find out, presuming that's the error and the processor makes the same error. Link to post Share on other sites More sharing options...
Timmyjoe Posted March 17, 2011 Author Share #3 Posted March 17, 2011 Hi Pico, I'm processing the film myself. Been doing it since 1976, so I think most of the bugs are worked out. Did a number of tests, exposure, processing, etc. and it pointed to ISO 200 being the best rated speed for the Tri-X with this lens/body combination. Then went out and shot a roll at ISO 200 and again, all seems somewhat underexposed to me. Someone mentioned the shutter speeds above 250 are notoriously off on M body Leicas. Has anyone here heard of that? Link to post Share on other sites More sharing options...
too old to care Posted March 17, 2011 Share #4 Posted March 17, 2011 Someone mentioned the shutter speeds above 250 are notoriously off on M body Leicas. Has anyone here heard of that? I have never noticed this. I always down the ISO by about 25-30% because I like dense negatives. Unless the developer is old, they usually come out fine. Since I shoot mostly wide open (f2 Cron), I use the faster shutter speeds. Link to post Share on other sites More sharing options...
gyoung Posted March 17, 2011 Share #5 Posted March 17, 2011 I shoot transparency film all the time, with an M6ttl and and M3 with Voigtlander meter, with 35 Summicron aspheric plus the original M3 Summicon 35, no difference of technique or results with any combination of these, or with the other lenses, 21 Elmarit asph, 50 mm f/2 and f/1.4 90/2.8 or 135/4 & 2.8. (+ a few others I won't bore you with). I presume the diaphragm is working allright? Make sure the blades are connected to the aperture ring? Gerry Link to post Share on other sites More sharing options...
Timmyjoe Posted March 17, 2011 Author Share #6 Posted March 17, 2011 Thanks folks, I'm starting to think it's a shutter issue (the camera is 11 years old and never been serviced). Will do some more tests. The shutter appears to be right on at 1 second, but I have no way ot testing the other speeds independently. The diaphragm on the lens appears to be working fine, it opens and closes as I turn the aperture ring. Link to post Share on other sites More sharing options...
earleygallery Posted March 18, 2011 Share #7 Posted March 18, 2011 Advertisement (gone after registration) Fitting the 35mm lens makes the metering 'spot' in your M6 much larger. Are you sure this isn't the cause? Have you tried using readings off your handheld meter? Link to post Share on other sites More sharing options...
Xmas Posted March 18, 2011 Share #8 Posted March 18, 2011 Hi If the frame edge to edge is uniformly exposed it probably is not the shutter, but lots of people will tell you it needs a CLA, never had that done to one of mine. But remove the battery from the M6 and borrow a hand held meter and/or use this link. Sunny 16 rule - Wikipedia, the free encyclopedia Treat the film as 200 ISO, only use 1/125, this is a test. Try half the shots with a different lens. As James suggested the spot is a bit larger with the 35mm, you should read the user manual for the M6 again as well, it explains in gory detail, google for PDF file. If that works ok then you need to put the battery back and start comparing things,... Noel Link to post Share on other sites More sharing options...
Timmyjoe Posted March 18, 2011 Author Share #9 Posted March 18, 2011 I went back and pulled the negatives I have shot in the last week, and really studied them. There's a ton of detail in the shadow areas. I'm now starting to suspect my Nikon Coolscan 9000 scanner. It's always given me really good (diffusion style enlarger) results in the past, which is why I was trusting it, but it's sure doing a lousy job on these negatives. I am going to do one more test, shooting a scene 1000/sec-f2, 500/sec-f2.8, 250/sec-f4, etc. to make sure the shutter is okay, but I think the problem may be in the scanner. Thanks for everyone's help. Link to post Share on other sites More sharing options...
Timmyjoe Posted March 18, 2011 Author Share #10 Posted March 18, 2011 Hi Folks, Just shot a test where I lit a scene and then shot it as above, 1000/sec-f2, 500/sec-f2.8, 250/sec-f4, 125/sec-f5.6, 60/sec-f8, 30/sec-f11, 15/sec-f16 with the Summicron, and then adjusted the light and shot again 1000/sec-f1.4, 500/sec-f2, 250/sec-f2.8, 125/sec-f4, 60/sec-f5.6, 30/sec-f8, 15/sec-f11, 8/sec-f16 with the Summilux. Sure enough, both images shot with a shutter speed of 1000/sec are underexposed by about a stop. Both images shot with a shutter speed of 500/sec are underexposed by about 2/3 of a stop and both images shot with a shutter speed of 250/sec are underexposed by about 1/3 of a stop. All the rest of the images have the same exposure. Is this something that a CLA will remedy, or should I just try to compensate when I am shooting at those shutter speeds? Thanks for any and all info on this. Link to post Share on other sites More sharing options...
tgray Posted March 18, 2011 Share #11 Posted March 18, 2011 A CLA should fix that. Link to post Share on other sites More sharing options...
too old to care Posted March 18, 2011 Share #12 Posted March 18, 2011 From my experience a camera usually over exposes as it gets older. The grease dries up, the springs weaken, etc. causing the shutter to lag. I would give it a good service and put it back in new working order. Link to post Share on other sites More sharing options...
gyoung Posted March 19, 2011 Share #13 Posted March 19, 2011 From my experience a camera usually over exposes as it gets older. The grease dries up, the springs weaken, etc. causing the shutter to lag. I would give it a good service and put it back in new working order. ...but it seems that the opposite is often true with Leica shutters, my M3 did this a long while ago when the shutter lubricants dried up through old age, the faster speeds got faster leading to underexposure, an overhaul cured it. Gerry Link to post Share on other sites More sharing options...
too old to care Posted March 19, 2011 Share #14 Posted March 19, 2011 I learn something everyday. Did not know Leica speeds got faster as they aged. Thanks, Wayne Link to post Share on other sites More sharing options...
Timmyjoe Posted March 20, 2011 Author Share #15 Posted March 20, 2011 Wayne, your theory is still correct. From what I have been told, the reason the shutter speeds get faster as the camera ages is because the tension on the first shutter curtain (I'm probably using the wrong term) is weakening. Ergo, the shutter speed is faster because with the first shutter curtain going slower, and the second shutter curtain going at it's normal speed, the shutter is actually open for a shorter period of time. Make sense? Link to post Share on other sites More sharing options...
gyoung Posted March 20, 2011 Share #16 Posted March 20, 2011 Wayne, your theory is still correct. From what I have been told, the reason the shutter speeds get faster as the camera ages is because the tension on the first shutter curtain (I'm probably using the wrong term) is weakening. Ergo, the shutter speed is faster because with the first shutter curtain going slower, and the second shutter curtain going at it's normal speed, the shutter is actually open for a shorter period of time. Make sense? I think that would produce uneven exposure across the frame. I don't know what the reason is, there are other quirks I have discovered in 40 + years of owning the same M3 body, part of the fun! Gerry Link to post Share on other sites More sharing options...
too old to care Posted March 20, 2011 Share #17 Posted March 20, 2011 I based my original assumption that the shutter times would lengthen based on not on my Leica experience, but Pentax Spotmatic experience that I bought new in 1968. Both my M6 and the Pentax use the same design, mechanical clock works to control the release of the second curtain and cloth curtains. I used that camera until about 5 years ago when it finally died. Over that period I had to have the camera cleaned twice after the clock works starting running slow. You could hear it at the slower speeds, but it was consistently slow across the entire range that resulted in over exposures. However, since it was not a Leica, I cannot say for sure if this assumption is correct. I have only owned a Leica since 98, thus it is still aways off from a CLA. Thanks, Wayne Link to post Share on other sites More sharing options...
Timmyjoe Posted March 31, 2011 Author Share #18 Posted March 31, 2011 Through in the towel, sent it in for service. Need the shutter speeds to be accurate. Thanks for everyone's help. Link to post Share on other sites More sharing options...
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