M2 Shutter speeds and test results

[MrBan]

Advertisement (gone after registration)

Hi all, 

I recently acquired a very nice M2 from a local Leica store a few weeks ago. I am new to film. I have put a roll of Portra 400 through it and it seems fine, however I wanted to verify that the shutter speeds are reasonably accurate so I built a little DIY project to measure the shutter speed. Without going into the details of the project (got inspiration from here: https://www.diyphotography.net/how-to-build-your-own-laser-powered-diy-shutter-speed-tester/), the measurement principle is simply measuring the duration of an optical light source being received on an optical receiver. The camera shutter sits between the optical light source and the optical receiver. When the shutter opens the measurement starts, and when it closes the measurement ends. Shutter speed is the delta between those two points in time. Whether this measurement is really valid for the shutter type in the M2, I am not certain but it should be close enough I hope. 

Results are attached. The yellow column shows the average of 5 repeated measurements. Measurement spread is very low, i.e. very consistent. The "Target" shutter speed is simply the inverse of the setting on the camera, e.g. 1/125 equates to 4 milliseconds. The "Error" is in stops. A positive Error indicates a slower than wanted shutter speed resulting in an overexposure.  For example for 1/1000, the shutter duration should be 1 millisecond, but I measure 3.4 milliseconds which is a 1.77 stop error. 

Now I **think** the meter is very accurate and the measurement uncertainty is a lot smaller than the fastest shutter speed duration but I cannot be certain. The results show very accurate speeds all the way from 1sec to 1/125sec (max 0.3 stops error). However for 1/1250, 1/500, 1/1000 the errors are pretty large. 

May I ask if anyone, from experience, could comments as to whether this could be an expected set of results for a camera with shutter speed issues? I am trying to figure out whether my camera needs the shutter speed seeing to or whether I have an issue with my measurement. 

My understanding is that with colour negative film like Portra 400 which I used, it would be difficult to distinguish exposure deltas between say 1/1000 (at at F4) and even 1/125 (at say F11 to keep the exposure equivalent between the two shutter speed settings) because of the exposure latitude of the film and visually it would be hard to distinguish. If I rate the film at box speed then maybe I stand more change of seeing deltas in the developed images? With digital it would be super clear if there is a 1.77stop error, but with film my understanding is it would be harder to visually detect. Maybe I have this wrong and I can run a test to clearly see if there is a real exposure issue at 1/1000 where the error is greatest. 

Many thanks in advance.  

 

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!

[spydrxx]

I've used a similar commercially manufactured shutter tester for a number of years. Based solely on my results, I'd say your camera needs adjusting, the errors on the higher shutter speeds are outside of what are normally considered acceptable ranges. I typically look for no more than 25% error. Sometimes that may be unachievable at a particular speed due to wear. Before jumping to conclusions, though, I'd repeat the measurement 7-10 times to determine consistency of error. Only one reading can often be a fluke.

[MrBan]

26 minutes ago, spydrxx said:

I've used a similar commercially manufactured shutter tester for a number of years. Based solely on my results, I'd say your camera needs adjusting, the errors on the higher shutter speeds are outside of what are normally considered acceptable ranges. I typically look for no more than 25% error. Sometimes that may be unachievable at a particular speed due to wear. Before jumping to conclusions, though, I'd repeat the measurement 7-10 times to determine consistency of error. Only one reading can often be a fluke.

Thanks. The results are an average of 5 measurements and the spread between them was very low.

I did factor in a service when I purchased the camera, but will try to find a good independent technician.

[spydrxx]

If you're in the USA I can recommend DAG (Don Goldberg) or Youxin Ye. Both have done excellent work for me for years.

[MrBan]

16 minutes ago, spydrxx said:

If you're in the USA I can recommend DAG (Don Goldberg) or Youxin Ye. Both have done excellent work for me for years.

Thanks. I am in Germany. Need to find a good reputable independent.