Leaf shutters and accuracy

[Kev M]

Do leaf shutters tend to go awry after a while? Reason for asking is I developed a roll where I'd used my 80 and 250(I think) and the exposures are miles apart. It could have been operator error but I'd like to know that the kit is all good anyway.

Can anyone think of a way of testing the shutter speeds on 5 different lenses that will give a direct comparison between them? The only thing I can think of is taking a picture of something like a wall with all five lenses on the same roll and at the same exposure so that they all get developed the same. The problem is I've got 50, 80, 150, 250 and 500mm lenses which makes shooting exactly the same scene with each lens a problem, especially when the MFD of the 500mm is 8metres.

Is there another way of testing the timings? I don't really want to send all 5 back to Tamron for a service, it'll cost me an arm and a leg.

 

[Knikki]

Just had a mooch around and found a couple of bits using a software program and a microphone Link 1 APUG Forum and this one Click to link 2.

Could be worth looking or search around the Large Format forums as I think nealry all those lens are leaf shutter type so some one may have a better idea.

You could always try an independent repaires to check them out, but again coast maybe an issue

Sorry simple don't know any other easier method

 

[CT]

Leaf shutters are operated by a main spring which can weaken over time and affect the timings. It's usually most noticable with the long shutter speeds. Usually if you're getting a good 1 second, there's not likely to be much wrong with the shorter speeds, so that's probably your best indication Trev without pretty specialist equipment - compare the 1 second exposures on each lens.

 

[Ceejay]

Kev
When I had my Hasselblad I used to get it checked every year by them. One lens a 250mm Sonnar kept giving odd readouts on their checking kit, normally somewhere between 1/320 to 1/380 instead of 1/500 (which I was told was never achieved anyway) so before each service or check I would fire the shutter about 10-20 times and they started to get about 1/460, this happened for about three years before I changed systems to 6X7. One of the techs put it down to me only using 1 sec to 1/60 regularly.
It was the only lens out of five that ever played up in this way
Try using all the speeds occaisionally, it may help !

C

 

[CT]

Try using all the speeds occaisionally, it may help !

C

I agree with that - mechanical kit benefits enormously from being exercised. A lot of problems with older kit can be resolved by a few firings to loosen things up - particularly if it's been standing unused.

 

[Kev M]

Cheers for the tips guys, Nick I'll have a read of those links later. My kit doesn't get used often at all. Perhaps once a week or so I need to stick it on multi-exposure and fire it off at all speeds a few times.