Shutter Testing (Digital Timer)

B

bwcolor

Mentor
Local time
4:16 PM
Joined
Jul 26, 2009
Messages
2,345
I've got a few cameras that need to be sorted out and one of the things that needs to be sorted is shutter accuracy. I noticed that Zhou sells a digital device for measuring shutter speed. Just wondering if anyone has tried any of the sub $150.00 devices for determining "exact" shutter speed?
 
None of the cheap shutter testers are really usable for focal plane shutters, like those in Leicas and most other 35mm cameras. The reason is that you actually need to know the speed of each shutter curtain. They have to travel at the same speed, or you get uneven exposure. The cheap ones they sell on Ebay measure the with a single sensor in the middle of the film gate. This gives the average speed, but professional testers use two sensors, one on each side of the film gate, to measure the shutter speed on each side to see if both are the same. They need to be or you get uneven exposure
 
The curtain speed of each should be the same, yes, as it is the width of the gap between the curtains (Ie. the delay between the two curtains) which determines the amount of exposure. If the second curtain runs at a faster or slower speed to the first, exposure will differ across the film gate as it gains or lags on the first curtain.

I purchased one of the affordable testing units from ebay myself, however I have not had a chance to try it yet (besides which, I usually only work on leaf shutters).

However I wonder if, depending on the characteristics of the light source being used, you might be able to test each side of the film gate independently, as the exposures should be repeatable within spec plus or minus a few percent anyway. It should therefore be possible to ascertain the exposure on each side, with a deviation in exposure averages from side to side being indicative of capping, yes?

Clearly, a more expensive unit has advantages for testing FP units, but given the above, perhaps the more affordable ones may still be of some use? Any FP shutter specialists want to comment?

Regards,
Brett
 
Sarcophilus Harrisii said:
Some good screen shots there. Can you check for capping this way too Stewart?

Regards,
Brett
Click to expand...

No idea, I'd just paid a fortune on a rebuild and I just wanted to check it had been worth the money.

I don't check cameras normally unless there is something wrong with the contact sheets
 
Good enough for testing a camera you have no intention of fixing or are going to fix yourself. This was a technique used by National Camera Repair Home study course 40 years ago. Okay for then, not now, unless as I said it's just FYI. Testing it because you paid for an overhaul (from someone who probably has a $5000 Kyoritsu tester) and want to see if it's correct? It creates an argument in your own head. Don't be surprised if a tech with possibly decades of experience doesn't respond. "Speeds aren't right, pictures of my TV 'prove' it". A record player and protractor? John
 
John Hermanson said:
Good enough for testing a camera you have no intention of fixing or are going to fix yourself. This was a technique used by National Camera Repair Home study course 40 years ago. Okay for then, not now, unless as I said it's just FYI. Testing it because you paid for an overhaul (from someone who probably has a $5000 Kyoritsu tester) and want to see if it's correct? It creates an argument in your own head. Don't be surprised if a tech with possibly decades of experience doesn't respond. "Speeds aren't right, pictures of my TV 'prove' it". A record player and protractor? John
Click to expand...

Did I tread on a sore toe there?
 
You must log in or register to reply here.
Back
Top