Jump to content

Checking accuracy of shutter speeds on a film camera


Recommended Posts

Advertisement (gone after registration)

I have an M6 on order and only 14 days to check it out and reject if necessary.

 

I need to check the obvious things such as light leaks, RF accuracy, light meter, shutter speed and viewfinder dust. I'm not sure if there's anything else.

 

With regard to shutter speed, I'm thinking of making a 'normal' exposure of an 18% reflectance target for the range of shutter speeds (or as many as possible) using aperture and possibly a ND filter to produce a sequence of correctly exposed images of the mid grey target.

 

I plan to use low ISO film and evaluate a scan of the negs, and possibly the 6"x4" prints (but as there could be printing errors it's probably less valuable compared to the the scan and the raw negs).

 

Does that seem sensible, or is there another technique I could use?

Link to post
Share on other sites

Don't go overboard. Choose a bright overcast day. Through the focus way-off, perhaps to minimal distance. Point the lens to the grey sky. Make many exposures, each with an equivalent exposure at different shutter speeds. (Like 1/1000th at F/2, 1/500 at F2.8...) You know the drill. If the density varies, you have an issue.

.

Edited by pico
  • Like 2
Link to post
Share on other sites

I would test it with a slide film/E-6 and an incident lightmeter. (Several) same object going through all stops. Simple.

I see the logic of using E6, difficulty may be getting the film, then processed before the deadline. However the camera is warranted for 6 months, even if I miss the 2 week window the retailer should sort it out if the SS is errant.

Link to post
Share on other sites

For checking the slow speeds I found a turntable quite useful: http://www.l-camera-forum.com/topic/242755-mit-fliegenden-fahnen/

The platter turns at 33 1/3 rpm which is exactly 200° per second. That would be useful for speeds from 1 sec to 1/20 sec. Use a smaller marker than I did.

It's a long long time since I had a turntable - possibly 25 years :)
Link to post
Share on other sites

Advertisement (gone after registration)

Don't go overboard. Choose a bright overcast day. Through the focus way-off, perhaps to minimal distance. Point the lens to the grey sky. Make many exposures, each with an equivalent exposure at different shutter speeds. (Like 1/1000th at F/2, 1/500 at F2.8...) You know the drill. If the density varies, you have an issue.

.

Yes that would work, simple too.

And we have more overcast than sunny days in the uk :-(

Edited by Steve Ricoh
Link to post
Share on other sites

If you have an old CRT tv, use the TV shutter test. Remove the lens, open the back, and watch the screen through the shutter. You'll see a slash of bright lines on the screen, fewer lines as the speed increases. Pick a distance so the screen fills the frame. At 1/60 the entire screen is bright, 1/125 half the screen, 1/250 a fourth, etc. the bright area will be a diagonal slash based on the moving speed of the curtains. At 1/1000 a very narrow band, but should be the same width across the frame.

Too bad it doesn't work on modern LCD TVs, as the results are instant. I keep an old TV in my office for the old cameras I collect, even though I also have a digital shutter tester.

  • Like 2
Link to post
Share on other sites

The last of my old CRT TVs went to recycling years ago, it was difficult to give them away, so recycle it was, WEE!

 

I'm not one to count my chickens before the hatch, but....

 

If, the shutter speed is incorrect, does it generally mean all the shutter speeds in the range will be offset by the same proportion, for example all shutter speeds out by 25%. Or is it the case that only some of the shutter speeds are out of calibration?

 

If the latter, what accounts for some of the SSs to be out of cal, whilst others are spot on?

 

Is it something to do with the gap between the curtains which can be correct at one end of the scale, and out at the other. Confused.com

Link to post
Share on other sites

A couple of years ago I bought a shutter tester from the famous auction site, it was around $90, and I've used it to test a number of older cameras, making it a worthwhile purchase. What I have learned from this experience is that many cameras (I sold my M6 before getting the tester, so not sure it applies) exhibit variances in each speed, and what I always looked for was that the variances were within 1/6 of an f stop, knowing that the latitude of film would basically take up the slack. So I would test each speed a couple of times, average it out and make note of any particular speed which exceeded my threshold. Even in cheap cameras it was rare to find the speeds off by more than 1/3 stop, unless the camera was rally in need of serious repairs.

  • Like 1
Link to post
Share on other sites

There is a way to use a dslr to test shutter speed accuracy and it works really well, you basically have the dslr on B and use the shutter in the test camera, then compare to dslr using its own shutter sounds complicated but its really not.

Link to post
Share on other sites

There is a way to use a dslr to test shutter speed accuracy and it works really well, you basically have the dslr on B and use the shutter in the test camera, then compare to dslr using its own shutter sounds complicated but its really not.

Can you provide more details of how you do this please?

Link to post
Share on other sites

Just shoot a test roll, if the results are OK you're good to go.

 

Some if not all of the speeds will be off by a certain %, you just need to make sure it's within working tolerances and that there's no other issues like shutter bounce or light leaks.

 

Don't over complicate matters.

  • Like 1
Link to post
Share on other sites

Why have it CLA'd if it turns out to be working fine though? If it ain't broke don't fix it!

Aren't they a bit like cars, especially cars that have been under used. If you buy an old car that hasn't been turned over for years, received wisdom recommends draining and replacing the oil (and filter of course). In a camera lubricant can separate or become sticky and ineffective with age. The camera was manufactured in 1996 and there's no maintenance record accompanying the unit.

However the camera I've just purchased seems to be quite smooth by feel of the film advance, and the shutter sounds ok, but as I have no prior experience with an analogue film camera, things may not be as good as it seems.

Link to post
Share on other sites

Aren't they a bit like cars

 

No, not really. Cars need to be maintained for safety more than anything. Oil in a car becomes contaminated and loses it's properties with use leading to wear on the engine.

 

Whilst lubricants in a camera can dry out after time, and mechanical shutters start to lose their accuracy, you really shouldn't need to service it unless there is a problem. Others will say regular servicing will prevent problems happening but personally I think it's best not to pull mechanical stuff apart unless you have to. How often do we read about people finding more problems with gear after being serviced than they had before!

 

Also bear in mind that you will probably invalidate your warranty if you get anything done by a third party whilst it's still under warranty.

  • Like 1
Link to post
Share on other sites

No they are not like cars which require frequent oil filter and oil changes. 10 years of camera usage, especially a well made camera, without a CLA isn't unusual, unless it was used hard by a professional. Most well made cameras (Leicas, Nikons, Canons & others) can easily go 15-20 years before needing a CLA unless they are exposed to unusual conditions, damaged, or very heavily used. Yes a few speeds may verge on the edge of tolerance ranges, but mostly the film, especially negative film, will accommodate those variances, as they are usually less than 1 f/ stop.

Link to post
Share on other sites

Ok, cars are a bad analogy, but mechanical watches are closer. The manufacturer of my watch recommends a service every 2 years, but the independent repair man I visit recommends a service every 5 years, but no longer. Of course I'm not trying to compare the mechanical wear of a watch with a camera, since the rates are completely different. But they both need a lub and possibly adjustment, mechanical things do.

Link to post
Share on other sites

Steve - do you have a Leica technician nearby?  Most of the good second hand film camera shops have someone on hand with a machine to check shutter speeds.  It is very easy to check with the proper tools.  That's what I would do.  The odds are that all is ok.  But if there is a problem it may not be at all speeds and so in order to be sure there are no problems (which, given that the camera is built like a tank, if there are problems at any shutter speed you want to promptly return it (there are plenty of perfect ones out there)) you really need to check all speeds.  Why not make a trip to Red Dot Camera or one of those places in town?

  • Like 1
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...