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02-14-2012, 09:02 AM   #1
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Testing old 35mm cameras!

hey guys, just wondering on how to properly test a 35mm camera to make sure everything is working correctly like they would in a camera shop. im still in highschool but have a dream of becoming an slr camera repair man and photographer. thanks for helping out!

02-14-2012, 09:43 AM   #2
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I think that depends a lot on the camera, different brands different tests; different ages, different tests. Big difference between a Spotmatic and a SF-1.

But some things will be the same. Some tests need specialized gear, like shutter curtain timing really needs a bench oscilloscope or dedicated test gear. Testing the light meter also requires instruments to verify the accuracy. Both of those can be done at home without the gear but results will only be approximate.

Beyond that, when I'm buying a camera:
1) Check the mirror seals for deterioration
2) Verify that the mirror moves smoothly
3) Check the shutter curtain to see if it moves smoothly; change the speed and see if that changes the curtain behavior
4) Check for fungus mold, mostly lenses but could be in the camera too
5) Check the film winder and verify it operates. Real test would be using a roll of film. I have an old roll that I keep just for that purpose, test and then wind it back up for re-use.
6) Check the viewfinder, make sure it is not fogged or scratched, both the eye piece and the focusing screen.
7) Check the battery compartment; make sure there is no corrosion.
8) Check the delay timer if there is one
9) Move all controls and make sure the knobs / levers all work
10) Check the on board flash if present
11) Test the display screen or indicator lights depending on what is present; all should be evenly lit and operating
12) Test the light meter by moving the aim point from bright to dark. This is an operation test, not an accuracy test.

Note that the above are just things to check while at the pawn shop or whatever, not intended to be a full CLA. For that I think you really should have the repair manual or at least training on the camera.

Last edited by jatrax; 02-14-2012 at 09:48 AM.
02-14-2012, 09:47 AM   #3
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Shops have things like shutter testers and the like, which are necessary to ensure accuracy of the equipment.
A good alternative though is to shoot a roll of film with the lens at maximum aperture, and make an exposure at each shutter speed. Develop the film and either visually see if the exposures are changing evenly (least accurate), or using a camera with a spot meter, measure each neg to see if the exposures are increasing one stop at a time (better, but not ideal), or use a densitometer to measure each frame to see if the exposures are increasing evenly (best method). I suspect that densitometers can be had fairly cheaply these days on ebay. They were a mainstay of photo labs, because they were required for quality control. However, a lot of labs have closed, and the equipment is sitting unused in storage barns all over the country now.
After you have determined shutter accuracy, you can repeat the test using one shutter speed, and check the lens at each stop, measuring things the same way.
You can also inspect the frame spacing for evenness, and by operating the camera, you will see if the mechanisms are running smoothly.

Now, having said all this, I think that if you want to repair cameras, it might make a nice hobby, but if you want to do something for a living that you can support yourself with, go to a trade school and become an electrician or other tradesman. In 20 years, they will be in very short supply, and will pretty much be able to write their own paycheques for however much they want to earn.
02-14-2012, 09:50 AM   #4
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1) Do a visual test for any camera damage.
2) Test the meter and shutter with no film in the camera.
3) Run a roll of film through the camera and make notes of any issues.
4) Check the processed results for exposure and other issues.
5) Regardless of the results send the camera to Eric for a full CLA.

Phil.

02-14-2012, 09:56 AM   #5
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i bet the gear for that can get pretty expencive then. i am definatly enjoying colecting and and "atmpting" to repair cameras as a hobby although i am not good at it at all but its still fun.


I work at cummins inc. at its home location in columbus. i am a student draftsman/engineer. i want to relate this kind of job else where in the future since i have already studied it and have taken classes for about 3 and a half years now. any tips on working with the big guys at pentax or any ideas of how to get into that kind of carrer with a camera company?
02-14-2012, 09:58 AM   #6
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QuoteOriginally posted by gofour3 Quote
1) Do a visual test for any camera damage.
2) Test the meter and shutter with no film in the camera.
3) Run a roll of film through the camera and make notes of any issues.
4) Check the processed results for exposure and other issues.
5) Regardless of the results send the camera to Eric for a full CLA.

Phil.
whos eric?
02-14-2012, 10:10 AM   #7
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QuoteOriginally posted by carlyn.warnock Quote
whos eric?
Erik Hendrickson, a retired Pentax repair technician. He now runs a business out of his home. The word is, his rates are reasonable and his work is first-rate. He's the goto guy for repairs on film Pentax cameras.

His website: Home
02-14-2012, 12:42 PM   #8
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Accurate shutter testing was very easy when we had analog CRT TVs. If you still have one on cable or on a VCR (so that it fills the screen at the correct scan rate) you can still judge the shutter very accurately by removing the lens, open the back, and view the screen through the shutter as you trip each speed several times. With a horizontal-running focal plane shutter you will see a diagonal slash down the screen where the width of the slash is proportional to shutter speed. The slash should also be constant width - showing the "slit" between the curtains is not varying across the frame.
With a bit of experience it's easy to tell if 1/1000 is correct and repeatable; and if so the other speeds down to where the slow-speed escapement acts will usually be OK also.
I also have a shutter speed tester sold on eBay by Zhou, who makes leather cases for Leica. It gives a pretty accurate digital readout, but only at one point at a time. That combined with the TV test to see evenness of exposure gives a good evaluation of shutter health.

02-15-2012, 10:56 AM   #9
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TV Shutter test

Here's an example of the CRT TV shutter test I mentioned. Hold the camera so the shutter movement is horizontal. (This is from a K-5 so I rotated the camera and cropped in.) The bright "slash" may appear at any top/bottom position depending when the TV scan started relative to the shutter action, so you may have to try several times to see a full-width slash. The slope of the slash varies with the curtain speed. You judge the width of the slash. If you take a picture of it like this, you can actually count the number of scan lines and calculate an exact shutter speed. The slash may curve as the curtains speed up as they move, but the width should stay constant.
Name:  Shutter Test.jpg
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02-16-2012, 05:35 PM   #10
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If you are going to do a roll of film, take shots at all shutter speeds. I have seen dark on one side light on the other due to trailing and leading curtain lag. Use the sunny 16 rule, shutter =1/ISP at F16 on a sunny day, and with a good lens use each aperture and set shutter accordingly . Check negative density afterwards, all should be the same.
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