Testing Shutters and Aperture Diaphragms
When considering buying a used camera, make sure that you test the shutter of the camera. You want to make sure that all elements of the used camera are in good working order before you make the final decision to buy. Here we will discuss the testing of two types of shutters: leaf shutters and focal plane shutters.
Leaf Shutters
Start the testing by trying all of the shutter speeds. Its the slower shutter speeds that will have the most problems. Count as you test the speed by saying one one hundred. What you are looking for is that the one second shutter speed is working okay. The half shutter speed should be about half of the one second count. If there are any problems with the speed of the shutter it will be apparent right away. Shutters are very costly to repair and depending on the camera type can cost you anywhere from 0 to 0.
Leaf shutters sometimes can be sticky. This stickiness is usually caused by someone trying to repair the shutter by putting watch-makers oil on it. Sometimes the oil will seep into the leaf shutter from the angle of the lens helicoid. The leaf shutter, as well as the diaphragm, should never have any oil on it and when it is being repaired should have what is called a dry lubrication applied. If the shutter is sticky you could attempt to take the lens apart and clean it with naphtha but this can be a lot of wok and it might be more worth your while to pay the 0 to have it looked at professionally.
To test to see if the shutter is sticky you will need to release the shutter in a variety of positions. Sometimes the sticking will only be apparent when you turn the camera upside down or when it is pointing in a downwards position. You may think that you are never going to shoot with the camera pointing upside down but this is irrelevant. Test the camera in this position anyway. If the camera shutter is sticking while you are in this position the friction will always be there. This can throw off the timing of the camera even if the shutter isnt actually sticking.
When a leaf shutter hasnt been used for some time it can become slow and sluggish. The shutter might warm up if you release it a few times in succession. By using this method of repeatedly releasing the shutter, without actually taking a picture, you can bring an old camera in the junk pile back to life.
Many older cameras have odd shutter interlocks in place to prevent you from double-exposing pictures. Some of these interlock features can be hard to determine. In this case you will want to find a manual for the camera so that you understand exactly how the camera, and the leaf shutter, operates.
Focal plane shutters
The above points and recommendations for a leaf shutter can also be applied to the focal plane shutter.
When you are testing a focal plane shutter make sure that the cloth shutter curtains are clean and that there are no pinholes evident that have been caused by someone pointing the camera into the sun without first having the lens cap on. Hold the camera and point it towards a bright light while having the back of the camera open. If the camera is tight from light you wont be able to see any pinholes.
Check to make sure that the shutter doesnt have any folds or tears in it. The following shutters are known for having fragile focal point shutters: brass or titanium foil shutters (such as the Hasselblad 2000 series or the Canon rangefinders) and lightweight steel shutters. If the camera hasnt been handled carefully the previous owner could have caused shutter damage simply by sticking their finger into the curtain.
Aperture Diaphragms
Some cameras, such as TLRs and Rangefinders, may have fewer diaphragm problems than other cameras. This is because the diaphragms are hard-wired into the camera setting and wont be able to move when you are taking a picture. An SLR camera will have more diaphragm problems for the simple reason that the diaphragm needs to be open wide in order for you to focus correctly. When the camera is focused and ready to go the diaphragm needs to stop automatically before the shutter is released. This type of diaphragm mechanism can cause some severe camera problems.
Just like a leaf shutter the diaphragm can become sticky with oil. To test for this problem you need to set the diaphragm at its smallest aperture (f/22 or f/32) and then set the shutter speed to the bulb setting. Look into the camera lens and check to see if the diaphragm closes down at the exact moment that the shutter opens. Do this simple test a few times to check for any diaphragm sticking.
If you are testing a Pentax mount lens you will need to take the lens off of the camera. Then set the lens aperture of the lens to the auto setting and the camera aperture to f/22 or lower. There will be a small tab on the back of the lens that you need to press a few times to make certain that camera lens smoothly closes down without any sticking. For other camera lens mounts you should be able to determine which cam or nubbin is causing the diaphragm to shut down. Look in from the back of the camera to be certain that there isnt any oil evident on the blades of the diaphragm.
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