BetterPhoto Q&A
Category: New Answers

Shutter and advance lever jammed

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March 08, 2003

This camera has a shutter release lock. The "L" position on the shutter speed dial (around the shutter release) locks it. Ensure it's not in the "L" position!

Beyond this, it could have an old roll of film jammed up inside it. Does the rewind crank turn freely? Again, if you don't have a manual, see the one on-line for rewinding film and attempt to rewind it. If all else fails, open the back and ensure there's no film inside. If there is, you should be able to pull it out. If film did jam up, users often try to force the winder and strip out the sprocket holes in the film . . . leaving little pieces of film around inside the camera. If you find this, check the inside thoroughly and carefully pluck any pieces you find out. Be extra careful around the shutter curtains. They are fragile and will not withstand poking your fingers into them.

BTW, this looks very suspiciously like one of the later Pentax "K-mount" models made for Sears. If so, and if you get it working, the Pentax "K" cameras are, in general, long-lasting workhorses.

-- John

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March 08, 2003

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March 08, 2003

Cameras of this type have a "focal plane shutter." If you look in the back of the camera you will see a rectangle that the film travels across. This is called the "film gate." Inside this rectangle you should see what looks like black or dark gray metal foil. This is one of the two shutter curtains. Some cameras use very thin fabric instead of the metal curtains yours has. There is an opening curtain and a closing curtain. When the shutter is cocked (film wound) you see the opening one. When you trip the shutter, the opening one travels across the film gate and winds up on the other side. The closing one is released after a time delay to cover the film gate. The length of the delay between them determines the shutter speed. When you wind the film for the next frame, it winds up the closing curtain and pulls the opening one back across without allowing any gap between them along with advancing the film to the next frame. The curtains in yours are made of very thin metal and travel vertically. In some cameras they are made of lightproof fabric and travel horizontally.

Imagine a pair of curtains on a window, but instead of only being able to meet in the middle, each one is wide enough to completely cover it. Start with one bunched up completely at one end with the other completely covering the window. Then start opening one the one that's covering the window. After it's partway (or completely) across, start pulling on the other one at the same rate to cover the window. Afterward, pull them back without any gap between them to start over. This is how a focal plane shutter works.

The mirror is between the back of the lens and the shutter curtains. Both before and after the shutter has fired, it should hang down at a 45 degree angle with the top of the mirror attached just below the viewfinder at the back (closest to the film), and the bottom closest to the lens. The image formed by the lens is reflected by this mirror upward into the prism, which reflects it out the viewfinder. When the shutter fires, the mirror must be moved out of the way. Just before the shutter opens, the mirror is flipped up and covers the bottom of the viewfinder prism. After the shutter closes, it is allowed to drop back down again. I have a cutaway diagram of an SLR on my web site that shows all this:
http://johnlind.tripod.com/science/sciencebody.html#TypeSLR

To see the mirror, you must remove the lens. Don't mess with the mirror either, and don't touch its surface. It, and its hinge mounting are just as fragile as the shutter curtains. In addition, it is also "front silvered." The mirrors you are accustomed to have the silvering behind the glass. The mirrors in SLR's have the silvering on top of the glass. Removing fingerprints from these mirrors is not simple and should be done by someone who truly *knows* how to clean one. Cleaning one improperly can easily rub the reflective silvering off its surface! If you can see through the viewfinder, the mirror is down. If you cannot, the mirror is up. If the mirror is up, DON'T try to pull it back down.

Your camera has an electronic shutter. Whether the mirror is up or down, ensure you have good batteries in the camera and that they're oriented correctly. Even if they're newly purchased, I've gotten some bad batteries a couple times in the past. Unfortunately this camera doesn't have a battery check switch. It does have a "BAT Low" indicator in the viewfinder. However, if they batteries are totally dead or were put in backwards, this indicator will not work. If you can see through the viewfinder (mirror is down), you should be able to find some combination of lens aperture and shutter speed setting that moves the meter needle.

If the mirror is up:
You won't be able to move the meter needle even if you have good batteries. It requries light coming through the lens and being reflected up into the prism by the mirror. Usually the reason a mirror is locked up on cameras with electronic shutters is dead batteries. The mirror flips up as it released and moved mechanically, but the shutter cannot open as it is electronically operated. Another common possibility is corroded battery contacts from batteries that leaked inside the battery box. Also a possibility is "inverted" batteries put in backwards. Puting good batteries in (correctly oriented), and turning the camera on usually fixes this. The shutter finally opens and closes, and the mirror drops back down. If not, then try puting the shutter speed dial in the "B" (bulb) position. On some cameras, this is sometimes required to "reset" things electronically after power is restored to the electronics.

Hoping this might help you.

-- John

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March 08, 2003