If the ground glass is held in place by a thin, black metal frame that is held in place by a small screw in each of the four corners, it is a 500 C. If the ground glass is held in place with a silver tab on the left and right sides, it is a 500 C/M.
Here is the procedure you can follow to check the operation of the camera, as taken from one of my newsletters:
When something goes wrong with your camera, such as a broken main spring or flash contact in your lens, you'll know immediately because all of a sudden the camera will jam or the flash won’t fire. If the mirror spring in the body breaks, you'll know it because the body will jam up. Of course, it's not good when these things happen, but at least you'll notice it right away, and you can switch cameras and continue shooting.
The big problems happen when something goes wrong with the camera and you don't notice it, like sluggish diaphragm blades in your lens, or a broken shutter blade that's hiding at the edge of the shutter.
You would be amazed at how many photographers have something go wrong with their camera, but don't notice it until it's too late. One of my customers got a call from his lab, informing him that every negative he shot at a wedding was three to four stops overexposed.
He brought the lens to me, and I discovered the problem was that a small spring that controls the diaphragm actuating ring had become unhooked. Although he had the lens set on f 11, the lens was shooting all the way open at f 2.8.
Needless to say, this was a nightmare for my customer. It cost him a lot of time and money, the cancellation of a wedding that had already been booked by a family member of the bride, and serious damage to his reputation.
Why am I telling you about this unfortunate incident? To illustrate a point that no photographer should ever forget:
NEVER TAKE YOUR CAMERA FOR GRANTED! NEVER ASSUME THAT YOUR CAMERA IS WORKING PROPERLY! CHECK IT OUT BEFORE AND DURING EVERY JOB!
I am now going to tell you how to check your camera out prior to a job.
Camera body: Remove the lens and magazine. Press the release button, and hold it in. While you are holding it in, check to see that both of the rear flaps are opening all the way. Now let go of the release button, and check to make sure that both flaps have closed completely.
Lenses: Set the shutter speed ring to one second, and set the f stop ring to the largest opening (smallest number). Look into the front of the lens and fire the camera. The shutter blades should close down, then open instantaneously, stay open for one second, and then close again. While you are watching this happen, check to make sure that none of the shutter blades are broken or appear to be out of place. Also, notice how long the one second exposure actually is. You can pretty much tell how long one second is. If the shutter is dragging at one second, it is an indication that the shutter needs to be cleaned and lubricated.
Wind the body again, turn your strobe on, and attach the synch cord to the lens. Set the shutter speed ring to the fastest speed and set the f stop ring to the largest opening (smallest number). Point the camera and the strobe to a light colored surface, and, while looking through the back of the camera body, fire the camera. You should see a brief, large round flash of light through the lens. If you see no flash of light at all through the lens, check to insure that the "VXM" lever on the lens is in the "X" position (only on the older C lenses). If you see part of the shutter blades instead of a round flash of light, there is a problem, and that lens should not be used. Check each of your lenses using this procedure. If you are photographing a wedding, it is a good idea to perform this particular check each time you change film magazines.
For older C lenses only: Set the shutter speed ring to one second, and set the f stop ring to the smallest setting (largest number), and, while looking into the front of the lens, press the depth of field preview lever on the lens. When you press it in, the diaphragm blades should quickly snap closed. If they close sluggishly, it is an indication the lens needs to be serviced.
For newer C, CF, CFi and CFe lenses only: Set the f stop ring to the smallest setting (largest number), and move the stop down lever to the stopped down position. The lever should lock in this position. Look at the diaphragm blades, and insure that they have closed down to the smallest opening. While watching the diaphragm blades, press the end of the stop down lever. It should return to its normal operating position, and the diaphragm blades should open all the way.
Film magazine: Remove the lens from the body and put the magazine on. Remove the dark slide and try to remove the magazine from the body. It should not come off the body with the dark slide removed. Insert the dark slide in the magazine and try to fire the body. The body should not fire when the dark slide is inserted. Take the magazine off the body and remove the dark slide. Look at the serial number plate on the magazine and make sure that the light trap or light trap foil is not sticking out of the side of the magazine, into the image area.
Older magazine 12 without the plastic flip out crank: Lift one side of the advance key and turn it counter-clockwise. You should see the number 1 in the film counter window. Fire and wind the camera 12 times while watching the film counter window and the red/white indicator window. Each time you fire the camera, the signal flag should change from white to red. When you wind the camera, the number in the film counter window should advance to the next number. After the 12th exposure, wind the camera and try to fire it again. It shouldn’t fire after the 12th exposure. Lift one side of the advance key again and turn it counter-clockwise. The number wheel should return back to number 1.
A-12 magazines with the plastic flip up crank: Flip up the black plastic film advance crank and turn it clockwise. It should stop turning the moment the red/white indicator changes to all white. At this point, the number 1 will show in the film counter window. Fire and wind the camera 12 times while watching the film counter window and the red/white indicator window. Each time you fire the camera, the signal flag should change from white to red. When you wind the camera, the number in the film counter window should advance to the next number. After the 12th exposure, wind the camera and try to fire it again. It shouldn’t fire after the 12th exposure. Now remove the insert from the magazine. The number wheel should return back to number 0.
Note: The newer A-12 magazines do not have a number 0. In this case, you will not see any number in the window.
David S. Odess - Factory trained Hasselblad technician
