Text and Photos by Bob Warkentin
For quality underwater photographs showing the proper mix of water, marine life and human interaction, remember the old sayings "know your diving area" or "you just gotta be there".
So, let's set the stage for Murphy's TUG-OF-WAR play! The players are (1) the strength of Hercules' thumb coupled to (2) his mindset TUG-OF-WAR insistence to (3) force the camera's metal gears to (4) force the camera's plastic gears to (5) STRETCH his roll of film for JUST ONE MORE FRAME!
You begin to search a reef you have never dove before for that proper mix of subject material. After a while of searching, becoming familiar with the reef and taking so-so pictures of so-so subject material, all of a sudden its right there in front of you: that proper mix with no back scatter and you've got your BC just right!
Anxiously cocking your camera, about half way or so through your required cocking motion you feel your film advance lever stop short of full cock, telling you "You are finally out of film!". Hurriedly you begin to STRAIN and TUG on your film advance lever with your thumb as you say to yourself "There's just gotta be a little more film hiding in the canister!"
Remember, although thin, photo films are very strong. Also, the other end of the film has (for obvious reasons) been attached to the canister's spool with a strong piece of tape. So, for your Nikonos V (and probably all cameras), your TUG-OF-WAR literally breaks ("murders") many plastic internal gears which are caught between the strength of your Herculean hand to advance the gears just for a little more film, and the strength of the film and tape not to give you any more!
To understand how things in the camera get broken, we must get real technical about construction and your "cocking" operations! There is a spring loaded, long METAL gear axle located (hidden from view) inside the hollow PLASTIC film sprocket (photo 1) which extends all the way up into the upper camera chamber where the film advance assembly is located (see photos 3 & 5 as well). This metal gear axle is equipped with a METAL screw "finger" mounted to it at 90 degrees. Also, in the top of the internal chamber of the PLASTIC sprocket are 3 PLASTIC notches I call "wagon wheel spokes" (photo 2). During all shutter speed settings except "R" rewind, the metal "finger" sits in the plastic notch.
Mechanically, your simple "cocking" operation is engineered to move many gears (some are visible in photo 5), which, in turn, (1) makes the axle rotate causing (2) the axle's metal "finger" to push (against) the flat surface of the plastic wall of a "spoke" inside the sprocket in order to (3) rotate the sprocket to achieve (4) the advancement (pulling) of your film out of the canister for your next shot. So, when your thumb feels the advancing lever tighten up (a restriction) during film advancing, this is simply because there is no more film to freely unwind off of the spool.
Next, mechanically, although you may never have noticed it while turning the shutter speed dial past the "B" setting going towards "R", about half way between you should begin to feel some slight restriction to the turning of the dial as compared to that experienced between other speeds. This feeling is simply due to the changing of gear operations in the camera: the spring loaded metal axle inside the film sprocket is being pushed downwards (photo 3) taking with it (disengaging) the metal "finger" out of and away from the plastic sprocket's "wagon wheel spoke" notch.
As long as the originally flat wall of the "wagon wheel spoke" remains flat, turning the camera to "R" causes the axle's "finger" to simply slide down the wall disengaging the sprocket for leftward rotation (rewinding) of the film. But, unknowingly, your STRAINING the film advance lever to TUG OUT that one more shot has now forced the axle's metal "finger" to become IMBEDDED into the no longer moving, once flat, plastic wall of the sprocket's "spoke". As long as the film (and camera) remains tightly STRAINED between the spool and the sprocket by your over zealous TUG-OF-WAR, the axle's "finger" will remain IMBEDDED and hung up in the "spoke" and will no longer simply slide down the face of the once smooth "spoke" when turned to "R".
Realizing that you really are out of film, you make mental notes of the war stories of the 37th photo that got away as you are returning to the surface to reload the camera. Its not until you begin to rewind the film that you get your FIRST INDICATION of a possible problem other than just being out of film.
When a TUG-OF-WAR "hang up" of internal gears has occurred, it will be exhibited to you while are now turning the shutter speed dial half way past "B" on your way to the "R" setting. But, if you have never been aware of the existence of a feeling of some restriction, or you had never given it any thought in the first place, then the unexpected degree of restriction you will now encounter won't be able to warn you of pending doom.
Since you have now felt an extreme restriction even though the shutter speed dial is only half way into the "R" setting, you first assume that the camera must be in the proper "R" position after all, regardless of the fact that the dial is not yet fully aligned to "R". Thus, you flip out the rewind crank handle and begin to crank up the film. As you begin to force the handle to wind the film, you feel it difficult to move the crank. As your hand applies more force, you notice that you have now broken the crank handle away from the camera!
In frustration, you return again to the shutter speed dial and apply additional strength to force the dial to turn further towards the "R" position. As you apply, and continue to increase, force from your hand to make the dial turn to "R", all of a sudden you feel the dial "break free" of the restriction and turn. Removing your hand from the dial to inspect your handy work, you notice that the dial did turn but this time the dial has now been moved beyond the "R" position. You again try the remaining pieces of the broken rewind crank and again find that it won't turn nor rewind the film.
Realizing that the "R" position of the dial must, after all, be properly lined up with the white mark on the camera, you again begin to turn the dial from beyond "R" (the zone on the dial containing no numbers). However, there is as much restriction to the turning of the dial as there was before. Again, through the strength of your hand, you manage to overcome the resistance and the dial is now aligned with the white camera mark. Breathing a sigh of personal relief, you again grab the remainder of your broken rewind crank only to find that it still won't move. End of ACT 3.
There are two internal plastic gears which move as you rotate the shutter speed dial. One of these gears (photo 4), which is PERMANENTLY mounted to the big film advance assembly, when rotated into different positions is used for things like changing the mechanical shutter speeds, blocking the accidental pushing of the trigger from opening the shutter and letting in light during rewinding of film, turning on the electronic main switch, and disengaging sprocket gears for the rewinding operation.
Made of plastic, this gear (photos 5 and 6) gets broken when the speed dial is intentionally forced back to "R" after it had has been accidentally forced past "R".
Intermission: At this point in the play, either you or a photo pro takes the camera into the dark to unload the camera and save the film.
Back in the room light, you begin to inspect the film canister, and the insides and out of the camera for visual problems: none found except the broken rewind crank which you find can still be rotated by hand, even without its handle. So, after reloading film and closing up the camera and turning the shutter speed dial off of "R" to whatever shooting speed you normally use, you try advancing the cocking lever of the camera: nothing works! You then press the trigger: nothing works! Lever; trigger; lever; trigger; still, nothing works! Well, that's the end of ACT 5 as well as your use of your camera for the rest of your dive trip.
In a nut shell, what has happened as a result of your trying to play TUG-OF-WAR between the strength of your hand to STRAIN out just one more picture and the strength of the film is that (1) the gears inside the plastic sprocket have become jammed, causing you to have to (2) use extreme force to turn the speed dial to "R" and override the jam, which usually results in (3) the dial being turned past "R", which results in (4) unfortunately your breaking internal parts of the camera when returning the speed dial back to "R", and worst of all, this is (5) not an in-the-field repairable problem unless you just happen to have expensive parts with you!
True, we all usually go to the end of our rolls of film before we rewind them. And, whatever the excuse, we know there are times when we have tried just a little harder than usual to get that last frame out of the canister. But all of this damage could have simply been avoided if you had trained yourself to realize the feeling of "rewind restriction" and took alternative measures.
Teach this "normal restriction" feeling to yourself first without any film in the camera at all and turn the dial into "R"; then load up a roll, fire only 2 or 3 shots to put a normal tension onto the film and then turn to "R". Remember from above, the feeling of restriction always appears about half way between "B" and "R". Compare it to that feeling of between speed to speed selection!
To experience "abnormal restriction", begin by first being sure the camera is not cocked (fire the camera!) and is in any shutter speed other than "R" (let's use "A" just for the sake of argument). Now, open the camera and hold your finger tightly against the sprocket. Try to cock the camera a little with your other hand, simulating the strain put onto the camera's gears by the film. While keeping your finger on the sprocket, use the other hand to turn the speed dial from "A" to "M90", to "B", and then to "R". About half way to "R", you will feel the very stiff, "abnormal restriction" of the over strained gears. Know the difference!
If you believe you have felt a strained condition present during rewinding, don't force anything. Just open and unload the camera by hand in the dark room. If you do, you will find that the camera still works and hasn't been damaged. From then on, unless you just love sitting in the dark winding film by hand, I suggest always saving a few shots for those great photos at occur only at the end of every dive. I'd rather come back with only 30 shots exposed than a jammed camera.
Reprinted with permission from Bob Warkentin's Southern Nikonos Service Center, Inc.
9459 Kempwood, Houston, TX 77080 713/462-5436