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02-05-2020, 11:38 AM   #1
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Spotmatic just got serviced, but mostly unexposed rolls of film

Hey all,

Using a Spotmatic I hadn't used in about 15 years. Just got it serviced and cleaned a few weeks ago, and the first two rolls it shot were either a. entirely unexposed, or b. only about a third exposed.


Have never had problems with the camera before, and obviously could be bad work on the film advance.


But one other thing I am wondering about: This is the first time I've ever used this camera without a battery in it, and had the lens on the automatic setting (rather than the manual) for most of that shooting. Without the battery is the aperture not doing what it's supposed to?

Thanks for any thoughts...

02-05-2020, 12:01 PM   #2
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QuoteOriginally posted by electrickoolaid Quote
Hey all,

Using a Spotmatic I hadn't used in about 15 years. Just got it serviced and cleaned a few weeks ago, and the first two rolls it shot were either a. entirely unexposed, or b. only about a third exposed.


Have never had problems with the camera before, and obviously could be bad work on the film advance.


But one other thing I am wondering about: This is the first time I've ever used this camera without a battery in it, and had the lens on the automatic setting (rather than the manual) for most of that shooting. Without the battery is the aperture not doing what it's supposed to?

Thanks for any thoughts...
Sounds to me like a film advance issue (not sure what you mean by "only about a third exposed" -- a third of the frames were exposed, and the rest unexposed?).

The battery is only for the TTL meter, and does not control the aperture mechanism or any other mechanical functions.

I make a habit of tensioning the rewind knob immediately after loading the film, then making sure it turns a bit as each frame is spooled from the cassette. Usually if it's working for the first 3 or 4, the film is properly engaged in the take-up spool.


Something that may be happening is the rewind release button on the bottom plate has become unscrewed to the point that the wind-on mechanism is disabled, even though you can still pump the advance lever and cock the shutter (again, you can tell if the rewind knob fails to turn during film advance).

You can manually screw the release button back down with your finger tips in the field, but for a lasting fix, take off the bottom plate, unscrew the button, put a drop of nail polish on its threaded post, and screw it back on, allowing the nail polish to dry before attempting to use it again. You can do this with film loaded.
02-05-2020, 02:49 PM   #3
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QuoteOriginally posted by electrickoolaid Quote
Thanks for any thoughts...
Welcome to the Pentax Forums!

Since your camera has been recently serviced, you would probably best served by going back to the shop with both camera and negatives and asking the tech to explain what happened. I would not suggest trying to fix this yourself or attempting a work-around.


Steve
02-05-2020, 07:08 PM   #4
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QuoteOriginally posted by electrickoolaid Quote
Hey all,

Using a Spotmatic I hadn't used in about 15 years. Just got it serviced and cleaned a few weeks ago, and the first two rolls it shot were either a. entirely unexposed, or b. only about a third exposed.


Have never had problems with the camera before, and obviously could be bad work on the film advance.


But one other thing I am wondering about: This is the first time I've ever used this camera without a battery in it, and had the lens on the automatic setting (rather than the manual) for most of that shooting. Without the battery is the aperture not doing what it's supposed to?

Thanks for any thoughts...
Not a Spotmatic expert, but doesn't Auto use the meter? Doesn't the meter need the battery?

02-05-2020, 07:42 PM   #5
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QuoteOriginally posted by MadBill Quote
Not a Spotmatic expert, but doesn't Auto use the meter? Doesn't the meter need the battery?
"Auto" on a Spotmatic's M42 lens means auto aperture actuation vs. fully manual aperture and requires zero electricity.


Steve
02-06-2020, 07:01 AM   #6
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QuoteOriginally posted by stevebrot Quote
I would not suggest trying to fix this yourself or attempting a work-around.
The rewind release button is very simple to check and 'fix' (as described), and is a somewhat likely culprit.

Spotmatic film loading can be finicky if you're not used to it. I have three, and have been actively shooting and 'fixing' their little idiosyncrasies for >20-years (my first fell out of active use simply because a metal clip wore through a strap lug).

The first two hurdles you have to cross are getting the take-up sprockets to engage the film sprocket holes before you close the back (the little slots on the take-up spool are next to useless and can't be relied upon to overcome the resistance of dragging film out of the cassette and across the pressure plate).

Then, you need to make sure the film is between the rails. If you manage to get the film properly engaged, but one edge is pinched between a rail and the back, it will stress the whole film advance (assuming it doesn't seize up until you open the back), and possibly damage the film. I know it sounds simple and idiot proof -- but I'm an idiot.

Forcing the advance lever to overcome the extra resistance from improperly loaded film can actually tear the film in half (I know, I've done it).

Finally, there's the rewind release button in the bottom plate. I don't what kind of cement (if any) was applied to keep it in place in mfg, maybe shellac, whatever, after ~50-years, it will fail, and the button will start to unscrew itself until it is sitting so high on the post that it is depressing it 100% of the time. Rewind-release. You can flap the advance lever and fire the shutter all you want, but no more film will be spooling from the cassette, as you can observe, the rewind knob stops turning.

This can happen mid-film (I know, I've done it). It's entirely possible it passed the CLA inspection and failed after, for whatever reason. Such are vicissitudes of vintage camera operation.
02-06-2020, 12:39 PM   #7
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QuoteOriginally posted by dsmithhfx Quote
The rewind release button is very simple to check and 'fix' (as described), and is a somewhat likely culprit.
The question is not whether the check/fix is easy. it is whether it is worth the trouble or wise given that the camera was fresh from a CLA. An attempt at self-repair, if not properly done, would make it difficult for the service center to honor their warranty.

As for loading difficulties...I understand (have three Spotmatics) and tend to agree, though the roll with some good and some blank seems to indicate something else.


Steve
02-06-2020, 12:51 PM   #8
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If high shutter speeds didn't come out and slower speeds did, I suspect it needs re-adjustment of the shutter curtain travel times. Sometimes cameras that have not been used for a while take a bit of use before that stabilizes. Anyway, you need to send it back to get re-done.

02-07-2020, 08:07 AM   #9
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QuoteOriginally posted by pentaxus Quote
If high shutter speeds didn't come out and slower speeds did, I suspect it needs re-adjustment of the shutter curtain travel times. Sometimes cameras that have not been used for a while take a bit of use before that stabilizes. Anyway, you need to send it back to get re-done.
The Spotmatic has two distinct gear trains; one for speeds of 1/60 or slower and another for speeds of 1/125 and faster. As Pentaxus stated, the higher shutter speeds may need adjustment. It is possible that the leading (or opening) shutter curtain is dragging, allowing the trailing (or closing) curtain to catch up. Normally, the opening and closing curtains form a moving slit that travels across the film plane. The higher the shutter speed, the narrower the slit.

As others have pointed out, the "Auto" setting on a Spotmatic lens does not control the aperture setting. It is now considered somewhat of a misnomer. Before the 1960's, lenses were often completely manual or "preset". With a manual lens, you must set the aperture yourself. With a preset lens, there are two aperture rings. One has the normal detents for the various f/stops and the other simply closes the iris to the preset aperture.

In the late fifties/early sixties, lenses began to appear on the market that stayed open until the moment of exposure. Then, the camera "automatically" stopped the aperture down to the selected value. You still had to manually set the aperture on the ring, but on Pentax screw mount lenses, there is a little silver pin on the lens. When you press the shutter release, the camera pushes that silver pin, stopping the lens down to the shooting aperture.

However, if you had the lens on auto and left it set at the widest aperture, you still should see images on the negatives, albeit severely overexposed. If the film is truely blank, I would look for film advance issues or shutter issues.

I suggest you run a test roll through the camera, using one exposure for each possible shutter speed. Don't worry too much about getting a "proper" exposure; you just want to have each shutter speed used. All frames should have something recorded. If, for example, they all look good up to 1/60 second, but 1/125 and faster have no exposure, then you clearly have a high-speed shutter train issue. They may be okay to 1/250, for example, but fade out at faster speeds. That would mean that the gear train is working (although it may still need adjustment), but that the trailing curtain is catching up to the leading curtain. Remember, at higher speeds, that moving slit is pretty narrow. I believe at 1/1000, the slit is only 4 or 5 mm wide, so it wouldn't take much for the leading curtain to slow enough to allow the trailing curtain to catch it.
02-07-2020, 10:01 AM   #10
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QuoteOriginally posted by noblepa Quote
I suggest you run a test roll through the camera, using one exposure for each possible shutter speed.
You can also 'fire blanks' with the back open and point it at a strong light source for a rough idea of whether a speed works at all.
02-07-2020, 12:42 PM   #11
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QuoteOriginally posted by noblepa Quote
In the late fifties/early sixties, lenses began to appear on the market that stayed open until the moment of exposure. Then, the camera "automatically" stopped the aperture down to the selected value. You still had to manually set the aperture on the ring, but on Pentax screw mount lenses, there is a little silver pin on the lens. When you press the shutter release, the camera pushes that silver pin, stopping the lens down to the shooting aperture.
Much earlier terminology on "automatic" is even more confusing now. Before 1932 Leica cameras had no built-in rangefinder. To focus you used an external rangefinder to measure the distance, and then adjusted the camera lens scale to that same distance to get it in focus. In 1932 Leica introduced the model II that had a built-in rangefinder. The lens linked to the rangefinder so that as you turned the lens focus mount it coupled to the rangefinder so you could see the double image converge. Leica called this "automatic focusing", as when you manually turned the lens until the rangefinder converged, the lens was then "automatically" in focus. They meant you didn't need to transfer the rangefinder reading to the lens manually.
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