Kodak 3A Infinite focus

Micronorton · Sep 16, 2014

I just started shooting with my 3A the other day and after developing I noticed my mountainous expansive shots were all out of focus while other images with objects closer tended to be dead on. While the 3As have focusing suggestions, these only go out to 100ft distance. Does anyone have a suggestion for infinite focus?

Best,

Chase

snapguy · Sep 16, 2014

scale

Doesn't your 3A have a focusing scale on the bed of the camera, similar to those on the Speed Graphic? There should be an "infinity" symbol on this scale which looks like an "8" lying on it's side. Also, I believe the camera has a ground glass in the back and you can focus using that tool. Nice camera.

NedL · Sep 17, 2014

Welcome to APUG!

My 3A has an infinity symbol, although there were a number of versions over many years, so it's possible that some had a "100ft" mark instead ( I vaguely think I have an Autographic Jr. 1A that is like that. ) There is a little "toe" that sticks forward and you want the front of that to be at the infinity line.

On the right hand side, looking from behind the camera, you should see a lever that will catch the lens carrier and allow you to smoothly move it over the scale focus marks. The infinity mark can be a little tricky, because it is right where the mechanism "catches" the lens carrier. On mine, if I'm not careful and paying attention, it can lose its "grip" when set at infinity and the lens will slide in toward the camera a little. That would cause a shot at infinity to be out of focus.

On one of my autographic 1A's some owner was not careful and that "toe" that marks the scale is bent back a little. So the camera is always focused slightly closer than it indicates. With that camera, I just stop down a little and all is well.

Snapguy, some 3A's do have a GG back, but it was the exception and an add-on I think. I've never seen one.

Have fun with your 3A, that's a very fun camera to use!

Micronorton · Sep 17, 2014

Sadly, mine does not have the infinity symbol. The furthest marking is 100 feet (perhaps the equivalent to infinity?). No GG, just modified 120 rolls. Fun camera indeed! love the unique 6x14 format for architecture

NedL · Sep 17, 2014

I've got an older 3A ( that I actually purchased only for the lens itself )... I just got it out and it is like yours. The "100 feet" marking is definitely for "infinity". Like "100 feet or more". The mechanism on that older camera is also different from what I described, but nevertheless, try to double check that the lens is tight up against the stop for 100 feet and hasn't slid back at all.

Must admit it's a mystery that it could be in focus at shorter distances, where I'd think it would be more critical. I don't know if you have facilities to make paper negatives, but that could provide a very quick way to make tests and try to figure out what's happening. And you could try stopping down some more and making a longer exposure...

Micronorton · Sep 17, 2014

Here are the two of three successful shots from the first shoot on the 3A. These were purely for test value with very little focus on the framing/composition. I really appreciate your input and will repost with some shots tested on the 100ft setting.

Best,

Chase

shutterfinger · Sep 17, 2014

Mount your camera on a tripod. Open the back and hold a piece of ground glass against the film plane as film would be. Focus the lens on infinity by moving the front standard on the rails with the rails fully retracted. With the front standard locked and square to the film plane set the infinity stops against the front standard or set the focus scale pointer to infinity.
Now look through the view hood and adjust the ground glass to match the film plane.
Use an infinity target that is at least 5000 feet away.
A temporary ground glass can be made by putting transparent tape on a sheet of standard glass or a piece of clear plastic. The tape side goes toward the lens. A sheet of wax paper will work also but is not as sharp.

I can provide instructions for removing the view opening ground glass if needed.

Trask · Sep 17, 2014

shutterfinger said:
A temporary ground glass can be made by putting transparent tape on a sheet of standard glass or a piece of clear plastic. The tape side goes toward the lens. A sheet of wax paper will work also but is not as sharp.

You can also go to an art supply store and get some very "fine-grained" tracing paper that you can tape into the film plane.

tokam · Sep 17, 2014

Shutterfinger has the right idea. For clear plastic I use a cut down CD jewel case. Make sure it's a clean, new one. Apply frosted Scotch in strips and butt them
up against each other. The trouble with wax paper and tracing paper is getting them flat in the film plane. Not worth the aggravation when 10 mins with CD case and tape
provides a much better solution.

John Koehrer · Sep 17, 2014

Keep in mind the lens may be moving beyond the marked infinity or the stop may be bent forward. Infinity as far as the camera/lens is only several hundred X the focal length of the lens so something down the road a piece(couple of city blocks) is adequate.

shutterfinger · Sep 17, 2014

Keep in mind the lens may be moving beyond the marked infinity or the stop may be bent forward. Infinity as far as the camera/lens is only several hundred X the focal length of the lens so something down the road a piece(couple of city blocks) is adequate.

Focusing on an object a few hundred feet away results in out of focus mountains, moon, stars when set as infinity.
Always set infinity with the lens wide open.
I was using coastal hills 3000 to 4000 feet away as an infinity target and any focal length lens set using this target was always soft when viewing Celestial objects wide open. I found a building about 6000-7000 feet away and using it as an infinity target requires no additional adjustment of the focus for any celestial object bright enough to be seen in the viewfinder or on the ground glass.

Always use a loupe to set the focus if you want more than just good enough stopped down.

John Koehrer · Sep 18, 2014

Pretty hard to find an unobstructed target a mile away in a big city, maybe not in mid peninsula, Ca.
Still maintain 5k feet isn't needed. Never had to use it.

rjbuzzclick · Sep 18, 2014

Also check that all of your lens elements are screwed in tight. I had an Argus A that had focus problems until I discovered that the rear element was 2-3 turns out from tight.

NedL · Sep 18, 2014

rjbuzzclick said:
Also check that all of your lens elements are screwed in tight. I had an Argus A that had focus problems until I discovered that the rear element was 2-3 turns out from tight.

+1
I almost wrote last night to say exactly this. That example image is too far out of focus for the subtle scale focus problems we're talking about. It made me wonder if the lens elements are screwed in all the way or even if one might be missing.

OptiKen · Sep 18, 2014

What film do you shoot with your 3A? Has it been modified for 120 roll or sheets or ????

Kodak 3A Infinite focus

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