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Kalart Rangefinder adjustment

 
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Hobbes



Joined: 05 Jun 2009
Posts: 2
Location: Salinas, CA

PostPosted: Tue Jun 09, 2009 7:19 pm    Post subject: Kalart Rangefinder adjustment Reply with quote

I just bought a Speed Graphic whose Kalart Rangefinder needs adjustment. I followed the steps outlined at http://www.graflex.org/speed-graphic/kalart-adjustment.html but I can't get the rangefinder to track accurately at all distances. I even tried tinkering with the "undocumented" infinity adjustment under the prism.

Every time I make an adjustment for one of the settings (i.e., rear scale, front scale, or infinity), the adjustment throws the other settings out of whack.

Does anyone have any additional tips for me? Thanks for your help.

Rob
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Les



Joined: 09 May 2001
Posts: 2682
Location: Detroit, MI

PostPosted: Tue Jun 09, 2009 9:48 pm    Post subject: Reply with quote

The way I do it is to find an infinity point (something a couple of blocks away, a traffic light works well) then put a stick in the yard @ 25ft. and t he same height as the camera, so you can swivel from the INF target to the 25ft target easily without tilting.

Set the INF. then go 25ft. go back to INF, and tweak, back to 25ft and tweak, back to INF and it should be pretty close. Repeat until they both work.

Then set up a 15ft. stake not too far from the 25ft. Work these back and forth, occasionally checking the INF point too.

After the 4 or 5th one, you can get this process down to about half an hour. the first time will take twice that, and as you might have guessed, it's not good to do this after you've had a double latte with a Red Bull chaser.
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troublemaker



Joined: 24 Nov 2003
Posts: 715
Location: So Cal

PostPosted: Fri Jun 12, 2009 5:57 am    Post subject: Reply with quote

It does. Each adjusment will effect the others until the RF is brought into happy calibration.
WARNING ! Be very careful about tweeking the lower prism. The spring steal mounting has a tendency to snap off if you so much as look at it funny.
I can get a nice Kalart to come around in about twenty minutes after I set up my targets and tools (with a standard lens). Mean ones can take well over three hours, and with longer lenses a little compromise is expected. I've had a couple that required repairs, cleaning, and so forth before they could be made to opperate well, and one that gave me fits until I decided it is actually just worn out. But for the most part they are a far sight easier to work on than 35mm RF cameras. So expect to spend some time figuring it out.
Sometimes the stops need to be re-set, or the eccentric tweeked two or twenty times, and occasionally the coupling arm requires re-positioning (which can be frustrating if you don't have it figured out), and after two hours of this you still haven't started the calibration yet only to find out after two more hours that you have to move the arm again to get more adjustment out of the eccentric. Once you have a good starting point you square your stops and snug the set screws lightly so as not to divit the soft aluminum rails and re-check everything for infinity and start your calibration process. One can use the arm (hardest), the stops and front standard in square, and the eccentric to find the proper 1/16 to 1/8" foward position for the correct infinity location of the rails in relation to the squared and locked down front standard with the lens in best infinity focus on the GG. With the rails 1/16 to 1/8" forward of the rearmost position (all the way back), this is where the RF should allign the split beams at an infinity target. It should have enough travel in the coupling arm to go beyond when the rails are racked all the way back for proper closing, hence not stress the RF by forcing the coupling arm beyond the RF's internal stop. When I set up an RF from scratch and have to install the arm I put it on and simply manipulate the arm with a finger until I get it positioned as mentioned above, and then when I think I have it right I use the actual rails and focussing knob to find my start position for the rails and coupling arm with the eccentric centered or a little forward of center. Then set up the lens and front standard, square, re-check GG and start calibration process.
After the camera is calibrated the stops are re-checked for square. If moved slightly this can be compensated for by using the eccentric without loosing calibration.
After being satisfied I have the best possible adjusment, I'll give the forward set screws on the stops a final snug, and then set the rear screws which I leave untightened until I am completely done.
Lastly, with the camera set up for infinity I allign the focussing scale inf marks and go rest my eyes for a while before going back through a last target focuss check and ready to shoot film.
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Hobbes



Joined: 05 Jun 2009
Posts: 2
Location: Salinas, CA

PostPosted: Mon Jun 15, 2009 3:26 pm    Post subject: Reply with quote

Thanks for the replies to my question.

The lens I'm using the camera with is a Schneider Xenar 1:4.7/135mm. I'm pretty sure that the infinity stops are positioned correctly on the camera. The ground glass shows infinity at focus when I move the front standard forward with the focusing knobs about 1/16th of an inch.

According to the Kalart instructions on adjusting the rangefinder, the approximate points of adjustment for a 13.5cm, f:4.5 lens are 15 for the rear scale and 3.5 for the front scale. (13.5cm and f:4.5 seem close enough to my 135mm/ f4.7 Xenar.) After I set the rangefinder for infinity and start to work on the 25 and 15 ft. distances with the rear focus adjustment, I find that I need to set the rear scale adjustment to about 11 or 12 to get the mid-distances in allignment.

When I start to work on focusing 8 and 4 foot targets with the front focus scale adjustment, I can't shift the front scale high enough to get the close distances into alignment in the rangefinder. In other words, the front scale "wants" to go lower than 1 in order to get the 4 foot target into coincidence in the rangefinder.

Does this description of my problem give you any better clues as to what I need to do?

(I haven't fiddled with the positioning of the actuating arm on the shaft that connects it with the rangefinder.)

Thanks again for your help. I've really enjoyed reading around in the forum for tips on how to use the Graphic.

Rob
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troublemaker



Joined: 24 Nov 2003
Posts: 715
Location: So Cal

PostPosted: Mon Jun 15, 2009 11:46 pm    Post subject: Reply with quote

Did you move the prism ?
If so, perhaps this moved the useable range of the mid and close scales too far forward or back?
If you have enough adjustment left in the eccentric down on the rails, you can shift the infinity position back or forward and see if this will get you in range.
The Kalart should adjust down to 4ft with a 135mm lens. But keep in mind this is pretty close for using a Kalart as any slight shift, tilt, or swing of the camera will take a 135 out of focus and most close work is done on the GG. Just look at the RF split images and move the camera a little and you'll catch my meaning. Dead on at infinity, 25, 15, and 8ft with 6ft being very close and 4ft in the ball park so to speak is about as good as it gets. Shorter lenses like an 80mm on a 23 series camera will focus at 4ft pretty accurately, even a little closer.
A longer lens like a 7" on a 4x5 has about a 8ft accuracy limit, with 6ft asking a lot.
With a 135 lens you shouldn't be at the limit of adjustment as you stated.
If you shift infinity with the prism and or eccentric you'll need to re-set the lens, so maybe try it without moving the stops first so as to prevent adding more dimples with the set screws. The reason I say this and suggest to folks to avoid gouging the top of the rail with the stops' set screws is that a slight adjustment may find the set screws trying to move the stop and sink down into the old dimple, and thereby changing your adjustment or shifting the stop out of square.
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BetterSense



Joined: 17 Nov 2009
Posts: 18
Location: Dallas

PostPosted: Tue Nov 17, 2009 4:13 pm    Post subject: Reply with quote

Quote:
With the rails 1/16 to 1/8" forward of the rearmost position (all the way back), this is where the RF should allign the split beams at an infinity target.


I adjust my infinity stops so that my lens is infinity-focuse with the rails racked all the way back. My vernier scale-focus indicator lined up this way when I got the camera. Why do you suggest infinity should be reached with the rails slightly forward? It seems simple to be able to rack the rails all the way back and be assured of infinity focus.

I have a kalart that I think was adjusted for a 135mm lens. The 127mm lens that's on it is in calibration only approximately, and only for distances greater than 10 feet. The brass screws on my kalart are rounded, so I can't adjust it. Even so, having a working rangefinder is a great thing. It really transforms what's possible with the camera.
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45PSS



Joined: 28 Sep 2001
Posts: 3246
Location: Mid Peninsula, Ca.

PostPosted: Tue Nov 17, 2009 8:21 pm    Post subject: Reply with quote

Back when the Press Camera was King photographers of the day liked to be able to focus past infinity then come back to infinity therefore Graflex states in their service manuals to rack the yoke fully reward then forward .040 +/- .010 inch and lock the yoke prior to setting the lens infinity and infinity stops. 1/16=.0625; 1/8=.125; 1/32=.01325; 3/64=.046875; 5/128=.0390625

This Kalart adjustment site may be of help also:
http://www.xs4all.nl/~lommen9/kalart/index.html

I printed several pages of lens test targets and mounted them on a 20 inch by 24 inch artist canvas then mounted that to a simple light stand. On level ground lay the end of a 50 foot or 100 foot tape measure under the camera at the film plane then sit the test targets at the distance mark you wish to test the focus at. Use a loupe on the ground glass for the most accurate focus.
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