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Thread: Kalart Rangefinder accuracy and fast lenses

  1. #1

    Join Date
    Jan 2005
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    7

    Kalart Rangefinder accuracy and fast lenses

    Hello,

    Would anyone know if the Kalart RF on a 4x5 Speed Graphic is accurate enough to focus a 150mm f2.8 lens wide open? I've acquired such a lens (ex-aerial) in barrel, and would like to have it mounted for handheld use on a Graphic if I could focus it accurately. I have a slower and lighter lens for tripod work, and was wondering it this was worthwhile.

    Thanks in advance for your help.

  2. #2

    Join Date
    Dec 2001
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    NJ
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    Kalart Rangefinder accuracy and fast lenses

    Um, I have a 4"/2 on my 2x3 Speed and the Kalart focuses it well. But I rarely shoot it wide open.

    Which 150/2.8 ex-aerial camera lens do you have and what is its back focus? I ask because I recently acquired a 6"/2.8 Elcan and was astonished to find that its back focus is < 50 mm.

    Cheers,

    Dan

  3. #3

    Join Date
    Jan 2005
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    7

    Kalart Rangefinder accuracy and fast lenses

    Dan,

    That's good to hear. Maybe I have more than a paperweight.

    The lens is made by Actron corp., and it says Type II on the front. The size of the thing, and a piece of white cardboard, leads me to believe that it covers (or at least illuminates) 4x5. It was probably intended for use on 5" rollfilm. The back focal distance is 3 3/4", so it should be ok on a Speed. It's quite heavy but most of the weight seems to be due to the motorized aperture, which I will remove anyway. The rear element might have to be screwed in separately from the back of the camera as it's too wide for the throat of the Speed.

    I was going to play around with it wide open for informal portraits; at around 10ft I should have enough depth of field and nice isolation.

    Cheers,

    Vamsi

  4. #4

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    NJ
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    Kalart Rangefinder accuracy and fast lenses

    Vamsi, very interesting.

    FYI, the rear of my 4"/2's barrel is too big to pass through my 2x3 Speed's front standard. And since the barrel is straight from the mounting flange back, attaching the rear cell from behind isn't an option. The late Steve Grimes put it on board for me, it is held to the board by a custom flange that passes through the board and screws into the rear of the lens. Consider having such a flange made if nothing else works.

    Cheers,

    Dan

  5. #5

    Join Date
    Oct 2004
    Posts
    122

    Kalart Rangefinder accuracy and fast lenses

    Dear Vamsi,

    This may not be relevant, but the Graflex rangefinder (top mounted) on my Crown Graphic turns out to be very accurate. I could only test it using f/4.7 on a 135mm lens, and it would only focus down to about 3 feet, but it agreed with my best focusing effort on the ground glass and the negative was sharp where it should have been.

    If your rangefinder is anything like mine, you could adjust it to be very accurate in the distance range you are interested in.

    Neal Wydra

  6. #6

    Join Date
    Feb 2001
    Location
    Greenbank, WA
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    2,605

    Kalart Rangefinder accuracy and fast lenses

    Vamsi: If you follow the Kalart manual precisely in calibrating the rangefinder (available off the Grafelx.org site), including the bit about the height of the target on the closer adjustment, I think you will find you can get it to be essentially as accurate as using the ground glass. I think the people who criticize these are using ones which aren't properly calibrated or are broken. When they work, they really work well. You sometimes have to go through the entire calibration procedure at the three distances more than once, since an adjustment here can affect an adjustment elsewhere. When adjusting it, there is one screw which locks counterclockwise, this is counterintuitive (even though it has an arrow next to it) and it is really easy to break off the screw head, so watch that. One calibrated, they can sometimes become slightly off for no good reason, so verify the performance now and then on the ground glass. Good luck.

  7. #7

    Kalart Rangefinder accuracy and fast lenses

    Vamsi,
    I use a 2x3 Century Graphic with the same side-mounted Kalart rangefinder as on the 4x5 models. I regularly use a f2.8 80mm Xenotar, and about half the time wide open or close to it. I have found the rangefinder very accurate from infinity to as close as 3 ft. I spent about 2 hours adjusting the rangefinder. Go to graflex.org for the directions. If I remember I will post an image when I get home.

    It's also good to re-check the rangefinder every few months just to be safe. I found that one of the screws I had not re-tightened enough.

    Darin

  8. #8

    Kalart Rangefinder accuracy and fast lenses

    Recalibrating the rangefinder isn't too bad a task. I followed the path of least resistance from graflex.org. It took me an evening once I had a manual, etc. I did some checks on objects off at 6-12' post calibration. It couldn't have been off more than a few inches - which I think would have been OK for a 150/2.8 wide open - don't have a depth of field chart in front of me. Don't know how the calibration held up as I sold the camera a couple months later.

    Chris

  9. #9

    Join Date
    Jan 2005
    Posts
    7

    Kalart Rangefinder accuracy and fast lenses

    I just got back to check all the responses. Thanks again for the suggestions.

    I will send the lens off to SKG. Dan, I may not have the same problem with the lens that you had, since the central portion of the lens, where the aperture is, is quite a bit narrower than the ends; I expect they will figure this one out at the shop, and will ask them to add such a flange as yours if needed.

    I've downloaded the instructions and the manual for adjusting the RF from the graflex.org site (which seems to have a ton of other info besides), and will give it a go.

    The only information about the Actron company I got from the web was that it was a military contractor, whence my guess that the lens was from an aerial camera. Any information to satisfy my (entirely idle) curiosity about the company would of course be appreciated.

    Cheers,

    Vamsi

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