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The 8" (203mm) F/5.6 Optar on Century 23
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Dan Fromm



Joined: 14 May 2001
Posts: 2057
Location: New Jersey

PostPosted: Mon Feb 29, 2016 1:54 pm    Post subject: Re: 203mm with Kalart Reply with quote

MultiFormat Shooter wrote:
78ltd wrote:
According to my 66/67 Graflex Catalog, it said the Kalart was for use with 80-150mm lenses on the Century Graphic, which was the only camera using it then.


If the bellows draw is 180 mm or less then it should work. Since the Raptar 203mm has 5" (127mm) of bellows draw, then I would think that it should work.


I think you're confusing the 8"/5.6 TeleOptar/TeleRaptar with the 8"/7.5 Optar. The f/5.6ers are telephoto lenses with short flange-to-film distances for their focal length. The f/7.7 is a lens of normal construction (imitation 203/7.7 Ektar, really), has a much longer flange-to-film distance and won't focus much closer than infinity on a Century.

You also don't quite understand how a Kalart works. It measures how far forward the bed and lens have been moved from the infinity position, uses linkages that I don't understand to translate that distance into the subject's distance. It doesn't care where the infinity stops are.
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MultiFormat Shooter



Joined: 26 Jan 2016
Posts: 16

PostPosted: Mon Feb 29, 2016 2:35 pm    Post subject: Re: 203mm with Kalart Reply with quote

Dan Fromm wrote:
I think you're confusing the 8"/5.6 TeleOptar/TeleRaptar with the 8"/7.5 Optar. The f/5.6ers are telephoto lenses with short flange-to-film distances for their focal length.


I was referring to the 8" (203mm) Tele-Optar; it was my fault for not being clear in my post that I meant the telephoto not the 203mm f/7.7 "regular" lens.

If the Kalart doesn't care where the infinity stops are, shouldn't it be able to synch with any lens? Not being "smart," I am seriously trying to understand how the Kalart works.
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Henry



Joined: 09 May 2001
Posts: 1593
Location: Allentown, Pennsylvania

PostPosted: Mon Feb 29, 2016 3:03 pm    Post subject: Reply with quote

Yes, Dan, I was beginning to suspect the same. One thing for sure: the 203 Optar will not work with the Kalart. But the OP did say f5.6 203mm, which should have tipped me off at once that it was the Tele, since the 203 Optar is f.7.7 (IIRC).
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Dan Fromm



Joined: 14 May 2001
Posts: 2057
Location: New Jersey

PostPosted: Tue Mar 01, 2016 2:06 am    Post subject: Re: 203mm with Kalart Reply with quote

MultiFormat Shooter wrote:
If the Kalart doesn't care where the infinity stops are, shouldn't it be able to synch with any lens? Not being "smart," I am seriously trying to understand how the Kalart works.


Fair question. This gets into the linkages that I've never quite understood.

They use somehow use geometry to translate bed movement to movement of focused distance from infinity. The linkages' adjustments for focal length have limited travel. This is what limits the range of focal lengths the RF can be adjusted for.
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MultiFormat Shooter



Joined: 26 Jan 2016
Posts: 16

PostPosted: Thu Mar 03, 2016 12:57 am    Post subject: Re: 203mm with Kalart Reply with quote

Dan Fromm wrote:
The linkages' adjustments for focal length have limited travel. This is what limits the range of focal lengths the RF can be adjusted for.


Okay, thanks, that makes sense. It sounds like a telephoto would have a better chance of working than a non-telephoto of the same focal length (not saying it actually will, though).
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Dan Fromm



Joined: 14 May 2001
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Location: New Jersey

PostPosted: Thu Mar 03, 2016 1:07 pm    Post subject: Reply with quote

No, from the Kalart RF's point of view focal length is focal length.

The only difference between a tele lens and a lens of normal construction of the same focal length, from the camera's point of view, is where the front standard sits on the bed when the lens is focused to infinity. From the user's point of view, a tele lens will require less extension to focus to infinity so will be a more comfortable fit on the camera.
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William Hallett



Joined: 07 Jan 2012
Posts: 69

PostPosted: Thu Mar 03, 2016 3:55 pm    Post subject: Reply with quote

A Kalart responds to the displacement of the bed from the infinity position. It is not affected by infinity stop placement, because it is actuated by the cam attached to the back of the bed. A telephoto lens moves the same distance to focus on a given object distance as does a regular lens of the same focal length, even though it sits much closer to the film plane. Therefore, if the Kalart won't work with a regular 203 mm lens, it also shouldn't work with a 203 telephoto.
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Henry



Joined: 09 May 2001
Posts: 1593
Location: Allentown, Pennsylvania

PostPosted: Thu Mar 03, 2016 5:34 pm    Post subject: Reply with quote

Then that settles it. My 203 Optar f7.7 (non-Tele) focuses infinity at the far outer end of the bed, way beyond the reach of the Kalart arm. And even if the Kalart did work, I'd always focus with the loupe on the ground glass.
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William Hallett



Joined: 07 Jan 2012
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PostPosted: Thu Mar 03, 2016 10:53 pm    Post subject: Reply with quote

If your 203 can be focussed at infinity with the track all the way back into the case (i.e. the normal position for infinity), then the arm of the Kalart will still be in contact with the cam. The question is how much track movement the Kalart will allow before the cam loses contact with the arm. On my 2x3 Pacemaker Speed this distance is about 15 mm with the Kalart set up for the usual 101 mm lens. That should in theory be enough travel to focus a 203 down to about 10 ft. However, I don't know whether this amount of travel is still available when the Kalart's internal adjustments are changed for a different focal length lens, and I don't know whether the Kalart is actually intended to function properly through all of that 15 mm travel. (For a 101 mm lens, 10 mm travel takes you to the end of the focussing scale at 4 ft, and that may indicate the actual useful range.)
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Henry



Joined: 09 May 2001
Posts: 1593
Location: Allentown, Pennsylvania

PostPosted: Fri Mar 04, 2016 2:41 pm    Post subject: Reply with quote

Sorry, I had it backwards in my previous post. It is indeed infinity focus when bellows draw is short, not long. Oops...
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