Lens length vs. coupled rangefinder on Speed Graphics

[Chadinko]

Forgive me if this has been asked before; I can't find an exact answer to my question and it's raining like crazy here so I can't go outside and experiment with it. I have two 4x5 Speed Graphics, one a 1964 with a top-mounted rangefinder and the other a 1948 or 49 with the side-mounted RF. The older one has a beautiful Ilex Paragon 163mm lens in an Ilex #3 shutter, and I have two shutters and lenses for the newer one (but only one lens board as yet, so the other lens lives in a box in a plastic pouch) -- a 135 Optar f/4.7 in a Full-synchronization Graphex and a 127 Ektar from about 1946 in an x-sync only Graphex.

The Ilex pretty much lives on the 1948 camera, since the body trigger mechanism on that one has long since gone to the great camera graveyard in the sky, so the two Graphex shutters are interchangeable on the 1964 model. I've experimented and believe I have identified the positions on the bed for the slight difference in focal lengths, but I'm wondering if that difference is enough to throw off the rangefinder, which seems to be accurate for the 135mm that was on the camera when it was given to me.
127-135 isn't that much of a disparity in focal lengths.

 

[shutterfinger]

A rangefinder is adjusted to a specific lens or a cam is cut for the lens. The marked focal length only gives a rough idea of the lens focal length. A 135 marked lens may be 132 to 138 millimeters; a marked 127 may be 122 to 133 millimeters in actual focal length. If you're real lucky and have a marked 127 that is longer and a marked 135 that is shorter then the rangefinder error may not be that great.
The list of cams for the Top (Graphic) rangefinder is http://www.graflex.org/speed-graphic/top-rangefinder-cams.html

When the lens focal length disagrees with the rangefinder setting/cam then the closer you focus from infinity the greater the error in focusing. Lens that are within a millimeter of one another will be off at distances of 10 feet or less while lens that are several millimeters different the focusing error will be noticeable between 25 to 50 feet. Stopping the lens down may help hide the focusing error.

since the body trigger mechanism on that one has long since gone to the great camera graveyard in the sky

The body side release is a weak point. The common failures are the cable becomes corroded inside the housing and does not move freely. Penetrating oil or a light weight machine/clock oil applied to the inner cable may help.
The other failure is the cable connection at the release becomes loose and does not transmit the movement of the release to the cable.
The cable removal/reassembly is covered in the Front Standard/Bellows repair section of http://www.graflex.org/manuals/45-Pacemaker-Speed-and-Crown-Graphic.pdf
The cable attachment must match the diagram for the format on manual page 17/pdf page 23 exactly.

 

[Chadinko]

hen the lens focal length disagrees with the rangefinder setting/cam then the closer you focus from infinity the greater the error in focusing. Lens that are within a millimeter of one another will be off at distances of 10 feet or less while lens that are several millimeters different the focusing error will be noticeable between 25 to 50 feet. Stopping the lens down may help hide the focusing error.

Thank you -- this is exactly what I wanted to know.

The body side release is a weak point. The common failures are the cable becomes corroded inside the housing and does not move freely. Penetrating oil or a light weight machine/clock oil applied to the inner cable may help.
The other failure is the cable connection at the release becomes loose and does not transmit the movement of the release to the cable.
The cable removal/reassembly is covered in the Front Standard/Bellows repair section of http://www.graflex.org/manuals/45-Pacemaker-Speed-and-Crown-Graphic.pdf
The cable attachment must match the diagram for the format on manual page 17/pdf page 23 exactly.

The side releases on both my Graphics work perfectly. I don't use them much, but I've done a little bit of focal plane stuff with both cameras and they work fine. What I meant was that the hardware that attaches to the linkage that actually physically pushes on the shutter trigger on the lens is no longer there, since the Ilex #3 is a much larger and a very different mechanism to the Graphex, and that mechanism is intact on the newer body. What that means is that I can put the Graphex shutter on the older camera, but I can't put the Ilex on the newer one unless I disassemble that mechanism so the #3 shutter will fit.

And thank you for the link to the service manual. It'll go into my folder of camera service manuals I'm slowly collecting.

 

[shutterfinger]

And thank you for the link to the service manual. It'll go into my folder of camera service manuals I'm slowly collecting.

Then visit http://www.southbristolviews.com/pics/Graphic/graphicmanuals.html . Some of the manuals there are compliments of me.

What I meant was that the hardware that attaches to the linkage that actually physically pushes on the shutter trigger on the lens is no longer there,

Kinda hard to fix it if it does not exist.

 

[Chadinko]

Then visit http://www.southbristolviews.com/pics/Graphic/graphicmanuals.html . Some of the manuals there are compliments of me.

Commencing download...

Kinda hard to fix it if it does not exist.

Truer words were never written.