Rangefinder swap from Graphic 4x5 to 2x3.

[gearlover]

Will a Crown Graphic 4x5 rangefinder work on a 2x3 Graphic? If so, is it possible for an amateur to do it....and what about cam availability?

[Dan Fromm]

Ask on www.graflex.org

The 4x5 Graphic rangefinder (that's the one made by Graflex, is integral with the top of the body) can't be swapped to a 2x3.

I think, but its been a long time since I've read the installation manual, that Kalart rangefinders (side finder) do interchange. But ask on www.graflex.org, that's where the people who really know hang out.

Kalarts don't have cams. A Kalart can be set up for one lens. One (1). Setting up a Kalart for another lens is a time-consuming process, best not done in the field. If you have a 2x3 Graphic and want to interchange lenses, you'd best focus on the ground glass.

[Jim Jones]

A Hugo Meyer rangefinder may be a viable alternative to the Kalart finder. It's been decades since I've adjusted one, but models with external scales might be adjustable in the field for various lenses.

[wombat2go]

If you are using a telephoto (150 mm +) an accurate rangefinder is certainly worthwhile.
On a more normal lens for 2 x 3 etc, for example a 75 mm to 105mm lens, the rail travel between infinity and 5 metre (15 foot) is actually quite limited
With 105mm lens, I measured on ground glass, second row being the travel along the rail:
----inf-----20 metre-----5 metre----
----0-------2.38mm-------4.75mm----

or
----inf-----65 foot----16.5 foot----
----0-----3/32 inch-----3/16 inch---

When you get below about 2 metre (6.5 foot) The rangefinder is fairly useless and the ground glass is required, as you will likely have the lens stop opened up too..

Now, also on a 105 mm lens on the medium format, used outdoors at long distances,
The DOF at f/16 with say 1500 pixels in height, is about from 4 to 8 metre (13 to 26 foot)
So looking at the above rows, it seems reasonable just to scale focus.
As we know, scale focussing a 90 to 105 lens at f/16 on medium format gives good sharp shots from a few metre to infinity.

I looked at the method on graflex.org for creating cams for a 105mm on a Graflex, and gave up immediately.
I got a small stainless scale rule, cut it to length, drilled it on the xy table to match the existing screws on the right side of the rail on my Speed 4x5,
and made a little table on cardboard with the above measurements.
So far i havn't even used it !!