4X5 Whad-IZ-it? Your head scratcher for the day...

[David A. Goldfarb]

Maybe it held some special medium like porcelain disks for gravestone portraits, or round holographic plates, or a glass disk for some scientific purpose.

 

[grat]

I would guess it's used for either collimation, or finding the focal plane. But it seems complicated for finding the focal plane, and simple for collimation.

And not to make a habit of arguing with Don H (hi! ), this looks like it's designed to slide under a ground glass / spring back, and be held in the same way the ANSI film holder standard is. I don't see how you'd fit a camera to it, or a lens-- you'd have light leaks around the edges, unless it was lined with felt at some point.

 

[jimgalli]

My guess was it held an SLR onto the back of a 4X5 for a school portrait photog. Focus using the slr prism through an old school portrait lens.

 

[jtk]

For making captions on duplicate slides

 

[Don_ih]

I don't see how you'd fit a camera to it

As I said earlier, the camera would mount on a tube (interchangeable for different camera mounts) that would slip into the hole with a flange to block the light, and it would be held in place by the retaining screw in a groove in the tube (so you could rotate the camera any way). As in, I said that's how I'd do it if I had to come up with something to attach any slr to any 4x5 camera.

used for either collimation, or finding the focal plane

Why would you need to do that with a view camera?

Oh, and we're not arguing. We're just discussing. None of us know what it is...

 

[AgX]

Only 3, me included, go for the camera adapter.

 

[gone]

The ultimate enhanced interrogation tool. You wouldn't even need to use it, just a picture of it and us guys would tell you everything we knew, no problem.

 

[AgX]

I brought up the idea of it being a means to align the standars to each other, but on its own it makes of course no sense. One would need a counterpart at the front with illuminator and screen. And then the hole with something to attach makes no sense, a calibrated fixed mirror would do it.
But maybe someone reinvents such aligning tool.

Or even better, digs up that patent.

 

[jimgalli]

The ultimate enhanced interrogation tool. You wouldn't even need to use it, just a picture of it and us guys would tell you everything we knew, no problem.

Ummm . . . you guys have been telling me everything you know ........................................................and I'm not impressed.

 

[maltfalc]

this thread is a perfect example of why i'm rarely on photrio. too many people who have no idea what they're talking about just making up absolute bs. if it's about 1/4" thick it fits a graflok back with the gg removed.

 

[grat]

this thread is a perfect example of why i'm rarely on photrio. too many people who have no idea what they're talking about just making up absolute bs. if it's about 1/4" thick it fits a graflok back with the gg removed.

True. But the light-trap ridge should be ~ 1.6mm if it conforms to the standard for 4x5 film holders. As an estimate, I would think it's more in the region of half an inch thick, but no real dimensions were provided other than "it fits in a 4x5 film holder place".

Further, if I were making this for a graflok back, I'd put the groove(s) in the side to avoid any doubt.

 

[woodlandSerenade]

this thread is a perfect example of why i'm rarely on photrio. too many people who have no idea what they're talking about just making up absolute bs

The thread is clearly meant as a light-hearted puzzle of sorts. People laying out their best theories is analogous to a normal community discussion. That shouldn't be an irritation. With all due respect, there is absolutely nothing to get upset about.

 

[AgX]

this thread is a perfect example of why i'm rarely on photrio. too many people who have no idea what they're talking about just making up absolute bs. if it's about 1/4" thick it fits a graflok back with the gg removed.

Blaming others unfoundedly for telling bullshit and by this dispersing people without then coming up yourself with the true use of this thing is just cheap.
To put it mildly.

 

[maltfalc]

True. But the light-trap ridge should be ~ 1.6mm if it conforms to the standard for 4x5 film holders. As an estimate, I would think it's more in the region of half an inch thick, but no real dimensions were provided other than "it fits in a 4x5 film holder place".

Further, if I were making this for a graflok back, I'd put the groove(s) in the side to avoid any doubt.

standard film holders are 1/2" thick. this is clearly much thinner. graflex backs use side grooves, graflok backs have slide locks that fit over the grooveless 1/4" edges of adapters.

 

[Don_ih]

if it's about 1/4" thick it fits a graflok back with the gg removed.

Then .... what is it?

 

[grat]

standard film holders are 1/2" thick. this is clearly much thinner. graflex backs use side grooves, graflok backs have slide locks that fit over the grooveless 1/4" edges of adapters.

Having cameras with Graflex and Graflok backs, I'm familiar with both-- But my grafmatic, which is most definitely designed to work with a graflok back, has a groove approximately 1/4" from the darkslide back. My RH8, (also designed for the graflok back) however, has a 1/4" plate that the graflok fits over.

I'll admit-- due to the lack of references, this is probably less than 1/2", and may even be 1/4"-- but where are the rub marks? Or is this an unused item?