Converting a speed graphic into an SLR

[maltfalc]

Absolutely… you are correct… it’s your idea and your photography… and you are clearly set on doing it your way. We don’t need to understand and you don’t really seem to want us to understand. It’s all good. I’m eagerly awaiting a sketch of your concept. A timeline of the sequence of operation would also be nice because the various descriptions appear to possibly include contradictions. I love innovative solutions, especially elegant designs, and I’m actually interested in understanding…

you've got 6 pages of me spending i don't know how many hours now straightforwardly answering the same questions over and over and over again, including every question you've asked me. there's already a basic "timeline of the sequence of operation" on page five. spoiler alert: it's basically the same as any other lf slr. if that's not enough there's plenty more details scattered throughout the thread. if you actually manage to pin down one of these "possible contradictions", let me know what it is.

[BrianShaw]

you've got 6 pages of me spending i don't know how many hours now straightforwardly answering the same questions over and over and over again, including every question you've asked me. there's already a basic "timeline of the sequence of operation" on page five. spoiler alert: it's basically the same as any other lf slr. if that's not enough there's plenty more details scattered throughout the thread. if you actually manage to pin down one of these "possible contradictions", let me know what it is.

Well, okay. I guess I’ve been put in my place. I’ll be going simplex… rx only… awaiting the great reveal. Good luck on your project.

[Paul Ewins]

I think your biggest challenge is going to be working out how to detach and reattach the rear of the bellows when you convert from Press camera mode to SLR mode and back again. Everything else has already been done one way or another. FWIW the Gowlandflex SLR uses a different system with a mirror that slides sideways rather than swings up.

[maltfalc]

I think your biggest challenge is going to be working out how to detach and reattach the rear of the bellows when you convert from Press camera mode to SLR mode and back again. Everything else has already been done one way or another. FWIW the Gowlandflex SLR uses a different system with a mirror that slides sideways rather than swings up.

graflex solved most of that challenge for me already. detaching them is just a matter of pulling off two little clips at the top and bottom. they're easy to get to by removing the gg or lens board. i'll probably replace those with sturdier, easier to grip versions with d rings or something. i've looked into sliding mirrors before, sideways or dropping like a guillotine shutter, as well as split mirrors with the lower front section of the mirror flipping down on it's own so the rest of the mirror won't hit shorter lenses as it flips up, and hinged mirrors with the lower front section of the mirror flipping backwards and folding up against the underside of the rest of the mirror, and spring loaded rotating disk mirrors with wedge shaped cut-outs and adjustable tension that do double duty as the reflex mirror and the shutter and don't black out the viewfinder when you take a photo but instead just create a brief shadow sweeping across the image.

[Havoc]

and spring loaded rotating disk mirrors with wedge shaped cut-outs and adjustable tension that do double duty as the reflex mirror and the shutter and don't black out the viewfinder when you take a photo

You looked at pellicle mirrors? No blackout at all with them. Will be hard to find in large size but can be made. OTOH your mirror will not have to be as large as 4x5 as it sits closer to the lens. National Photocolor still makes them.

[maltfalc]

You looked at pellicle mirrors? No blackout at all with them. Will be hard to find in large size but can be made. OTOH your mirror will not have to be as large as 4x5 as it sits closer to the lens. National Photocolor still makes them.

looked into them and already have one that should be the correct size for 4x5. not crazy about the light loss though or shooting through an extra layer of glass i need to keep clean or having to deal with the stray light coming through the viewfinder without a mirror flipped up to cover it. if the standard flippy mirror turns out to suck i can always swap them later, but i was thinking of using the pellicle mirror as a beam splitter for taking red/cyan colour photos with b&w film.

[ethics_gradient]

Curious if you have any examples of your photography, OP. Perhaps we could offer some additional insight?

[maltfalc]

Curious if you have any examples of your photography, OP. Perhaps we could offer some additional insight?

i'm building an slr to expand my LF photography into areas i'm not currently well equipped to shoot, so nothing i can think of that would be relevant to a thread about building an slr, no.

[Drew Bedo]

And now for an off-the-wall suggestion:

During the international internet dustup surrounding the Polaroid conversions back in the early 2K decade, I often wondered about creating a 4x5 SLR based on the Polaroid SX-70 folded light path. The SX-70 format in large medium format or smallish LF already.

The camera might be made so as to fold like the Polaroid, or more simply designed to be rigid.

Changing lenses and focal length could be dealt with by using interchangeable "film backs" (on the bottom) to increrasse the back focus distance.much like swapping lens cones on other cameras. and adding in a focusing eyepiece.

Heck, it might be possible to build a proof of concept prototype from an SX-70 or One-Step body.

No, this is not helpful to the Speed Graphic/SLR project of this thread, but perhaps some other DIY guy will pick it up.

Cheers to all.

[Embdude]

Sounds like something Peter Growland would have already tried. I have a Linhof 4x5 reflex housing but it attaches to the rear of the camera and moves the film plane back considerably. It was part of the Aristophot system. It limits the use of lenses less than 300mm at normal lengths but it is completely nondestructive. Your plan sounds better for a weight and size... like a 4x5 visoflex housing... I have often wondered how those large Kodak copy lens prisms would work as a 4x5 slr prism viewfinder.. good luck!