Using RB67 lenses on 4x5?

[speedtrials]

Hey Rodney,
I've been thinking of giving this a shot. I have a 35mm fisheye for Bronica SQ that I want to use. Can you post some of your results with this type of setup?

Cheers,
Nick

Well, it's the only way that I've found to enjoy a 37mm fisheye on 4x5. Some great new perspectives on the world, believe me...

[SocalAstro]

Rodney,

I've been thinking of doing the same thing actually. I too would love to see a picture taken with this lens to see how much actual coverage one gets on a 4x5.

-Leon

Well, it's the only way that I've found to enjoy a 37mm fisheye on 4x5. Some great new perspectives on the world, believe me...

[vinny]

cut a hole in the back of a rear rb lens cap, glue that to a copal #3 lens board, mount lens on camera, shoot.

[rdenney]

Rodney,

I've been thinking of doing the same thing actually. I too would love to see a picture taken with this lens to see how much actual coverage one gets on a 4x5.

-Leon

A fisheye produces a round image with a diameter roughly three times the focal length of the lens. For most fisheye lenses, the coverage is 180 degrees edge to edge of that round image. If the focal length is one-third the film diagonal, then we call it a full-frame fisheye. If the focal length is one-third the narrow dimension, we call it a circular fisheye. But the lenses are the same and differ only in focal length.

So, a 35mm fisheye would produce a round image approximately 105mm in diameter and would be a full-frame fisheye on the ~6x7 format and a circular fisheye (almost) on 4x5. I have a 30mm fisheye which is a full-frame fisheye for 6x6, and a 16 which is full-frame for 24x36. On 4x5, they would make round images roughly 90 and 48mm in diameter. Might be less than meets the eye.

Rick "a 55mm fisheye for 4x5--now your talkin'!" Denney

[Rodney Polden]

The RB-lenses-on-4x5 is an ongoing project for me at present, and thanks go to Erie Patsellis for getting this far - his description of the modifications for mounting the lenses were what got me started. (Thanks again, Erie!)

The 37mm Mamiya gives an image circle around 90 mm, so it certainly doesn't cover 4x5, but with that lens, I was actually aiming to end up with circular images on a black b/g. Most of the long lenses in the RB range seem to cover 4x5, though I cannot speak to sharpness in the corners as yet. Longer lenses are less interesting for me though, since I have LF lenses that already do the job better. For others, that might be worth pursuing.

What I hadn't allowed for with the fisheye, was the "petal" style fixed lens-hood coming so obtrusively into the image. As yet, I haven't reconciled myself to the idea of grinding those lens-hood elements off the front of the lens. Maybe I will, because the perspective certainly is intriguing, but I guess it will inevitably "change" (to put it mildly) the resale value of a lens I paid $1400 for, as well as removing the option of um, well, having a lenshood. When I'm shooting on the RB, the lens-hood is really quite a bonus, and keeps a lot of otherwise inevitable sun-flare out of the image.

My plan was to use the lens on a MPP Mk 8, but so far I have only achieved infinity focus on my Horseman monorail with bag bellows, mostly due to the additional extension that comes from the modified RB lensboard thickness. Hand-held on the Horseman monorail? Probably not. Still working on getting the movements (tilt mostly) that I was also looking for.... There's not easily enough space to accommodate a recessed stage to take the RB lensboard-mod, at least not on 4x5.

Is there a word in the English language that means "toooomanyprojectsonthego"?

[ruckusman]

I'd love to know any details you could share on the Toyo RB67. I used to have a Mamiya camera front mount attached Linhof Technika board, but my shutter cocking mechanism wasn't at all good.