5x7 fisheye???

[jb7]

If it's a matter of degree, the 47 is wider-

A fisheye adapter might help, but I don't have one of those to try...

[rdenney]

For 5x7, which has about a 210mm diagonal, you'd need a 70mm fisheye to cover the full frame. The diameter of the circular image created by a fisheye is usually about three times the focal length. I don't know of any 70mm fisheye lens, though there may have been some specialty lens for a technical application produced at some point in the long history of optics.

I've always thought it would be neat to have a 50mm fisheye to use on 4x5.

About the longest focal length fisheye lenses I've heard about are the 35mm Pentax 67 fisheye and the 37mm Sekor for the RB/RZ 67. The latter would have a shutter, at least, but it's spendy even used.

I have the Pentax, which I just acquired recently. I've used the (very decent) 30mm Arsat fisheye on various 6x6 cameras, and can usually find good use for such a lens. When I need that approach, I'll use the Pentax and settle for smaller prints.

The Arsat, by the way, would make a reasonable circular fisheye on 4x5, though one would have to cut away the little ears that are supposedly a shade but are really stops to keep the cap from touching the glass. It would provide a fisheye circular image about 90mm in diameter. The Mamiya, at 37mm, would more closely fill the 5" small dimension of 5x7, but I'd be reluctant to grind off those ears from a lens I paid a thousand bucks for!

Rick "preferring the circular rendition of rocks and close-up landscapes compared to a rectilinear ultra-wide" Denney

[Brian C. Miller]

The fisheye effect isn't just a matter of focal length. You need to have a 180-degree FOV. The lens needs to bug out from the housing, and it would have to use a retrofocus design. I know that I've seen pictures of 4x5 fisheye, and it was done using a lens adapter.

From Half-Fast Stuff, here's a 4x5 fisheye. For 5x7, I think you'd need an adapter.

[rdenney]

From Half-Fast Stuff, here's a 4x5 fisheye. For 5x7, I think you'd need an adapter.

I guess I inadvertantly stole their idea for converting an Arsat fisheye for use as a circular fisheye on 4x5. I have two of those Arsats, and one might get an experiment at some point. The other figures large in my 6x6 portfolio.

But the OP asked for a full-frame fisheye (as is a 16mm fisheye on 24x36), and that requires a longer focal length, especially for 5x7. He'd either have to make do with a circular fisheye (and crop to the largest rectangle, or use a medium-format camera.

It isn't just the 180-degree coverage that makes it a fisheye. It's also the spherical projection. Aesthetically, fisheye lenses do to things that lenses with rectilinear distortion do not: 1.) enlarge the central subject with respect to the surrounding scene, and 2.) render round objects in the corner of the frame as round objects, instead of as stretched objects. Round objects can be faces. I've used a full-frame fisheye for group photos, where I looked down on the crowd from the top of a ladder. By working to the top of the frame as much as possible, I moved the vanishing point for vertical perspective as close to the center of the frame as I could, which minimizes the barrel distortion effect on the bodies. But even the people in the corners looked like people with human faces. That would not have been the case with a rectilinear lens. With a fisheye, any line going through the center stays straight. On 6x6, I could center the horizon and then crop off the top, moving the horizon up in the picture without it becoming curved. Those are just a couple of examples of how the fishiness can be managed or taken advantage of.

Rick "who never understood it until he owned one" Denney

[jb7]

ok, so I don't understand fisheyes, beyond their application in meteorology, or skateboarding...

[Andy Eads]

I once modified a Mamiya 37mm fisheye lens from the RB series cameras. I had the lens hood tabs ground off. I canibalized a dead body for the mouning flange and bolted that up to a Linhof kardan board for the 4x5 camera I was using. It was tricky to cock the shutter but the cable release worked fine. It was slow to use but I got some images that enlarged to a 40" diameter image. the 37mm lens will throw a circle just under 3.75" so 4x5 was all I needed. Hope this helps.andy

[W K Longcor]

Years back ( sometime in the 80's -- maybe?) I did used one of those cheap fisheye adaptor lenses ( Spiratone, I think) on a 4x5. Got a nice 4 inch circle on the Ektachrome film. Fun project and made the client very happy. Different focal length lens will give different size circle. I know I aalways got a nice circle image with an 80mm les on the Hasselblad - and got coser toth "fiull frame fisheye effect with a 150mm les on the same camera. I'm guessing for a full frame fiseye effect on 5x7, you might need a 14" or 16" main lens with the fisheye lens on the front -- probably with a step-down adaptor ring of some sort, based on the front diameter of lenses of these focal lengths. As with all work of this type -- you test and experiment before going after the important photographs.

[Brian C. Miller]

Here's a Spiratone 0.15x 180-degree lens on a Nikkor 150mm.




And here's the test shot on Fujifilm FP100C45.



2-1/4 inch image circle, and it really is 180 degrees.

[EdSawyer]

The mamiya RZ 37mm can have the front hood removed fairly easily. The whole front group unscrews. One could get a repalcement part from Mamiya for not much $, and remove the "ears" easily. I did the reverse of this for a 37mm I had for a while, it came with no ears, I bought the new part from Mamiya ($100 or so) and put it on. I later sold the lens and bought a better version. I still have the "earless" front piece if someone with an RZ 37mm wants to make a full-circle fisheye.