Big Lenses
This page is dedicated to lenses that are large, all formats!
6x7 Lenses
I discovered that a company called Fotodiox makes an adapter to hang Pentax 6x7 lenses on an assortment of 35mm class SLR's. Or maybe it would be better to say hang a SLR on a Pentax 6x7 lens...
Interestingly it has both the Inside and Outside bayonets on the Pentax 6x7 side of the adapter. The adapter has no provision to trigger the AF function in the Canon body. On that note, I have a T-Adapter for my telescope to hang a Canon digital body that does have the contacts to make the camera signal when it is focused.
My Canon Rebel XSi looks ridiculously cute with the 6x7 lens mount adapter attached...
20" long with the lens shade retracted. I haven't put it on a scale, but this is definitely a tripod only setup...
First step was to make a support bar to remove stress from the tripod mounting foot on the lens. A 2" Aluminum bar 1/4" thick was drilled and tapped for the attachment to the foot on the lens (500mm Pentax SMC Takumar 6x7) and provide several tripod plate attachment points. The location of teh tripod plate in these images is the balance point of the lens with my Rebel XSi body attached.
The next step was to make a support for the front of the lens. I used Fusion 360 to design a brace to be 3D printed. The parts will be printed with PETG at 40% density. A pair of thumb screws from the top will clamp on the non moving part of the lens.
3D printer running. took just under 6 hours to print at 40% density. Finished parts on the right.
The part came out quite well given I determined the ID of the ring using a thin tape measure and the trusty HP15C. When I did the design in CAD, I sliced a 0.030" gap to divide the part in two, figuring this would allow for some clamping force. That came out perfect, what didn't was the part of the lens I had checked for rotation (it doesn't) but it does move in and out. The desired support can be had without the upper part of the ring and everything moves without binding. I had to shave about 0.030" off of the bottom of the "foot" to get the correct fit.
Close shot of the lens in the cradle. On the right we have a saner application of the lens adapter a Pentax 67 SMC 75mm lens. If the adapter proves out to work as I expect, this $45 adapter really expands my Canon SLR lens assortment. For shorter, less massive, lenses the tripod mount foot on the bottom of the adapter will work well.
I had Dan Stone custom make a case for this beast. The lens is in extremely good condition and it would not remain so during transport and use over time. The case was sized to accommodate the Canon EF adapter which will pretty much live on this lens.
My smaller Bogen tripod and ball head supports the camera well as long as one uses a remote cable to take the shot. I do have my olde reliable monster Bogen, but elected to see how my normally used tripod would work. Balance point is a little behind, so there is a slight forward tendency when the ball head is loosened. Balance point is spot on with the 6x7 body attached.
Quickie setup and test shot from the front yard. The truck is sitting over a block away. No particular care was taken to attain a precision focus. Camera body set in manual mode, set the desired aperture and roll the control to center the +/- indicator in the viewfinder. With the sensor multiplier, this is effectively a 800mm lens...
Future plans are to go out to the Gilbert Riparian Water Ranch and shoot pictures of pelicans. Yes, we have white pelicans in the Phoenix area.