135mm Tele-Rokkor aperture pin kludge
Included in a lot of unwanted lenses given to me by a friend was this 135mm f/3.5 MC Tele-Rokkor-QD lens, shown here with my home-made Nikon / Minolta adapter. Having adapted an old Isco Tele-Westanar 135mm pre-set lens for use on my Nikon D40 and D60 with great results, I decided to see if I could do the same with this lens.
The first problem to overcome was how to get a Minolta mount lens to fit on a Nikon body. An old Nikon / T-mount adapter got me halfway to my goal. My junk lens / body mount drawer provided a mount salvaged from an old Minolta tele-converter. With a bit of filing followed by careful press fitting in a vise, I was able to fit the Nikon and Minolta parts together. Some black plastic electrical tape was used to cover several holes that would have caused light leaks. Using this home-made adapter results in the loss of infinity focus... not a problem for close-up photography.
The second problem was something I hadn't thought of. I wanted to use this lens for macro shooting where focusing is critical. Hand-holding makes stop-down shooting difficult where you need the aperture open wide to focus accurately, then stop down to the taking aperture to get the shot. Because the lens wasn't mounted on a Minolta body, no aperture coupling lever linkage was available. I had planned to use the lens depth of field preview button to stop down an instant before tripping the shutter, as I do with the old Tele-Westanar with its "pre-set" button, but the Rokkor's DOF
button was inactive... the aperture remained wide open. I could stop down to focus, but accurate focusing with the resulting exceedingly dim viewfinder image became nearly impossible.
An easy solution came in the form of a tiny 1 inch long craft store clothespin. Opening the clothespin by its gripping end closes the end that you normally squeeze. Moving the Rokkor's aperture lever to the right as far as it could go allowed the pin's squeeze tabs to fit in the lever's slot. Releasing the clothespin resulted in it gently locking the aperture lever at its limit of travel. This resulted in the depth of field preview button working as it should, despite the absence of any lens / camera body linkage. The depth of the home-made adapter keeps the clothespin from protruding within the mirror box of the Nikon body. Now it's a simple matter to use the Rokkor as you would any normal pre-set lens. The aperture remains open for easy focusing, then the DOF preview button is pressed to close down to the taking aperture immediately before hitting the shutter.
Results are excellent when used for macro shooting and creating this adaptation was definitely worth the effort.
Because the adapter extends the lens out from the camera body, infinity focus isn't available. When the lens is set for infinity, the actual focus distance is 30 inches, with a field width of 5 inches. Mounting a Raynox DCR-150 with the lens still set at infinity, gives a field width of 1 inch at a lens to subject distance of 6 inches. A Raynox DCR-250 drops the field width to 5/8 inch at a distance of 3.5 inches. Reverse mounting the objective from a Cimko 75-200mm lens produces even more magnification with the field width shrinking to 1/2 inch at a working distance of 2.5 inches.
DSC-4727
135mm Tele-Rokkor aperture pin kludge
Included in a lot of unwanted lenses given to me by a friend was this 135mm f/3.5 MC Tele-Rokkor-QD lens, shown here with my home-made Nikon / Minolta adapter. Having adapted an old Isco Tele-Westanar 135mm pre-set lens for use on my Nikon D40 and D60 with great results, I decided to see if I could do the same with this lens.
The first problem to overcome was how to get a Minolta mount lens to fit on a Nikon body. An old Nikon / T-mount adapter got me halfway to my goal. My junk lens / body mount drawer provided a mount salvaged from an old Minolta tele-converter. With a bit of filing followed by careful press fitting in a vise, I was able to fit the Nikon and Minolta parts together. Some black plastic electrical tape was used to cover several holes that would have caused light leaks. Using this home-made adapter results in the loss of infinity focus... not a problem for close-up photography.
The second problem was something I hadn't thought of. I wanted to use this lens for macro shooting where focusing is critical. Hand-holding makes stop-down shooting difficult where you need the aperture open wide to focus accurately, then stop down to the taking aperture to get the shot. Because the lens wasn't mounted on a Minolta body, no aperture coupling lever linkage was available. I had planned to use the lens depth of field preview button to stop down an instant before tripping the shutter, as I do with the old Tele-Westanar with its "pre-set" button, but the Rokkor's DOF
button was inactive... the aperture remained wide open. I could stop down to focus, but accurate focusing with the resulting exceedingly dim viewfinder image became nearly impossible.
An easy solution came in the form of a tiny 1 inch long craft store clothespin. Opening the clothespin by its gripping end closes the end that you normally squeeze. Moving the Rokkor's aperture lever to the right as far as it could go allowed the pin's squeeze tabs to fit in the lever's slot. Releasing the clothespin resulted in it gently locking the aperture lever at its limit of travel. This resulted in the depth of field preview button working as it should, despite the absence of any lens / camera body linkage. The depth of the home-made adapter keeps the clothespin from protruding within the mirror box of the Nikon body. Now it's a simple matter to use the Rokkor as you would any normal pre-set lens. The aperture remains open for easy focusing, then the DOF preview button is pressed to close down to the taking aperture immediately before hitting the shutter.
Results are excellent when used for macro shooting and creating this adaptation was definitely worth the effort.
Because the adapter extends the lens out from the camera body, infinity focus isn't available. When the lens is set for infinity, the actual focus distance is 30 inches, with a field width of 5 inches. Mounting a Raynox DCR-150 with the lens still set at infinity, gives a field width of 1 inch at a lens to subject distance of 6 inches. A Raynox DCR-250 drops the field width to 5/8 inch at a distance of 3.5 inches. Reverse mounting the objective from a Cimko 75-200mm lens produces even more magnification with the field width shrinking to 1/2 inch at a working distance of 2.5 inches.
DSC-4727