Using Rubinar Lenses with various cameras
These lenses all are fitted with the standard 42mm male threaded mount which makes them compatible with most "T" ring adapters as well as extension tubes of many maufactureres including Zenit.
The lenses were designed around cameras with a flat frontpiece such as the Zenit 122. The built in flash of most popular cameras protrudes forward sufficiently
to block the lens from mounting with the "T" adapter except for the Zenit which does not have a protruding flash and uses the standard 42mm lens mount.There follows a series of suggestions with instructions to overcome this mounting difficulty with nearly all SLR cameras with the built in flash.
The 42mm thread and receptacle on the camera are matched, no adapter is required. The exposure meter system in the Zenit works well but is somewhat limited in range requiring the use of neutral density filters to bring the brightness within range of the meter, film speed and shutter speed range.
Canon Rebel 2000 film camera
The Rubinars can be mounted directly to this camera but the camera must first be slightly modified. The under side of the flash protrusion is a simple plastic shield for the flash bulb. Removing it can easily be done with a fine jewlers saw and doing so does not harm the camera in any way. With the plastic underside of the flash protrusion removed all the Rubinars can be mounted directly to the camera using adapter rings as sold by RuGift. The automatic exposure system of this camera functions normally if set to aperture priority and the viewfinder gives excellent finding and focusing ability. If you wish to use a film camera with these excellent lenses this is an inexpensive way to do so and the modification to the camera does not produce any harm to the camera for its normal useage.
However either of the techniques following can also be used with the Rebel 2000 without any modification to the camera.
Canon Rebel 2000 film camera and Rubinar 500mm lens with adapter ring
Canon Digital Rebel 300D and all other EOS models using mounting rings
All the Canon EOS cameras and other brands as well can be used with the Rubinars by way of adapter ring and the shortest Zenit extension tube.This combination moves the lens forward sufficient to clear the flash housing though with the 500mm the flash head must be flipped up. Moving the lens forward a few millimeters also moves the infinity focus forward and the lens may not focus at infinity though it will focus to about 100 meters as is. To correct this issue refer to the final section of this document. The camera is set for aperture priority and the automatic exposure systems performs normaly. The aperture will read 0.0 which should be ignored.
Canon Digital Rebel D300, adapter ring, Zenit short
extension tube, Rubinar 500mm lens
Canon Digital Rebel 300D and all other EOS models using the standard "T" ring adapter
The standard "T" adapter popularly used to match most SLR cameras to optical devices has an inherent thickness of approximately 10mm which is sufficient to move the Rubinars forward enough to clear the flash housing of most cameras. This too moves the focus point forward and may limit distance focusing to 100 meters more or less. This can be easily corrected by following the procedure outlined in the final paragraph and photo of this document. The exposure system should be set for aperture priority and the camera will read an aperture of 0.0. This should be ignored.
Canon Digital Rebel and all other EOS cameras and the MC TMK-2X Teleconverter
The quality of the Rubinars is so high that they easily tolerate the addition of a 2x teleconverter. The TMK-2 which is available from RuGift works well when used with the T adapter. While Sigma, Canon and other teleconverters work equally well they produce some difficulty in using the auto exposure system of the camera. If the latter are used it will be necessary to insulate the electrical contacts between the converter and camera. With the TMK-2 and adapter there is no electrical contact made between the lens and camera which permits the auto exposure system to function normally in aperture priority mode. The aperture will read 0.0 which should be ignored.
Canon Digital Rebel D300, adapter ring, Zenit TKL-2 Teleconverter, Rubinar 500
Correcting the Rubinars for infinity focus when used with adapters to clear the flash protrusion.
Each of the Rubinars can easily be adjusted so as to allow deep infinity focusing with either of the extended adapters in place. Since they each make very high quality astronomical photos adjusting them becomes a necessity. They are set at the factory with the infinity stop labeled "W" to go just past the indicating line. The design of the lens however permits this point to be shifted thus moving the focus point a greater distance behind the lens mounting flange. The procedure is simple and does not harm the lens in any way. First remove the flexible plastic band around the lens which is normally used for a focus grip. This will expose three small locking screws which can be loosened about one turn each with a find jewelers screwdriver.
The entire focusing ring will then slip off the front of the lens housing. This will expose the adjustable stop mechanism shown in the photo. Loosen the three
screws holding the aluminum ring and rotate it clockwise (when viewed from the camera position)about 20mm then retighten the three holding screws. At this
point the lens can be mounted to the camera and check for infinity focus in the viewfinder. The correct position is when the lens will focus just past infinity.
Place the focusing ring over the assembly, position the "W" at the indicator line and tighten the screws. Replace the flexible plastic focusing grip and
the job is done.
Note: It is not recommend doing the adjustment to the 1000 mm lens because of those little ball bearings which fall out and are impossible to get back in. The lens will function well without them but changing the back focus on the 1000 is a difficult job and is best done by a professional and trained person. It is better to use the 2x teleconverter which works great on all digital cameras.