This project is intended simply as a guide for folks who are willing to modify their lenses, and feel comfortable with partially disassembling them, and generally doing things that would horrify lots of devotees of precision equipment.   But if you love the Kiev 60, you're probably not so hung up on such things, anyway.  Still --

YOU UNDERTAKE THIS PROJECT AT YOUR OWN PERIL.  IF YOU SCREW IT UP, OR IT DOESN'T WORK, BY ALL MEANS TELL ME WHAT WENT WRONG SO I CAN POST IT FOR OTHERS, BUT DO NOT BLAME ME FOR IT!  All I know is mine works fine.

Now, let's get started.

    This page describes a method for modifying the Rubinar 500mm f5.6 Maksutov mirror lens, which is designed for 35mm, so that it can be used on a Kiev 60 or Pentacon 6.  The Rubinar 500mm lens, like many long lenses, actually has plenty of covering power and easily covers the 6x6 format.

    The method described here involves removing an infinity stop in the lens, which will allow it to focus "beyond infinity" (on a 35mm camera) so that it achieves proper infinity focus when mounted on a Kiev 60.

    This page also presents a few ideas for building a lens mount adapter so that you can affix the Rubinar lens to the Kiev 60 camera.  When complete, your lens will be useable on both 35mm and Kiev 60 or Pentacon 6.

    I believe the method described will work for the MTO-11 1000mm lens, the other MTO lenses, and the Rubinar 1000mm lens as well.  I have not yet tried either of these lenses, however, so if someone tries it, let me know how it goes, please.

    One correspondent has adapted the 300mm f4.5 Rubinar mirror lens with good success.  Notes and images are here: 300mm Rubinar Notes

    I am not confident that the system described here will work for a Kiev 88, which as I understand it has a longer film to flange distance than the Kiev 60.  If anyone tries a Kiev 88 modification, please let me know and I'll post a link or describe the findings here.

-    A Rubinar 500mm f5.6 Maksutov casegrain mirror lens.
-    Standard miniature screw drivers.
-    A sacrificial 80mm Arsat or Volna (see if you can find a dead one before you sacrifice a good one.)
-    A Dremel tool with cutting wheels, cylindrical metal cutter, and grinding wheel
-    Epoxy
-    Bondo (TM) metal filler
-    Access to a lathe
-    Flat black paint

STEP 1: Removing the Infinity Stop

Slide the rubber focus grip material forward on the focus ring of the 500mm Rubinar mirror lens.  Under the rubber material you will find three small set screws.  Back them off.  Now the aluminum focussing collar will slide off the front of the lens.  Note the position the collar was in so you can put it back in right spot.

Under the focussing collar you will see a shiny aluminum collar with a protrusion which locks against a similar black metal collar on the back part of the lens (the latter has the focus index mark engraved on it).  This shiny aluminum piece is the infinity stop.  Operate the lens a bit by turning it back and forth.  Observe that the infinity stop prevents the lens from collapsing down too small and thus focussing "beyond infinity."   The infinity stop also prevents the front of the lens barrel from turning too far the other way so that the two halves screw apart completely.

Equidistant around the shiny aluminum infinity stop you will find three small holes, with the same sized tiny set screws deep in them.  Back the set screws out.  Now the infinity stop collar will turn freely as you turn the front of the barrel.  Separate the two lens halves by unscrewing them all of the way, and carefully remove the infinity stop.  Put it and the set screws away in a ziplock baggie somewhere safe.

Now is a good time to clean those distressing bits of aluminum shavings out of the grease in the helical threads of your lens.  Isn't quality control in the FSU great?

Now carefully screw the two halves back together.  Be sure the helical is properly threaded -- it should turn smoothly just like it did before you took the infinity stop out.  If you mount the lens on a 35mm camera now, you will find that you can now focus it "beyond infinity."  You will also find that you can focus a lot closer than you could before.  Be careful, though: you don't want to focus so close that your lens inadvertantly comes apart in the field!

Here are some pictures of a Rubinar 1000mm and the process for removing the infinity stop.  These are lifted from an astronomy enthusiast's  website.  I did not bother to photograph the process as I did it, since this is all available on line already.  The link to the site is:

http://home.t-online.de/home/mmushardt/rb4.htm

The author describes the process for using either of the 1000mm mirror lenses as telescopes with a longer imaging path.

The 1000mm Rubinar is constructed in a fashion identical to the 500mm Rubinar.

Here are the set screws that hold the focus collar in place:

Here is an image of the lens separated into two halves with the focus collar off.
 
 

Here is the lens with the focus collar removed (left side), the inifinity stop removed (shiny aluminum ring on the right), and the two lens halves screwed back together.  All that remains is to slide the focus collar back on and tighten the set screws into their detents.

The astronomy website noted above also describes removing the infinity stop for the MTO-11.  It looks like all you have to do is back off a single screw!  How simple!   Here is a direct quote on modifying the MTO-11:
 
 

The Maksutov type, MTO 11 CA:

For the Maksutov type the removal of the stop is pretty simple. You just have to remove or shorten the screw in the ring with the threads for the tripod. Then you can turn the focus ring over the stop and the focus plane travels to greater distances from the rear end, so you can even use accesory parts with optical paths up to more than 100 mm. But remember: the effective focal length is increasing, reducing your focal ratio! By the way, this is a convenient way to improve the performance as a guiding scope.

STEP 2:  Building the Mount Adapter

    You have a lot of options for a mount adapter.

    The main consideration here is that the mount must not be more than 14mm thick from the very back of the lens mount to the part that comes up flush against the Rubinar mounting thread assembly.   If it's thicker than 14mm, you will not get infinity focus.

    You might use a Kiev 60 extension tube as the basis for your adapter, in combination with a small M42 screw mount extension tube.  You can take a look at my focus-adapting teleconverter page for some ideas (follow the link below).

    I used the rear of a defunct Arsat 80mm lens to make my M42 to P6 adapter.  I took a 10.5mm M42 screw mount extension tube, cut off the back threads (i.e. the male threads) with a Dremel and cutting disk, and then epoxied the extension tube into the Arsat lens mount.  The remaining gap I filled with Bondo (TM) metal filler to achieve a pretty bombproof assembly.  The trouble here is that the Arsat lens mount is a hair too thick.  I had to mill off about 3mm to achieve infinity focus on a lathe, and this settled the issue completely.

    One possibility would be to modify a reversing ring ($6 from Hartblei).  I plan on buying several of those for projects...

    Here's a picture of my adapter:

IT WORKS!

Here is a link to a page with a few photos I shot the day I completed the modifications: TEST SHOTS.

There are some more test shots with a modified 300mm Rubinar here: 300mm Rubinar Notes.

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