# Converting a lens for my Nikkormat



## mimstrel (Apr 9, 2009)

I'm not sure if I should post this here or in the Equipment area.  I took a risk buying a lens that I wasn't sure would fit on my camera.  I found one review online that said it would work with Nikon non-AI cameras, so I thought, "Well if it doesn't, its a $15 lens including shipping, and I'm only buying it to screw around anyway, it's not like I expect it to be anything good."

Well, it arrived in better shape than expected... but of course doesn't fit my camera.  It has some kind of conversion ring on it already - just not one that fits Nikon - so I started wondering, is there an economical way to convert it to work with my Nikkormat?  

The lens is a Sun-Zoom Macro lens, 60-150mm, multi-coated.  Like I said, it was a cheap eBay lens for me to play around with, so I'm not up for spending a lot of money on it.

Thanks!


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## compur (Apr 9, 2009)

Depends on what mount it has.  If you don't know, post some pictures of it (the mount end).


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## mimstrel (Apr 9, 2009)

Alright here's a couple of pictures of the mount that is on the lens to begin with, and the mount on the conversion ring it came with.  Sorry the photos are so bad, batteries are now officially dead on my digi... I'm re-charging now, so if these aren't good enough I can try again later.


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## mimstrel (Apr 9, 2009)

mmmkay here's the other two pics...


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## Dwig (Apr 9, 2009)

Yes, its possible in theory, but it will be a difficult task.

What you have is a YS system lens. The YS system is an interchangable mount system that evolved out of the T/T2-mount system. The YS mounts have the same basic specifications as the T/T2 mounts with the addition of a simple autodiaphram mechinism. A YS mount for Nikon, to replace the Pentax thread mount you have, will be difficult to find as they haven't been made for nearly 40 years. If you find one, it should come with a "prong" attachment that needs to be screwed onto the f/stop ring in addition to the mount itself.

You should be able to substitute a T2-mount (often incorrectly called a T-mount) for the YS mount but doing so would disable the autodiaphram making the lens much more difficult to use.


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## mimstrel (Apr 9, 2009)

I can't use an auto-diaphragm with my nikkormat anyway, I thought?  My other lenses are fully manual, so as long as this lens can be used in fully manual mode, I'm not losing out on anything.
I'll try getting a T2 mount and see how that works.  
Thank you!


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## Dwig (Apr 10, 2009)

mimstrel said:


> I can't use an auto-diaphragm with my nikkormat anyway, I thought?  ...



You appearantly are not familiar with the term. A major feature in the Nikon F of 1959 and its series of "Auto-Nikkors" was the fully automatic diaphram.

SLRs pose problems. You view through the lens that you take the picture with. You want to view at a wide aperture so the VF is bright and DOF is shallow to allow for ease of focus. You also want to shoot at a different aperture. Manually closeing the aperture to the shooting setting after focusing and composing is slow and difficult if you have to turn the aperture ring.

Auto-diaphram mechinisms close the aperture for you when the shutter trips. You set the lens on, say, f/8, but the actual aperture remains at maximum until you trip the shutter. It then closes to f/8, or whatever is set, for the exposure.

Classes of diaphram action are:

Manual: a simple iris or stop wheel. You view through the aperture set so common practice is to open the lens, focus, and compose and then manually to the aperture ring to the shooting aperture, take the picture, and then manually open the aperture for the next shot.

Pre-set: two rings. One is marked with f/stops, the second, usually marked "O-C" for open and close, is the actually aperture ring. You use it the same as a manual aperture except that you set the f/stop marked ring in advance and control the actual aperture with the O-C ring. This allows faster stop-down and re-open without having to look at the ring or count clicks.

Semi-auto diaphram: The setup is like a Pre-set except that the camera body operates the internal equivalent of the O-C ring. You cock it open and when the shutter is tripped the body closes the aperture by operating a lever or pin on the back of the lens. You have to manually recock the system after the exposure to return to a bright full aperture VF images.

Fully-auto diaphram: The body's control includes both closing and opening of the aperture. The diaphram just blinks down to the working aperture during the exposure, reopening to full aperture after the exposure.

This latter class was a rare thing in 1959 when the F was introduced. None of this has anything to do with exposure control, either manual or auto exposure.


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