Sekor Nikkorex 135mm 1:2.8 surprise

I found this Nikkorex lens in a box full of grimy old camera gear in a curbside clean-up. You know, one of those moments where you should see the red flags and stop accordingly, but you don't.

The focus ring was stuck tight. Seemed otherwise tidy though, and was by far the cleanest thing in the box. Aperture works smoothly and the glass looked perfectly clear.

This evening, in a fit of madness just before heading off to bed, I tried to open it a little just to see what was going on in there. My largest rubber wrench was a perfect fit for the nameplate. I pulled the front lens with a lens puller and something dark popped out too. In my initial confusion I thought that the black paint around the lens group was flaking, but then I realised what I was looking at...




...yeah, i'm pretty sure that's not going to help anything.

I'm no expert on glass stress fractures, but those chip patterns are along the rear edge of the lens group and to me they look as though they were caused by a force from the rear, such as by being dropped into place or overtightened against their stop. This was my first time doing anything with this lens and I have no clue to its history before I found it in a box.

It seems like the optical path would still be clear if all those shards were cleaned out. I'm yet to confirm that's the actual cause of the stuck focus ring. There were no signs of this at all before I removed the group, but it seems implausible that it's not related. I'd probably be certifiable to keep going with this, right? Right?

Think of it as an exercise in learning that might produced an interesting lens when done OR may result in a pile of parts.

There are many tutorials on lens refurbishment on YouTube.

At least you'll learn the internal workings of the lens.

I am curious if it might not turn out to be a weirdly flawed lens that could be kept on the shelf for very specific situations that demand a unique perspective.

I would clean out all the chips and blacken the fractured edge surfaces on the side with paint or a Sharpie marker. It will probably not affect the imaging noticeably.

As far as I know, this is one of the budget lenses made by Mamiya in Nikon mount to go along with the budget Nikkorex SLR. Nico van Dijk says it is "rare and collectible" http://www.nicovandijk.net/nikkorexlenses.htm I guess there's a collector for everything, including Nikkorexes.

It'll probably be fine. I can't see how light could enter there. You could always paint the edges w/ flat black acrylic paint. That's what I did on this non ai H Nikkor 85 1.8 lens that was bargain priced. It has this big chunk of glass chipped out of the front element on the edge of the front element. I put a small bit of black paint on the chip and tried my best to make the lens flare. It won't. The head shot (lol) was in blazing Az sun from one side, and the sculpture had all these reflections from strong light.

Kino said:

Think of it as an exercise in learning that might produced an interesting lens when done OR may result in a pile of parts.. I am curious if it might not turn out to be a weirdly flawed lens that could be kept on the shelf for very specific situations that demand a unique perspective.

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After some thought, I agree. It's a learning situation, whichever way it turns out. And I like to return things to functionality, rather than perfection, because function gives life and flaws give character.

reddesert said:

As far as I know, this is one of the budget lenses made by Mamiya in Nikon mount to go along with the budget Nikkorex SLR. Nico van Dijk says it is "rare and collectible" http://www.nicovandijk.net/nikkorexlenses.htm I guess there's a collector for everything, including Nikkorexes.

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I guess that's me now I've only recently jumped on board the Nikon (and Nikon-adjacent, in this case) train, being a long-time Canon person, so if I can get it working I'll be glad to have another lens to play with. It does seem rare, there's only been one sold in the last year on ebay. And I've never seen another lens where the aperture had to be cocked before each shot, so it is definitely a curiosity.

momus said:

That's what I did on this non ai H Nikkor 85 1.8 lens that was bargain priced.

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A good move. That's the lens that pursuaded me to get a Nikon. It's gorgeous. Great shots!