I ended up doing a lot of trial and error on this one, did not photograph it.
Several months ago I bought a Summicron off of Ebay for $150- had a front element that was opaque. Fully disclosed, sold for parts. I had two front elements from parts lenses, figured "easy Swap".
Wrong. Got the lens, took out the retaining ring, managed to get the front element out using a suction cup, took several tries. Put the new element in. It would not go into place, and wedged in at an angle. The lens was a 153x batch, the front element was from a 162x batch. I should have measured them with calipers first. After prying the 162x front element out, introducing an edge chip in the process, tossed the parts into a box.
Last week, had some time for lens work. The original element was "ever-so-slightly" larger than the fixture, explaing the tight fit. The new optic was 0.1mm larger in diameter. The second spare front element I had was from a later lens, and was 0.15mm larger than the original. Grabbed a file and "bored out" the brass to accommodate the new front elements. I used a small file with a squared off head, and used fast circular mothions. File, measure, file, BORING!
I tried each of the elements with the lens, and the 162x front element produced good results on the M8. The later element back-focused, meaning the focal length of the lens with that element was too long. Blackened the edge of the chipped 162x front element, put it back in.
Several months ago I bought a Summicron off of Ebay for $150- had a front element that was opaque. Fully disclosed, sold for parts. I had two front elements from parts lenses, figured "easy Swap".
Wrong. Got the lens, took out the retaining ring, managed to get the front element out using a suction cup, took several tries. Put the new element in. It would not go into place, and wedged in at an angle. The lens was a 153x batch, the front element was from a 162x batch. I should have measured them with calipers first. After prying the 162x front element out, introducing an edge chip in the process, tossed the parts into a box.
Last week, had some time for lens work. The original element was "ever-so-slightly" larger than the fixture, explaing the tight fit. The new optic was 0.1mm larger in diameter. The second spare front element I had was from a later lens, and was 0.15mm larger than the original. Grabbed a file and "bored out" the brass to accommodate the new front elements. I used a small file with a squared off head, and used fast circular mothions. File, measure, file, BORING!
I tried each of the elements with the lens, and the 162x front element produced good results on the M8. The later element back-focused, meaning the focal length of the lens with that element was too long. Blackened the edge of the chipped 162x front element, put it back in.
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