Type 1 Rigid Summicron- Front Element Replacement

[Brian Sweeney]

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.

[Brian Sweeney]

Results with the lens:
wide-open at F2, closest focus. On the M8:


At F4:



The interior of the lens has some very slight haze around the edges.

But it does not seem to be an issue, and not worth further disassembly. I do not push my luck too far.
F2:


At F4:


Into the sun at F2:





And infinity at F2:



So- on the 1950s Leica lenses, the glass and fixtures seem to be much more individual fits than on other lenses. I got lucky, so boring paid off.

[ampguy]

Hi Brian,

From what I understand, there may have been 2 versions of the Rigid v1 8 element before the DR.

You might have mixed elements between the first 2.

What happens if you just leave the front 8th element off, wouldn't that be a 7 element v2 type lens, more microcontrast, less ghosting, more vignetting?

[Ranchu]

Looks excellent!

[Brian Sweeney]

This is the 50mm lens, and is a 7 element in 5 group design. I believe that some optical tweeking took place with later lenses, including the one element from the lens in the 2M block that did not work. I've taken apart 6 of these now. One of them had been assembled with three of the groups put in backwards. Leaving the front optic off- you will not get an image.

It could be that some optical tweeking took place between the 153x lens and ther 162x lens. But given that it did work after boring out the fixture- the front element had to be the same focal length as the original.

[Brian Sweeney]

Took this lens out today, picnic at a local park with a playground. Ir cut filter and heavystar vented shade.

Wide-open at F2:


Stopped down to F4:



The light haze does not seem to have any adverse effect on the blown highlights. +2/3EV on the exposure, ISO 160 on the M8.

Seems sharp, despite the hack job.

[Rob-F]

Looks good! I notice the very first picture, at F/2, has "swirly bokeh." I never noticed that with my DRS, which supposedly has the same optical cell as the rigid. I'll have to see if I can produce that, next time I shoot with it.

Good results, for hand working it with a file. You would think there would be centering issues. But if there are any, I don't notice any problems in the pictures.

[sanmich]

Did you manage to readjust the focal length/ focus?

[Brian Sweeney]

This lens had issues, another one was the optics module would not come out of the mount. So- it ended up being the same focal length as the original with the new front element. The second element I tried produced a slightly longer focal length, and I could not compensate.

On swirly bokeh, used wide-open and close-up with a lot of background stucture, the Rigid Summicron will still produce it.



Above is with my original type 1 Rigid Summicron, wide-open and close-up.

[kbg32]

Great job!

[robin a]

Tha MASTER at work...........looks Great !!

Robin

[Brian Sweeney]

After getting the replacement front element jammed in because I did not use the calipers- "Master of Mistakes". I think that was an episode from "Sagwa the Cat" that was on PBS that Nikki watched. The idea is that the character made all the mistakes, and everyone else learned from them.

[Ronald M]

Elements do not swap even between lenses of the same production series. Even if you got a fit, the optical cell might have a different focal length which requires a different mount. Elements are hand picked for a particular lens.

On the other hand, there is a small chance you get lucky. Very small.

[Brian Sweeney]

I have swapped a lot of elements in other lenses. Canon 50/1.5, Canon 50/1.2, Jupiter-3's, Sonnar 5cm f2 and 5cm F1.5, and more. Usually the focal length remains close enough that adjusting the shim of the optics cell within the focus mount corrects the difference. At most, I've had to change the shim by 0.1mm after the swap. This lens was stuck in place, and I could not pull off the shimming trick.

[raid]

The Cron looks good, Brian. Well done again.

[sfox]

Brian,
Just got this from a sale of this lens. Great work !

[Brian Sweeney]

You will be pleased with this lens. I have one that is "near perfect", and this one matches it.