Olympus 40mm F2.8, Quick Cleaning of internal Haze

[Sonnar Brian]

The Olympus 40mm F2.8 arrived yesterday, this morning had a chance to take out the rear group and clean the haze from each side of the aperture blades. This is a rare lens, especially including the Finder and front cap. I've wanted one for a while- when one popped up here on RFF, grabbed it.
Disassembly: Spanner and a small suction cup. Rear Baffle comes out easily by hand. I decided to just take out the rear group, as it was easily accessible. Learned a long time ago to keep things simple when working on a lens without having instructions. Lots of turns to get it out. Lift out with the Pen type suction cup. I took out the front retaining ring, but the front element did not easily drop out. SO- with the previously mentioned advice, cleaned the haze out through the back of the lens. That worked. Haze came off the rear group as well, re-assemble and test.

 

[Sonnar Brian]

Quick test, used on a cheape Chinese adapter for a 50mm lens.
I will redo with a Voigtlander adapter. The 40mm focal length means the thickness of the adapter is critical I noted a slight front-focus. I can correct that, after using a precision adapter first.


The haze is Gone.

 

[Miles.]

Awesome that it turned out well!

Any guess what the engraving on the rear mount means?

 

[Sonnar Brian]

@milescl

No idea- After ruling out Russian Submarine K-119 as being built decades after the lens.
I've seen other odd engravings on internal parts of lenses.

Olympus Zuiko Coated 4cm F2.8 修理報告

Olympus Zuiko Coated 4cm F2.8というレンズは、比較的に珍しい機種の一種だと認識して…

japanlensassociation.com

I found a picture of the teardown, and this confirms the optical formula as a 1-1-1-2, 5 element in 4 groups. Now that I see the breakdown, the construction of the front group makes sense. I think it's like the Xenar Special. I'll make a second attempt at taking out the front element.

 

[Darinwc]

Like you, I've been wanting one for years. I collect mainly Olympus gear and LTM gear.. so this would be the perfect combo. Alas, have not scored one yet. There was one on eBay recently in a lot but the lot went for much more than I was willing.
Harder to find good deals anymore!

Nice job cleaning up the lens!

 

[hilltime]

Lucky you. Got one years ago on a Leotax DIV, which was probably purchased as the same time as the body, according to Paul Sokk, in his awesome research of the Leotax brand. Took many years to find the original finder and even longer for the front cap. You scored all at once!

 

[Sonnar Brian]

@hilltime - Yes, but as conservation of inconvenience go- Glad it was ME that bought this one!!!

It did not focus to infinity, and severe front focus,
After finding the pictures on the Japanese Website, I removed the Barrel from the Mount. Two Shims- Notched for a guide pin use to align the barrel in the mount.
SO- severe front focus: Shims were 0.45mm and 0..25mm. AFTER removing the 0.25mm shim, focus is perfect.
Mechanics on this lens, being kind: 1950~1952, Olympus first and only entry into the Leica Lens Market, even this high SN lens shows they were doing a lot of machining by hand and "Fit and Finish"- left rough where people would not see.

The threads- I needed to use light oil on the retaining ring to get the barrel back into the mount. Shims- the Guide Pin means the shims must be a minimum thickness. Whoops. Need to add shims and the lens no longer will focus correctly.

An interesting collectible lens. For collectors.


I cleaned the Q-Tip lint out before re-assembling. BUT- soak Q-Tip in light machine oil, clean threads. Required. Trust me.


The machining reminded me of my very early Simar 5cm F1.5, 74th made. The SN on this one is higher than what is listed on

Zuiko 4cm f/2.8 for Leica - Camera-wiki.org - The free camera encyclopedia

camera-wiki.org

I'm very happy to have it! Now it focuses correctly. The front element- did not want to budge and I've learned the hardware to know when to quit.

I also opened and cleaned the finder. Back eyepiece easily unscrews, along with fixture that it sits in. PURRFECT now. Meow.

 

[Miles.]

For posterity, here's my serial # data for this lens:
Earliest Known: 60062
Latest Known: 61772

 

[hilltime]

Looks like you sure did a lot to make this focus correctly and nice glass. My ser # is 61688 which according to the Wiki article was very close to the highest #, even though yours is still later. I have only used this one time on the DIV, and did about 10 shots before switching to another lens the Topcor 5cm/ f2.8. Focus seemed OK with film. Love it’s vintage look even though it’s not the sharpest knife in the drawer!

 

[Sonnar Brian]

@milescl - You need to write a book.
@hilltime - When first looking at the pictures, not pixel peeping, I thought "Okay lens, soft". Pixel peeping- realized it was the focus that was off, but DOF for a 40mm F2.8 lens covers a lot of error. After removing the shim- much better. Gray and Rainy, will test this lens in the Sun once it re-appears.