Olympus Zuiko Auto-S 50/1.8: Front lens group cannot be separated

Andreas Thaler · Nov 21, 2023

A 50/1.8 Zuiko, heavily molded, was quickly disassembled:

The rear lens group consists of two lenses lying one on top of the other that are easy to clean:

The unpleasant surprise comes from the front.

The front lens group forms an optical unit - literally:

The fungus sits between two lenses:

This „UFO“ cannot be cracked, neither from above nor from below:

Even acetone to loosen a bond didn't help.

Maybe the Dremel with a cutting wheel can do it?

This is how the UFO flew off the table towards the spare parts box

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All information provided without guarantee and use at your own risk.

albada · Nov 21, 2023

In your photos, the front element appears to be secured by a threaded ring with no notches in it for a spanner. You could try cutting two notches with the Dremel.

Mark

Andreas Thaler · Nov 21, 2023

albada said:
In your photos, the front element appears to be secured by a threaded ring with no notches in it for a spanner. You could try cutting two notches with the Dremel.

Mark

Thanks!

From what I have found, this unit is welded or glued and intended to be a replacement part. But since I've given up on the lens anyway, I can try using the Dremel.

Anyway a component should only be designed in such a way that it does not have to be damaged during service.

As far as I remember, I didn't proceed also with the rubber barrel to untwist by friction.

ic-racer · Nov 21, 2023

I got this Horseman "Teleconverter" on the back of a 150mm Topcor lens around 2012. I never used it because it was very hazy and all the haze was under the last element. I cleaned every one of the twelve surfaces except two.

Just the other day I "found" this while looking for something else and I tried acetone on the area with the red arrow. To my surprise it was then able to unscrew and I could clean the last surface. The hazy surface.

The 4x5 negatives exposed with the now-clean converter are drying as I type.

Andreas Thaler · Nov 21, 2023

My fear is that I will misalign the optical unit if I use force.

Flighter · Nov 21, 2023

Hi Andreas

Andreas Thaler said:
From what I have found, this unit is welded or glued and intended to be a replacement part. But since I've given up on the lens anyway, I can try using the Dremel.

I think you are right, looking at the exploded diagram it looks like the front group of 3 elements was not designed to be disassembled.

I think there were a number of design changes over the life of the 50mm, yours is the latest 'MIJ' version - so called because 'Made in Japan' is written on the front ring. It is reputed to be the sharpest of the f1.8 50mm Zuikos. The previous version just had 'Japan' on the front ring and is of similar design.

On earlier versions (which have the serial number on the front ring and 'lens made in Japan' on the mount at the rear) as shown below, the front group can be disassembled to give access to all 3 elements, as shown below.

Andreas Thaler · Nov 21, 2023

Thank you!

Anyway, this is a shame, isn‘t it?

Flighter · Nov 21, 2023

Andreas Thaler said:
Thank you!

Anyway, this is a shame. Isn‘t it?

It is indeed, most aggravating!

OAPOli · Nov 21, 2023

I'm not sure if that's the case here but some lenses are "burnished" in their housing. That's when the metal is folded and rolled on the element's chamfered edge. It can be removed but it's usually destructive.

Andreas Thaler · Nov 21, 2023

OAPOli said:
I'm not sure if that's the case here but some lenses are "burnished" in their housing. That's when the metal is folded and rolled on the element's chamfered edge. It can be removed but it's usually destructive.

The same should be true for the Canon FDn 50/1.8:

Beware of kit lenses when it comes to repair

Andreas Thaler · Nov 21, 2023

Already known?

The Unofficial Olympus OM Sales Information File

Flighter · Nov 21, 2023

Andreas Thaler said:
Already known?

The Unofficial Olympus OM Sales Information File

Yes, that's a useful site. Interesting to see that it has diagrams of the two different lens configurations for the 50mm f1.8, the yellow one on the left from the page on the 50mm lens is the older version and the one on the right in the instructions that are linked to on that page is the newer version.

I'm also pleased to see that Mark Dapoz's The Olympus Hardware Resource Page at http://olympus.dementix.org/Hardware/ is back on line, it had been offline for a while

Andreas Thaler · Nov 21, 2023

Neofito · Nov 23, 2023

what amaze me is that fungus are able to grow there... what a PITA those spores.

Olympus Zuiko Auto-S 50/1.8: Front lens group cannot be separated

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