Paxette Xenar 2.8/50mm stuck aperture

[Pancolart]

I've got this corroded Xenar M39 (probably Paxette). I succeed releasing focusing but aperture ring is frozen.
Can someone tell me where is a layer of turning so i could also assume where it got stuck.
There are two possibilities:

[philslizzy]

I don't have this particular lens on any of my Vitos, but most can be opened at the front with a friction tool. A ball of Blu-Tak should do it. Make a 'worm of it and circle it round the name bezel, squash the worm into the palm of your hand and rotate the lens anti-clockwise.

If this works you will probably take off the front element too. Mark the front of the lens with a marker pen first so you know which way to put it back. A good soaking with lighter fuel ought to free the aperture. Let it soak in and keep rotating the lens. Leave it for an hour or so.

You could go in through the back which normally screws off via a slotted ring. The double element will drop out, so be careful which way you put it back!

hope this helps.

Thinking later... try a little lighter fluid down where you have put the arrows. This at least may make it easier to get the front off.

Let us know how you get on.

[Pancolart]

Thank you for info Phil. The problem i think is aperture ring, not the blades. Thus i do not need to reach blades but try to turn aperture ring. Sadly i do not know what (or where) exactly the rings are separated. There are two options where i put arrows. I already soaked both with fluid and bruised my hands but ring does not turn. My last resort will be pushing something between the rings that are corroded. But which ?

[philslizzy]

The rear of the lens will unscrew exposing the aperture blades, put some lighter fluid in there. It could free up the aperture ring. But it looks like corrosion is jamming the ring. Some of the alloys used in these cameras corroded years later.

I'm sure penetration oil or WD40 will do the job but it could leave a mess and will all need flushing out with lighter fuel. I can't see it damaging the glass but the lubricant on the helical will go so it will need replacing.

Its a common lens and won't be expensive to replace if you bugger it up.