fungus? rust? suggestions please

I'm struggling to get a decent picture of this



this is the back of a da35al, that doesn't look like the fungus that I've seen in the past on lenses.

Possible that there has been exposure to moisture?

Lens works perfectly - and yes it was an ebay bargain.

distinct brownish lines on a single blade.

Looks like it has been dropped in the sea and not washed out and dried afterwards.
Hope it truly was a bargain. Was it honestly described?

John

I think so.

this one:http://www.ebay.co.uk/itm/SMC-Pentax-DA-35mm-f-2-4-Prime-Lens-/140909102896?ssPa...

Ideally I'd like to partly dismantle and clean the iris - but I've not found any guide.

If it has rust in it (as it appears) it will never truly go away. A rebuild with new parts might be successful, but at what cost!?

I note that the seller is shown as a 'business seller' so you have the right of return under the distance selling regulations if you are not happy with the lens.

The optics don't look clean either so it would appear to have been misdescribed in any event. If it were me I'd return it and source another one.

John

PS Act fast as there is a time limit to return items under the distance selling regs. See
http://www.out-law.com/page-430#goods

To be fair, the optics are actually fine - probably looks bad because I had trouble trying to capture the marks - needing to shoot sideways through the rear element.

I've stripped it to the point of getting the aperture ring out and there isnt any sign of water marking inside.

Ideally I'd like to know more about the build before I go any further.

I found someone on the other forum who fixed a manual focus problem through striping and reassembly - I've sent him a pm asking about what he did.

Good luck, hope you get it sorted then.

John

If it is not impacting performance and you are happy with it for the price paid - leave well alone.

I have successfully stripped, cleaned and rebuilt many MF primes.

I have also successfully stripped and cleaned several AF's - if only I could get that rebuild bit right

Seriously - unless you really know what you are doing and have the tools - AF are very difficult to strip and rebuild - spring loaded bits tend to fly out in all directions or refuse to go back in place!

Carl

Carl,

I know exactly what you mean!

Like you, I've done manuals OK. Just need a little warning of the 'Ping! what was that?' bits.

It seems fine, in fact if I hadn't been warned by the listing I may well not have noticed. But if it is reasonably easy to strip....


this thread : http://www.pentaxforums.com/forums/pentax-slr-lens-discussion/201543-da35-2-4-st...

doesn't have much detail but that doesn't look too complex - at least its a prime - the zooms are the ones I've had trouble with in the past.