disassemble DA 55-300

Does anyone know how to disassemble DA55-300mm for cleaning fungus inside the lens? I tried to open the rear mount. Then find it hard to continue after take apart the amount. Besides, I tried to open the front glass by finding a notch in the front ring. yet none there. THen I take off the cover the front ring, and find some screws there. Unfortunately I failed to open the last two screws since they became damaged after unscrewing for a few times and they are stuck there? any idea?

The best advice is too late - don't mess with lenses unless you know what you are doing and have the right tools for the job.

I'm surprised there is fungus in a 55-300mm lens as they have not been around long eniough to expect that. Are you sure it's fungus?

To save the lens now a lens repairer would seem the best bet, but it may not be worth what it would cost.

I am really suprised that you even attempted to strip down this lens!

It is a precision job and is best left to a specialist repair facility!

I'm afraid that you may have damaged your lens, and would suggest that your best course of action is to get it repaired and serviced by a specialist repair facility, as you have just done more harm than good.

Kindest regards,

Peter.

All my lens service/repairs have been handled by Michael Spencer, factory trained 47 years experience, if it can be repaired then he's your man!
Very friendly and helpful, ring him for a chat and advice 01246 250767

http://www.camerarepairs-r-us.co.uk/

Regards,

John

Thanks everyone. I bought it as second hand. new and cheap but it turns out there are two fungi. With my university student budget, I don't think it is worthy to clean it in pentax service center. Then after watching many examples of disassemble lenses for cleaning. I made up my mind to dismantle it. Yet its structure a bit different from primes. I　assemble it. It still works. I don't now how to deal with it. If not clean, the fungi will be obvious? Is it ok for put it together with other clean lens? I just quarantine it in a separate drawer. Then it turns out that there is two more spots. Shall I wrap it in a plastic bag and put it in a fridge? I will learn more and dismantle it and clean it later. Pity no such example in the youtube or google. Not such examples for disassemble DA zoom lens so far.Hong Kong is quite humid and hot actually.When I disassemble it, I find nowadays the lens are mainly plastics and not metal at all except for the rear mount ring.Morever the plastic are not as good as before. The hole for screwing tells that since it is crispy

The main problem I have with cleaning fungus is dust. You can spot and clean the fungus easily but you will inevitably get some dust inside when you rebuild the lens.

A can of compressed air does help!

You may also have fun resetting the infinity focus depending on the lens design. I tend to put my Super A on a tripod and lock it in position aimed at a hilltop some miles away, then tweak the infinity position until spot on. The Super A has a split focussing screen so you can tell when it's right as the hilltop forms a smooth line. I've used this trick three times now and it's very effective.

Just seconding what JR wrote - how can such a new lens already have fungus?!!!

Poor storage? Box unsealed in a damp area for a while?

I had a buddy spend a couple of months in the top end of Australia (90% humidity) and 2 of his DA lenses picked up fungus, so if the conditions are right it wouldn't take long at all.