Well without any technical knowledge or particular skill, but a love of tinkering and investigating and an essentially 'free' lens that wouldn't have been any real loss had I failed...I decided to tackle trying to clean away some fairly bad fungus growing inside a lens I bought. I thought it might be good to document the steps, as though this applies to this particular lens, many lenses share the same assembly, and plus-or-minus minor differences, the tutorial might work just as well with nearly any lens, for cleaning fungus or dust or condensation. The lens I was working on was a Konica Hexanon 50mm F1.7 - a super sharp and legendary fast prime I bought used, afflicted with the fungus.
Note that there are two ways to get into a lens - rear element, or front element. By all accounts the rear element access is more complex and dangerous, with more chance of losing small parts, throwing off alignment, etc. The front element is much more simple by comparison, less risk of damaging things, and less precision needed in reassembly. So as long as the area you want to clean is on the inside of the front element or the 2nd element just inside, this method would be preferred.
I've never opened up a lens before, so I dug around for some basic instructions online, and despite my own fears and the warnings of others, it didn't look too challenging.
So, here's what I did - this documents the process for this particular lens, but most lenses will have a very similar construction and similar process:
1. What a horrible documentarian I am! I failed to start off with a photo of the actual fungus!! I tried massively brightening this first shot and circled where it is - it was a fairly large patch with some spidery veins running off from it - it shows up here as a large dark shadow area, inside the front element:
2. The front name ring that surrounds the front element is simply screwed on - and to unscrew you need a simple spanner wrench...without one of those, often anything rubber with some traction can work the ring off by friction. I used the rear element lens cap, with an elastic band pressed between it and the ring - counter-clockwise turns and I felt it loosen pretty quickly:
3. Once that's off, you will see 3 screws inside. On the Konica, these held the black metal bezel that makes up the inner lens frame or tube, surrounding the element. I've tilted the lens to try to show the tiny little screws inside:
4. Once removed, the outer tube can be grasped, and turned counter clockwise - it unscrews from the lens - it's deeply threaded and takes lots of turns, but was quite easy and comes right off:
5. Now the lens element assembly is sticking out in the open...it too unscrews counter-clockwise, and is now quite easy to grab. Once you work it off, the lens element comes off as a single piece with the black surrounding plastic...the rear element can now be accessed:
Here's the actual front element assembly, after a cleaning. I carefully wiped the fungus off the lens' element with a damp microfiber towel - not rubbing too hard to avoid abrasions, and turning the towel often to avoid reusing a dirty section. I also went ahead and cleaned out the inside of the lens body. The aperture blades are fully exposed and accessible from the front like this - I closed them town to minimum aperture to avoid anything falling in by the center elements:
That was it - just put everything back in again in reverse - all quite easily. No worries about alignment as everything simply screws back in to its stopping points. I was shocked how easy this process was - I might even consider doing something similar with another older lens I have that has quite a bit of dust inside the front element.
Some quickie sample pics afterwards to confirm it was all put together properly and focused correctly and sharp:
Yep...I'd call that sharp and clean! Any questions or additional info needed, I'd be glad to share. Anyone who's got a junker lens, with bad dust, condensation, oil, fungus, mold, etc - don't throw it away just yet - give this a try if you've got nothing to lose anyway. And if you're confident enough, you might even be willing to try it as a maintenance technique on lenses that get a bit too dirty inside. I wouldn't recommend getting out there and voiding your warranty on new lenses...but older lenses that need a little care can be restored like new. I've gotten past my initial fears of doing so, and will likely work on several other older lenses to clean them up.
Sony DSLR-A68 / Sony 18-250mm / Minolta 50mm F1.7 / Tamron 150-600mm / Minolta 300mm F4 APO
Sony A6300 / 18-55mm F3.5-5.6 / 55-210mm F4-6.3 / 10-18mm F4 / 35mm F1.8 / 16mm F2.8 / FE70-200mm F4 G OSS / FE70-300mm F4.5-5.6 G OSS / via manual adapter, lots of Pentax K mount, Konica K/AR mount, and Leica M mount manual lenses