While looking for some lenses in Contax/Yashica mount for both mirrorless and film, I happened across a buy now offer on eBay for a used Yashica ML 28-85mm f/3.5-4.5 Macro. These are scarce to locate and probably more sought after than other C/Y Yashica branded zoom lenses, as they have a reputation for edge clarity, color rendition, and sharpness. When they do show up for sale, they may not always be in the best optical and/or mechanical shape due to some inherent design issues.
This particular lens was listed at a good price but as noted from the seller, it was suffering from heavy hazing on the internal elements. Aside from that, it was fully functional and in reasonably good cosmetic condition. I clicked the 'Buy Now' button and had it in-hand several days later. This wasn't going to be my first lens tear down or cleaning, but it would be my first attempt with a zoom lens.
Hazing at this scale is a well known issue for this particular lens. Since this is a push-pull zoom that isn't sealed in any way, it will 'pump' air that's drawn from outside its body and direct it into the cavity between the front element group and the second optical block behind that. This compressed air flow can churn up and atomize the old oils and solid lubricants inside the lens into a shotgun particulate blast that adheres to everything within that air gap. The off-gassing residue from the helical grease when added to any other sucked-in contaminants will contribute to the buildup over time. This is a lens that may require a regular maintenance schedule, but it's a fantastic lens that warrants a little extra effort every year or two - if - you're up to the task to clean it, or can pay someone else to. An alternative strategy might be to remove and replace all of the original lubricants with modern formula types, but I doubt that would extend or eliminate the need for routine cleaning.
The good news is that this lens is far simpler to disassemble and then access those affected elements than what I'd guessed. There's a lot of separate and somewhat complex mechanical actions taking place whenever a zoom collar is turned or push or pulled, but in this case all of the areas I needed to clean weren't affected by those actions. The sequence posted here to fully tear-down / clean / reassemble the pieces, took far less time to complete than the time it took to photograph and document the entire process from start to finish. Using the right tools it can easily be finished in no more than an half an hour or so - even if you've never attempted anything like this before. It really wasn't much different than cleaning a prime lens, where the target elements to clean are in front of the diaphragm.
I've posted the steps and photos in their own album to view the whole process. Make sure to click on 'Show Captions' if you prefer to view the sequence in the lightbox.
[ NOTE: All of the photos from the tear down and cleaning were shot on a Nikon P7700 CoolPix in Close-Focus mode. It was mounted on a unique 1960's chrome tripod from it's horizontally adjustable crank arm. ]
If you would be interested in performing a deep-cleaning on a lens of your own, but you may not have some or all of the tools like those I normally use, I've included a shopping list of links and resources for you to investigate. I currently use everything in the list, except for the rubber bulb blower, since I use my vintage Feola pump blower for lens tear downs (it's highly effective, but easily quadruple the cost of the newest bulb types - if - you can find a good late-50's metal type that still works).
I would however caution anyone willing to take on any lens or camera related disassembly for cleaning (or even repairs), to take some extra care in selecting the quality of the tools you intend to use. There are certainly an assortment of different ones to choose from, with a wide range of prices - but you'll kick yourself silly if you end up with gashes in your lens barrel's painted finish, or worse yet, if you massively scratch a glass element as the result of using a flimsy and unstable spanner. Don't view these tools as a one-time cheap purchase that you'll toss in the trash when you're done. Most of these are inexpensive as it is, but I would not suggest going cheaper unless you're confident about something else's quality. Tools like these should serve you well for any similar cleaning or repair tasks in future years. Consider the question... Would you want your surgeon to use a pocket knife during your heart transplant?
I haven't included any paper-stick cotton swabs in the list (plastic or wooden sticks can contaminate what you're cleaning), or the 99% alcohol or Goo Gone, or any other cleaner solutions. You'll be able to get the swabs for cleaning applicators (in multiple quantity choices) and the alcohol from your local drug or discount store just as cheaply as anything you'll find online. The neoprene I have isn't always available in the small sheet size I use, but you can substitute cloth placemats or the 24"x13.7" Rubberized Black Playmat I use in my lap tray (below) for a surface that your removed parts or screws won't catapult from if you drop them. For face ring removals, you could try the thin foam sheets used for packing electronics gear, or the ones used to separate stacked items like plates or dishes... They should be a stiffer closed-cell foam type that won't easily get sliced or torn.
One last item that isn't shown in the photos and wasn't used this time around, is something I use as a safety catch-all with the messier and more parts-intensive tasks... a 15"x20" Fiberglass Cafeteria Tray that I can additionally use as a work-surface to place in my lap if I don't want to be stuck at a regular work table. The lip around the edge keeps things contained, and it's light and stable enough for extended use 'off-table' - and - it's also large enough to keep tools and parts within easy reach for lap work.
|Horizontal 12-65mm spanner - Japan Hobby Tool ($30-35)
|-- Also available on eBay ($40+)
|R.o.R. Lens cleaning solution
|2oz Pump Bottle
|Thick, ultra soft, and lint-free photo wipes
|PEC-PAD 4"x4" 100 ct.
|Thin, low lint, absorbent tissue wipes
|KimWipes 280 ct.
|Powder-free, 4mils, disposable gloves
|Comfitwear Latex 100 ct.
|Powder/Rubber-free, 4mils, disposable gloves
|Dynarex Nitrile 100 ct.
|Debris/Dust lens brush
|Lg. Natural Bristle Brush
|For loosening 2-Hole cap screws
|Staedtler 6" Divider
|Dust blower with a stronger air flow
|Watchmaker's Bulb Blower
|Extends a cleaning swab's reach
|5.5" Straight Forceps
|Small parts retrieval + wipe holder
|Gooseneck inspection lamp (no laser)
|Magnetic Base LED Light
|Precision mini-hex bits and Driver
|TEKTON 27-Piece bit set
|General sources for tools, grease, etc.
|Japan Hobby Tools (in Japanese)