Zany rear lens cap alternatives

xkaes · Oct 27, 2022

I'm in need of a rear lens cap for an M42 lens, but I figure that I have something lying around that I can use, FOR FREE, instead of paying $5+ for one -- let's say a top from an empty bottle of prescription pills, etc.

Any ideas?

And there is no need to exclude discussion of any other rear lens caps! I could use Minolta, T-mount, Maxxum/Sony, etc. rear lens caps too.

I'm also on the lookout for a 100mm FRONT lens cap, but that's different ball of wax.

gone · Oct 27, 2022

I've used plastic jar lids, the tops off prescription meds, shampoo bottle tops, all sorts of things. The rear elements are usually a lot smaller than the front, so it's possible to rummage up one at home.

4season · Oct 27, 2022

Scraps of mat board can be fabricated into decent push-on caps.

I've also 3D-printed very decent L39 body caps and rear lens caps using data files from Thingiverse, but quality of the submitted files varies considerably, and OM and K body caps that I printed from data files found on Thingiverse were barely usable, and frankly I'd have done better to order new Chinese product which can be very reasonably priced, particularly if you buy in body cap + rear lens cap 10-packs. For instance:

Sony A / Minolta AF
https://www.ebay.com/itm/403132260800

M42
https://www.ebay.com/itm/224411574534

Minolta MD
https://www.ebay.com/itm/224411574022

Pentax K
https://www.ebay.com/itm/402294308019

I didn't even try to look for the absolute best deals, but even so, we're talking around 67 cents per cap (shipped!), plus tax.

BAC1967 · Oct 28, 2022

If you find something with a close fit but too loose, you can use self adhesive felt to make up the difference. I do that often with push on filter adapters.

E. von Hoegh · Oct 28, 2022

xkaes said:
I'm in need of a rear lens cap for an M42 lens, but I figure that I have something lying around that I can use, FOR FREE, instead of paying $5+ for one -- let's say a top from an empty bottle of prescription pills, etc.

Any ideas?

And there is no need to exclude discussion of any other rear lens caps! I could use Minolta, T-mount, Maxxum/Sony, etc. rear lens caps too.

I'm also on the lookout for a 100mm FRONT lens cap, but that's different ball of wax.

I have some old Zenits which are good only as rear caps for m42, due to the ~70% viewfinder coverage.
Front caps, I've made for my old LF lenses sets of velvet lined leather covered caps, built up of layers of thin cardboard. They look like they were made 100+ years ago. You don't need to line and cover them, bare cardboard works fine for protection.

xkaes · Oct 28, 2022

BAC1967 said:
If you find something with a close fit but too loose, you can use self adhesive felt to make up the difference. I do that often with push on filter adapters.

"Self adhesive felt". I've never heard of that, but I'll check it out. I'm sure I can use it for a million other things that ALMOST fit.

E. von Hoegh · Oct 28, 2022

xkaes said:
"Self adhesive felt". I've never heard of that, but I'll check it out. I'm sure I can use it for a million other things that ALMOST fit.

And light seals. And mirror buffers, if you can find it thick enough. It never deteriorates, although I'm not sure of the adhesive.

xkaes · Oct 28, 2022

I ordered a small batch of 2mm thick stuff. Apparently it has a lot of uses, but usually comes in much thicker sizes.

Alan Edward Klein · Oct 28, 2022

BAC1967 said:
If you find something with a close fit but too loose, you can use self adhesive felt to make up the difference. I do that often with push on filter adapters.

Does the felt leave "dust" from its fibers?

xkaes · Oct 28, 2022

I've never seen that as a problem with the front lens caps that I have that use "felt" for grip. That's very common with older press-on lens caps.

BAC1967 · Oct 29, 2022

Alan Edward Klein said:
Does the felt leave "dust" from its fibers?

I’ve never had a problem with dust from the fiber.

xkaes · Nov 5, 2022

Anyone have any ideas for M42 or T42 rear lens cap alternatives? They ought to be interchangeable.

xkaes · Nov 5, 2022

I just received a pack of 2mm, stick-on, felt pads. Very inexpensive and usable for everything from lens caps that are too loose to the bottoms of chair legs to avoid scratches on the floor.

Alan Edward Klein · Nov 5, 2022

xkaes said:
I just received a pack of 2mm, stick-on, felt pads. Very inexpensive and usable for everything from lens caps that are too loose to the bottoms of chair legs to avoid scratches on the floor.

How do you use these on lens caps?

250swb · Nov 6, 2022

All very exciting but according to my currency converter a new M42 rear lens cap is only $2.28 (£1.99) with free postage on eBay. Use your time wisely.

mshchem · Nov 6, 2022

I checked, replacement cost for a Leica cap, soft molded elastomer, to cover vented hood on Summilux 35mm f1.4 is $65 plus sales tax . Heck that's almost enough for 2 rolls of Velvia!!!

maltfalc · Nov 7, 2022

$5? https://www.aliexpress.com/wholesal...rchText=m42+lens+cap&spm=a2g0o.home.1000002.0

btaylor · Nov 8, 2022

My 2 M42 rear lens caps and 2 M42 body caps just arrived from an eBay purchase- a whopping $4, shipping included all the way from Azerbaijan to LA. Just sayin…

Zany rear lens cap alternatives

Privacy & Transparency

Privacy & Transparency