Old style asahi pentax lens cap - question

Spock · 10-06-2009, 11:41 PM

Anyone know how these old metal lens caps attach?

I am looking to get one to replace the screw on one on my DA15. (The DA15 has a built-in retractable hood that may preclude to use of such lens caps).

*Asahiflex* · 10-07-2009, 12:01 AM

Originally Posted by Spock

Anyone know how these old metal lens caps attach?

I am looking to get one to replace the screw on one on my DA15. (The DA15 has a built-in retractable hood that may preclude to use of such lens caps).

These Takumar caps, of which I have many

are held in place by nothing else than friction. On the inner rim there's a strip of "suede" for the necessary friction and prevention of scratching of the lens.

Spock · 10-07-2009, 12:52 AM

Thanks. It doesn't sound like it would fit on the DA15. Pity. I'm guessing that only recent caps that sit flush on the end of the filter thread would fit.

Sean Nelson · 10-07-2009, 01:11 AM

Pentax also made spring-loaded caps with two tabs that grip onto the filter threads. I have several of them for a 49mm thread which came with the 28, 50 and 100mm lenses I bought back in the 70s and 80s.

Steinback · 10-07-2009, 01:13 AM

They look nice but as they age the metal lens caps can be a pain to use. The felt lining gets crushed down and the caps tend to just fall off. I expect the felt could be replaced but I've mostly picked up generic centre pinch lens caps for day to day use.

Spock · 10-07-2009, 01:16 AM

Originally Posted by Sean Nelson

Pentax also made spring-loaded caps with two tabs that grip onto the filter threads. I have several of them for a 49mm thread which came with the 28, 50 and 100mm lenses I bought back in the 70s and 80s.

Yes I considered those too. I suspect that those wouldn't fit on the DA15 as they overlap the filter ring and would thus foul the DA15's built-in retractable hood - which sits flush with the outside edge of filter ring when retracted.

wasser · 10-07-2009, 01:37 AM

Originally Posted by Spock

Yes I considered those too. I suspect that those wouldn't fit on the DA15 as they overlap the filter ring and would thus foul the DA15's built-in retractable hood - which sits flush with the outside edge of filter ring when retracted.

They don't. I've got that type of cap and a DA15.

Unless you've got a filter on the lens, it will have to fit flush to the filter ring.

Spock · 10-07-2009, 02:12 AM

Originally Posted by wasser

They don't. I've got that type of cap and a DA15.

As I suspected. Thanks

I have however tried a more modern flush fitting Pentax cap off my F80-200 F4.7-5.6 and that fits great.

Only trouble is I am planning to see the 80-200 and would like to sell it with the original caps. It's strange that the only type of Pentax lens caps not currently available on ebay as these ones.

*knyghtfall* · 10-07-2009, 03:28 AM

Originally Posted by Spock

Yes I considered those too. I suspect that those wouldn't fit on the DA15 as they overlap the filter ring and would thus foul the DA15's built-in retractable hood - which sits flush with the outside edge of filter ring when retracted.

Could consider fitting the pinch caps on the hood itself - that's what I did, putting a 52mm pinch cap on the hood of my FA 77 (filter size 49mm). My problem with the FA 77's original push on cap was that it kept falling off since I keep a UV filter on it, which would protrude out when the retractable hood is fully retracted. With the pinch cap on the hood itself - problem solved!

Spock · 10-07-2009, 05:16 AM

Originally Posted by knyghtfall

Could consider fitting the pinch caps on the hood itself - that's what I did, putting a 52mm pinch cap on the hood of my FA 77 (filter size 49mm). My problem with the FA 77's original push on cap was that it kept falling off since I keep a UV filter on it, which would protrude out when the retractable hood is fully retracted. With the pinch cap on the hood itself - problem solved!

Good suggestion but the DA15 has a petal-style hood so I don't think it would work.

*knyghtfall* · 10-07-2009, 08:18 AM

Originally Posted by Spock

Good suggestion but the DA15 has a petal-style hood so I don't think it would work.

I start enlightened. One alternative I can think on is to get a plastic push on cap, which holds better than a metal one with the felt lining that can get depressed. That's the standard lens cap for my F 17 - 28 fisheye, which had a similarly odd filter rim with the sides cut away. You can see the image of the lens rim and cap here:
[SOLD] Pentax-F 17-28mm fish eye, $249 shipped US/CA, $269 shipped world wide

You can probably find a third party plastic push on cap for yours, like this:
51mm Push On Cap - eBay (item 390102668766 end time Nov-04-09 17:10:59 PST)

Hope that helped.

wasser · 10-07-2009, 12:25 PM

A push on cap may not work too well with the DA15. The petal hood isn't smooth. The cap would rest on a slightly raised and very narrow space. I'm not sure it would provide the necessary friction to hold the cap on.

I can't find this anywhere else, but this appears to me a modern Pentax 49mm pinch cap. It should work.

Pentax O-LC49 49mm Lens Cap - Only £7.99 - SRS Microsystems

Spock · 10-07-2009, 08:26 PM

Thanks everyone. Much as it would have been nice to have an old style cap on this metal lens, looks like my only option (apart from the screw-on cap) is one of these modern style flush-fitting pinch caps.