[cpk]

I picked this up in another thread but can't find it now that I have some questions to ask. Here is the link to the product:

http://optechusa.com/lens-mount-cap.html

Here also is an email I sent to Op/Tech to which they have yet to respond:

"I am interested in the lens mount cap for Pentax lenses, especially the double one. Pentax had two versions of their own lens mount cap. The original one was flush where it met the lens mount and was meant for the older manual lenses. Their newer one, which comes with their digital lenses, has a plastic flange where it meets the lens mount. The flange is indented and covers the several different contact points on the lens. The older cap leaves these contact points bare. Do your caps, both versions, have this flange with the indentation?"

Another issue I realized after sending the email concerns the O-ring seal. Does it interfere with the contact points on the lens by keeping then depressed when the cap is in place? This might weaken any mechanism within the lens which keeps them raised above the surface of the lens flange.

I would appreciate hearing from those who have tried these caps as to their construction and effectiveness.

[atupdate]

This may be the thread you were looking for. The double cap discussion starts about 1/2 way down on page 1.

https://www.pentaxforums.com/forums/pentax-camera-field-accessories/148449-di...ag-primes.html

Tim

[cpk]

Thanks for pointing me back to the original thread. My questions are not answered in that thread, however, so my new thread still stands.

[dgaies]

Thanks for pointing me back to the original thread. My questions are not answered in that thread, however, so my new thread still stands.

Well, I just ordered a couple of the double ended caps in question so I can post again in a few days when they arrive if someone doesn't answer your question first.

Actually, I guess I'll attempt to answer both your questions now anyway

As far as the coverage, the caps cover the entire bottom of the lens mount, including all the contacts. See the picture in this post.

As for an issue with holding the contacts down while the cap is on, I see no issue there to worry about. The contacts are held in place with springs that keep the contacts extended. When the lens is mounted, or the cap is on, the contacts are depressed slightly and the spring compresses a bit. Either way the springs are neither in their fully extended, nor their fully compressed state. It won't have any negative effect on the springs in terms of weakening them to keep the caps on (much the same way leaving the lens mounted won't have any ill-effect either).

[steve1307]

I agree with dgaies about the contacts. Pressing on the contact with the plastic or O-ring is not really any diffent to mounting on a body or even onto a normal Pentax cap.

I have a couple of these and use them well .... most of the time. The Optech caps are not quite as easy to remove and replace as the Pentax caps as I noted in another thread a few months ago.


"

The only thing with these is they are a tighter fit which is good for security but slightly more difficult for swapping.
The other thing is they must be aligned in one particular postion only to mount on. ie you have to align the "bump" on the cap with the red dot.
Pentax end caps are better in that they can mount in 3 postions on the lugs so easier & quicker to fit on.

If you look at a Pentax cap all 3 retaining lugs are the same about 15mm long.
On the Optech, one is 15mm long but the other two are 25mm long, and there looks to be slightly more taper angle on the lug compared to the Pentax which is why it tightens more when fitted up to the end stop.

"

[cpk]

Thanks all for your responses. My Toronto camera store is investigating their availability here through Op/Tech's Canadian supplier. If I can't get a couple through them, I will order directly from Op/Tech.

[dgaies]

Thanks all for your responses. My Toronto camera store is investigating their availability here through Op/Tech's Canadian supplier. If I can't get a couple through them, I will order directly from Op/Tech.

If you can't end up getting them locally, you might be able to order them from Adorama or BHphoto as well. If either would be able/willing to just throw a few in a padded envelope and send them first class, the shipping wouldn't be more than a few dollars. If all else fails, PM me and I'll can always buy a few extra and send them it to you (assuming the Canada Post strike is resolved).

[cpk]

Thanks, dgaies. I will keep that in mind. This is the first day of mail delivery after the strike/lockout was resolved by parliamentary decree. The only piece of mail I got was from the tax man saying I owed them nothing.