[LaurenOE]

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Ok, I just ordered two (OpTechs) for Pentax.
I'll report back to see how they work!

[LaurenOE]

Ok, I just ordered two (OpTechs) for Pentax.
I'll report back to see how they work!

Well, I got the OpTech caps, and while they are great quality, I don't think they are going to work for me.

The O-Ring in the caps align with the lens pins, and as you tighten the cap, you are in essence rubbing the O-Ring against the lens pins.

Not good in my opinion.

Besides, the WR of Pentax lenses use an O-Ring that is at the periphery of the lens mount ring.

Subtle details, but the O-Tech caps are out for me.

Oh well.

[derekkite]

I have one that I think came with a Sigma lens that I bought. It says For SA / KPR. It is an end cap for the K mount lenses.

On my DA*300 it mates with the WR gasket. This is what they look like. As you can see, the inner diameter fits the K bayonet, and the outer diameter is larger. They are unusual for a lens cap as you need to line up a mark with the red dot on the lens or they don't go on.

It seems you get a body cap as well as a lens cap here. Not certain if the body cap would be useful.

2X Rear Lens Cap for Sigma SA KPR SD9 SD14 Body SA Mount | eBay

[LaurenOE]

I have one that I think came with a Sigma lens that I bought. It says For SA / KPR. It is an end cap for the K mount lenses.

On my DA*300 it mates with the WR gasket. This is what they look like. As you can see, the inner diameter fits the K bayonet, and the outer diameter is larger. They are unusual for a lens cap as you need to line up a mark with the red dot on the lens or they don't go on.

It seems you get a body cap as well as a lens cap here. Not certain if the body cap would be useful.

2X Rear Lens Cap for Sigma SA KPR SD9 SD14 Body SA Mount | eBay

Interesting.

I have some Sigma brand lens caps, so I wonder if these "knock-off" are modeled after them?

Now to go and find the Sigma caps in my "spare-cap" storage.

[bdery]

The main problem with the Sigma caps is that they can go on only at a specific angle, otherwise they will not attach and often get stuck at odd angles. I really do not like them, enough that when I met a Sigma rep, I told him so. "I know..." was his answer.

[walter]

There are all kinds of rear lens cap designs floating around for 3D printing-- Someone could download one and make a few improvements, notably making the flange so it seals. I think printing something of that size would cost $8-$10, with cost going down as numbers go up. Maybe if we all wanted a few volume price would bring it down!!! I'm currently stuck with lenses in a drybag when the weather is iffy...

Here's my version, not sure if it'll be useful for anyone though. I figure there are probably about 3 people out there with both a Pentax DSLR and a 3D Printer. If the dimensions are off by more than a few tenths of a millimeter it won't fit correctly. I don't use actually use any WR lenses, but wanted a rear lens cap that fits securely (the Pentax caps sometimes come loose, especially with my MF lenses) and I wanted a shorter cap (it's about 3mm / 20% thinner than the standard caps).

[LaurenOE]

Here's my version, not sure if it'll be useful for anyone though. I figure there are probably about 3 people out there with both a Pentax DSLR and a 3D Printer. If the dimensions are off by more than a few tenths of a millimeter it won't fit correctly. I don't use actually use any WR lenses, but wanted a rear lens cap that fits securely (the Pentax caps sometimes come loose, especially with my MF lenses) and I wanted a shorter cap (it's about 3mm / 20% thinner than the standard caps).

Wow..that is SWEEEET.

While I have a Metal Mill and Lathe, I do not have a 3D printer (yet).

Awesome!