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09-28-2010, 10:42 PM   #1
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diy: Ideas on making Kenko 1.5x Pz-AF SHQ into WR?

I've been looking around for a teleconverter to attack to my DA* 300mm lens. Tom on the forum seems to be selling the Kenko 1.5x Pz-AF SHQ teleconverter a lot, so that looks like a decent obtainable option.

The thing is I really want to somehow make the thing into WR as I would be taking that + the 300mm + K-7 into pretty wet conditions in the future.

Pictures:
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/19694-tamron-t...er-pics-2.html
https://www.pentaxforums.com/forums/photographic-equipment-sale/116262-sale-k...worldwide.html

As you can see there is quite a bit of room between the metal mount on both sides and the TC casing. I'm pretty confident if I could find properly sized gaskets, I think the combo would WR enough.

I'd also need some way to adhere the gasket to the TC enough so it doesn't fall off. Either a gasket with one side that has self-adhesive, or just some plain old super-glue.

Any ideas on gaskets/adhesive or general suggestions?

Edit: Especially on the lens side, the gasket would need to exactly match the outside diameter of the metal mount so the lens gasket has something to connect with. This could even be something metal.


Last edited by sjwaldron; 09-29-2010 at 12:46 AM.
09-28-2010, 10:45 PM   #2
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Well I have no ideas but I'd love to hear some. I've got a DA* 300 as well and I was saddened to learn Pentax hasn't provided us with a WR TC (or really any TC for that matter).
09-28-2010, 10:47 PM   #3
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Well judging by the pictures I think something could work. We just need to find the right stuff.
09-28-2010, 11:15 PM   #4
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Sorry, but i don't think this is a great plan. Its going to take careful study and careful cutting to get the right compression to cause tightness all the way around. And if you get fragments of adhesive or gasket into the camera interior, you may have other problems to deal with.

You're better off with duct tape (i'm kidding). Actually what i use is a small patch of cloth that i drape over the lens to keep standing water off the joint and lens. I've used this often in rain and snow with my Tamron 18-250, and just wring out the cloth once in a while to dry it out. The other option is to buy one of these patented plastic sleeves to go over the lens.

If you do try adhesive, make sure by testing that its easily removed without extensive work or chemicals. Not a good plan i think.

09-29-2010, 12:45 AM   #5
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QuoteOriginally posted by philbaum Quote
Not a good plan i think.
Points noted. I enjoy doing stuff like this, so I'm aware of the screwing up and paying for my mistakes.

I have not heard of those plastic sleeves, where would I find information about them? How do they protect the connection between the lens (or TC) and camera mount?

I think small dabs of super glue to keep the gaskets attached to the TC would be enough. Compression will be what makes the seals function. I would be attaching the seals around the mounts of the TC, which with the Kenko it looks like there is quite a bit of room available.

Lenses look to have around a 2.25in mount OD, so the ID of the seals would need to be around that. I'm thinking Neoprene would be the best material for WR if a thin enough thickness can be found.


- I would buy a round gasket/washer with the exact dimensions I need. With enough looking I think it's possible to find something pre-made. Measurements would need to be done on the TC as the diameter doesn't seem exact between lenses.
If I get the TC I'll try a few things out.

- I will be mindful of the thickness. It needs to be thick enough that a seal is made. Looks like the Kenko has a ridge on both ends (metal mount to exterior, which will be beneficial in keeping the seal in place

- Looking at the two WR lenses I have, the rubber seal on the mount is very slightly protruding past the metal mount. Of course the camera body has no seal, it's just that the mount itself is wider than the lens mount.

Last edited by sjwaldron; 09-29-2010 at 01:37 AM.
09-29-2010, 05:27 AM   #6
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I think there are two issues here, one is making a TC that was designed for the power zoom lenses work with a WR lens, the second is weather proofing.

I will begin with the second, forget it.

OK lets look at the first question.

There has been some debate in the past about this, as some Power Zoom teleconverters have electronics installed. Some of this is a translation of aperture contacts so the lens plus TC correctly codes the final aperture to the camera, some of this is in the data pin which feeds MTF data, focal length, etc back to the camera for the AF to function.

Depending on each individual TC, the Data pin may or may not work properly with a WR lens because it does not inderstand the messages being sent back

Also it is hard to know what the two PZ pins do, one myst be power for the lens, but what about the other??? Does it also offer communications?

the easiest way to make the TC function, if it does not is to take it apart and remove all the electronics, simply put jumpers pin to pin. This will function, but the camera will see the native aperture and focal length of the lens (just like sigma TCs) which means that on some cameras like the K10D the exposure will be off and also the focal length for shake reduction will not accouont for the TC.

But it will focus correctly/
09-29-2010, 07:52 AM   #7
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hello Lowell,

I'm pretty sure it is verified by now that the TC works with SDM lenses. If it doesn't I'll take your ideas into account as I ordered one from Tom today. The only issue I've heard of with this TC is that the aperture of 300mm (in my case) will be sent back to the camera body, making SR a bit less useful. I have a K-7 currently.

As for WR, I think it will be pretty easy and effective assuming I can find properly sized gaskets/washers online in a good material like high-end neoprene rubber. I found one custom gasket site so far, but they want a minimum 100pc order, so that's pretty much out (would cost around $60 shipped for 100 gaskets).

Once I get the TC, I do some measurements and start looking in more detail.

Edit: The only other issue would be the button which is used to lock in the lens. Might have to see if I can get some caulk or something inside that area once I get the TC and examine it.

Last edited by sjwaldron; 09-29-2010 at 08:02 AM.
09-29-2010, 08:52 AM   #8
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QuoteOriginally posted by sjwaldron Quote
hello Lowell,

I'm pretty sure it is verified by now that the TC works with SDM lenses. If it doesn't I'll take your ideas into account as I ordered one from Tom today. The only issue I've heard of with this TC is that the aperture of 300mm (in my case) will be sent back to the camera body, making SR a bit less useful. I have a K-7 currently.

As for WR, I think it will be pretty easy and effective assuming I can find properly sized gaskets/washers online in a good material like high-end neoprene rubber. I found one custom gasket site so far, but they want a minimum 100pc order, so that's pretty much out (would cost around $60 shipped for 100 gaskets).

Once I get the TC, I do some measurements and start looking in more detail.

Edit: The only other issue would be the button which is used to lock in the lens. Might have to see if I can get some caulk or something inside that area once I get the TC and examine it.
the reason I say forget trying to make the TC WR is that in my opinion, WR should never be used as the primary protection. WR is a nice insurance if your primary protection fails, but it should never be the primary protection.


Last edited by Lowell Goudge; 09-29-2010 at 09:08 AM.
09-29-2010, 11:17 AM   #9
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QuoteOriginally posted by Lowell Goudge Quote
the reason I say forget trying to make the TC WR is that in my opinion, WR should never be used as the primary protection. WR is a nice insurance if your primary protection fails, but it should never be the primary protection.
So far my K-7 and DA* 300 were fine with freezing rain and hail.

I didn't say it would be my only form of protection, but I think it would suffice.
09-29-2010, 12:00 PM   #10
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I wouldn't use superglue on a gasket- I think you'd be better off with something compliant so that when the gasket squishes, the joint doesn't break. Rubber cement? Easy to clean off too, if you decide to remove it.
09-29-2010, 12:48 PM   #11
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QuoteOriginally posted by markdesmarais Quote
I wouldn't use superglue on a gasket- I think you'd be better off with something compliant so that when the gasket squishes, the joint doesn't break. Rubber cement? Easy to clean off too, if you decide to remove it.
If I was going to seal two faces that would need to come apart at some future time I would use something like Hylomar instant gasket, it's basically a silicone type of gasket substitute.

I would put it thinly on one face then wait until it was tacky then mate the faces.
The big problem is judging how much to use so it doesn't squeeze inside the lens.

On a non WR lens on my K10 I use a rubber O ring that's a tight fit on the back of the lens and then push it tight up against the camera body. I smear the O ring with Vaseline very lightly.
Does it work? Who knows? I've used the kit 18-55 in torrential rain without any problems. Possibly I was lucky?

If you have a joint between the extender and the lens that has a plain bit on each, ie, nothing turning like an aperture ring, then how about a bit of inner tube from something like a small motorcycle cut into a short length and stretched over the joint?
09-29-2010, 01:34 PM   #12
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It will be interesting to see who could do this WR in a TC. What about making a bay in the metal base and put an o-ring by pressure. there will be no glue to mess with. A machinist will nee to check it out and if the metal mount can be taken out and then put back. Just a though
09-29-2010, 04:06 PM   #13
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QuoteOriginally posted by jjdgti Quote
It will be interesting to see who could do this WR in a TC. What about making a bay in the metal base and put an o-ring by pressure. there will be no glue to mess with. A machinist will nee to check it out and if the metal mount can be taken out and then put back. Just a though
My friend works in a machine shop. I'll probably shoot some ideas off of him to see if he has any better ones. I can't tell from pictures what material is between the casing and metal lens/body mounts. If the material is thick enough, it could be modified to slip a o-ring in there (just like the WR lenses are) that would be held in place without adhesive. I would probably only do that on the camera body side though. The lens side might require something solid due to how WR lens gaskets are. I don't think I want to go that extreme though.


QuoteOriginally posted by Lloydy Quote
If I was going to seal two faces that would need to come apart at some future time I would use something like Hylomar instant gasket, it's basically a silicone type of gasket substitute.
I would think bathroom caulk would work too, just let it completely dry and there is an instant gasket attached to both sides of the TC. The issue is there could be a mess if not done properly.


QuoteOriginally posted by markdesmarais Quote
I wouldn't use superglue on a gasket- I think you'd be better off with something compliant so that when the gasket squishes, the joint doesn't break. Rubber cement? Easy to clean off too, if you decide to remove it.
Yeah, that sounds like a better idea as long as the solvent is alcohol and not acetone.
09-29-2010, 04:12 PM   #14
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QuoteOriginally posted by Lloydy Quote
I smear the O ring with Vaseline
Drop the Vaseline and switch to silicone / dielectric grease.
Less destructive on plastic parts. Even the fumes from a petroleum product can raise hell with anything plastic.

Last edited by Ex Finn.; 09-29-2010 at 04:18 PM.
09-29-2010, 08:04 PM   #15
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Bet you're gunna need a Dremel.
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