Help with T-mount (I think!) 500mm mirror lens

Edgar_in_Indy · 07-09-2012, 09:42 AM

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I bought a group of camera items off someone on Craigslist several months ago, and among the items was a "Phoenix / Samyang" 500mm mirror lens with some kind of universal mount. I've been itching to play with the lens, mostly just out of curiosity. I tried to research the lens, and thought it was a T-mount, so I bought the following T-mount adapter on eBay (click on the picture for a link to the eBay listing):

The adapter came with an inner ring installed in it which is much smaller than the lens mount. When I take the inner ring out of the adapter, the adapter almost fits the lens mount, but it's just a tiny, tiny bit too small. The adapter does fit on my camera perfectly.

Below are pictures of the lens. If you need to see more detail, you can click on any of the pictures to see the full size image. The last picture shows the lens with the adapter it came with (maybe an Olympus adapter?). The adapter I purchased can be seen beside the lens. So did I just purchase the wrong type of adapter? Or is there a chance that my adapter is out of spec?

Thanks!

FYI, the pictures are courtesy of my Pentax K-x and a Sigma 50-150mm f/2.8, both of which I currently have for sale in the Marketplace.

Last edited by Edgar_in_Indy; 07-09-2012 at 10:10 AM.

thazooo · 07-09-2012, 12:22 PM

I believe you need to take the remaining ring from the old t mount off, and then install your new pentax t mount adapter. From ur pictures it appears to still be attached.

Edgar_in_Indy · 07-09-2012, 12:55 PM

Originally posted by thazooo

I believe you need to take the remaining ring from the old t mount off, and then install your new pentax t mount adapter. From ur pictures it appears to still be attached.

I believe you're right. Looking at the lens with the naked eye, I just assumed it was all one piece, but now that I'm looking at the picture zoomed in, it does appear that there is a separate ring still attached. In my defense, I would just point out that I was looking at the lens in a poorly lit room.

I don't remember seeing any set-screws in the ring, but maybe it's just screwed on.

Paleo Pete · 07-10-2012, 06:43 AM

Probably is just screwed on, and unless I'm mistaken, I think these came as M42 mounts. I may be wrong, it may be a T mount, I've never had one in my hands, although I have looked at several in online auctions and not been able to get one yet. If it's M42, then a T mount would not fit the original threads on the lens where the mount ring is currently screwed on. M42 and T mount are both 42mm diameter, but different thread pitches. It's beena while since I looked it up, but I think M42 is 42x1 and T mount is 42x.75. (that may be backward) Anyway it's just enough difference they won't interchange and T mount also holds the lens about 5/16 inch away from the camera flange while M42 sits flush.

And I might be way out in left field too...

Edgar_in_Indy · 07-10-2012, 07:04 AM

I was able to get it last night. Thazoo was correct, there was still a ring from the other mount. It was on there really tight, so at first I didn't think it would come off. I finally did get it off, and was able to see that that the old adapter was labeled Minolta mount. I now have the lens mounted on my K-x and will try to play with it this morning.

**TER-OR** · 07-10-2012, 07:40 AM

I had the exact same issue with a Vivitar 1970-vintage 500mm non-mirror lens. It confused me until I realized there was another part of the B-mount adapter I had to remove. After that, the K-mount adapter went on easily. It's still not an easy lens to use, but when I get everything right, it's really good.

07-09-2012, 09:42 AM	#1
Edgar_in_Indy Veteran Member Join Date: May 2010 Location: Indiana, USA Photos: Gallery Posts: 2,685	Help with T-mount (I think!) 500mm mirror lens Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here. I bought a group of camera items off someone on Craigslist several months ago, and among the items was a "Phoenix / Samyang" 500mm mirror lens with some kind of universal mount. I've been itching to play with the lens, mostly just out of curiosity. I tried to research the lens, and thought it was a T-mount, so I bought the following T-mount adapter on eBay (click on the picture for a link to the eBay listing): The adapter came with an inner ring installed in it which is much smaller than the lens mount. When I take the inner ring out of the adapter, the adapter almost fits the lens mount, but it's just a tiny, tiny bit too small. The adapter does fit on my camera perfectly. Below are pictures of the lens. If you need to see more detail, you can click on any of the pictures to see the full size image. The last picture shows the lens with the adapter it came with (maybe an Olympus adapter?). The adapter I purchased can be seen beside the lens. So did I just purchase the wrong type of adapter? Or is there a chance that my adapter is out of spec? Thanks! FYI, the pictures are courtesy of my Pentax K-x and a Sigma 50-150mm f/2.8, both of which I currently have for sale in the Marketplace. Last edited by Edgar_in_Indy; 07-09-2012 at 10:10 AM.

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07-09-2012, 12:22 PM	#2
thazooo Pentaxian Join Date: Sep 2006 Location: Mississippi, USA Photos: Gallery Posts: 854	I believe you need to take the remaining ring from the old t mount off, and then install your new pentax t mount adapter. From ur pictures it appears to still be attached.

07-09-2012, 12:55 PM	#3
Edgar_in_Indy Veteran Member Join Date: May 2010 Location: Indiana, USA Photos: Gallery Posts: 2,685 Original Poster	Originally posted by thazooo I believe you need to take the remaining ring from the old t mount off, and then install your new pentax t mount adapter. From ur pictures it appears to still be attached. I believe you're right. Looking at the lens with the naked eye, I just assumed it was all one piece, but now that I'm looking at the picture zoomed in, it does appear that there is a separate ring still attached. In my defense, I would just point out that I was looking at the lens in a poorly lit room. I don't remember seeing any set-screws in the ring, but maybe it's just screwed on.

07-10-2012, 06:43 AM	#4
Paleo Pete Veteran Member Join Date: Jun 2010 Location: Texas Photos: Gallery \| Albums Posts: 2,880	Probably is just screwed on, and unless I'm mistaken, I think these came as M42 mounts. I may be wrong, it may be a T mount, I've never had one in my hands, although I have looked at several in online auctions and not been able to get one yet. If it's M42, then a T mount would not fit the original threads on the lens where the mount ring is currently screwed on. M42 and T mount are both 42mm diameter, but different thread pitches. It's beena while since I looked it up, but I think M42 is 42x1 and T mount is 42x.75. (that may be backward) Anyway it's just enough difference they won't interchange and T mount also holds the lens about 5/16 inch away from the camera flange while M42 sits flush. And I might be way out in left field too...

07-10-2012, 07:04 AM	#5
Edgar_in_Indy Veteran Member Join Date: May 2010 Location: Indiana, USA Photos: Gallery Posts: 2,685 Original Poster	I was able to get it last night. Thazoo was correct, there was still a ring from the other mount. It was on there really tight, so at first I didn't think it would come off. I finally did get it off, and was able to see that that the old adapter was labeled Minolta mount. I now have the lens mounted on my K-x and will try to play with it this morning.

07-10-2012, 07:40 AM	#6
TER-OR Site Supporter Join Date: Apr 2009 Location: Dundee, IL Photos: Gallery \| Albums Posts: 6,699	I had the exact same issue with a Vivitar 1970-vintage 500mm non-mirror lens. It confused me until I realized there was another part of the B-mount adapter I had to remove. After that, the K-mount adapter went on easily. It's still not an easy lens to use, but when I get everything right, it's really good.