One more try: How to adjust a 12mm fisheye?

RioRico · 02-05-2011, 05:51 PM

There exists a somewhat common lens made in the 1970s and variously badged as Accura, Beroflex, Berolina, Panomar, Sigma, Spiratone, Universa and Vemar, and maybe other names too. It's a fixed-focus 12mm fisheye with Waterhouse stops for f/8-11-16, and it's on a T2 mount. And I need to fix mine, and I don't know how. And it's bugged the sh!t out of me for a couple years now.

Problem: Mine may have been mis-built or mis-adjusted. It gets sharp focus at around 6 inches / 155mm but no further. It used to be at around 3 inches, but I shaved about 1mm from the T2 adapter. Maybe if I grind away another 2mm, I'll have something other than YACL (yet another closeup lens). Should I diddle with the rear lens element, or what? Further detail: Apparently 2 versions exist. The first cut has a one-piece rounded lend cover, the second has a two-piece hood/cap assembly. Mine is the second type.

Does anyone here know how to adjust a Vemar 12/8 to attain infinity? HELP!!

alohadave · 02-05-2011, 07:25 PM

This page may help:

http://thesybersite.com/general/12mm-fisheye/index.htm

Apparently, it's a fixed focus design.

gp1806 · 02-05-2011, 07:29 PM

I have the first type. I've read that yours is better. I had the opposite problem, I was trying to get it to focus closer. I was unscrewing it from the T mount to try to get a closer focus, infinity isn't a problem with mine. So the only thing I can think of is that it isn't screwed into the T mount all the way, or the T mount you have is somehow wrong. Try it with different T mount.

RioRico · 02-05-2011, 09:19 PM

Originally posted by alohadave

This page may help:

http://thesybersite.com/general/12mm-fisheye/index.htm

Thanks. I've read that page a couple dozen times over the last couple years. I've checked about every 12mm reference I could gargle-up over the last couple years. I just haven't asked this question here lately. Ever hopeful...

Originally posted by gp1806

the only thing I can think of is that it isn't screwed into the T mount all the way, or the T mount you have is somehow wrong. Try it with different T mount.

I've tried eight (8) different M42 and PK T- and T2-mounts. With a rasping blade on a hand drill, I've ground away some of the T2-mount parts, and that's gained me a little focus distance. It looks like I may have to grind away yet more there. I just hoped that I could find a fix involving nothing more than screwdrivers, lens spanner, pliers, etc, and not have to dig-out my big power grinder from the depths of a storage shed.

gp1806 · 02-06-2011, 10:09 PM

I think I'd go with a belt sander over a grinder. I have better control with putting the sander in a vise and holding the part on the belt. Keep a bowl of water handy to cool the T mount when sanding.

JeffJS · 02-07-2011, 10:59 AM

You mean one of These?

Spiratone 12mm f8 - a set on Flickr

I've spent hours with a lathe trying to modify a Tmount adapter to get best focus. The linked above photos are the best I can get with it. That lens is going for about $90 on ebay judging from the last 2 I watched. Haven't listed mine yet. If you tell me when you're going to list yours, I won't compete with it.

RioRico · 02-08-2011, 10:40 PM

Originally posted by JeffJS

Haven't listed mine yet. If you tell me when you're going to list yours, I won't compete with it.

Thanks! I hadn't thought to list it, but that idea does seem attractive now. I ground off a bit more, super-tightened everything, stopped down to f/16, and extended the focus out to maybe 15m. But it's still disappointing, and my DA10-17 gives much better results. If you want to list yours now, go ahead. I probably won't be able to get my next batch of items up for a week. Cheers!

JeffJS · 02-08-2011, 11:13 PM

Originally posted by RioRico

Thanks! I hadn't thought to list it, but that idea does seem attractive now. I ground off a bit more, super-tightened everything, stopped down to f/16, and extended the focus out to maybe 15m. But it's still disappointing, and my DA10-17 gives much better results. If you want to list yours now, go ahead. I probably won't be able to get my next batch of items up for a week. Cheers!

Not going to do it right now.. Don't have my trusty K5 back yet to take the product shots so it'll probably be March before I go ahead and list it.

It's a fun lens to play with but it's way too specialized for my liking. I bought it from a guy on the marketplace and I'm betting he was happy to be rid of it. Fish-eye really isn't my thing. I'll be happy to get most if not all of my money out of it. Most of all, I'll be happy to be rid of it. I'll even let go of my turned down t mount adapter if a Pentax person wants it (must go with the lens).

02-05-2011, 05:51 PM	#1
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	One more try: How to adjust a 12mm fisheye? There exists a somewhat common lens made in the 1970s and variously badged as Accura, Beroflex, Berolina, Panomar, Sigma, Spiratone, Universa and Vemar, and maybe other names too. It's a fixed-focus 12mm fisheye with Waterhouse stops for f/8-11-16, and it's on a T2 mount. And I need to fix mine, and I don't know how. And it's bugged the sh!t out of me for a couple years now. Problem: Mine may have been mis-built or mis-adjusted. It gets sharp focus at around 6 inches / 155mm but no further. It used to be at around 3 inches, but I shaved about 1mm from the T2 adapter. Maybe if I grind away another 2mm, I'll have something other than YACL (yet another closeup lens). Should I diddle with the rear lens element, or what? Further detail: Apparently 2 versions exist. The first cut has a one-piece rounded lend cover, the second has a two-piece hood/cap assembly. Mine is the second type. Does anyone here know how to adjust a Vemar 12/8 to attain infinity? HELP!!

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02-05-2011, 07:25 PM	#2
alohadave Veteran Member Join Date: Jan 2008 Location: Quincy, MA Photos: Gallery \| Albums Posts: 2,024	This page may help: http://thesybersite.com/general/12mm-fisheye/index.htm Apparently, it's a fixed focus design.

02-05-2011, 07:29 PM	#3
gp1806 Veteran Member Join Date: Mar 2009 Location: Chicago suburbs Photos: Albums Posts: 848	I have the first type. I've read that yours is better. I had the opposite problem, I was trying to get it to focus closer. I was unscrewing it from the T mount to try to get a closer focus, infinity isn't a problem with mine. So the only thing I can think of is that it isn't screwed into the T mount all the way, or the T mount you have is somehow wrong. Try it with different T mount.

02-05-2011, 09:19 PM	#4
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263 Original Poster	Originally posted by alohadave This page may help: http://thesybersite.com/general/12mm-fisheye/index.htm Thanks. I've read that page a couple dozen times over the last couple years. I've checked about every 12mm reference I could gargle-up over the last couple years. I just haven't asked this question here lately. Ever hopeful... Originally posted by gp1806 the only thing I can think of is that it isn't screwed into the T mount all the way, or the T mount you have is somehow wrong. Try it with different T mount. I've tried eight (8) different M42 and PK T- and T2-mounts. With a rasping blade on a hand drill, I've ground away some of the T2-mount parts, and that's gained me a little focus distance. It looks like I may have to grind away yet more there. I just hoped that I could find a fix involving nothing more than screwdrivers, lens spanner, pliers, etc, and not have to dig-out my big power grinder from the depths of a storage shed.

02-06-2011, 10:09 PM	#5
gp1806 Veteran Member Join Date: Mar 2009 Location: Chicago suburbs Photos: Albums Posts: 848	I think I'd go with a belt sander over a grinder. I have better control with putting the sander in a vise and holding the part on the belt. Keep a bowl of water handy to cool the T mount when sanding.

02-07-2011, 10:59 AM	#6
JeffJS Inactive Account Join Date: Aug 2008 Location: Michigan, USA Photos: Gallery \| Albums Posts: 7,484	You mean one of These? Spiratone 12mm f8 - a set on Flickr I've spent hours with a lathe trying to modify a Tmount adapter to get best focus. The linked above photos are the best I can get with it. That lens is going for about $90 on ebay judging from the last 2 I watched. Haven't listed mine yet. If you tell me when you're going to list yours, I won't compete with it.

02-08-2011, 10:40 PM	#7
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263 Original Poster	Originally posted by JeffJS Haven't listed mine yet. If you tell me when you're going to list yours, I won't compete with it. Thanks! I hadn't thought to list it, but that idea does seem attractive now. I ground off a bit more, super-tightened everything, stopped down to f/16, and extended the focus out to maybe 15m. But it's still disappointing, and my DA10-17 gives much better results. If you want to list yours now, go ahead. I probably won't be able to get my next batch of items up for a week. Cheers!

02-08-2011, 11:13 PM	#8
JeffJS Inactive Account Join Date: Aug 2008 Location: Michigan, USA Photos: Gallery \| Albums Posts: 7,484	Originally posted by RioRico Thanks! I hadn't thought to list it, but that idea does seem attractive now. I ground off a bit more, super-tightened everything, stopped down to f/16, and extended the focus out to maybe 15m. But it's still disappointing, and my DA10-17 gives much better results. If you want to list yours now, go ahead. I probably won't be able to get my next batch of items up for a week. Cheers! Not going to do it right now.. Don't have my trusty K5 back yet to take the product shots so it'll probably be March before I go ahead and list it. It's a fun lens to play with but it's way too specialized for my liking. I bought it from a guy on the marketplace and I'm betting he was happy to be rid of it. Fish-eye really isn't my thing. I'll be happy to get most if not all of my money out of it. Most of all, I'll be happy to be rid of it. I'll even let go of my turned down t mount adapter if a Pentax person wants it (must go with the lens).