Zuiko (Olympus OM) lenses on a Pentax?

aegisphan · 03-25-2008, 06:03 PM

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.

You just need to cut the downwad part. Unfortunately, after the mod, the infinity focus is off by ~0.2mm (ya, that small). If you have a second body, then you can do a further mod to achieve infinity focus (if you're interested i can show you). This mod will reduce the registration distance of your body accordingly so it will affect your K-mount lenses (the K-mount will focus a bit beyond infinity when you manually focus to infinity). I think it won't affect autofocus, but i'm not so sure.

As for me, I do the infinity focus adjustment on the lens itself. I've done it on the Planar 85/50 and the Distagon 35/28. The Distagon is easier to adjust, while the Planar is more difficult. The Contax Planar 85 has double helicoid design so you screw it up, it might become a real mess.

To distinguish between the AE and MM, you have to look at the smallest stopdown number. If it's in green, that would be the MM version. If it's in white, that's the AE version. Currently, the best price for a Planar 85 would be 450, hovering more around 500ish all the way to 600 on ebay. Most of the AE i've seen were made in Germany, while most of the MM i've seen were made in Japan. There is a myth about the German-made being the superior one, though it's not true. That's why sometimes you might see a very high price Planar 85 simply because it's a German-made version.

The symptom that you describe for the CZ is known as "Curvature of Field", which is displayed noticeably on the Distagon 28/2. The "focus shift" is another issue, and only happens on the Planr 85/50. Mr. Chambers did contact Zeiss about both of these issues, and they were confirmed by Zeiss.

The issue is not as bad as it sounds. You just don't see any improvement from f/1.4 to f/2.8 as a result. Mr. Chambers recommended to focus at f1/.4 for f/1.4 shot, f/2 for f/2 shot, and f/2.8 for the rest.

pcarfan · 03-25-2008, 06:12 PM

aegisphan

I really appreciate you taking the time to explain this to me. Unfortunately I only have the one K10D, I'll have to do a bit of research in to this infinity focus issue and also will be looking out for the MM version of the lens. It has to be a bargain for me to get it because of the infinity focus and the need for stop down metering. But, I'll be hunting for some contax glasses now

Thank you for all your help.

aegisphan · 03-25-2008, 06:17 PM

You're welcome

. I might just give you the link to the original post regarding this matter. The thread is a bit messy, that's why I didn't post it at 1st.

CONTAX CLUB °Q½×°Ï :: Æ[¬Ý¤å³¹ - C/Y lens on Pentax DSLR

Edit: I forgot to mention, but you can always go with the A* 85/1.4. It's similar in price with the Zeiss one. It actually performs neck-to-neck with the Canon 85/1.2L:

Zeiss ZF 85mm f1.4: First Impressions

This Canon beats the Zeiss ZF 85 hand down. So that's one more thing for you to consider.

For the Contax line, there are many legendary lenses that would be considered to be the best of the 35mm world (Distagon 21, Hollywood 28, Jahre 85, etc.). So if you go through with the mod, rest assure that your option would contain the highest optical quality anyone can offer.

pcarfan · 03-25-2008, 07:09 PM

Originally posted by aegisphan

You're welcome

. I might just give you the link to the original post regarding this matter. The thread is a bit messy, that's why I didn't post it at 1st.

CONTAX CLUB °Q½×°Ï :: Æ[¬Ý¤å³¹ - C/Y lens on Pentax DSLR

Edit: I forgot to mention, but you can always go with the A* 85/1.4. It's similar in price with the Zeiss one. It actually performs neck-to-neck with the Canon 85/1.2L:

Zeiss ZF 85mm f1.4: First Impressions

This Canon beats the Zeiss ZF 85 hand down. So that's one more thing for you to consider.

For the Contax line, there are many legendary lenses that would be considered to be the best of the 35mm world (Distagon 21, Hollywood 28, Jahre 85, etc.). So if you go through with the mod, rest assure that your option would contain the highest optical quality anyone can offer.

Pentax A* 85 1.4 is currently in ebay with 9 min. to end at $1,025...too hefty already and I am just going to watch it to see how high it goes.

$1176.01 was the final bid...

Last edited by pcarfan; 03-25-2008 at 07:18 PM.

Pentaxke · 03-26-2008, 05:08 AM

Boy, now I regret fully to have sold my Contax equipment at the late nineties...

I'm left with only question: which should I do? The cam mod or the lens mod. I have only one Zuiko for the moment, but if this works, then I would not totally exclude buying me some more Zuiko/Contax stuff... Would a Contax mod of the body work mount for all Zuiko's as well?

aegisphan · 03-26-2008, 08:05 AM

The body mount will work with all Zuiko, since the mount shape would be the same for all of them. My Zuiko 21 has a little problem of clearing the mirror, but I just remove the small black ring in the back, and it works.

For Zuiko, you have to do almost everything like a mount conversion (remove the AE arm, lock the auto diaphragm into place, and/or add a spacer around ~0.4mm). However, you don't need to find a PK mount for the conversion. FYI, the Zuiko actually fits better than the Contax.

Big Dave · 03-26-2008, 05:07 PM

Originally posted by Pentaxke

Dave, English not being my first language (nor my second) and this being somewhat 'scary' to do for me (I'm not the best DIY'er at home

) , could you please go a little slower with me?

If I get this right, then (in chronological order) I should

buy me a Pilips screw driver?
unscrew the Oly mount (I see three little screws - I guess that are the ones?
buy me a driller (ok, I have one, but not sure if I have a drill with this tiny thickness)
use the Oly mount as counterpart to know where the wholes should be drilled in the Pentax mount (I have a 50 f/1,7 which is already taken apart, so finding one should be no problem)
Counterdrill to get the screw go in completely.

Now, talking of a little challenge... Pfew, sweat is already braking out, and I'm not yet started.

Questions:

Is my checklist ok?
How do I know how to place the two mounts on each other? I use the red dot as allignment?
The OM mount is designed to stay open. How can I adjust that?

Txs for the help all this way already... I'm considering in doing this very seriously, but then I can use all help I can. Txs again...

Marc,
Reworking any camera body or lens is a very precise procedure. If you don't fill cpmfortable doing this, it is best left to others. Attempting the process on a cheap lens of the same brand is a good exercise. I would hate to see you ruin a fine lens in the attempt. A pre AI Nikkor 85mm F1.8 would be a much easier conversion. It can even be used on the Pentax without conversion. Care must be taken that the light baffle doesn't contact the camera interior. Your procedure is basicly correct, but doesn't adress possible problems. The screws may be held in with glue of some sort etc. Maybe a friend has the polished skills required. Attached is a picture of my K100D with a 35mm F2 Nikkor. I love that lens.

Dave

Last edited by Big Dave; 04-26-2008 at 12:48 PM.

Pentaxke · 03-26-2008, 07:05 PM

Well, I already disassembled the mount from the Zuiko. Was a peace of cake. Everything all right, and I didn't loose any screws in the process. Boy, I'm relieved...

Now the big thing for me is: go through with it, or not? I found a K-mount Vivitar 50 f/2 in the drawer I wasn't aware of, so I have a mount to fix on the Zuiko. Getting it of is a real pain, but if I get me a good screwdriver, I think that won't be too much of a problem neither...

Once I've done that, then I guess I can ask a friend of mine to drill the holes. I still haven't seen my question answered though: how do I align the two mounts to drill the holes? Should I align the red dots? And how do I add a spacer of +/- 0,5mm?

And the other question still remains: should I mod the mount of the camera? That is a question only I can answer I guess, but I feel not to comfortable in modding a camera in perfect shape. Och well. There is always the ist D that is dead to try it out and see what it does...

Big Dave · 03-26-2008, 11:25 PM

Hi Marc,
After you removed the mount, did the diaphram snap shut? My Cosina did. If it did not you will need to find a way to spring load it to the closed position. One way would be to epoxy the depth of field button on the mount in the depressd position. If you use the olympus mount, you will need to saw and file away the old bayonet mount. This will leave a nice flat surface to add the M42 adapter, which has a 0.5mm mounting flange. Looking at the mount end of the lens, the diaphram lever is on the left and the calibrations are on the top. This is the normal position of the lens when mounted. Place the bayonet adapter in the camera and mark the top of flange just under the pentaprism. This point will be aligned with the top screw of the lens mount. I use tape to hold the parts in position while drilling. If you choose to use the Vivitar mount, you will need to have a spacer made to replace the OM mount. It will be thinner then the OM mount to accomadate to thicker Vivitar mount. Judging from my 50mm Olympus lens, it should be 4.5mm thick with the bayonet mount attached. If this distance isn't maintained, you won't be able to focus at infinity properly. The spacer would need to be drilled to match the OM mount and have clearence for the levers etc. I thought about reworking a camera, but I have not found on cheap enough to use. A K100D with a Nikon mount would be very nice for me. Below is a link to one of these adapters.

Cheers, Dave

M42 lens adapter to Pentax PK - eBay (item 310034227465 end time Mar-28-08 23:36:54 PDT)

Pentaxke · 03-27-2008, 05:02 AM

Hi Dave,

no, it didn't actually. With or without the mount, the diaphragm stays wide open. Seems like I have to think of sth to get it closed.

I'm going to put the matter to rest untill I can see my friend and ask him what he should do.

I keep you informed.

BTW: now I understand the idea better of the M42==>K adapter: you dust the flange of the OM mount away and place the adapter on top of that. How do you add the adapter? By soldering?

Big Dave · 03-27-2008, 09:04 AM

Marc,
I drilled the adapter to match the OM mount. I then counter sunk the holes so that the three flathead screws would hold the assembly togather. You may have to accuire some flat head screws if the existing screws are buttonhead. I thought about using Gorilla brand glue to bond the adapter to the mount, but it wasn't necessary since the screws were flathead and long enough to do the job. I have used the glue before with good results. Just don't try to take it apart. If you glue the assembly togather, you will need to counter drill the holes to allow the screw heads to be recessed. I bought a box of 10 new adapters off Ebay for $75 shipped to use for various projects. Take your time.

Dave

aegisphan · 03-27-2008, 09:32 AM

Here is a visual guide for you Marc

Manual Focus Forum / Lens mount conversion: Olympus OM -> P/K

My approach is different from Dave or the author of the above post; however, since we all used different lenses so I can't really comment on that. I hope this would somewhat help with the whole process.

Pentaxke · 03-28-2008, 11:22 AM

Now that is a very useful link! txs!

scribble · 04-17-2008, 01:11 PM

Ok, now for one more late reply to this thread.

Once you cut the M42 Retention ring, will it still work with the Pentax M42-K mount adapter?

Thanks!
Steven

newpentaxman · 04-22-2011, 07:22 PM

info@leitax.com
this place from europe makes an adapter for this very job. unscrew the three
screws and put on the new mount and your in business. unfortunately it's not cheap. 105.15 american dollars. including shipping.

03-25-2008, 06:17 PM	#18
aegisphan Veteran Member Join Date: Nov 2007 Location: New Mexico Posts: 815	You're welcome . I might just give you the link to the original post regarding this matter. The thread is a bit messy, that's why I didn't post it at 1st. CONTAX CLUB °Q½×°Ï :: Æ[¬Ý¤å³¹ - C/Y lens on Pentax DSLR Edit: I forgot to mention, but you can always go with the A* 85/1.4. It's similar in price with the Zeiss one. It actually performs neck-to-neck with the Canon 85/1.2L: Zeiss ZF 85mm f1.4: First Impressions This Canon beats the Zeiss ZF 85 hand down. So that's one more thing for you to consider. For the Contax line, there are many legendary lenses that would be considered to be the best of the 35mm world (Distagon 21, Hollywood 28, Jahre 85, etc.). So if you go through with the mod, rest assure that your option would contain the highest optical quality anyone can offer. Last edited by aegisphan; 03-25-2008 at 06:26 PM.

03-26-2008, 05:07 PM	#22
Big Dave Veteran Member Join Date: Jan 2008 Location: San Antonio, Texas Photos: Gallery Posts: 547	Originally posted by Pentaxke Dave, English not being my first language (nor my second) and this being somewhat 'scary' to do for me (I'm not the best DIY'er at home ) , could you please go a little slower with me? If I get this right, then (in chronological order) I should buy me a Pilips screw driver? unscrew the Oly mount (I see three little screws - I guess that are the ones? buy me a driller (ok, I have one, but not sure if I have a drill with this tiny thickness) use the Oly mount as counterpart to know where the wholes should be drilled in the Pentax mount (I have a 50 f/1,7 which is already taken apart, so finding one should be no problem) Counterdrill to get the screw go in completely. Now, talking of a little challenge... Pfew, sweat is already braking out, and I'm not yet started. Questions: Is my checklist ok? How do I know how to place the two mounts on each other? I use the red dot as allignment? The OM mount is designed to stay open. How can I adjust that? Txs for the help all this way already... I'm considering in doing this very seriously, but then I can use all help I can. Txs again... Marc, Reworking any camera body or lens is a very precise procedure. If you don't fill cpmfortable doing this, it is best left to others. Attempting the process on a cheap lens of the same brand is a good exercise. I would hate to see you ruin a fine lens in the attempt. A pre AI Nikkor 85mm F1.8 would be a much easier conversion. It can even be used on the Pentax without conversion. Care must be taken that the light baffle doesn't contact the camera interior. Your procedure is basicly correct, but doesn't adress possible problems. The screws may be held in with glue of some sort etc. Maybe a friend has the polished skills required. Attached is a picture of my K100D with a 35mm F2 Nikkor. I love that lens. Dave Last edited by Big Dave; 04-26-2008 at 12:48 PM.

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03-25-2008, 06:03 PM	#16
aegisphan Veteran Member Join Date: Nov 2007 Location: New Mexico Posts: 815	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. You just need to cut the downwad part. Unfortunately, after the mod, the infinity focus is off by ~0.2mm (ya, that small). If you have a second body, then you can do a further mod to achieve infinity focus (if you're interested i can show you). This mod will reduce the registration distance of your body accordingly so it will affect your K-mount lenses (the K-mount will focus a bit beyond infinity when you manually focus to infinity). I think it won't affect autofocus, but i'm not so sure. As for me, I do the infinity focus adjustment on the lens itself. I've done it on the Planar 85/50 and the Distagon 35/28. The Distagon is easier to adjust, while the Planar is more difficult. The Contax Planar 85 has double helicoid design so you screw it up, it might become a real mess. To distinguish between the AE and MM, you have to look at the smallest stopdown number. If it's in green, that would be the MM version. If it's in white, that's the AE version. Currently, the best price for a Planar 85 would be 450, hovering more around 500ish all the way to 600 on ebay. Most of the AE i've seen were made in Germany, while most of the MM i've seen were made in Japan. There is a myth about the German-made being the superior one, though it's not true. That's why sometimes you might see a very high price Planar 85 simply because it's a German-made version. The symptom that you describe for the CZ is known as "Curvature of Field", which is displayed noticeably on the Distagon 28/2. The "focus shift" is another issue, and only happens on the Planr 85/50. Mr. Chambers did contact Zeiss about both of these issues, and they were confirmed by Zeiss. The issue is not as bad as it sounds. You just don't see any improvement from f/1.4 to f/2.8 as a result. Mr. Chambers recommended to focus at f1/.4 for f/1.4 shot, f/2 for f/2 shot, and f/2.8 for the rest.

03-25-2008, 06:12 PM	#17
pcarfan Veteran Member Join Date: Sep 2007 Location: Dayton, Ohio Photos: Gallery \| Albums Posts: 2,978	aegisphan I really appreciate you taking the time to explain this to me. Unfortunately I only have the one K10D, I'll have to do a bit of research in to this infinity focus issue and also will be looking out for the MM version of the lens. It has to be a bargain for me to get it because of the infinity focus and the need for stop down metering. But, I'll be hunting for some contax glasses now Thank you for all your help.

03-25-2008, 07:09 PM	#19
pcarfan Veteran Member Join Date: Sep 2007 Location: Dayton, Ohio Photos: Gallery \| Albums Posts: 2,978	Originally posted by aegisphan You're welcome . I might just give you the link to the original post regarding this matter. The thread is a bit messy, that's why I didn't post it at 1st. CONTAX CLUB °Q½×°Ï :: Æ[¬Ý¤å³¹ - C/Y lens on Pentax DSLR Edit: I forgot to mention, but you can always go with the A* 85/1.4. It's similar in price with the Zeiss one. It actually performs neck-to-neck with the Canon 85/1.2L: Zeiss ZF 85mm f1.4: First Impressions This Canon beats the Zeiss ZF 85 hand down. So that's one more thing for you to consider. For the Contax line, there are many legendary lenses that would be considered to be the best of the 35mm world (Distagon 21, Hollywood 28, Jahre 85, etc.). So if you go through with the mod, rest assure that your option would contain the highest optical quality anyone can offer. Pentax A* 85 1.4 is currently in ebay with 9 min. to end at $1,025...too hefty already and I am just going to watch it to see how high it goes. $1176.01 was the final bid... Last edited by pcarfan; 03-25-2008 at 07:18 PM.

03-26-2008, 05:08 AM	#20
Pentaxke Veteran Member Join Date: Oct 2006 Location: Belgium Photos: Gallery \| Albums Posts: 476 Original Poster	Boy, now I regret fully to have sold my Contax equipment at the late nineties... I'm left with only question: which should I do? The cam mod or the lens mod. I have only one Zuiko for the moment, but if this works, then I would not totally exclude buying me some more Zuiko/Contax stuff... Would a Contax mod of the body work mount for all Zuiko's as well?

03-26-2008, 08:05 AM	#21
aegisphan Veteran Member Join Date: Nov 2007 Location: New Mexico Posts: 815	The body mount will work with all Zuiko, since the mount shape would be the same for all of them. My Zuiko 21 has a little problem of clearing the mirror, but I just remove the small black ring in the back, and it works. For Zuiko, you have to do almost everything like a mount conversion (remove the AE arm, lock the auto diaphragm into place, and/or add a spacer around ~0.4mm). However, you don't need to find a PK mount for the conversion. FYI, the Zuiko actually fits better than the Contax.

03-26-2008, 07:05 PM	#23
Pentaxke Veteran Member Join Date: Oct 2006 Location: Belgium Photos: Gallery \| Albums Posts: 476 Original Poster	Well, I already disassembled the mount from the Zuiko. Was a peace of cake. Everything all right, and I didn't loose any screws in the process. Boy, I'm relieved... Now the big thing for me is: go through with it, or not? I found a K-mount Vivitar 50 f/2 in the drawer I wasn't aware of, so I have a mount to fix on the Zuiko. Getting it of is a real pain, but if I get me a good screwdriver, I think that won't be too much of a problem neither... Once I've done that, then I guess I can ask a friend of mine to drill the holes. I still haven't seen my question answered though: how do I align the two mounts to drill the holes? Should I align the red dots? And how do I add a spacer of +/- 0,5mm? And the other question still remains: should I mod the mount of the camera? That is a question only I can answer I guess, but I feel not to comfortable in modding a camera in perfect shape. Och well. There is always the ist D that is dead to try it out and see what it does...

03-26-2008, 11:25 PM	#24
Big Dave Veteran Member Join Date: Jan 2008 Location: San Antonio, Texas Photos: Gallery Posts: 547	Hi Marc, After you removed the mount, did the diaphram snap shut? My Cosina did. If it did not you will need to find a way to spring load it to the closed position. One way would be to epoxy the depth of field button on the mount in the depressd position. If you use the olympus mount, you will need to saw and file away the old bayonet mount. This will leave a nice flat surface to add the M42 adapter, which has a 0.5mm mounting flange. Looking at the mount end of the lens, the diaphram lever is on the left and the calibrations are on the top. This is the normal position of the lens when mounted. Place the bayonet adapter in the camera and mark the top of flange just under the pentaprism. This point will be aligned with the top screw of the lens mount. I use tape to hold the parts in position while drilling. If you choose to use the Vivitar mount, you will need to have a spacer made to replace the OM mount. It will be thinner then the OM mount to accomadate to thicker Vivitar mount. Judging from my 50mm Olympus lens, it should be 4.5mm thick with the bayonet mount attached. If this distance isn't maintained, you won't be able to focus at infinity properly. The spacer would need to be drilled to match the OM mount and have clearence for the levers etc. I thought about reworking a camera, but I have not found on cheap enough to use. A K100D with a Nikon mount would be very nice for me. Below is a link to one of these adapters. Cheers, Dave M42 lens adapter to Pentax PK - eBay (item 310034227465 end time Mar-28-08 23:36:54 PDT)

03-27-2008, 05:02 AM	#25
Pentaxke Veteran Member Join Date: Oct 2006 Location: Belgium Photos: Gallery \| Albums Posts: 476 Original Poster	Hi Dave, no, it didn't actually. With or without the mount, the diaphragm stays wide open. Seems like I have to think of sth to get it closed. I'm going to put the matter to rest untill I can see my friend and ask him what he should do. I keep you informed. BTW: now I understand the idea better of the M42==>K adapter: you dust the flange of the OM mount away and place the adapter on top of that. How do you add the adapter? By soldering?

03-27-2008, 09:04 AM	#26
Big Dave Veteran Member Join Date: Jan 2008 Location: San Antonio, Texas Photos: Gallery Posts: 547	Marc, I drilled the adapter to match the OM mount. I then counter sunk the holes so that the three flathead screws would hold the assembly togather. You may have to accuire some flat head screws if the existing screws are buttonhead. I thought about using Gorilla brand glue to bond the adapter to the mount, but it wasn't necessary since the screws were flathead and long enough to do the job. I have used the glue before with good results. Just don't try to take it apart. If you glue the assembly togather, you will need to counter drill the holes to allow the screw heads to be recessed. I bought a box of 10 new adapters off Ebay for $75 shipped to use for various projects. Take your time. Dave

03-27-2008, 09:32 AM	#27
aegisphan Veteran Member Join Date: Nov 2007 Location: New Mexico Posts: 815	Here is a visual guide for you Marc Manual Focus Forum / Lens mount conversion: Olympus OM -> P/K My approach is different from Dave or the author of the above post; however, since we all used different lenses so I can't really comment on that. I hope this would somewhat help with the whole process.

03-28-2008, 11:22 AM	#28
Pentaxke Veteran Member Join Date: Oct 2006 Location: Belgium Photos: Gallery \| Albums Posts: 476 Original Poster	Now that is a very useful link! txs!

04-17-2008, 01:11 PM	#29
scribble Senior Member Join Date: Feb 2007 Location: Kentville, NS Photos: Gallery Posts: 208	Ok, now for one more late reply to this thread. Once you cut the M42 Retention ring, will it still work with the Pentax M42-K mount adapter? Thanks! Steven

04-22-2011, 07:22 PM	#30
newpentaxman Inactive Account Join Date: May 2010 Location: ohio Posts: 218	info@leitax.com this place from europe makes an adapter for this very job. unscrew the three screws and put on the new mount and your in business. unfortunately it's not cheap. 105.15 american dollars. including shipping.