M42 adapters, Pentax vs Generic

newarts · 03-04-2009, 08:17 AM

As a naive beginner, I purchased a few flangeless, generic M42 adapters and had few difficulties with them. I remove the spring & leave them permanently on the lens.

A number of posters have not had this experience with generics and imply all knock-off M42 adapters are junk & only genuine Pentax adapters should be considered. They are simple devices and I found the conflicting user experiences hard to understand so decided try to identify critical differences.

All my non-pentax brand adapters are chrome plated brass and are well built. Usually they cost about $13-$15 delivered. I remove the spring & leave them on my m42 lenses. The only trouble I've ever had is if too much force is used when mounting, they will occasionally over-rotate*. I measured everything & could find no obvious dimensional faults.

Finally I purchased a Pentax Brand adapter for a direct comparison so I could reconcile the conflicting experiences. I could find no material or dimensionally significant differences between the branded adapter and the knock-offs.

What then is the critical difference?

I removed the spring, put the Pentax adapter on the camera and could NOT get it to over-rotate, so I looked closely at the adapter. It turns out that the ends of the knock- off's ears all have fillets while the ear ends flanking the spring of the Pentax brand are finished square as shown in the following photo: (Pentax left, knock-off right):

I squared off the ear ends flanking the spring location on the knock-off & the over-rotation problem went away!

In the interest of completeness, the ears on my three kinds of knock offs are not quite as long circumference-wise as the Pentax adapter's and the ear edges are chamfered, but these differences seem to have no functional effect.

My advice is if you are going to get one adapter and don't like modifying things, get the Pentax brand. If you are going to get many adapters to leave on lenses, consider the knock-off's for about 1/2 the cost each. For a total of three adapters the knock-off's will save you only about $45-50 total but are easy to modify if you so desire.

Dave

*The over-rotation problem is not a serious difficulty in the first place, especially if one drills a hole in the mount for the locking pin to secure the lens' position.

stevebrot · 03-04-2009, 10:01 AM

Newarts...Glad that you have had nothing but good luck and managed to save some money in the process. I respect your technical opinions and appreciate this post. I particularly appreciate the detailed explanation of how to fix the over-rotation issue. There are several different knock-offs out there. Some, the Bower for instance, are supposed to be pretty good. Others are pretty nasty.

I am one of the people who bought a nastier version from Adorama. I would include a picture, but the item has been returned for refund. To summarize my issues:

On first mounting, it took over 2 hours to remove the adapter from the camera body.
Fit on the camera was tight and not smooth when mounting.
The adapter travel went beyond the stop point. This will affect meter accuracy on non-crippled mounts by one or more stops depending on how far it goes. There is also the potential for damage to the aperture ring coupler on non-crippled mount cameras.
The threads of the adapter were poorly finished out such that small metal shards were present in the threads and on the mounting surfaces. At the end of my adventure, the mirror of my Ricoh XR-2s was littered with metallic debris. There was also permanent damage to the flange surface and threads of my previously pristine Vivitar 135/2.8. (Some of the metallic debris may also have come from the underside of the camera mount and/or the adapter due to the poor fit...cringe...)

Given the above list, I think that I can justify the extra $15 for the Genuine Pentax adapter. I also feel that it is appropriate to properly warn any noobies of the risk. For more experienced users who are planning on removing the spring, who know the other required modifications, and who are also savvy enough to thoroughly clean the adapter before use, the cheap adapters are probably a good deal.

Steve

(P.S. The crummy adapter appeared to be made of polished aluminum, not brass...at least the shards were silver...

)

wlank · 03-04-2009, 10:47 AM

Originally posted by stevebrot

Some, the Bower for instance, are supposed to be pretty good. Others are pretty nasty.

I've had 2 of the Bower adapters and neither was acceptable. To be fair and evenhanded I will say that others in the forum have reported good results with Bower. There is another brand the name I can't remember. which is reported as very good. I think Mike Cash uses it. Maybe he will see this thread and help us.

Jewelltrail · 03-04-2009, 09:20 PM

Quote:

Newarts:
I removed the spring, put the Pentax adapter on the camera and could NOT get it to over-rotate, so I looked closely at the adapter. It turns out that the ends of the knock- off's ears all have fillets while the ear ends flanking the spring of the Pentax brand are finished square as shown in the following photo: (Pentax left, knock-off right):

Newarts: I am happy with my Bower, but have been living with the over-rotation problem. I think this is great that you took the time to do this and then shared it with all us--I am very grateful--thanks.

I could be wrong, but my reading of the non-Pentax adapter complaints are when the adapter is first put into the camera without the lens. I think that with the spring lock removed the danger of locking up is removed.

To be safe, the Pentax adapter needs to be used if you plan to mount it on the camera and screw the lens in first. I like the Bower, but have also heard complaints from forum members so I will only use it screwed onto the lens. I am very happy I never got one stuck in the camera like Steve reports.

Again, thank you Newarts! Your tip will make my shooting more fun.

stevebrot · 03-04-2009, 09:29 PM

Originally posted by Jewelltrail

Newarts: I am happy with my Bower, but have been living with the over-rotation problem. I think this is great that you took the time to do this and then shared it with all us--I am very grateful--thanks.

I could be wrong, but my reading of the non-Pentax adapter complaints are when the adapter is first put into the camera without the lens. I think that with the spring lock removed the danger of locking up is removed.

To be safe, the Pentax adapter needs to be used if you plan to mount it on the camera and screw the lens in first. I like the Bower, but have also heard complaints from forum members so I will only use it screwed onto the lens. I am very happy I never got one stuck in the camera like Steve reports.

Again, thank you Newarts! Your tip will make my shooting more fun.

My bad experience came with the adapter screwed onto the lens first and then mounted on the camera like any other K-mount. I use the Pentax adapter the same way.

Steve

Jewelltrail · 03-04-2009, 11:26 PM

Quote:

My bad experience came with the adapter screwed onto the lens first and then mounted on the camera like any other K-mount. I use the Pentax adapter the same way.

Steve

Okay, there goes that theory--thanks for this report. Was the spring clip intact when this happened too?

stevebrot · 03-05-2009, 09:32 AM

Originally posted by Jewelltrail

Okay, there goes that theory--thanks for this report. Was the spring clip intact when this happened too?

The spring clip was still on the adapter.

Steve

Fl_Gulfer · 03-05-2009, 09:48 AM

So what is the easies way to get the Pentax version off your camera? It always stays on the camera instead of the lens.

stevebrot · 03-05-2009, 10:40 AM

Originally posted by Fl_Gulfer

So what is the easies way to get the Pentax version off your camera? It always stays on the camera instead of the lens.

I use the Genuine Pentax with the spring attached. Here is my flow:

Adapter is kept on the lens (much handier than fishing through the bag)
Lens mounts to the camera like any other K-mount
Remove lens by unscrewing
Remove adapter from body using fingernail (very quick with Genuine Pentax version)
Replace adapter on lens

The reason I have left the spring attached is because I have been hesitant to mar the bases of my nice M42 lenses. My attitude on that has changed somewhat and I was ready to notch the base of my Jupiter-9 and convert it semi-permanently to K-mount. The original rational for the brand-x adapter purchase was to remove the spring and have it reside on the J-9. I have since decided that I prefer to get a second Genuine Pentax adapter and float both units among my M42 lenses.

Steve

newarts · 03-05-2009, 11:15 AM

Originally posted by stevebrot

I use the Genuine Pentax with the spring attached. Here is my flow:

Adapter is kept on the lens (much handier than fishing through the bag)
Lens mounts to the camera like any other K-mount
Remove lens by unscrewing
Remove adapter from body using fingernail (very quick with Genuine Pentax version)
Replace adapter on lens

The reason I have left the spring attached is because I have been hesitant to mar the bases of my nice M42 lenses.

I think you needn't mar the bases of your m42's to leave a springless adapter on them. The locking pin isn't 100% required if the mount won't over-rotate clockwise due to the non-filleted ear.

If it won't over-rotate, the remaining risk is that it will untwist counterclockwise accidentally & fall off. But this contingency can be prevented simply by assuring there is a snug fit by tapping lightly on the appropriate end of an ear (or otherwise modifying it) so it jams in place when the lens is mounted. Friction will hold the lens in place.

However it may not be worth the effort & your work-flow seems hard to beat.

Iowa Dave

stevebrot · 03-05-2009, 02:58 PM

Originally posted by newarts

I think you needn't mar the bases of your m42's to leave a springless adapter on them. The locking pin isn't 100% required if the mount won't over-rotate clockwise due to the non-filleted ear.

If it won't over-rotate, the remaining risk is that it will untwist counterclockwise accidentally & fall off. But this contingency can be prevented simply by assuring there is a snug fit by tapping lightly on the appropriate end of an ear (or otherwise modifying it) so it jams in place when the lens is mounted. Friction will hold the lens in place.

However it may not be worth the effort & your work-flow seems hard to beat.

Iowa Dave

My Jupiter-9 and Vivitar lenses have pretty stiff focusing, that is why I leave the spring in!

Steve

Jewelltrail · 03-06-2009, 12:07 AM

Newarts:

Quote:

I think you needn't mar the bases of your m42's to leave a springless adapter on them. The locking pin isn't 100% required if the mount won't over-rotate clockwise due to the non-filleted ear.

If it won't over-rotate, the remaining risk is that it will untwist counterclockwise accidentally & fall off. But this contingency can be prevented simply by assuring there is a snug fit by tapping lightly on the appropriate end of an ear (or otherwise modifying it) so it jams in place when the lens is mounted. Friction will hold the lens in place.

However it may not be worth the effort & your work-flow seems hard to beat.

Iowa Dave

Dave: I have to say my thinking is with yours on these adapters. Now that you have solved the over-rotation problem, this approach, IMHO, is the least expensive, quickest, and most practical. Thanks again!

Jewelltrail · 03-06-2009, 12:12 AM

Quote:

My Jupiter-9 and Vivitar lenses have pretty stiff focusing, that is why I leave the spring in!

Steve

I do not have a Jupiter lens---yet, though I am thinking about that 85 I hear about. However, as you know, I own a couple of M42 Vivs and the focus ring creates new challenges for me. So far I have managed, but it is annoying when the lens is not anchored. Newarts problem solving for the over-rotation will help me with one direction of the focus ring though.

03-04-2009, 08:17 AM	#1
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	M42 adapters, Pentax vs Generic As a naive beginner, I purchased a few flangeless, generic M42 adapters and had few difficulties with them. I remove the spring & leave them permanently on the lens. A number of posters have not had this experience with generics and imply all knock-off M42 adapters are junk & only genuine Pentax adapters should be considered. They are simple devices and I found the conflicting user experiences hard to understand so decided try to identify critical differences. All my non-pentax brand adapters are chrome plated brass and are well built. Usually they cost about $13-$15 delivered. I remove the spring & leave them on my m42 lenses. The only trouble I've ever had is if too much force is used when mounting, they will occasionally over-rotate. I measured everything & could find no obvious dimensional faults. Finally I purchased a Pentax Brand adapter for a direct comparison so I could reconcile the conflicting experiences. I could find no material or dimensionally significant differences between the branded adapter and the knock-offs. What then is the critical difference? I removed the spring, put the Pentax adapter on the camera and could NOT get it to over-rotate, so I looked closely at the adapter. It turns out that the ends of the knock- off's ears all have fillets while the ear ends flanking the spring of the Pentax brand are finished square as shown in the following photo: (Pentax left, knock-off right): I squared off the ear ends flanking the spring location on the knock-off & the over-rotation problem went away! In the interest of completeness, the ears on my three kinds of knock offs are not quite as long circumference-wise as the Pentax adapter's and the ear edges are chamfered, but these differences seem to have no functional effect. My advice is if you are going to get one adapter and don't like modifying things, get the Pentax brand. If you are going to get many adapters to leave on lenses, consider the knock-off's for about 1/2 the cost each. For a total of three adapters the knock-off's will save you only about $45-50 total but are easy to modify if you so desire. Dave The over-rotation problem is not a serious difficulty in the first place, especially if one drills a hole in the mount for the locking pin to secure the lens' position.

03-04-2009, 10:01 AM	#2
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Newarts...Glad that you have had nothing but good luck and managed to save some money in the process. I respect your technical opinions and appreciate this post. I particularly appreciate the detailed explanation of how to fix the over-rotation issue. There are several different knock-offs out there. Some, the Bower for instance, are supposed to be pretty good. Others are pretty nasty. I am one of the people who bought a nastier version from Adorama. I would include a picture, but the item has been returned for refund. To summarize my issues: On first mounting, it took over 2 hours to remove the adapter from the camera body. Fit on the camera was tight and not smooth when mounting. The adapter travel went beyond the stop point. This will affect meter accuracy on non-crippled mounts by one or more stops depending on how far it goes. There is also the potential for damage to the aperture ring coupler on non-crippled mount cameras. The threads of the adapter were poorly finished out such that small metal shards were present in the threads and on the mounting surfaces. At the end of my adventure, the mirror of my Ricoh XR-2s was littered with metallic debris. There was also permanent damage to the flange surface and threads of my previously pristine Vivitar 135/2.8. (Some of the metallic debris may also have come from the underside of the camera mount and/or the adapter due to the poor fit...cringe...) Given the above list, I think that I can justify the extra $15 for the Genuine Pentax adapter. I also feel that it is appropriate to properly warn any noobies of the risk. For more experienced users who are planning on removing the spring, who know the other required modifications, and who are also savvy enough to thoroughly clean the adapter before use, the cheap adapters are probably a good deal. Steve (P.S. The crummy adapter appeared to be made of polished aluminum, not brass...at least the shards were silver...) Last edited by stevebrot; 03-04-2009 at 10:21 AM.

03-05-2009, 10:40 AM	#9
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Fl_Gulfer So what is the easies way to get the Pentax version off your camera? It always stays on the camera instead of the lens. I use the Genuine Pentax with the spring attached. Here is my flow: Adapter is kept on the lens (much handier than fishing through the bag) Lens mounts to the camera like any other K-mount Remove lens by unscrewing Remove adapter from body using fingernail (very quick with Genuine Pentax version) Replace adapter on lens The reason I have left the spring attached is because I have been hesitant to mar the bases of my nice M42 lenses. My attitude on that has changed somewhat and I was ready to notch the base of my Jupiter-9 and convert it semi-permanently to K-mount. The original rational for the brand-x adapter purchase was to remove the spring and have it reside on the J-9. I have since decided that I prefer to get a second Genuine Pentax adapter and float both units among my M42 lenses. Steve

03-05-2009, 11:15 AM	#10
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965 Original Poster	Originally posted by stevebrot I use the Genuine Pentax with the spring attached. Here is my flow: Adapter is kept on the lens (much handier than fishing through the bag) Lens mounts to the camera like any other K-mount Remove lens by unscrewing Remove adapter from body using fingernail (very quick with Genuine Pentax version) Replace adapter on lens The reason I have left the spring attached is because I have been hesitant to mar the bases of my nice M42 lenses. I think you needn't mar the bases of your m42's to leave a springless adapter on them. The locking pin isn't 100% required if the mount won't over-rotate clockwise due to the non-filleted ear. If it won't over-rotate, the remaining risk is that it will untwist counterclockwise accidentally & fall off. But this contingency can be prevented simply by assuring there is a snug fit by tapping lightly on the appropriate end of an ear (or otherwise modifying it) so it jams in place when the lens is mounted. Friction will hold the lens in place. However it may not be worth the effort & your work-flow seems hard to beat. Iowa Dave

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03-04-2009, 10:47 AM	#3
wlank Inactive Account Join Date: Dec 2007 Location: Santa Teresa, New Mexico Photos: Gallery Posts: 1,130	Originally posted by stevebrot Some, the Bower for instance, are supposed to be pretty good. Others are pretty nasty. I've had 2 of the Bower adapters and neither was acceptable. To be fair and evenhanded I will say that others in the forum have reported good results with Bower. There is another brand the name I can't remember. which is reported as very good. I think Mike Cash uses it. Maybe he will see this thread and help us.

03-04-2009, 09:20 PM	#4
Jewelltrail Veteran Member Join Date: May 2008 Location: Rhode Island Photos: Albums Posts: 4,180	Quote: Newarts: I removed the spring, put the Pentax adapter on the camera and could NOT get it to over-rotate, so I looked closely at the adapter. It turns out that the ends of the knock- off's ears all have fillets while the ear ends flanking the spring of the Pentax brand are finished square as shown in the following photo: (Pentax left, knock-off right): Newarts: I am happy with my Bower, but have been living with the over-rotation problem. I think this is great that you took the time to do this and then shared it with all us--I am very grateful--thanks. I could be wrong, but my reading of the non-Pentax adapter complaints are when the adapter is first put into the camera without the lens. I think that with the spring lock removed the danger of locking up is removed. To be safe, the Pentax adapter needs to be used if you plan to mount it on the camera and screw the lens in first. I like the Bower, but have also heard complaints from forum members so I will only use it screwed onto the lens. I am very happy I never got one stuck in the camera like Steve reports. Again, thank you Newarts! Your tip will make my shooting more fun.

03-04-2009, 09:29 PM	#5
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Jewelltrail Newarts: I am happy with my Bower, but have been living with the over-rotation problem. I think this is great that you took the time to do this and then shared it with all us--I am very grateful--thanks. I could be wrong, but my reading of the non-Pentax adapter complaints are when the adapter is first put into the camera without the lens. I think that with the spring lock removed the danger of locking up is removed. To be safe, the Pentax adapter needs to be used if you plan to mount it on the camera and screw the lens in first. I like the Bower, but have also heard complaints from forum members so I will only use it screwed onto the lens. I am very happy I never got one stuck in the camera like Steve reports. Again, thank you Newarts! Your tip will make my shooting more fun. My bad experience came with the adapter screwed onto the lens first and then mounted on the camera like any other K-mount. I use the Pentax adapter the same way. Steve

03-04-2009, 11:26 PM	#6
Jewelltrail Veteran Member Join Date: May 2008 Location: Rhode Island Photos: Albums Posts: 4,180	Quote: My bad experience came with the adapter screwed onto the lens first and then mounted on the camera like any other K-mount. I use the Pentax adapter the same way. Steve Okay, there goes that theory--thanks for this report. Was the spring clip intact when this happened too?

03-05-2009, 09:32 AM	#7
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Jewelltrail Okay, there goes that theory--thanks for this report. Was the spring clip intact when this happened too? The spring clip was still on the adapter. Steve

03-05-2009, 09:48 AM	#8
Fl_Gulfer Veteran Member Join Date: Jul 2007 Location: Florida Gulfer Photos: Albums Posts: 3,054	So what is the easies way to get the Pentax version off your camera? It always stays on the camera instead of the lens.

03-05-2009, 02:58 PM	#11
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by newarts I think you needn't mar the bases of your m42's to leave a springless adapter on them. The locking pin isn't 100% required if the mount won't over-rotate clockwise due to the non-filleted ear. If it won't over-rotate, the remaining risk is that it will untwist counterclockwise accidentally & fall off. But this contingency can be prevented simply by assuring there is a snug fit by tapping lightly on the appropriate end of an ear (or otherwise modifying it) so it jams in place when the lens is mounted. Friction will hold the lens in place. However it may not be worth the effort & your work-flow seems hard to beat. Iowa Dave My Jupiter-9 and Vivitar lenses have pretty stiff focusing, that is why I leave the spring in! Steve

03-06-2009, 12:07 AM	#12
Jewelltrail Veteran Member Join Date: May 2008 Location: Rhode Island Photos: Albums Posts: 4,180	Newarts: Quote: I think you needn't mar the bases of your m42's to leave a springless adapter on them. The locking pin isn't 100% required if the mount won't over-rotate clockwise due to the non-filleted ear. If it won't over-rotate, the remaining risk is that it will untwist counterclockwise accidentally & fall off. But this contingency can be prevented simply by assuring there is a snug fit by tapping lightly on the appropriate end of an ear (or otherwise modifying it) so it jams in place when the lens is mounted. Friction will hold the lens in place. However it may not be worth the effort & your work-flow seems hard to beat. Iowa Dave Dave: I have to say my thinking is with yours on these adapters. Now that you have solved the over-rotation problem, this approach, IMHO, is the least expensive, quickest, and most practical. Thanks again!

03-06-2009, 12:12 AM	#13
Jewelltrail Veteran Member Join Date: May 2008 Location: Rhode Island Photos: Albums Posts: 4,180	Quote: My Jupiter-9 and Vivitar lenses have pretty stiff focusing, that is why I leave the spring in! Steve I do not have a Jupiter lens---yet, though I am thinking about that 85 I hear about. However, as you know, I own a couple of M42 Vivs and the focus ring creates new challenges for me. So far I have managed, but it is annoying when the lens is not anchored. Newarts problem solving for the over-rotation will help me with one direction of the focus ring though.