[sterretje]

...
So, that could be the reason why it won't focus at anything over 35 yards away?
...

That is the reason

When you buy an adaptor, you must check if it states that it allows infinity focus. If it does not state it explicetly, good chance that it doesn't (unless you know what you have to look for). And, fyi, the Pentax one does allow infinity focus.

[glee46]

Your best adapter with the genuine pentax m42 will eventually come.

Even with the adapter, it is still advisable to take pre-cautions especially in dismounting. You don't want to find yourself dropping the adapter into the sensor. I find a great video with instruction that you can reference

and I have few tips on dismounting in Hin's Tech Corner: Informative M42 mounting YouTube video

Once you get your genuine adapter, the troubles is all worth it as you can pretty much meter in Av mode with M42 lens. Though you won't have the F aperture recorded in the EXIF, I find the Av mode working quite well in metering in my K20D

All the best,
Hin

Thanks Hinman, I've watched your video a few times now & one of the very easy, informative ones around.

I look forward to getting the full use of the (7) M42 Lens I've purchased. I love how great they are even though I've only been able to use them without infinity focus.

I think I saw on your site as well where you converted one of these adapters into a full K-mount. Maybe, I can use these 2 from Fotodiox for that as well.

That is the reason

When you buy an adaptor, you must check if it states that it allows infinity focus. If it does not state it explicetly, good chance that it doesn't (unless you know what you have to look for). And, fyi, the Pentax one does allow infinity focus.

It's that damn fine print that will get you one way or the other. I'm just glad there's some fine people here who been where I want to go..

Thanks to all for the input.

[henryp]

I had to use a Dremel & cut the stupid thing off.

I am very sorry for the difficulty you encountered and have alerted our buyer to it and to this thread. I know it does not alleviate your issue but yours is the only return for this item in our sales database going back to Jan 1st. More than a dozen sold during that interval.

In reply to another post:
Generic (Bower) Lens Mount Adapter - Universal Lens (M42) on Pentax K Body
and
Pentax MOUNT ADAPTER K Mfr# 30120 which is out of stock at this time.

[glee46]

I am very sorry for the difficulty you encountered and have alerted our buyer to it and to this thread. I know it does not alleviate your issue but yours is the only return for this item in our sales database going back to Jan 1st. More than a dozen sold during that interval.

In reply to another post:
Generic (Bower) Lens Mount Adapter - Universal Lens (M42) on Pentax K Body
and
Pentax MOUNT ADAPTER K Mfr# 30120 which is out of stock at this time.

Thank you for taking care of this problem.

I wanted to point out that the Fotodiox M42 adapter, while it's easier to use, does not focus to infinity and I would not recommend it.

The Bower seemed to be a quality made adapter, but on mine, I guess the screw was loose.

It messed up some of the thread and me cutting it off didn't help matters. However, I think I can use one of these Fotodiox adapters and do a hack that Hindman showed on his web site & use it on the damaged 135mm. I did get the Genuine Pentax M42 & I'm using it on my other M42 lenses with no problem.

Thanks again for all the input..

[stevebrot]

I warned about the Bower's adapter long time ago in

Hin's Tech Corner: Warning on Bower M42 adapter


All the best,
Hin

As did I on this Web site...

...not a good idea unless you remove the retention spring and even then, the quality of machining is sub-par on many copies.


Steve

---------- Post added 03-16-11 at 08:55 PM ----------

it as you can pretty much meter in Av mode with M42 lens

Better to use M mode with the current generation bodies which have accurate metering in that mode...


Steve

[glee46]

In reply to another post:
Generic (Bower) Lens Mount Adapter - Universal Lens (M42) on Pentax K Body
and
Pentax MOUNT ADAPTER K Mfr# 30120 which is out of stock at this time.

From what I can tell, it looks like Pentax MOUNT ADAPTER K Mfr# 30120 would work more like the genuine Pentax one. When you get those in stock I'll order one.

---------- Post added 03-17-11 at 05:53 AM ----------

Hin's Tech Corner: m42 adapter

and without a doubt, I always recommend the genuine adapter from Pentax. Many of the 3rd party adapter have large flange that will prevent the lens for infinity focus.
Hin

I cut off the Bower off my 135 mm with a Dremel. I purchased the Genuine Pentax Adapter.

As posted before, the threads got messed up by the Bower. Due to that, I'm not even going to try and use the Genuine Pentax.

However, the Fotodiox M42 Adapter goes on the 135mm with no problem. However, no infinity focus.

I don't understand why the Fotodiox is keeping it from infinity focus. Is it due to wide Flange?

Can the Fotodiox be cut back using the dremel and put on my M42 135mm?

Thanks for any input.

[Ira]

So I'm still trying to understand, because this has affected people here and will continue to affect new users:

Does B&H sell the original Pentax adapter or not?

[glee46]

So I'm still trying to understand, because this has affected people here and will continue to affect new users:

Does B&H sell the original Pentax adapter or not?

I know this one is not the original here: Pentax MOUNT ADAPTER K Mfr# 30120 However, it looks better than the Bower & if I can't hack the Fotodiox to work on my 135mm then I'll end up having to try and get someone to re-thread the thing if that's possible. I can get the Fotodiox to screw on the 135mm where as the original Pentax adapter won't. Go figure..

[sterretje]

I don't understand why the Fotodiox is keeping it from infinity focus. Is it due to wide Flange?

You obviously don't believe me Just compare the genuine Pentax (I understand you have it in your hands now) when mounted on the camera with the Fotodiox when mounted on the camera. The Pentax fits fully inside the mount. Does the Fotodiox? If not, the lens will be too far from the sensor and the focal point (at infinity) will lay slightly in front of the sensor.

I don't now if you ever played with a magnifying glass and the sun (which is at infinity) to put a piece of paper (or so) on fire. When you concentrate the sunlight using a magnifying glass, you aim to get a light 'dot' as small as possible by moving the magnifying glass closer or further away from the paper. When the dot is on its smallest, you are exactly in focus. Move the magnifying glass a little away from the paper and the dot becomes blurry. This is exactly what happens with your lens and the flanged adaptor; you can not get the lens (magnifying glass) close enough to the sensor (the paper) to get the dot as small as possible on the sensor (paper).

Look at the first picture (at the right) of this wiki article about focal length. Light coming from infinity (at the left) concentrates to a single point through a lens with focal length f on the sensor F. If you move the lens slightly to the left (away from the sensor (this is what happens with your flanged adaptor), you can see what happens with the projection of the light on the sensor; it becomes 'bigger' so it's no longer a single point but a small circle (a blurred point).

Can the Fotodiox be cut back using the dremel and put on my M42 135mm?

If you start modding the fotodiox, there is a chance that you will never get it out of your camera.

[excanonfd]

If you start modding the fotodiox, there is a chance that you will never get it out of your camera.

That's just scaremongering. I may have ruined one black anodized aluminum m42 adapter, but at no time was it in any danger of being stuck either on the lens or the camera.

I don't understand why the Fotodiox is keeping it from infinity focus. Is it due to wide Flange?

Can the Fotodiox be cut back using the dremel and put on my M42 135mm?

Thanks for any input.

It is precisely because of the wide flange - the wide flange adds about 1mm to the lens mount, which makes the lens go beyond the registration distance of 45.46mm by just slightly under 1mm.

You don't need a dremel to modify a fotodiox type adapter. It's poorly anodized aluminum, and an 80grit sandpaper will remove material quick enough. However, it didn't work for me. "pacerr" reports in another thread that he was able to modify one of these black adapters to achieve inifinity focus like those Pentax facsimile, but I have not been able to replicate his success.

I placed a sheet of 80 grit sandpaper on a flat surface, push the black m42 adapter on to the sandpaper firmly and stroke it back and forth, intermittently rotating the adapter to avoid sanding one area excessively. I have reduced the thickness of the flange to 1.36mm (all outer flange reduced to chaff) vs 0.7mm for the Pentax adapter. I screwed this modified adapter to an m42 lens and mounted it on the camera. There is no resistance, the lens actually moves in and out from the camera mount slightly. If I remove enough material from the modified adapter - reduce the thickness to match the genuine product's flange thickness, it would probably work. But the problem of removing so much material from the adapter also moves the lens alignment dot further south from the lens' focus hash mark. If I sand the flange down to match the Pentax adapter, the alignment dot will probably end up at the 6 o'clock position. I abandoned this modification when I realized this.

Thanks,

[chedoy]

I bought a Bowen from B&H and also one off ebay, but they have always proved unwieldy for me. The are too hard to remove from the body, especially if changing lenses in the field. I did knock off some high points off both with a Dremel so they are easier to remove with the tool.

As for a flanged adapter from fotodiox, wasn't there a disclaimer that they cannot focus to infinity?

[glee46]

You obviously don't believe me
If you start modding the fotodiox, there is a chance that you will never get it out of your camera.

I believe you.
I'm trying to learn why it won't work. If I have that answer, then there might be a solution.

I have 3 choices.
1. Try to mod the Fotodiox because it does screw on onto my 135mm. (The original Pentax doesn't & I don't want to risk stripping the threads on the adapter or maybe even more on the 135mm)

2. Leave it the way it is and not have infinity focus.

3. Try to have the threads re-threaded.

I always try to see what answers might be out there.

After your post, there were some good ideas that I might try myself. Now that I see what needs to be done, I will try and see if I can do it and maybe even find a way to build a better mouse trap in the process.

---------- Post added 03-18-11 at 11:15 AM ----------

It is precisely because of the wide flange - the wide flange adds about 1mm to the lens mount, which makes the lens go beyond the registration distance of 45.46mm by just slightly under 1mm.

Thanks,

I was thinking about cutting off the flange. So that it's more like the Original Pentax adapter which fits into the body. I measured the two adapters, and once the outer ring is removed it will fit just like the original.
(Click to see larger image)


However, there is no release lever. That's where there could be a problem. If the lens is tighten too far, when you remove the lens, the adapter might stay inside of the body of the camera.

However, there are a few work a rounds that problem as well.

It looks like I'm going to make this a permanent adapter on this lens. So, once it works, I'll drill two pin size holes thru the adapter into the lens. Then, make sure they are flush, maybe glue them in and it's just like a K mount.

Unless I'm really missing something, I think it might work.

Okay, I'm ready to hear why this might or might not work..

---------- Post added 03-18-11 at 04:01 PM ----------

It's Working!

But not the way I planned. I took it over to this guys home-workshop to get his input. I told him what I wanted to do.
He gave me a weird look and than took the Original Pentax, the fotodiox, and the lens. While I was talking to his wife, he fixed it. Without even having to re-thread the lens. Took him less then 5 mins with a razor thin file to clean up the threads.

He's said when he has time, he'll work on my idea to see if it might work.

I'll get back to you on it.

Here's a few pics from it. It's raining like a dog here & I had the ISO up to 400 by mistake.

I picked this up yesterday-Tele-Takumar 300mm f/6.3



Now, I can hardly wait for a nice break in the weather next week to take it out and see what it can do..

---------- Post added 03-18-11 at 07:56 PM ----------

As for a flanged adapter from fotodiox, wasn't there a disclaimer that they cannot focus to infinity?

The description stated that the adapter did focus to infinity. After reading your question I went back to check to make sure as I had not read it when I ordered it. I called my friend and put a stop to him working on it, and then packed them both up and sent them back to Fotodiox for a full refund. Glad I didn't cut them up..

[sterretje]

That's just scaremongering.
...

Might be although I just would call it a warning; glee46 already had the unpleasant experience of a adaptor being stuck on the lens. Just did not want him to risk the adaptor being stuck in the mount and having to dremel it out of the camera.

[excanonfd]

Might be although I just would call it a warning; glee46 already had the unpleasant experience of a adaptor being stuck on the lens. Just did not want him to risk the adaptor being stuck in the mount and having to dremel it out of the camera.

I know what you mean... I bought many aftermarket adapters and encountering various problems with them, I bought a genuine article here in the marketplace without the lock spring and the screw - which was fine because I would have removed them immediately upon arrival anyways - to use as a benchmark. Taking careful measurements of the genuine adapter with a digital caliper and comparing them with the measurements from the aftermarket ones, with some judicious filing and sanding, and an occasional whack or two to the adapter, I am quite confident I can get most of the aftermarket adapters to perform as well as the genuine article. But as RioRico cautions, remove the lock spring and the the screw before mounting the adapter on anything!

Thanks,

---------- Post added 03-19-11 at 01:10 AM ----------

glee46,

If you read the rest of the post, you would know why just cutting off the outer flange will not work - the difference in the thickness of the remaining flange is still much thicker than the genuine adapter's flange. Sanding down the flange to match the genuine one will probably work but this will put your lens upside down when mounted to the camera. Anyways, it's all moot point now since you no longer have any mounts to modify.

Thanks,

[glee46]

Might be although I just would call it a warning; glee46 already had the unpleasant experience of a adaptor being stuck on the lens. Just did not want him to risk the adaptor being stuck in the mount and having to dremel it out of the camera.

Thanks for any & all advice.

I've taken my Dremel and put it away for now.

I'm going to work on cleaning, adjusting, learning how to use them, and making some hoods for them.

Thanks to all for putting up with my effort here. I really did learn a ton of information.