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11-30-2007, 08:08 AM   #1
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Dangerous third party lenses (PK-A/R)?

Mark Roberts in his excellent web page concerning K-mount compatibility issues (Pentax Lens/Camera Compatibility - Mark Roberts Photography) warns against Ricoh "P-series" bayonet lenses locking into the AF drive recess and thereby getting stuck on the body. I have a couple of Vivitar Series 1 lenses that have a mount designation "PK-A/R", and it looks like each has a small spring-loaded pin or ball bearing on the face of the bayonet. Not wanting to lock either of these on my K10D body (even though Mark's web site offers ways of getting a Ricoh P-series lens off), I thought I'd check here to see if anyone can confirm my suspicions about these mounts. If these are "bad", are there any suggestions on how to modify the mounts to fix the issue? I'm guessing drilling out the little ball bearing would do the trick, but perhaps there is a little less severe solution...

By the way, Mark says these Ricoh P lenses are an issue on all Pentax AF bodies, as the AF drive is the same for all versions, film or digital... and though I can't say for sure, I'm fairly certain both of these lense have been on my ZX-5n without a problem. Not that I'm in the mood to experiment, to see if I can get either of them stuck onto an AF body!

11-30-2007, 02:13 PM   #2
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This should clear up most of your questions regarding how to use these lenses on your Pentax body:

Sears 60-300(auto aperture, push pull zoom): Pentax SLR Talk Forum: Digital Photography Review
11-30-2007, 02:59 PM   #3
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I have a vivitar 28mm f/2.5 on PK mount

Vivitar 28mm f/3.5 on PK mount that has a large flange that get in the way for my lens to be usable on my K100D body

Last night I performed the 1st part of the operation and without any saws, any file, any tool other than a simple small screwdriver to dismount the cap by unscrewing the three screws:

Vivitar 28mm f/2.5 in PK mount with a Flange not suitable for K10/100D bodies. I paid $20 shipped for this Vivitar beauty, serial # 22761834 (by either Kiron or Kinon according to
Vivitar Lens Manufactuers )

#1
after 3 screws, the cap with the big flange is out


#2
Without the cap/flange


#3
The vivitar is a beauty to look at and it has a 67mm filter thread and the focusing ring is top notch


And the lens works without the cap/flange, and test shots on my Pentagon 50mm f/1.8 in M42 mount converted to K mount lens with the bower adapter. I unscrew the clipping mechanism and make the adapter permanntely mounted on the my Pentacon M42 lens. And I can unscrew the adapter with the rear end cap to convert the lens back from K to
M42 mount

And the test shots from my beautiful Vivitar 28mm f/2.5 shooting my Pentacon 50mm f/1.8 converted to K mount. That Vivitar is way sharp and I crop this to almost 60-70% crop and it is still very sharp in 100% crop

#4


#5


And even without putting back the cap/flange back to my Vivitar, the lens works on my K100D without the flange getting in the way on the K mount socket.

A happy man with a $20 beauty with a 28mm f/2.5 charmer. More of my gear:

Inexpensive gear with Pentax - Hin's Tech Corner



Hin

Last edited by hinman; 12-01-2007 at 03:43 PM.
11-30-2007, 03:38 PM   #4
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Yeah, I got a PK mount stuck on my brand new DS! Scared the s*** outa me. Thought I done broke the camera. Once I finally did get it removed, I dissasembled the lens and removed the pin. Works great now!
The lens previously worked just fine on my K1000 and ZX-50.

11-30-2007, 05:03 PM   #5
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Thanks for the link! Much better than drilling! Now to find my set of jeweler's screwdrivers...

It seems that more than one vendor/lens manufacturer "doubled up" their K-mount, so as to sell the same item to both Pentax and Ricoh users. I have a Tokina AT-X 35~70/2.8 that I'll have to examine carefully! Fortunately, it looks like Tamron did not "double up" with their Adaptall II design, as my PK/A adapters are well-behaved on my K10D...

Curt
11-30-2007, 05:17 PM   #6
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Hinman... I was starting to wonder if I was the only owner of that lens! I found the exact same thing... after using the 28mm f/2.5 on my older film cameras, I found it wouldn't mount on my K100d, so I simply unscrewed that rear flange as you did and it works fine.
he
Btw I can't say I use it much (in fact I listed it for sale) but you're right about the build quality/looks... I think this was common to all Kiron-made Vivitars. Neither third-parties nor first make em like that any more.
11-30-2007, 05:26 PM   #7
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LoL, just set the camera to AF. The AF slot screw should be enough to push the Ricoh pin up. Wiggle the lens a little bit and it sould come free.
11-30-2007, 10:04 PM   #8
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Hummm... might have tried this first - because when I did the disassemble trick, I erred and removed the wrong pin on my first try. Turns out said pin is essential to the "A" functioning of the lens. So now I have a K10D-safe Vivitar Series 1 28-105/2.8 K lens, versus an unsafe KA lens... sigh! I tried putting the necessary pin back in, but the little metal spring tab that makes contact (and thereby tells the camera the lens is in "A" mode, or some such) was bent up too much to provide a positive contact. Guess the moral of the tale is "look very carefully before doing much of anything!" Curt

12-03-2007, 09:36 AM   #9
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Hinman - That lens you disassembled did NOT fit on your K10D or K100D for any reason other than, it was made SPECIFICALLY for a manual focus camera only.

You removed the elongated shutter guide which interfered with the AF drive housing inside the camera - That lens would NOT even mount on either the K10D or K100D, or any other AF digital or 35mm, etc.

There are three small screws on the outside diameter. Removing those three screws allows you to remove the shutter release guide. Doing so allows you to mount it to an AF camera of ANY period.

I've been using a few of them Vivitar #22xxxxxx lenses this way for a long time now - Always look for 'Close-Focusing' Vivitars starting out with Serial # 22 - Close-focusing is where it's at. It adds a ton more functionality to the lenses.
12-03-2007, 10:01 AM   #10
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QuoteOriginally posted by Tom M Quote
Hinman - That lens you disassembled did NOT fit on your K10D or K100D for any reason other than, it was made SPECIFICALLY for a manual focus camera only.

You removed the elongated shutter guide which interfered with the AF drive housing inside the camera - That lens would NOT even mount on either the K10D or K100D, or any other AF digital or 35mm, etc.

There are three small screws on the outside diameter. Removing those three screws allows you to remove the shutter release guide. Doing so allows you to mount it to an AF camera of ANY period.
I don't think he suggested it was for any other reason but you're right, it physically won't fit on a K10d, or equally on a K100d, *Ist series, MZ series or any other AF body either... without modification... but as hinman and you have demonstrated, it's a very simple and harmless modification. So I don't think it can be called a 'dangerous' lens as per the thread title.
12-03-2007, 11:05 AM   #11
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QuoteOriginally posted by ZaphodB Quote
I don't think he suggested it was for any other reason but you're right, it physically won't fit on a K10d, or equally on a K100d, *Ist series, MZ series or any other AF body either... without modification... but as hinman and you have demonstrated, it's a very simple and harmless modification. So I don't think it can be called a 'dangerous' lens as per the thread title.
I agree - it is NOT dangerous as it can't even mount onto the camera. Though, it could be dangerous if you threw it in frustration.

Not sure if anyone mentioned this or not but, the lenses with that pesky Ricoh pin, not all are dangerous either. Only the lenses with the cylindrical pin are a problem. Lenses with the rounded-end pin are not problem. Either way though, certainly nothing some tape and a dremel can't take care within a minute.
12-03-2007, 12:22 PM   #12
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My lens work after needed modification

Tom,

Thanks for the extra info. Without the modification, my Vivitar 28mm f/2.5 don't even fit into K10/100D or my film body with Pentax pz-20 and it would be a waste for my $20 investment. And hence I try the modification from robertstech.com to saw down the flange. And in removing the cap as the 1st step, my $20 Vivitar now fits in on both of my K100D or my Pentax pz-20 bodies.

And here are test shots made in last two days: the lens works like a charm for me:

#1


#2


#3


Thanks,
Hin

QuoteOriginally posted by Tom M Quote
Hinman - That lens you disassembled did NOT fit on your K10D or K100D for any reason other than, it was made SPECIFICALLY for a manual focus camera only.

You removed the elongated shutter guide which interfered with the AF drive housing inside the camera - That lens would NOT even mount on either the K10D or K100D, or any other AF digital or 35mm, etc.

There are three small screws on the outside diameter. Removing those three screws allows you to remove the shutter release guide. Doing so allows you to mount it to an AF camera of ANY period.

I've been using a few of them Vivitar #22xxxxxx lenses this way for a long time now - Always look for 'Close-Focusing' Vivitars starting out with Serial # 22 - Close-focusing is where it's at. It adds a ton more functionality to the lenses.

Last edited by hinman; 12-03-2007 at 12:30 PM.
01-24-2008, 06:58 PM   #13
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Nice model RR, hinman. Ever try one of those pinhole lenses for photographing? I still have to get one of those...
07-30-2013, 12:48 AM   #14
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I finally dealt with a Ricoh flange. After I got the flange ring off, it was easy to saw the excess off along the length then break it off cleanly. The aluminum didn't need any deburing along the cut or at the break. One of the info dots on the mount was a pin that came out and lodged in the aperture mechanism preventing it from closing down all the way. That took a while to figure out/notice, but I put it back; I was lucky that I didn't lose the pin because I wasn't expecting something to fall out of the info dots. The "A button" wouldn't depress all the way and I had to use a bit of muscle on it after I took the ring that it was on off the lens. Before that, the lens couldn't be put into "Auto" mode. I would not have worked on the lens had I not noticed the tiny black screws that held the flange ring to the mount; the black on black made them very hard to see. Frequently while I was working on the lens (I might have spent an hour on it) I kept thinking, "Is it really worth it?" The lens is a "Craig Optics" 60-300 that I picked up today as part of kit that contained a Pentax "A" 50mm 2.0. This 50mm is why I bought the kit. I might have thrown the Craig lens away if I didn't fix the flange.
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