Tokina 28mm F2.8 M42 repair

Arjay Bee · 10-01-2006, 08:29 PM

Have a little homework project happening.
Picked this 28mm lens up at Cash Converters for not much. The aperture shutter only closes when I take the lens apart and move the actuating lever directly from the inside. The Auto manual slider works fine and the pin operates as it ought. Any help or pointers would be appreciated.

Does anyone have a 'how to' page on taking the aperture mechanism apart so that I can reassemble correctly? I don't want to adjust the focussing mechanism by mistake and make the problem worse. It does rattle a bit.

No fungus anyway and glass is in good order. The lens itself has average ratings as a unit but will allow better low light work at this focal length than currently held in lens collection.

On a positive side I bought a set of three m42 extension tubes that seemed to have a familiar knurl pattern on them. Get them home to find they are Pentax originals and they match the focus ring knurls on my Super Takumar 50mm 1.4. A very nice manual macro set now. Very happy.

Chilious · 10-01-2006, 09:30 PM

Hi Arjay.
Sometimes it's hard to find directions for repairing a specific lens. Here's a link for the disassembly and cleaning of the Super Takumar f1.4 50mm:
http://www.mypentax.com/tak50_1_4.html
and here's one for the 35mm takumar:
http://pentax-manuals.com/repairs/takumarlens_s.pdf
I had some problems with a Pentax zoom lens, but since this guides are for primes, they didn't work for me. Maybe they will help you.

Good luck,
Robert

Arjay Bee · 10-02-2006, 03:01 AM

Thank you for those Robert.

Of the two the tak50 is most similar but sill very different. I suspect there is grease all over the blades as they are very sluggish and sticky - enough that the spring to not open them when the aperture is forced open even though the external setting is wide open. Will try some grease solvent tomorrow and see if it makes a difference. Even the writer of that article warns against opening up that mechanism. Visions of spring loaded blades and ballberings flying around the room immediately present themselves.

Again thank you for that help. Here is another site for those exploring this way of utilizing the dwindling supply of M42 glass
http://www.kyphoto.com/classics/articles.html
And renovating old Pentax cameras:
http://www.pentax-manuals.com/manuals/service/servicemanuals.htm

10-01-2006, 08:29 PM	#1
Arjay Bee Pentaxian Join Date: Sep 2006 Location: Horn Island, Torres Straits, Q Photos: Gallery Posts: 4,715	Tokina 28mm F2.8 M42 repair Have a little homework project happening. Picked this 28mm lens up at Cash Converters for not much. The aperture shutter only closes when I take the lens apart and move the actuating lever directly from the inside. The Auto manual slider works fine and the pin operates as it ought. Any help or pointers would be appreciated. Does anyone have a 'how to' page on taking the aperture mechanism apart so that I can reassemble correctly? I don't want to adjust the focussing mechanism by mistake and make the problem worse. It does rattle a bit. No fungus anyway and glass is in good order. The lens itself has average ratings as a unit but will allow better low light work at this focal length than currently held in lens collection. On a positive side I bought a set of three m42 extension tubes that seemed to have a familiar knurl pattern on them. Get them home to find they are Pentax originals and they match the focus ring knurls on my Super Takumar 50mm 1.4. A very nice manual macro set now. Very happy.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Modifying the Tokina EL 28mm/2.8 M42 for manual aperture	sterretje	Do-It-Yourself	1	03-24-2012 03:49 AM
Soligor 28mm f2.8 M42 vs vivitar 28mm f2.5 M42	NaClH2O	Pentax SLR Lens Discussion	3	04-11-2011 11:16 AM
For Sale - Sold: Tokina 28mm f/2.8 P/K-A (Worldwide)	Duh_Vinci	Sold Items	4	11-29-2010 04:40 PM
tokina 28mm 1:2 lens P/K	jcool	Pentax SLR Lens Discussion	8	11-08-2010 11:45 PM
Tokina 70-210mm repair assistance	Paleo Pete	Pentax SLR Lens Discussion	2	10-22-2010 04:27 PM

10-01-2006, 09:30 PM	#2
Chilious Junior Member Join Date: Sep 2006 Location: Cluj-Napoca, Romania Photos: Gallery Posts: 28	Hi Arjay. Sometimes it's hard to find directions for repairing a specific lens. Here's a link for the disassembly and cleaning of the Super Takumar f1.4 50mm: http://www.mypentax.com/tak50_1_4.html and here's one for the 35mm takumar: http://pentax-manuals.com/repairs/takumarlens_s.pdf I had some problems with a Pentax zoom lens, but since this guides are for primes, they didn't work for me. Maybe they will help you. Good luck, Robert

10-02-2006, 03:01 AM	#3
Arjay Bee Pentaxian Join Date: Sep 2006 Location: Horn Island, Torres Straits, Q Photos: Gallery Posts: 4,715 Original Poster	Thank you for those Robert. Of the two the tak50 is most similar but sill very different. I suspect there is grease all over the blades as they are very sluggish and sticky - enough that the spring to not open them when the aperture is forced open even though the external setting is wide open. Will try some grease solvent tomorrow and see if it makes a difference. Even the writer of that article warns against opening up that mechanism. Visions of spring loaded blades and ballberings flying around the room immediately present themselves. Again thank you for that help. Here is another site for those exploring this way of utilizing the dwindling supply of M42 glass http://www.kyphoto.com/classics/articles.html And renovating old Pentax cameras: http://www.pentax-manuals.com/manuals/service/servicemanuals.htm

Thread Tools	Search this Thread
	Search this Thread: Advanced Search