Need help with a Tamron 28mm f/2.8 Adaptall CW-28

jessamyn · 10-03-2014, 02:42 PM

Hi everyone, I'm new here and I've come in need of your expert advice. I just bought an old Tamron 28mm lens on ebay, that I believe to be an Adaptall (version 1) with an adapter already on it. I bought this lens for my K-r, but I cannot get it to work. It fits, but I turn my camera on and nothing. I have read thread after thread trying to figure out which lens I actually purchased and what adapter I might need and I think I am even more confused than I was before. Is there anyone that could shed some light on this lens and its existing adapter?

Adam · 10-03-2014, 02:51 PM - **1 Like**

Assuming the lens mounts properly and the adapter isn't shorting the contacts (i.e. the camera menus work and nothing erratic happens), follow this guide:

https://www.pentaxforums.com/forums/54-pentax-lens-articles/110657-how-use-me...k-x-k-7-a.html

**marcusBMG** · 10-03-2014, 03:31 PM - **1 Like**

Lens should work like Pentax K or M lens with that mount. Check your set up (aperture ring etc).

More info:
Information page on Tamron adaptall, adaptall-2 system and lenses

**Just1MoreDave** · 10-03-2014, 04:03 PM - **1 Like**

The lens looks like it has an aperture control switch, probably to make it compatible with an M42 adapter and M42 cameras. That switch is visible in your photo of the side of the lens. You could try to slide the switch in either position. I'm not sure which one would work; it depends on how the adapter was designed.

wildlifephotog · 10-03-2014, 04:52 PM - **1 Like**

The lens is not an adaptall-2 type. It's a adaptall lens from 1976.
Be sure the adapter tabs are in the proper slots on the lens body.

Oldbayrunner · 10-04-2014, 05:18 AM - **1 Like**

Dump it....

From Marcus link....

"A first generation manual P-KM mount, easily distinguished from the later mount by the lack of a black flange with f numbers on, and only one tab. This is probably best avoided except to use specifically with certain early adaptall lenses" - See more at: Information page on Tamron adaptall, adaptall-2 system and lenses

**marcusBMG** · 10-04-2014, 05:53 AM - **1 Like**

Originally posted by Oldbayrunner

Dump it....

From Marcus link....

"A first generation manual P-KM mount, easily distinguished from the later mount by the lack of a black flange with f numbers on, and only one tab. This is probably best avoided except to use specifically with certain early adaptall lenses" - See more at: Information page on Tamron adaptall, adaptall-2 system and lenses

Yes you're right that is the 1st gen mount. But I should actually test the functioning of the darn thing since I have one and make a clearly definitive statement on my web page.
In any event the OP CAN use the mount, operating in Av, using the A-M switch to stop down manually. Which is what I tend to do with these AD-1 lenses in any case it's one of their advantages.

Try it out Jessamyn, set mode dial on AV, focus switch on MF, make sure you've set "use aperture ring" in the settings etc. Put the A-M switch on A - aperture will be wide open and will stay wide open when you click the aperture ring round to eg f5.6, f8 (whatever you want). Focus and frame. Then just before pressing the shutter, flick the A-M switch to M. You will see the viewfinder go dim because the iris closes. Press the shutter.

Addendum: you will almost certainly need to use the exposure compensation function (the wee button with +/- on it). Typically I am compensating up to around +1eV to get the exposure right.

Last edited by marcusBMG; 10-04-2014 at 09:41 AM.

stevebrot · 10-04-2014, 09:04 AM - **1 Like**

Originally posted by Oldbayrunner

Dump it....

From Marcus link....

Originally posted by marcusBMG

Yes you're right that is the 1st gen mount.

...and it is also mounted on a first generation lens and should function the same as any other K or M series K-mount lens*. Marcus' solution using the A/M switch in Av mode is unique and worth trying out.

Steve

* The second tab on the Adaptall-2 Pentax K,M adapter serves no purpose other than to locate and drive the second aperture scale used for viewfinder display on supporting cameras.

**marcusBMG** · 10-04-2014, 09:41 AM - **1 Like**

Originally posted by stevebrot

The second tab on the Adaptall-2 Pentax K,M adapter serves no purpose other than to locate and drive the second aperture scale used for viewfinder display on supporting cameras.

I hadn't appreciated that - cheers Steve
I had in fact just yesterday updated the description in the review secion for the PKA

jessamyn · 10-04-2014, 04:42 PM

Thank you so much for your replies! I'm going to try changing the various settings as suggested. I will report back if I had any success or possibly just $20 down the drain.

jessamyn · 10-04-2014, 04:48 PM

Originally posted by marcusBMG

make sure you've set "use aperture ring" in the settings etc.

That did it! Lens fully functioning now, thank you Marcus and everyone for your help.

**marcusBMG** · 10-05-2014, 05:23 AM

Thats great jessamyn, enjoy the lens. I don't have one in my adaptall collection, only the later 01B, but going by the reviews there's little between them and I rate the 01B. Get some good pics and post them in the adaptall lens club thread.

10-03-2014, 02:42 PM	#1
jessamyn New Member Join Date: Oct 2014 Photos: Albums Posts: 4	Need help with a Tamron 28mm f/2.8 Adaptall CW-28 Hi everyone, I'm new here and I've come in need of your expert advice. I just bought an old Tamron 28mm lens on ebay, that I believe to be an Adaptall (version 1) with an adapter already on it. I bought this lens for my K-r, but I cannot get it to work. It fits, but I turn my camera on and nothing. I have read thread after thread trying to figure out which lens I actually purchased and what adapter I might need and I think I am even more confused than I was before. Is there anyone that could shed some light on this lens and its existing adapter?

10-03-2014, 02:51 PM - 1 Like	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	Assuming the lens mounts properly and the adapter isn't shorting the contacts (i.e. the camera menus work and nothing erratic happens), follow this guide: https://www.pentaxforums.com/forums/54-pentax-lens-articles/110657-how-use-me...k-x-k-7-a.html Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

10-04-2014, 09:41 AM - 1 Like	#9
marcusBMG Site Supporter Join Date: Nov 2012 Location: North Wales Photos: Gallery \| Albums Posts: 2,870	Originally posted by stevebrot The second tab on the Adaptall-2 Pentax K,M adapter serves no purpose other than to locate and drive the second aperture scale used for viewfinder display on supporting cameras. I hadn't appreciated that - cheers Steve I had in fact just yesterday updated the description in the review secion for the PKA Last edited by marcusBMG; 10-04-2014 at 09:57 AM.

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10-03-2014, 03:31 PM - 1 Like	#3
marcusBMG Site Supporter Join Date: Nov 2012 Location: North Wales Photos: Gallery \| Albums Posts: 2,870	Lens should work like Pentax K or M lens with that mount. Check your set up (aperture ring etc). More info: Information page on Tamron adaptall, adaptall-2 system and lenses

10-03-2014, 04:03 PM - 1 Like	#4
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	The lens looks like it has an aperture control switch, probably to make it compatible with an M42 adapter and M42 cameras. That switch is visible in your photo of the side of the lens. You could try to slide the switch in either position. I'm not sure which one would work; it depends on how the adapter was designed.

10-03-2014, 04:52 PM - 1 Like	#5
wildlifephotog Inactive Account Join Date: Nov 2008 Location: USA Posts: 924	The lens is not an adaptall-2 type. It's a adaptall lens from 1976. Be sure the adapter tabs are in the proper slots on the lens body.

10-04-2014, 05:18 AM - 1 Like	#6
Oldbayrunner Pentaxian Join Date: Mar 2013 Posts: 1,665	Dump it.... From Marcus link.... "A first generation manual P-KM mount, easily distinguished from the later mount by the lack of a black flange with f numbers on, and only one tab. This is probably best avoided except to use specifically with certain early adaptall lenses" - See more at: Information page on Tamron adaptall, adaptall-2 system and lenses

10-04-2014, 05:53 AM - 1 Like	#7
marcusBMG Site Supporter Join Date: Nov 2012 Location: North Wales Photos: Gallery \| Albums Posts: 2,870	Originally posted by Oldbayrunner Dump it.... From Marcus link.... "A first generation manual P-KM mount, easily distinguished from the later mount by the lack of a black flange with f numbers on, and only one tab. This is probably best avoided except to use specifically with certain early adaptall lenses" - See more at: Information page on Tamron adaptall, adaptall-2 system and lenses Yes you're right that is the 1st gen mount. But I should actually test the functioning of the darn thing since I have one and make a clearly definitive statement on my web page. In any event the OP CAN use the mount, operating in Av, using the A-M switch to stop down manually. Which is what I tend to do with these AD-1 lenses in any case it's one of their advantages. Try it out Jessamyn, set mode dial on AV, focus switch on MF, make sure you've set "use aperture ring" in the settings etc. Put the A-M switch on A - aperture will be wide open and will stay wide open when you click the aperture ring round to eg f5.6, f8 (whatever you want). Focus and frame. Then just before pressing the shutter, flick the A-M switch to M. You will see the viewfinder go dim because the iris closes. Press the shutter. Addendum: you will almost certainly need to use the exposure compensation function (the wee button with +/- on it). Typically I am compensating up to around +1eV to get the exposure right. Last edited by marcusBMG; 10-04-2014 at 09:41 AM.

10-04-2014, 09:04 AM - 1 Like	#8
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by Oldbayrunner Dump it.... From Marcus link.... Originally posted by marcusBMG Yes you're right that is the 1st gen mount. ...and it is also mounted on a first generation lens and should function the same as any other K or M series K-mount lens. Marcus' solution using the A/M switch in Av mode is unique and worth trying out. Steve The second tab on the Adaptall-2 Pentax K,M adapter serves no purpose other than to locate and drive the second aperture scale used for viewfinder display on supporting cameras.

10-04-2014, 04:42 PM	#10
jessamyn New Member Join Date: Oct 2014 Photos: Albums Posts: 4 Original Poster	Thank you so much for your replies! I'm going to try changing the various settings as suggested. I will report back if I had any success or possibly just $20 down the drain.

10-04-2014, 04:48 PM	#11
jessamyn New Member Join Date: Oct 2014 Photos: Albums Posts: 4 Original Poster	Originally posted by marcusBMG make sure you've set "use aperture ring" in the settings etc. That did it! Lens fully functioning now, thank you Marcus and everyone for your help.

10-05-2014, 05:23 AM	#12
marcusBMG Site Supporter Join Date: Nov 2012 Location: North Wales Photos: Gallery \| Albums Posts: 2,870	Thats great jessamyn, enjoy the lens. I don't have one in my adaptall collection, only the later 01B, but going by the reviews there's little between them and I rate the 01B. Get some good pics and post them in the adaptall lens club thread.