[NRV Shooter]

My K10D won't detect the "A" setting on any of three Tamron Adaptall 2 lenses I have and allow me to select the aperture setting in Av mode. I have two different PKA Adaptall 2 adapters and switching them around between the lenses still doesn't help. I have the "Using aperture ring" set to "permitted" in the Custom Settings and all other camera settings correct, as far as I can tell.

I have an old Takumar "A" 70-200 mm that works fine, allowing the camera to detect the "A" setting and me to set the aperture as I choose. Of course this is not an Adaptall 2 lens but it tells me the camera is functioning properly when it can read the "A" setting.

Could the problem be that the contacts on the adapters and/or the lenses need cleaning? One of the adapters is brand new (old stock) and all the lenses are in almost as new condition.

Any help will be appreciated.

[snostorm]

Hi NRV Shooter,

I have about 5 PK/A adapters, and all of them have needed the mod described here:

https://www.pentaxforums.com/forums/maintenance-repair-articles/50689-fixing-...a-adapter.html

Some have needed a larger area scraped then indicated in the article, but I think this is somewhat lens/adapter/body dependent.

I think this will take care of your problem.

Scott

[NRV Shooter]

Thanks Scott! I remember seeing that information in the past and I feel sure it will cure my problem.

[NRV Shooter]

I scraped the tip of the small screw closest to the other three electrical contacts, as indicated in the picture in the link provided above by Scott. The tip of that small screw does not protrude above the plane of the adapter face and is actually sunken down a little. I scraped the same area on both of my adapters and they still don't work, with either of the Adaptall 2 zooms. As mentioned, one adapter was NIB old stock a few months ago when I acquired it and the other was used. Both lenses are in "new-like" condition. I have cleaned all the contact areas on both lenses and adapters.

I scraped very carefully, but to the extent that I felt would remove any residue or residual glues or coatings (I can see nothing of that nature on the screw heads, even with a magnifying glass) based on comments from others, again through the link provided, who indicated it was a very simple procedure which produced immediate positive results.

Am I just not scraping hard enough or maybe not in the right place?

Any other suggestions, like "get a bigger hammer"?

[fotaki]

I have only one PK/A adapter. It has been a little erratic in the past but I noticed it had some side-to-side play when mounted (when fully clicked home). I now know it's sweet spot and by a slight movement of both lens/adapter I rarely get any problems.

I don't know why this should happen but I it could be due to wear in used samples or machining differences when new.

Edit: BTW Before mounting the lens and adapter to the camera, make sure the lens aperture is set to 'A' (Auto).

[NRV Shooter]

Thanks John! I think I was setting the lens aperture to the widest f-stop, per the instructions. I'll try setting it to the A setting prior to mounting. I have tried moving the lens and adapters around after mounting, just to correct a problem such as yours, but that so far has produced no positive results.

[Steinback]

Are you pushing the little plastic button on the side of the adaptall mount to rotate the aperture ring the extra click that locks it into A mode? I missed the button the first time I used a KA adaptall mount.

[NRV Shooter]

Thanks for all of the help, as I finally got it working just now. I don't think I was getting the lens properly fully seated on the adapter. I mounted the lens to the adapter with the aperture setting to the lowest number (per Adaptall's instructions and Scott's suggestion), then made sure I seated the two firmly, rotated the aperture ring back and forth then fully seated it in the AE position, with a little help from the little black button, and I now get a nice F stop reading in the LCD.

A classic case of the nut behind the wheel being loose!

I have a Tamron Adaptall 300mm f5.6 prime with a button on the lower part of it which has a green "M" and a green "A" setting available. It looks a lot like the same button I have seen on some of the older Takumar lenses. The lens also has an AE position on the aperture ring and this lens works fine with the K10D in that AE position, allowing the camera to set an aperture in Av mode, just like my others will now do since I can now correctly mount the adapters. I assume the button indicates whether the lens is in "M" or "A" mode by which of the two choices is visible, i.e. if the "A" is showing (meaning the button is pushed over to the cover the "M") then the lens is in "A" mode. Can someone please explain the function of this switch, since the lens also has an AE setting?

Thanks again for all the help!