auto stop-down when using a P6 -> Pentax 645 adapter?

[andrew_pogrebennyk]

<p>Hi,<br>

I am considering buying a Pentax 645 body for CZJ Sonnar 180 MC. Can you tell me if the P6 -> P645 adapter supports the auto stop-down? I will be shooting also the landscapes where tele is appropriate and changing the aperture manually every time from 2.8 to a smaller one would be painful. Thanks.</p>

[richterjw]

<p>I don't have the Pentax but do have the P6-Mamiya adapter, and it does require manually changing the aperture. I mostly shoot cityscapes, so I'm on a tripod and relatively unaffected, but it can get laborious. JR</p>

[dougmiles]

<p>Certainly the larger Pentax 67 series lenses maintain auto diaphragm with the Pentax adapter 645 for 67 lens, but this convenience seems very unlikely when you cross brands. Even the Pentax adapters for 645 and 67 lenses to K-mount do not have auto diaphragm, nor do the various adapters for SLR lenses on Olympus Pen F, and it is indeed tiresome (and prone to error) to use adapted lenses manually.<br>

Now if someone has converted the 180 Sonnar to P645 mount that would be most useful! Or you might try the excellent P67 165mm f/2.8 with the Pentax adapter...</p>

[andrew_pogrebennyk]

<p>Jeremy, I see.. That means, most likely P6->P645 adapter also required manually changing the aperture.<br>

Doug, thanks for the information. Actually, I heard there are some 180 Sonnars adapter to Pentax 67. I'm just not looking for a P67 at the moment :)</p>

[danny_wong2]

<p>The P6 to Pentax 645 mount adapter does not have any mechanical linkage. The Pentax 67 to 645 aperature linkage was possible due to the extra clearence with the 67 lenses.</p>