I don't know how much help I can offer but here goes. I shoot with two Pentax K10D bodies and all three DA "pancake" lenses. Generally speaking, I have no exposure problems though when one of the bodies came back from Pentax repair (autofocus issue) it began to consistently underexpose by about 2/3 stop, regardless of the subject matter or meter mode. I use Exposure Compensation to adjust for this rather than send the body back to Pentax.
By "full frame" I assume you mean an FA lens or a lens made by a third party manufacturer in a Pentax mount. As you no doubt know, the only "full frame" cameras that Pentax makes are the film ones. I haven't heard of any exposure issues with the FA lenses on the digital bodies but I don't own any FA lenses so I can't speak from personal experience. .
My personal approach to flash nowadays is to use the built-in flash on the K10D to trigger an old Vivitar 283 off-camera equipped with a
Wein "peanut" slave. I set the Vivitar to one of its auto modes, flash comp on the K10D to -1EV (usually), and the exposure on the camera to Manual (when I don't use flash I normally use Aperture Priority). Maximum sync speed on the Pentax is 1/180sec so the shutter speed is never set higher. Aperture is determined by the auto mode the Vivitar is set at.
I have no experience with flashes dedicated to the Pentax so I can't help you there. However, many users on the Pentax forum are quite knowledgeable so I suggest you take a look. You'll have to register to post a message but that's easily done. Here's the link:
http://www.pentaxforums.com/
One final point and perhaps an obvious one. Cameras, lenses, meters, flashes, etc. are just tools and sometimes don't work the way we expect. So we have to make adjustments. But I'm sure you already know that!
Richard Martin specializes in Cityscape
and Waterscape stock
photography.
E-mail: marphoto@xxxxxxxxx
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--- On
Wed, 3/31/10, Kostas Papakotas <clenchedteethphotography@xxxxxxxx> wrote:
From: Kostas Papakotas <clenchedteethphotography@xxxxxxxx>
Subject: Full Frame Lens on 3/4 camera body and external flash compatibility....
To: "List for Photo/Imaging Educators - Professionals - Students" <photoforum@xxxxxxxxxxxxxxxxxx>
Date: Wednesday, March 31, 2010, 4:15 PM
|
well there ain't.....at least with Pentax...
made soem tests yesterday.....I got proper exposure using the 3/4 lens, but mounting the full frame lens changed things....I was getting consistenly underexposed frames but i managed to correct wih oen stop down and +1 stop of flash power....
Seems the camera reads the focal length from the lens chip but it is a value that does not corespond to the effective focasl length....
more I cannot deduce....
I wopudl appreciate your help though, kostas |
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