That said, the Pentax K7's video recording introduces some capabilities we've not seen in prior SLR models from competing manufacturers, and firmly establishes Pentax's credentials as a leading-edge purveyor of video-capable SLRs.
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While you can control the lens aperture on some competing SLRs by faking-out the exposure system, the Pentax K7 is the first video-capable SLR that we're aware of that lets you set the lens aperture explicitly. You can't adjust it during recording, but whatever value you set before you begin your clip is the one the camera will use. This is a great feature, one that's been sorely lacking in other video-capable SLRs. Groucho note: I think Canon just added this on their 5D Mk2 via a firmware update.
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The Pentax K-7 is unique among the video-capable SLRs we've tested to date, in that its body-based image stabilization can be used when recording movies. Not only does this make any lens you're recording with into an IS model, but we found that the image stabilization worked exceptionally well when recording videos. We've recorded videos with other SLRs using IS lenses, but the level of stabilization we found in the Pentax K7 seemed to significantly exceed anything we'd seen previously.
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We don't have a quantitative measurement of AF performance in our test suite, and as of this writing have been able to make only limited and fairly unscientific comparisons between the prototype K-7 and K20D, but our strong subjective impression has been that the Pentax K-7 achieves focus much more quickly in difficult situations of low light and/or low subject contrast than does the K20D. This contributed greatly to the sense of responsiveness we felt when using the Pentax K-7. Groucho note: YAY!
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While you could certainly expect somewhat reduced battery life in such temperatures, the Pentax K-7 is rated for operation down to 14 degrees F (-10 degrees C). That's quite a bit colder than most of the competition is rated to withstand: The Canon 50D, Olympus E30, Nikon D90 and Sony A700 are all rated only to 32 degrees F. Even pro-level bodies like the Canon EOS-1D Mark III and Nikon D3 are only rated for use down to 32F.
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Since the shutter button is generally located on one side of the body, it's very likely that hitting it abruptly will produce some momentary rotation of the body about the axis of the lens. This is the just sort of movement that the K-7's new SR system can now compensate for. (As far as we know, it's the only IS system out there that does this.) Pentax claims that the K-7's sensor can rotate by as much +/- 2 degrees to compensate for rotational vibration.
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Bracketing options are staggering, with White Balance, Saturation, Hue, High/Low key, Contrast, and Sharpness bracketing options in addition to simple Exposure bracketing. In the Custom menu, you can set the One-Push Bracketing option, which will make the Pentax K7 shoot all three bracketed images at once, rather than requiring you to squeeze off each shot. This increases the likelihood that you'll remember to shoot all three, and that they'll all look about the same.
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As I've mentioned in past reviews, the K20D and its predecessors were designed with the goal of emulating film's behavior so that photographers moving from film would get the results they would expect from a roll of daylight-balanced film. The Pentax K7's auto white balance system changes all that, recognizing what an auto white balance system is supposed to do: adjust for the light source as it changes.
Another sign that Pentax has made a thoughtful change to the auto white balance system based strongly on its tungsten lighting performance is found in Custom function 12: "AWB in Tungsten Light." Here you can set whether the Pentax K7 applies the default "Subtle correction" or "Strong correction" to tungsten lighting. Guess which I've chosen.
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Perhaps most surprising is the Pentax K7's demeanor: It's not just gentlemanly, it's downright smooth. Past Pentax SLR shutter designs made some unique noises, some good, others a little much. There were lots of odd winding sounds that lasted a little too long and made the cameras sound almost broken. Not the Pentax K7. It's quieter than any digital SLR I've used. The sound has no winding or even clicking sounds.
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The viewfinder blackout time on the Pentax K7 is among the fastest in its class. I can't time it, and I haven't heard what it's rated, but it returns the view so much faster than a K20D, or any camera that I own, that I can't help but fall a little deeper for the K7.
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Pentax has it right when they call the K-7 a camera with pro features at a semi-pro price. I'm tempted to warn pure amateurs away from the Pentax K7, as I did with the Nikon D300, so that they don't get lost in its wonderful tangle of fine-tuning options. But the good news is that if you lock the Pentax K7 into Green zone mode it turns off most of the options that can befuddle and just starts using Pentax's years of experience to take well-balanced photographs.