Obin Olson
Well-known member
Not sure what the correct posting area for this is but here goes....a very slick idea for RED cameras.....maybe?
Pentax K7 Shake Reduction/Image Shift System
Like a number of K-series cameras before it, the Pentax K-7 includes a body-based shake reduction (image stabilization) system. As with other body-based IS systems, the advantage of this approach is that it effectively makes all your lenses into IS models. (Which in the case of Pentax, includes something like 25 million flange-mount Pentax lenses manufactured over the past couple of decades.) As with most other features of the camera, though, the Shake Reduction system in the Pentax K-7 has been improved, and one of the improvements enables a couple of other features; ones we haven't seen in any SLR from any manufacturer to date.
Enhanced Shake Reduction. The Pentax K7's Shake Reduction unit adds several features over those of earlier models, including the ability to correct for rotational motion.
For a while now, we've been under the impression that Pentax's Shake Reduction systems not only compensated for vertical and horizontal movement of the camera, but for rotation about the lens axis as well. As it turns out, this in fact wasn't the case, the misunderstanding apparently tracing back to a translation error on documentation for the original K-100D.
That earlier misapprehension unfortunately steals a little of the thunder from the news that the SR system in the new Pentax K-7 now does compensate for rotational movement. We don't know how much this is a factor in real-life shooting situations, as our the IS testing that we've begun over on SLRgear.com doesn't currently test for this. It makes sense that it could be an issue, though, when you consider what's likely to happen when you punch the shutter button a little too aggressively. Guidebooks have for years advised photographers to squeeze off their shots, as punching the shutter button tends to jostle the camera and produce blurred images. 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.
Horizon Correction
Something entirely different. The Pentax K-7 can use it's Shake Reduction system to automatically level the horizon in your photos!
Time and experience (and possibly measurement) will tell how much difference the rotational correction capability of the Pentax K-7's SR system will make in capturing sharp images with slow shutter speeds. The ability to rotate the Pentax K-7's image sensor opens up what might be a more interesting application, though, and one that's potentially more broadly useful.
Given that the camera contains accelerometers (used for determining vertical vs horizontal orientation) that let it precisely determine the camera's position (and hence any tilt relative to an exactly horizontal or vertical position), it makes sense to combine that capability with its rotation-capable SR actuators to come up with an entirely new feature: Automatic horizon leveling, or Automatic Horizon Correction, as it's called on the Pentax K-7's menu system.
If you'll forgive our lapse from dispassionate editorial voice, what a brilliant idea! Tilted horizons are a huge problem for amateur photographers, and even not-so-amateur ones who are in a hurry, or who are simply paying more attention to the subject at the moment of exposure than to the orientation of the camera. Trust us, paying attention to both subject and camera orientation simultaneously is a harder skill to learn than it sounds.
1 Degree is more than it seems. Horizon Correction is limited to +/-1 degree, but that's a very useful amount of leveling, as can be seen here in this animation.
In Horizon-Correction mode, the sensor's rotation is limited to plus/minus one degree, but that's a very useful amount of adjustment: A one-degree tilt in a photo is quite evident (and surprisingly common, based on the images we see submitted to our Photo of the Day contest). Being able to have your camera automatically correct for minor misalignments (optionally, via a checkbox on Record Menu 3) strikes us as a exceptionally useful feature!
In the animation at right, the actual angle of the original, tilted shot was 1.3 degrees, and the camera corrected it to a tilt of just 0.3, exactly matching Pentax's spec for the +/- 1 degree correction.
Electronic Level
Even if you don't choose to use its automatic Horizon Correction function, the Pentax K7 has a useful Electronic Level feature that tells you whether your camera is level or not, in both landscape and portrait orientation. When enabled via a checkbox on Record Menu 3, the bar graph on the top-panel LCD readout that normally shows exposure compensation instead shows a row of dots indicating whether the camera is tilted or not, and in which direction. (Like a bubble level, the dots extend toward the side of the camera that's higher.) The exposure display inside the viewfinder likewise converts to a level display, but you can toggle both back and forth between exposure and level display by pressing the +/- button on the camera's top panel. Interestingly, when the Horizon Correction option is enabled, these displays don't indicate an out-of-level condition until the camera is tilted more than the +/-1 degree angle that the Horizon Correction feature can correct for. Each dot on the top LCD and in the viewfinder display appear to correspond to about 1/3 degree of tilt.
In Live View mode, a little bar graph display appears in the upper right hand corner of the LCD screen, displaying a series of dots to indicate tilt angle. When the camera is level, a green line appears to indicate that fact. The scale of the tilt indicator on the rear LCD seems to be slightly expanded over that of the top panel readout and viewfinder displays, with each dot corresponding to 1/4 degree of tilt.
The Electronic Level display in Live View mode is a bit more sensitive than that shown in the viewfinder and top-panel data readout.
When the Horizon Correction option is active, two white pips appear to mark the limits of its correction ability, and the level-indicating behavior of the graph changes accordingly.
When the Horizon Correction feature is enabled, two pips appear under the bar graph on the LCD display, indicating the +/-1 degree limit that HC can compensate for. Likewise, the green line appears when the tilt is within that +/-1 degree window, and the dots on the bar graph are green. Outside the +/-1 degree range, the dots turn yellow and the green line disappears. When the dots reach the limit of their range, they flash red to indicate an out-of-range condition. The animated screenshots above show the Electronic Level display at work in Live View mode, both with and without the Horizon Correction feature enabled.
Composition Adjustment
Move the sensor, not the camera Here's another really unexpected consequence of a body-based IS system: Use the IS actuators to shift the sensor for fine-tuning your composition when on a tripod!
When you're shooting on a tripod, you presumably don't need the Pentax K7's Shake Reduction capability, but why let those actuators go to waste? The Pentax K-7 has a feature unlike anything we've seen in any other DSLR camera before: You can use the Shake Reduction actuators to shift and rotate (albeit slightly) the image to make very fine adjustments to composition! Selecting this option from Record Menu 3 puts the camera into Live View mode, and lets you shift the image back and forth with the arrow keys, and rotate it slightly with the rear control dial! At any point, you can return to the sensor's default position by pressing the green button just under the rear control dial. (This button normally returns you to the programmed exposure after you've made adjustments manually.)
The animation at right shows how much you can shift the image, relative to the overall frame area. It's a surprisingly large amount, more than we expected. (We haven't tried it, but this should also work like a shift-lens does for shooting tall subjects without tilting the camera -- and producing converging verticals -- although the range of motion relative to what a dedicated shift lens can achieve is relatively small.)
Of course, nothing in this world comes entirely free of compromises, so there are naturally some involved with the Pentax K7's Composition Adjustment feature as well. The extent of the issue will depend on the particular lens in use, but any lens will have poorer optical characteristics (blur, chromatic aberration, coma distortion, etc.) the closer you get to the edges of its "image circle." Tilt-Shift lenses are designed to have unusually large image circles, and many ordinary lenses do better than you might expect as you move away from the center of the frame, but keep this in mind when using the Composition Adjustment feature with a digital-specific lens. (With Pentax lenses designed for the 35mm film frame, the image circle will be so much larger than the K-7's sensor that there shouldn't be any significant loss of image quality relative to having the sensor centered.)
(As an aside, note that this same trade-off between image quality and sensor displacement also comes into play with digital-specific lenses used with a body-based shake reduction system: Shots snapped with the sensor near the limits of its excursion will show poorer image quality on the edge of the frame that's closest to the edge of the image circle. -- And conversely, image quality may actually improve somewhat on the opposite edge.)
Pentax K7 Shake Reduction/Image Shift System
Like a number of K-series cameras before it, the Pentax K-7 includes a body-based shake reduction (image stabilization) system. As with other body-based IS systems, the advantage of this approach is that it effectively makes all your lenses into IS models. (Which in the case of Pentax, includes something like 25 million flange-mount Pentax lenses manufactured over the past couple of decades.) As with most other features of the camera, though, the Shake Reduction system in the Pentax K-7 has been improved, and one of the improvements enables a couple of other features; ones we haven't seen in any SLR from any manufacturer to date.
Enhanced Shake Reduction. The Pentax K7's Shake Reduction unit adds several features over those of earlier models, including the ability to correct for rotational motion.
For a while now, we've been under the impression that Pentax's Shake Reduction systems not only compensated for vertical and horizontal movement of the camera, but for rotation about the lens axis as well. As it turns out, this in fact wasn't the case, the misunderstanding apparently tracing back to a translation error on documentation for the original K-100D.
That earlier misapprehension unfortunately steals a little of the thunder from the news that the SR system in the new Pentax K-7 now does compensate for rotational movement. We don't know how much this is a factor in real-life shooting situations, as our the IS testing that we've begun over on SLRgear.com doesn't currently test for this. It makes sense that it could be an issue, though, when you consider what's likely to happen when you punch the shutter button a little too aggressively. Guidebooks have for years advised photographers to squeeze off their shots, as punching the shutter button tends to jostle the camera and produce blurred images. 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.
Horizon Correction
Something entirely different. The Pentax K-7 can use it's Shake Reduction system to automatically level the horizon in your photos!
Time and experience (and possibly measurement) will tell how much difference the rotational correction capability of the Pentax K-7's SR system will make in capturing sharp images with slow shutter speeds. The ability to rotate the Pentax K-7's image sensor opens up what might be a more interesting application, though, and one that's potentially more broadly useful.
Given that the camera contains accelerometers (used for determining vertical vs horizontal orientation) that let it precisely determine the camera's position (and hence any tilt relative to an exactly horizontal or vertical position), it makes sense to combine that capability with its rotation-capable SR actuators to come up with an entirely new feature: Automatic horizon leveling, or Automatic Horizon Correction, as it's called on the Pentax K-7's menu system.
If you'll forgive our lapse from dispassionate editorial voice, what a brilliant idea! Tilted horizons are a huge problem for amateur photographers, and even not-so-amateur ones who are in a hurry, or who are simply paying more attention to the subject at the moment of exposure than to the orientation of the camera. Trust us, paying attention to both subject and camera orientation simultaneously is a harder skill to learn than it sounds.
1 Degree is more than it seems. Horizon Correction is limited to +/-1 degree, but that's a very useful amount of leveling, as can be seen here in this animation.
In Horizon-Correction mode, the sensor's rotation is limited to plus/minus one degree, but that's a very useful amount of adjustment: A one-degree tilt in a photo is quite evident (and surprisingly common, based on the images we see submitted to our Photo of the Day contest). Being able to have your camera automatically correct for minor misalignments (optionally, via a checkbox on Record Menu 3) strikes us as a exceptionally useful feature!
In the animation at right, the actual angle of the original, tilted shot was 1.3 degrees, and the camera corrected it to a tilt of just 0.3, exactly matching Pentax's spec for the +/- 1 degree correction.
Electronic Level
Even if you don't choose to use its automatic Horizon Correction function, the Pentax K7 has a useful Electronic Level feature that tells you whether your camera is level or not, in both landscape and portrait orientation. When enabled via a checkbox on Record Menu 3, the bar graph on the top-panel LCD readout that normally shows exposure compensation instead shows a row of dots indicating whether the camera is tilted or not, and in which direction. (Like a bubble level, the dots extend toward the side of the camera that's higher.) The exposure display inside the viewfinder likewise converts to a level display, but you can toggle both back and forth between exposure and level display by pressing the +/- button on the camera's top panel. Interestingly, when the Horizon Correction option is enabled, these displays don't indicate an out-of-level condition until the camera is tilted more than the +/-1 degree angle that the Horizon Correction feature can correct for. Each dot on the top LCD and in the viewfinder display appear to correspond to about 1/3 degree of tilt.
In Live View mode, a little bar graph display appears in the upper right hand corner of the LCD screen, displaying a series of dots to indicate tilt angle. When the camera is level, a green line appears to indicate that fact. The scale of the tilt indicator on the rear LCD seems to be slightly expanded over that of the top panel readout and viewfinder displays, with each dot corresponding to 1/4 degree of tilt.
The Electronic Level display in Live View mode is a bit more sensitive than that shown in the viewfinder and top-panel data readout.
When the Horizon Correction option is active, two white pips appear to mark the limits of its correction ability, and the level-indicating behavior of the graph changes accordingly.
When the Horizon Correction feature is enabled, two pips appear under the bar graph on the LCD display, indicating the +/-1 degree limit that HC can compensate for. Likewise, the green line appears when the tilt is within that +/-1 degree window, and the dots on the bar graph are green. Outside the +/-1 degree range, the dots turn yellow and the green line disappears. When the dots reach the limit of their range, they flash red to indicate an out-of-range condition. The animated screenshots above show the Electronic Level display at work in Live View mode, both with and without the Horizon Correction feature enabled.
Composition Adjustment
Move the sensor, not the camera Here's another really unexpected consequence of a body-based IS system: Use the IS actuators to shift the sensor for fine-tuning your composition when on a tripod!
When you're shooting on a tripod, you presumably don't need the Pentax K7's Shake Reduction capability, but why let those actuators go to waste? The Pentax K-7 has a feature unlike anything we've seen in any other DSLR camera before: You can use the Shake Reduction actuators to shift and rotate (albeit slightly) the image to make very fine adjustments to composition! Selecting this option from Record Menu 3 puts the camera into Live View mode, and lets you shift the image back and forth with the arrow keys, and rotate it slightly with the rear control dial! At any point, you can return to the sensor's default position by pressing the green button just under the rear control dial. (This button normally returns you to the programmed exposure after you've made adjustments manually.)
The animation at right shows how much you can shift the image, relative to the overall frame area. It's a surprisingly large amount, more than we expected. (We haven't tried it, but this should also work like a shift-lens does for shooting tall subjects without tilting the camera -- and producing converging verticals -- although the range of motion relative to what a dedicated shift lens can achieve is relatively small.)
Of course, nothing in this world comes entirely free of compromises, so there are naturally some involved with the Pentax K7's Composition Adjustment feature as well. The extent of the issue will depend on the particular lens in use, but any lens will have poorer optical characteristics (blur, chromatic aberration, coma distortion, etc.) the closer you get to the edges of its "image circle." Tilt-Shift lenses are designed to have unusually large image circles, and many ordinary lenses do better than you might expect as you move away from the center of the frame, but keep this in mind when using the Composition Adjustment feature with a digital-specific lens. (With Pentax lenses designed for the 35mm film frame, the image circle will be so much larger than the K-7's sensor that there shouldn't be any significant loss of image quality relative to having the sensor centered.)
(As an aside, note that this same trade-off between image quality and sensor displacement also comes into play with digital-specific lenses used with a body-based shake reduction system: Shots snapped with the sensor near the limits of its excursion will show poorer image quality on the edge of the frame that's closest to the edge of the image circle. -- And conversely, image quality may actually improve somewhat on the opposite edge.)
