Pentax K-7 Live View

Like the K20D, the Pentax K-7 has a Live View mode, for framing subjects on the LCD instead of using the optical viewfinder. Compared to the K20D, the Pentax K-7's Live View mode is much enhanced. On top of the much better LCD, the Pentax K-7 adds contrast-detect autofocus mode, face detect AF (up to 16 faces can be detected in a frame), an optional live histogram, a dedicated Live View (LV) button, detailed information overlay, as well as unique features such composition adjustment and an electronic level.

Live View mode is toggled by pressing the LV button. Pressing LV raises the mirror an initiates Live View. Pressing LV again disables it. The K-7 automatically shuts Live View off after five minutes to prevent the sensor from overheating, and won't let you resume Live View mode until the internal temperature has reached an acceptable level. This is an improvement over the K20D's three minute limit. When using autofocus, you can magnify the image 2x, 4x, or 6x by pressing the INFO button. The four-way controller can be used to move the magnified area around the frame, and the green button is used to return to the center. When manual focus is used, magnification can be up to 10x, as an aid to focusing. Options are available in the Record menu to toggle information overlay on or off, or to add a grid display and live histogram, and to blink clipped highlights or lost shadows.

The illustration below (courtesy of Pentax) shows what info is available on the Pentax K-7 in Live View mode.

1	Exposure Mode	11	EV Compensation
2	Flash Mode	12	Histogram
3	Drive Mode	13	AE Lock
4	White Balance	14	Shutter Speed
5	Custom Image	15	Aperture
6	Extended Bracketing / Multi-exposure / Interval Shooting / Digital Filter / HDR Capture	16	EV Bar
7	Number of shots using Multi-exposure	17	ISO Sensitivity
8	Battery Level	18	Remaining Image Storage Capacity
9	Electronic Level	19	Face Detection Frame
10	AF Frame	20	Main Face Detection Frame

 

Composition Adjustment

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 digital SLR 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.)