Pentax K-5 live view
Live view mode is still accessed from any exposure mode by pressing a dedicated LV button,upon which the K-5 raises its mirror, and initiates live view. Pressing LV again disables it. Like its predecessor, the K-5 automatically shuts live view off after five minutes to prevent the sensor from overheating, and if the internal temperature threshold has been reached, won't let you resume live view mode until the sensor has cooled to an acceptable level. 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, higher magnification levels are available to a maximum of 10x, as an aid to precise focusing. Options are available in the Record menu to toggle information overlay on or off, or to add a grid displays and a live histogram, and to blink clipped highlights or lost shadows.
Contrast detection autofocus is noticeably faster than the K-7, even when the older camera is running the latest v1.11 firmware update, which improves contrast detection speed significantly over the original K-7 firmware, and subjectively, tracking also seems to be more precise. A new function of the K-5's contrast detection AF is that during the AF operation the K-5's live view feed automatically zooms in on the focus point -- whether it is manually selected, or set using face detection -- making it much easier to see if the lock was accurate. The zoom isn't performed instantly, but rather the view gradually zooms in to help reinforce where within the frame the camera is focusing. This function is something of a mixed blessing, however, in that it can't be disabled, and operates even when in AF-C mode, where you'd expect to be shooting a moving subject. (It does return to a normal view shortly after the initial focus lock, so you do at least see the full image view during focus tracking.) The zoomed view can still make it very tricky to continue to follow your subject and keep them inside the image frame while focusing, though, and we'd really like to see the option to disable this otherwise useful feature -- at the very least when Continuous AF is disabled, and preferably at any time of the photographer's choosing.
One final tweak of note is enabled solely because of new hardware in the K-5, but is worth noting anyway. Unlike the K-7, the K-5 has dual-axis electronic level sensors, and so it is now possible to view indications of both roll and pitch when in live view mode, making it easier to ensure the camera is level in both axes. The K-7 offered only a roll sensor, with no pitch indication available.
The illustration below (courtesy of Pentax) shows the selection of information that's available on the Pentax K-5's LCD display during live view mode.
1 |
Exposure Mode
|
10 |
Temperature warning |
2
|
Flash Mode
|
11 |
Electronic Level |
3
|
Drive Mode
|
12 |
Contrast AF Frame |
4
|
White Balance
|
13 |
Phase Difference AF frame / AF point |
5
|
Custom Image
|
14 |
EV Compensation |
6
|
Extended Bracketing
|
15 |
Histogram |
Multi-exposure |
16 |
AE Lock |
|
Interval Shooting |
17 |
Shutter Speed |
|
Digital Filter |
18 |
Aperture Value |
|
HDR Capture |
19 |
EV Bar |
|
7
|
Number of shots using Multi-exposure
|
20 |
ISO Sensitivity |
Cross Processing |
21 |
Remaining Image Storage Capacity |
|
8 |
Battery Level |
22 |
Main Face Detection Frame |
9 |
Adjusting Composition |
23 |
Face Detection Frame |
Composition Adjustment
Compared to the K-7, the Pentax K-5 allows an even greater range of adjustment, so long as you don't use the rotational correction -- as far as 1.5mm (24 steps) away from centered in either the horizontal or vertical axes. If the sensor is rotated even by one step, the adjustment range reverts to the same as that of the K-7 -- 1mm (16 steps) in any direction.The level of rotational adjustment is unchanged, at approximately one degree (8 steps) on either side of level. A nice touch is that the K-5 now indicates the level of adjustment that you've made, allowing you to remain aware of how much further adjustment is possible.
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 you might expect. (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 K5'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-5'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.)
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