Pentax K-01 Review

 
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Pentax K-01 Video Recording

High-definition video capture is now ubiquitous in current interchangeable-lens cameras, and all of the major manufacturers now provide some form of video capture in their compact system cameras. The Pentax K-01 offers a reasonably rich feature set, although it does lack a couple of consumer-friendly features found on some models. Videos can be recorded at up to Full HD resolution using H.264 compression, but there's no support for full-time autofocusing during movie capture, and nor does the K-01 have a wind cut function, both options that consumer videographers might typically expect to see. The K-01 does however support manual exposure control, manual audio levels control, external microphones, and adjustable frame rates, all functions that professional use typically demands. For those who like to cater to their creative side, the K-01 does offer a generous selection of pre-capture video filters.

Overall, we found the Pentax K-01's video feature set to be a worthwhile step forward from past Pentax interchangeable-lens models. Consumers may mourn the lack of full-time autofocus, but given its relatively slow and hesitant operation, it probably wouldn't have been terribly useful regardless. If you're willing to live without it and either focus manually or plan your shots around your depth of field, you should be able to achieve good results with the K-01.

Pentax K-01 Basic Video Specs

  • 1,920 x 1,080 (Full HD / 1080p), 1,280 x 720 (720p), and 640 x 480 (VGA) recording
  • MPEG-4 H.264/AVC compression at all resolutions; MOV file format; three quality levels
  • A choice of 29.97, 25, or 23.976 frames per second at all resolutions; for 720p mode only there's also a choice of 59.940 or 50 fps
  • Automatic or manual focus possible before or during movie capture, but only single AF operations are available while recording, not full-time AF
  • Manual focus peaking before capture starts, but not during capture
  • Optional infrared remote controls can start or stop recording; one model can also trigger AF operations remotely
  • Auto, aperture-priority, or full manual exposure, but no shutter-priority
  • Automatic or manual ISO sensitivity control in manual mode
  • Available exposure variables can be adjusted both before and during movie capture
  • Exposure compensation adjustment is available before recording starts
  • Digital image stabilization supported during video recording
  • Stereo audio recording via built-in, two-port microphone on front panel, or external stereo mic jack
  • Separate controls over levels from internal mic (5 step) or external mic (10 step); audio capture can also be disabled
  • Custom Image / Digital Filter functions are available in movie mode
  • Interval movie function can record timelapse movies at anywhere from one frame per second to one frame per hour
  • Playback functions include the ability to split videos at up to four different points, and extract still frames

Pentax K-01 Video: Image Size, Frame Rate, and Encoding

Full HD video. The Pentax K-01 offers three resolution levels for video recording, topping out at a maximum resolution of 1,920 x 1,080 pixels (commonly known as 1080p or Full HD).

The Pentax K-01's CMOS image sensor records high definition video at a maximum resolution of 1,920 x 1,080 pixels--otherwise known as Full HD or 1080p--with a 16:9 aspect ratio. In addition, there are two lower resolution options. The 720p mode is likewise 16:9 aspect, and captures high-def video at 1,280 x 720 pixels. A standard definition mode further downsamples the video stream to produce 640 x 480 (VGA or 480p) movies with a 4:3 aspect ratio. All resolutions offer an adjustable recording rate of 29.97, 25, or 23.976 frames per second. Additionally, in the 720p mode, you can opt for rates of 59.940 or 50 fps. All resolutions and frame rates provide a choice of three quality levels, ranging from one to three stars.

Unless audio capture is disabled, all movies include PCM stereo audio. No spec is provided for the audio sampling rate, though video players report 16-bit audio at a 32 kHz sample rate, with a bit rate of 1,024 Kbps.

The Pentax K-01 is the company's first K-mount camera to ditch inefficient Motion JPEG video compression in favor of MPEG-4 AVC / H.264 compression. This yields significantly smaller file sizes than in older Pentax digital SLRs, but also requires much greater processing power to play back or edit. The more sophisticated encoding used in the H.264 standard requires quite a bit of processor power to pull it apart and put it back together again, so frame-accurate editing of H.264 requires a fast processor and capable editing program.

The table below shows the specs for various video recording options.

Pentax K-01 Video Options
MPEG-4 H.264/AVC Format (.MOV files)
Resolution
Aspect Ratio
Frame Rate (fps)
Approx. Bit Rate
(*** Quality)

1,920 x 1,080

16:9

29.97

22-25 Mbps

25

20-22 Mbps

23.976

18-20 Mbps

1,280 x 720

59.940

22-25 Mbps

50

20-21 Mbps

29.97

14-15 Mbps

25

12-13 Mbps

23.976

11-12 Mbps

640 x 480

4:3

29.97

8-10 Mbps

25

7-9 Mbps

23.976

7-9 Mbps

Continuous movie recording is limited to approximately 25 minutes regardless of the capture settings, and maximum movie file size is 4GB. Pentax doesn't provide a recommended Secure Digital card speed rating to avoid issues with write speeds during video capture, but other manufacturers typically specify at least a Class 6 card, and the same is likely true with the K-01.

Here are some examples of video from the Pentax K-01, showing typical results under daylight and night conditions.

Pentax K-01: Video Samples
1,920 x 1,080
MPEG-4 H.264/AVC, 30 frames per second
Download Original
1,920 x 1,080
MPEG-4 H.264/AVC, 24 frames per second
Download Original
1,280 x 720
MPEG-4 H.264/AVC, 60 frames per second
Download Original
1,280 x 720
MPEG-4 H.264/AVC, 30 frames per second
Download Original
1,280 x 720
MPEG-4 H.264/AVC, 24 frames per second
Download Original
640 x 480
MPEG-4 H.264/AVC, 30 frames per second
Download Original
1,920 x 1,080
MPEG-4 H.264/AVC, 30 frames per second
Download Original
1,920 x 1,080
MPEG-4 H.264/AVC, 24 frames per second
Download Original
1,280 x 720
MPEG-4 H.264/AVC, 60 frames per second
Download Original
1,280 x 720
MPEG-4 H.264/AVC, 30 frames per second
Download Original
1,280 x 720
MPEG-4 H.264/AVC, 24 frames per second
Download Original
640 x 480
MPEG-4 H.264/AVC, 30 frames per second
Download Original



Pentax K-01 Video-Mode Focusing

For a consumer audience used to camcorders that can automatically focus during video capture (and who don't necessarily have the time and patience to learn to pull focus manually), autofocus is typically considered to be a pretty critical feature. The Pentax K-01 offers the ability to autofocus during capture, but only provides for single autofocus operations. You can trigger the autofocus system to operate before recording with either a half-press of the shutter button, or by pressing the AF button. Once recording starts, only the latter operates.

When focusing during video capture, depending on the lens and microphone in use, the audio levels, and the degree of focus adjustment required, AF noise is likely to be picked up on the audio track. With the 40mm XS kit lens and the K-01's internal microphone, AF noise is picked up very clearly as a strong buzzing, and this is a relatively quiet lens, for a screw drive type. SDM and DC-motor lenses will be much quieter. (We didn't have an SDM lens on hand during testing, but the 18-135mm DC travel zoom caused only a very faint buzz with the camera's internal mic.)

You can also manually focus the lens during a recording, and the true manual operation of AF on Pentax's K-mount lenses means you can do this more or less silently, simply by being careful about turning the focus ring. (Some interchangeable-lens cameras we've tested use "fly by wire" focusing, whereby the focus ring only instructs the camera to move the lens elements rather than moving them directly via a mechanical coupling, which can mean that small clicks can be heard on the audio track every time the focus setting is changed, regardless of how slowly you turn the focus ring. With true manual operation of its lenses, the Pentax K-01 doesn't have this problem, although it's possible that a third-party or older Pentax lenses might produce audible noise while their focus was adjusted.)

As we've noted in other SLR reviews, the good news with focusing for video is that you can get surprisingly good depth of field in video mode if the lens is stopped down, thanks to the relatively low resolution of the video image. With a pixel resolution of only 2.1 megapixels even in the Pentax K-01's 1080p Full HD video mode, images that would be unacceptably blurred as 16 megapixel still shots look perfectly fine as video frames. This not only provides greater depth of field at any given aperture, but is also more forgiving of diffraction limiting at very small lens apertures. Diffraction at small apertures means you'd usually want to avoid f/16 or f/22 for still images, but again, the results generally look perfectly fine at video resolutions. Given that you can manually specify the aperture, you may be surprised by how little focus adjustment is required when using a higher ISO sensitivity and slower shutter speed.

Pentax K-01 Video Exposure Control


Pentax K-01: Video Samples
1,920 x 1,080
MPEG-4 H.264/AVC, 30 frames per second, f/4
Download Original
1,920 x 1,080
MPEG-4 H.264/AVC, 30 frames per second, f/29
Download Original

The Pentax K-01 is the first K-mount camera from Pentax that offers fully manual exposure control during shooting, and also offers the Aperture-priority mode that's been found in past Pentax cameras. Unlike some competitors, there's still no Shutter-priority mode. There is, however, an optional auto / manual ISO sensitivity control in the Manual mode, effectively giving you something akin to the Shutter and Aperture Priority (TAv) mode found on Pentax's SLRs. This is great, because it lets you set both exposure variables as you choose, and the camera can adjust the sensitivity automatically to attain the metered exposure.

While the absence of shutter priority is a bit of a shame, this is still a big step forward from the video feature set of past K-mount cameras, which offered only Program or Aperture-priority modes. (The K-01 does, of course, allow Program autoexposure as well.) Interestingly, it's possible to adjust shutter speed, aperture, and ISO sensitivity during video capture, although with its very stiff E-dial, you can't really accomplish much with this feature unless using an external mic or a separate audio capture device. The E-dial makes a fairly strong clicking noise that's picked up by the camera's internal mics, when turned.

Surprisingly, the K-01's upper sensitivity limit is ISO 3,200 equivalent for video capture. We say that's surprising because the tiny Pentax Q, which has a much smaller sensor--albeit backside-illuminated--will roam as high as ISO 6,400 equivalent. In Program and Aperture-priority modes, +/-2.0EV of exposure compensation is available in 0.3 EV steps, and white balance settings also carry over to video mode.

Pentax K-01 In-Camera Image Adjustment for Movies

Catering to those who really want to express their creative side without relying on computers and complicated post-processing, the Pentax K-01 also includes some pre-capture functions that change the look of videos, in some cases quite radically.

The Custom Image effects are the more subtle, changing saturation, toning / hue, high / low-key adjustment, contrast, and sharpness, as well as filter effect for monochrome videos, to yield eleven different user-adjustable presets. These include Bright, Natural, Portrait, Landscape, Vibrant, Radiant, Muted, Bleach Bypass, Reversal Film, Monochrome, and Cross Processing.

The Digital Filter functions bring a more radical difference to the look of videos. For example, you can capture a video that's completely desaturated other than one chosen color, with the look of a film negative, or even with a quasi-fisheye effect added in software. In full, the list of Digital Filter effects in the K-01 includes Extract Color, Toy Camera, Retro, High Contrast, Invert Color, and Color. The Shading filter that's available for still images is not available in video mode. Note that Pentax states movies recorded with digital filters active may have dropped frames, likely due to the processing power required for the effects.

In addition to the filter functions, the Pentax K-01 has an unusual interval movie mode, which captures images for a preset length of time, at a preset interval. You can opt for an interval of 1, 5, 10, or 30 seconds, or of 1, 5, 10, or 30 minutes, and the maximum interval period of one hour. The recording time can run anywhere from four seconds to 99 hours, although the upper limit varies with the selected interval, and so it's not possible to configure an interval movie of more than a few hundred frames. Interval movies play back at an accelerated rate, and don't include sound. The video can be set to start immediately that the shutter button is pressed, or at a predetermined start time. For longer clips, you'll want to use the optional K-AC1202 AC adapter kit.

Pentax K-01 Video: Image Stabilization

Although the Pentax K-01's incorporates a sensor shift-type image stabilization system, this is disabled during video recording, in favor of what Pentax calls 'Movie SR'; in essence, digital image stabilization. Unlike a mechanical system, this allows completely silent operation, but there's no such thing as a free lunch. The system works by creating the video feed from a 'window' of pixels in one particular location on the sensor, with the location of the window moved around the sensor as needed to correct for motion. For this system to function, you need to leave a band of "spare" pixels around the periphery of the sensor, and in the process, the K-01 effectively increases the effective focal length crop significantly. While for telephoto videos this may in fact be desirable, it means that if you want the widest possible field of view, you'll want to disable image stabilization.

Note that even if you disable Movie SR, you don't recoup the wide-angle capabilities. The crop is increased at all times when in movie mode.

Pentax K-01 Video: Audio recording

Audio recording in movies is optional with the Pentax K-01. Audio can be turned on or off using the Sound function located in the Movie menu. Audio is recorded as 16-bit, 32 kHz stereo PCM, with a bit rate of 1,024 Kbps, captured via two microphones near the top of the front panel, with each channel having a separate single-hole grille on either side of the lens mount. External microphones can also be connected via a standard 3.5mm stereo jack, and thankfully this is located beneath a small rubber flap on the left-hand side of the camera's body that is easily reseated, not the large, ungainly and fiddly flap on the other side of the body.

Audio recorded with the camera's internal mic sounded clear, but we do no tests to measure frequency response or sensitivity, so can't comment quantitatively. The level of hiss recorded on audio tracks in relatively quiet environments was somewhat more noticeable than we're accustomed to on competing models, however.

Unlike many of its competitors, the Pentax K-01 provides for manual audio level control. There's a five-step control for the internal microphone, and a ten-step control for external mics. Unfortunately, there's no audio level display, nor any way to monitor audio from the camera body, and so you have no way to know whether you're in the ballpark or not without playing back a recorded video. (And even then, you're going to want to listen on an external device, as the camera's internal speaker is quite weak.) Nor is there a wind cut function, something which may be slightly more of an issue for the K-01's primary target buyers; we noticed a fairly significant amount of wind noise picked up in our own clips, shot in a light breeze.

Audio capture is automatically disabled for interval movies.

Pentax K-01 Movie Recording User Interface

The Pentax K-01's movie mode can be accessed via a separate position on the camera's mode dial. However, unlike past Pentax cameras, there's also a separate, dedicated Video button. In all modes, pressing this button will start / stop movie recording, although there's no way to preview the focal length crop of your movie before capture starts unless you're in Movie mode. Here, not only can you shoot with the dedicated Video button, but you can also start or stop capture with the regular Shutter button. The addition of a movie button, even without a crop preview, is a very positive change. It improves the ability to quickly grab spontaneous, unanticipated video clips, as you don't have to pay attention to changing the camera's operating mode before you can switch from still to video capture, or vice versa.

A few movie-specific setting adjustments are made in a dedicated Movie Menu, which has relatively few options. Other settings applicable to both still and video shooting are made in the still image menus. Options on the Movie Menu for video recording are:


Pentax K-01 Record Mode Menu Movie Options
Top-Level
Selection
Second-Level
Notes
Exposure Setting
- Program (P)
- Aperture-priority (Av)
- Manual (M)
Manual mode allows Auto or manual ISO; other modes use Auto ISO.
Movie Capture Settings
- Recorded pixels
- Framerate
- Quality level
Recording Sound Level
- Internal microphone
- External microphone
Five step control for internal mic; ten step for external mic
Movie SR
- On
- Off
Interval Movie
- Interval
- Recording time
- Start interval
- Start time



Rolling Shutter Artifacts

Pentax K-01: Rolling Shutter Artifacts
1,920 x 1,080
MPEG-4 H.264/AVC, 30 frames per second
Download Original
1,920 x 1,080
MPEG-4 H.264/AVC, 24 frames per second
Download Original
1,280 x 720
MPEG-4 H.264/AVC, 60 frames per second
Download Original
640 x 480
MPEG-4 H.264/AVC, 30 frames per second
Download Original

Essentially every video capable digital SLR/CSC currently on the market exhibits some level of motion-related distortion called rolling shutter artifacts. These are caused because the image data is captured and then read off the chip sequentially by rows, rather than each frame's data being captured all at once. In the case of the Pentax K-01, this means that image data for the last row of a given frame is captured and read out as much as 1/24th second after the data for the top row was captured. The effect on moving objects is like that of a focal plane shutter in an SLR, but more pronounced, because the video frame is read out much more slowly than the slit of a focal plane shutter moves across the sensor.

For a camera that scans video frames vertically (as all do that we're aware of), rolling shutter artifacts will be most noticeable for subjects that are moving rapidly side to side, or when the camera itself is being panned horizontally. Verticals in the scene will appear tilted to the right or left, depending on the direction of camera motion. As an example, consider the case of a camera being panned from left to right, with a flagpole or other vertical object in the middle of the scene when recording for a particular frame begins: If the top of the object was centered horizontally when the first line of the video frame is acquired, by the time the last line of the frame has been captured, the bottom of the object will have shifted to somewhere left of center: As a result, the vertical object would appear to be leaning to the right.

Computer Requirements for Viewing HD Video

A typical computer these days has little trouble dealing with still images, but high-definition video can be another matter. Depending on the file format involved, it can take a pretty beefy computer to handle HD-resolution video playback without stuttering or dropping frames. The MPEG-4 H.264/AVC image compression used by the Pentax K-01 is a fairly compute-intensive format, and its high maximum resolution of 1,920 x 1,080 pixels resolution means there's a lot of data in each frame to deal with. The net result is that you'll need a reasonably recent computer to play the K-01's Full HD video files smoothly, and will want a pretty powerful machine for Full HD video editing.

You can of course view your movies on a high definition TV via the Type-D HDMI output, or a standard-def TV via the combined USB / Video output. Note that neither cable is included in the product bundle, however.

 

Pentax K-01

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