Pentax Q Video

Pentax Q Video Recording

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

Overall, we found the Pentax Q's video feature set a little limited compared to many of its competitors, especially due to the lack of autofocus capability. If you're willing to live within those limitations though, you can certainly achieve useful results with the Pentax Q, especially when considering its size relative to other interchangeable-lens cameras.

Pentax Q 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
• 29.97 frames per second at all resolutions
• Autofocus only possible before movie capture starts
• Manual focus possible during movie capture, but High Performance-series lenses are fly-by-wire and so may still induce AF motor drive noise
• Much greater depth of field than with a large-sensor camera, so lack of autofocus less of an issue
• Recording can start or stop with optional infrared remote control
• Auto or full manual exposure, set before recording starts; no priority-mode exposure
• 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
• Audio capture can 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 Q Video: Image Size, Frame Rate, and Encoding

The Pentax Q'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 provide a fixed recording rate of 29.97 frames per second.

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 48 kHz sample rate.

The Pentax Q is the company's first interchangeable-lens 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 cameras, 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.

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 Q.

The Pentax Q seems particularly prone to something we've occasionally noticed on competing models: there's a noticeable delay of a little under a second between pressing the shutter button, and video capture starting. There's also a corresponding issue at the end of videos, which are cut off about a second or so before the point where the shutter button is pressed. Making things worse, the Q's audio capture doesn't seem to start for a second or so after the recording begins. If you want to be sure not to cut off something of importance, you want to bookend the action with some extra video at both ends, which you can crop back off in post-processing.

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

Pentax Q 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 Q lacks the ability to autofocus during capture, but its design mitigates this to some extent, making it less of an issue than it would be for most other interchangeable-lens cameras. The reason? It's smaller-than-most image sensor, which acts as something of a double-edged sword. For still imaging, it makes it harder to achieve a narrow depth of field effect, with buttery-smooth background bokeh. For video, though, that wide depth of field means that autofocus isn't as critical as it might otherwise be. It also means that as your subject moves around, you don't have to be spot-on with your focus adjustments. All you must do is keep it in the ballpark.

There's a slight gotcha, though. While all Q-mount lenses to date include a manual focus ring, not all have a direct mechanical connection to the focus ring. Unique-series lenses all have a mechanical connection, but with a very short focus throw that makes it hard to dial in a very slight adjustment. The High Performance-series lenses, though, are all fly-by-wire, and that can translate to focus motor drive noise being picked up by the camera's microphone, disturbing the audio portion of your clips. As you turn the focus ring, there's no direct mechanical connection; instead, you're simply commanding the focus motors in the lens to make the adjustments for you.

Pentax Q Video Exposure Control

The Pentax Q is the first camera from Pentax that offers fully manual exposure control during shooting, but unfortunately, it drops the Aperture-priority mode that's been found in past Pentax cameras. Hence you're now faced with an all-or-nothing proposition: let the camera determine all the exposure variables, or do all the work yourself. That's a bit of a shame, because while we're thrilled to see the addition of fully manual exposure for the folks who want the fullest possible control over the look of their videos, we have a feeling many amateur videographers would prefer to stay inside their comfort zone and control only one exposure variable to achieve a given effect, while letting the camera handle the rest for a correct exposure. Still, given the wide depth of field of the Q, the aperture-priority mode might not have proven as useful as it does on the company's large-sensor cameras.

As well as direct control of the shutter speed and aperture, it's also possible to manually control the sensitivity which the Pentax Q will use up to a maximum of ISO 6,400 equivalent. In Programmed mode, 3.0EV of exposure compensation is available in 0.3 EV steps, and white balance settings also carry over to video mode.

Pentax Q 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 Q 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 Q includes Toy Camera, High Contrast, Shading, Slim, HDR, Invert Color, Extract Color, Color, Water Color, Posterization, and Fish-eye. 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 Q 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 five 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-AC115 AC adapter kit.

Pentax Q Video: Image Stabilization

Although the Pentax Q'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, you effectively increase the effective focal length crop slightly. 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.

Pentax Q Video: Audio recording

Audio recording in movies is optional with the Pentax Q. Audio can be turned on or off using the Sound function located in the Movie menu. Audio is recorded as 48kHz, 16-bit PCM stereo, captured via two microphones near the base of the camera's front face, with each channel having a separate single-hole grille on either side of the lens mount. No provision is provided for an external microphone.

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. More troublesome is that the Pentax Q noticeably cuts off audio at the start of video capture. If you're planning to add a voiceover at capture time, you need to leave a significant pause on the order of a second or more, to be sure the first words aren't cut off. (Note that this brief silence is in addition to the fact that the Q seems to crop both ends of videos by a second or so, capturing a couple of seconds less in total than was indicated by the times the shutter button was pressed.

As with most of its competitors, the Pentax Q doesn't have any provision for manual audio level control. Nor is there a wind cut function, something which may be slightly more of an issue for the Q'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 Q Movie Recording User Interface

The Pentax Q's movie mode is accessed via a separate position on the camera's mode dial. Likely due to the space constraints of the Q's tiny body, there's no separate control button to start/stop movie recording. Instead, pressing the shutter button begins recording, and pressing it again stops it. Many interchangeable-lens cameras these days have a dedicated button to start/stop movie recording, and while newcomers will likely find the Q's use of the shutter button more intuitive, it draws a very clear dividing line between the camera's still imaging and movie capture functionality. This takes away somewhat from the ability to quickly grab spontaneous, unanticipated video clips, as you 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:

Rolling Shutter Artifacts

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 Q, this means that image data for the last row of a given frame is captured and read out as much as 1/30th 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 Q 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 Q'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.