Pentax K-01: Performance

Performance

It's got a DSLR-class sensor, a DSLR-class price tag, near-DSLR size and weight and can use lenses originally meant for SLR and DSLR cameras. Is the K-01 just a DSLR without the pentaprism?

Shooting Performance
While Pentax installed DSLR-class hardware in the K-01 they left out the DSLR-class start up time. The K-01 displayed a shooting screen about 1.25 seconds after start up and I was able to get off a first shot in about 2.25 seconds. Slow by DSLR standards but fairly typical for the mirrorless, interchangeable lens class. Startup of the K-01 consists of a double "clunking" sound accompanied by a vibration that can be felt through the camera body - a bit disconcerting the first time it happens to you. Turns out this is the sensor cleaning operation which is on by default for both power up and power down. This action can be disabled via internal menu, which results in only a single "clunk," no vibration and a marginally faster display time for the shooting screen.

First shot times remained about the same so K-01 owners can leave sensor cleaning enabled without losing any start up performance, secure in the knowledge the K-01 is not trying to shake itself apart. Single shot to shot times ran about 1.5 seconds.

When I first started shooting the camera, the K-01 steadfastly refused to produce the "up to 6 fps" continuous high-speed shooting rate claimed by Pentax. I tried changing the image quality and resolution of the JPEGs (the high-speed shooting rate is not available with RAW files), all the way down to 5 megapixels and "good" quality with no success - the K-01 would rattle off about 3 fps and then slow. I reset the camera to default specifications via internal menu and the K-01 cranked out the advertised 6 fps figure, and managed 9 shots before the buffer slowed things down - at full resolution and best image quality. Focus is established for the first shot of the sequence and then used for all subsequent shots in any particular burst. Write times for these nine shot bursts were fairly quick - about 2 seconds to clear the buffer using a 16GB 95MB/sec (633x) UHS-1 memory card.

On page one of the shooting menu there is a "lens correction" submenu that offers distortion correction and lateral chromatic aberration adjustment settings and it's the distortion correction setting that puts the brakes on the continuous high-speed shooting performance of the K-01. So now the question becomes whether we need to enable distortion correction (both lens correction items are disabled by default) with the kit lens. We'll have the answer to that question in the lens performance section of the review

Auto focus acquisition times and performance with the K-01 were disappointing - we measured 0.62 seconds in our studio test. In the field, even in good lighting conditions, the camera was a bit slow to acquire focus and on a disappointingly high number of shots would hunt back and forth before establishing focus. Face detection is the default setting for the autofocus method when the camera is in automatic shooting mode; there are also tracking, select and spot AF options available.

Unfortunately, AF method is one of those few settings unavailable folks shooting in full auto mode - you have to switch into the manual modes to take advantage of the alternate AF options and I found  spot seemed to give the best performance in terms of AF acquisition times and accuracy. It was an easier matter to establish and hold focus on the main subject with a half push of the shutter button and then recompose the frame as needed before initiating capture by completing the full push.

AF Acquisition (press-to-capture, no pre-focus)

Continuous Shooting

*Note: Continuous shooting framerates are based on the camera's fastest full-resolution JPEG continuous shooting mode, using the fastest media type available (300x CF, SDHC, etc.). "Frames" notes the number of captures recorded per burst before the camera stops/slows to clear the buffer.

Shutter lag came in at an equally disappointing 0.06 seconds - as site editor Allison Johnson remarked, "First camera in a while where I found any significant shutter lag." Truth be told, the K-01 shutter doesn't feel that slow but my first impression on picking up the camera was that the shutter was a bit pokey. After shooting a bit for the First Look review my impression was that shutter lag is minimal and that's still my feeling, but I did pull out my Nikon V1 and it does seem a bit quicker than the K-01.

The camera features in-body shake reduction (stabilization) which is enabled by default and may be disabled by the user. Shake reduction is available with any Pentax lens that is compatible with the camera, but users are cautioned that they must set the focal length of any lens for which focal length information cannot be automatically obtained - if the camera doesn't recognize the lens you need to tell it the focal length manually. In addition to enabling or disabling shake reduction, the user has the option to select mode 1 or mode 2 operation: mode 1 activates shake reduction at the moment of capture only and uses less power but does not provide live preview; mode 2 activates shake reduction for capture during live view, uses more power and enables preview.

The K-01 built-in flash has a guide number of 12 meters at ISO 100, which translates into an approximately 14 foot maximum range with the kit lens; higher ISO settings will naturally increase this distance. The flash head will deploy on its own when the camera is set for auto flash modes; manual deployment is required for all others. In addition to the automatic flash setting there is auto flash with redeye reduction, manual flash, manual flash with redeye reduction, slow speed sync, slow speed sync with red eye reduction, and trailing curtain sync flash options. Flash recycle times were quick with the K-01, averaging a bit less than 3 seconds with full discharges. The camera displays a handy red flashing lightning bolt on the upper left of the monitor while the flash is recycling; with the flash deployed the camera will not allow another capture until the flash is fully recharged.

The camera has a bracketing feature that will capture three images with either .3 or .5 EV gaps in exposure levels. There is a dynamic range setting that is enabled by default and features both highlight and shadow correction. Both of these corrections may be disabled by the user, simply turned on or left in the "auto" default setting. High ISO and slow shutter speed noise reduction (NR) are both enabled by default as "auto" settings. High ISO NR may also be user set for low, medium, high or custom settings as well as disabled altogether. Slow shutter speed NR may be set on or off in addition to the default setting.
Battery life for the K-01 is listed as 540 images (500 images with 50% flash usage), so a spare might not be a bad idea for all-day shooting sessions.

Finally, let's talk about the lack of the viewfinder on the K-01. In my opinion Pentax has missed the boat on this one - the K-01 lens mount is an open invitation to Pentax legacy glass owners to add this body to their collection and for everyone else who picks up the K-01 to add Pentax lenses to their collection and expand the shooting envelope with their new camera. The only problem is all lenses are not created equal and you'll be hard-pressed to find another Pentax lens that is as slim and light as the 40mm pancake kit lens.

Folks mounting larger and longer lenses on their K-01 will find the balance and handling are going to differ and trying to hold the camera steady with two hands held away from the body is a much more difficult proposition than a camera anchored by two hands with a third contact point between the eye, forehead, and viewfinder offering additional stability. If you plan to shoot exclusively with your K-01 on a tripod weight and balance issues disappear. For all the rest of us, they're a concern. You've got a big, mirrorless interchangeable lens camera already Pentax, incorporating a viewfinder into the K-01 shouldn't have been that difficult an exercise.

Lens Performance
The 40mm pancake lens designed for the K-01 is light and compact, so much so that you don't really notice a difference in handling with or without the lens on the body. The lens appears to have just the slightest bit of barrel distortion, but you have to look pretty hard as it's not readily apparent even with subjects such as ocean horizons. And there lies the answer to the question posed earlier about whether or not to enable distortion correction with the kit lens - I'm perfectly happy to live with the slight and barely noticeable distortion in order to retain the high-speed shooting capability of the camera, particularly since the camera doesn't possess a continuous auto focus capability in either high or low speed continuous shooting modes anyway.

The lens is fairly sharp across the entire frame, with a bit of softness in the corners that is not apparent, even under close scrutiny, in many shots. Chromatic aberration (purple fringing) was present in some high contrast boundary areas, but the effect is relatively benign and hard to notice except under extreme magnifications - 300 and 400%. The second option of the "lens correction" menu referred to back in the shooting performance section is "lateral chromatic aberration." I didn't see much change in images taken with the kit lens with this feature enabled or disabled. The user's manual warns that lens corrections in the K-01 can only be made when using DA, DA L, D FA or some FA lenses and that in any event the effects of lens correction function may be barely noticeable in some cases due to the shooting conditions or other factors.

Close focus distance for the lens is about 15.75 inches and combined with the 60mm focal length in 35mm equivalents does not make for a particularly strong macro shooting performance. Pentax will be happy to sell you a dedicated macro lens if you want to get really close up with tiny subjects.

Video Quality
Video quality in the K-01 is quite good and may be initiated with the mode dial in any setting with a single push of the red button. The camera does a little better if you're able to establish focus initially with a half push of the shutter button before initiating video capture, but the continuous auto focus function and video does a pretty good job of catching up fairly quickly as subject distances change during the course of a video capture. Users have the choice of program auto, aperture priority or manual control for video exposure calculation. The stereo microphones proved susceptible to wind noise however the camera is not equipped with a wind cut feature.

Because it utilizes a CMOS sensor, rolling shutter effect is a consideration for the K-01, but the camera does a pretty good job of dealing with this effect. Rolling shutter is only apparent under extremely rapid pans ? pan speeds well beyond what would ordinarily be encountered or employed by the typical user.

Image Quality
Default image quality out of the K-01 was quite good as to color rendition and sharpness - here's a shot of Kiwi being inspected by an Anna's hummingbird and another of one of the carnival rides at the San Diego County fair. Very accurate color renditions in both cases.

Somewhat surprisingly to me, the default color mode for the K-01 is "bright"; the second choice on the palette, "natural," offers a virtually identical histogram and either one of these is a good choice for an accurate reproduction of color.

Bright

Natural

There are a total of 11 color modes offered in the "custom image" menu - here are the "radiant" and "muted" variants as well.

Radiant

Muted

All of the 11 color modes offered in the custom image menu may be further user modified for saturation, hue, high and low key adjustment, contrast, and sharpness should the default settings not be to your liking.

The K-01 also offers a "digital filter" menu with six choices: extract color, toy camera, retro, high contrast, shading, invert color, and color. The color submenu allows the user to select from red, magenta, blue, cyan, green, or yellow filter effects for application to image captures. Here's a look at the invert color filter applied to the Oceanside pier.

I used auto white balance for all K-01 images and it worked quite well across a range of light including incandescent, cloudy, direct sun, flash and open shade. In addition to auto there are daylight shade, cloudy, fluorescent, tungsten, flash, CTE (color temperature enhancement) presets along with a manual mode. White balance fine adjustment is available in all modes.

Auto White Balance, 5500k fluorescent light

Multi segment is the default exposure metering method and was used for all images captured by the K-01 for this review. It did a fairly good job overall in most lighting conditions but as with many cameras had a tendency to lose some highlights in certain high contrast scenes. There are center weighted and spot metering options available as well, in all three methods are available in fully automatic and manual modes.

A newly designed sensor and processing engine along with a relatively modest 16 megapixel resolution on an APS-C sized sensor would suggest the K-01 should produce some fairly decent noise performance in higher ISO images. The K-01 did not disappoint - high ISO performance looks to my eye to be on a par or perhaps a bit better with the best APS-C sensor cameras that I have reviewed to date, be they DSLR or mirrorless interchangeable compacts.

Shots at 100 through 400 ISO are virtually identical, with 800 and 1600 not far behind. For a big print you'd obviously like to shoot and print at the lowest ISO possible, but if I had to I would make large prints out of a 1600 ISO shot out of the K-01. ISO 3200 and 6400 showed a bit more noise and loss of detail but are still pretty clean given their sensitivity.

ISO 100	ISO 100, 100% crop
ISO 200	ISO 200, 100% crop
ISO 400	ISO 400, 100% crop
ISO 800	ISO 800, 100% crop
ISO 1600	ISO 1600, 100% crop
ISO 3200	ISO 3200, 100% crop
ISO 6400	ISO 6400, 100% crop
ISO 12800	ISO 12800, 100% crop

ISO 12800 shows probably the greatest drop-off in any single step change in the native ISO range - if you pixel peep on all the images and looked at nothing other than the "a world of luxury and innovation" script below the Monteverde name on the inside of the pen box, you'll see that 12800 is the ISO setting where this fine print finally becomes illegible.

The K-01 has an expanded sensitivity setting in the custom settings menu which is off by default but may be enabled by the user and permits an ISO setting of 25600. We only shot the native ISO range for the studio shots but here's a look at 3200 through 25600 just to give you an idea what this additional step brings to the table.

ISO 3200	ISO 6400
ISO 12800	ISO 25600

Additional Sample Images