DCRP

Pentax K-7 Review

Using the Pentax K-7

Record Mode

Flip the power switch and the K-7 is ready to start taking pictures almost immediately. The dust reduction cycle runs at startup time, and you'll hear it, believe me.

Autofocus speeds depend on a number of factors, such as what lens you're using, and whether you're using live view. When shooting with the viewfinder and Pentax's two new "WR" lenses (18-55 and 55-200), the camera focused very quickly. Wide-angle focus times were between 0.1 and 0.3 seconds, with telephoto times of about 0.3 - 0.6 seconds. In other words, impressive. Low light focusing was generally very good, with focus times usually staying at a second of less, though I caught the camera going over that on a handful of occasions.

Live view autofocus speeds are a whole different ball of wax. If you're using either of the contrast detect modes, expect a delay of at least one second before the camera locks focus. More often than none, it'll be 2 or 3 seconds. In low light, things can be even slower. For best results, use the phase difference AF, which has the same focus speeds as the viewfinder, with about a second-long delays while the mirror flips down and then back up.

As for shutter lag, there won't be any if you're shooting with the viewfinder, or using contrast detect AF in live view. If you're using phase difference AF in live view, there's about a second of lag due to the mirror flipping action.

Shot-to-shot delays are minimal, regardless of the image quality setting or whether you're using the flash.

There's no way to delete a photo immediately after it is taken -- you must enter playback mode first.

Now, here's a look at the available image size and quality choices on the K-7:

Resolution Quality Approx. file size # images on 4GB SD card (optional)
14M
4672 x 3104
RAW (PEF) 24.7 MB 162
RAW (DNG) 24.8 MB 161
Premium 13.7 MB 292
Best 8.6 MB 467
Better 4.8 MB 826
Good 2.5 MB 1630
10M
3936 x 2624
Premium 9.8 MB 409
Best 6.1 MB 652
Better 3.5 MB 1149
Good 1.8 MB 2234
6M
3072 x 2048
Premium 6.0 MB 666
Best 3.7 MB 1068
Better 2.2 MB 1856
Good 1.1 MB 3549
2M
1728 x 1152
Premium 2.0 MB 2045
Best 1.3 MB 3176
Better 700 KB 5485
Good 400 KB 10057

Now those are some gigantic files! The K-7 supports two RAW formats: Pentax's proprietary PEF, or Adobe's open standard DNG. The advantage of DNG is that you can open the files in a lot more software applications than you can PEF.

The K-7 can take a RAW image alone, or along with a JPEG at the size of your choosing.

While Pentax has spent a lot of time packing the K-7 with innovative new features, one area that did not receive any attention is the menu system. It's the same clunky, antiquated menu system that has been on their cameras (compact and D-SLR) for years now. It gets the job done, but at the end of the day, it could really have used some refinement. The menu is broken down into four tabs, covering recording, playback, setup, and custom settings. Keeping in mind that not all of these options are available in each shooting mode, here's the full list:

Shooting options
  • Exposure mode (P, Sv, Tv, Av, TAv, M, B, X) - select an exposure mode when mode dial set to User
  • File format (JPEG, RAW, RAW+JPEG)
  • Image size (see above chart)
  • Image quality (see above chart)
  • ISO Auto setting
    • Range - can be anywhere from 100 - 6400
    • Parameters (Slow, normal, fast) - how aggressively the camera boosts the ISO
  • D-Range setting
    • Highlight correction (on/off)
    • Shadow correction (Off, low, medium, high)
  • Lens correction
    • Distortion correction (on/off)
    • Lateral chromatic aberration correction (on/off)
  • Program line (Auto, normal, high speed priority, deep DOF priority, shallow DOF priority, MTF priority) - pretty crazy feature that's used in P, Sv, TAv, and M modes
  • Extended bracketing
    • Type (Off, white balance, saturation, hue, high/low key, contrast, sharpness)
    • Amount (Varies)
  • HDR capture (Off, standard, strong)
  • Digital filter (Off, toy camera, retro, high contrast, extract color, soft, star burst, fisheye, custom filter)
  • Multi-exposure
    • Number of shots (2 - 9)
    • Auto EV adjustment (on/off)
  • Interval shooting
    • Interval (00:00:01 - 24:00:00)
    • Number of shots (1 - 99)
    • Start interval (Now, start time)
    • Set time - select when interval shooting starts
  • Composition adjust - see below
  • Movie settings
    • Size (1536 x 1024, 1280 x 720, 640 x 416)
    • Quality (Best, better, good)
    • Sound (on/off)
    • Movie aperture control (Auto, fixed)
    • Shake reduction (on/off)
  • Live view settings
    • Info overlay (on/off)
    • Show grid (on/off)
    • Histogram (on/off)
    • Bright/dark area (on/off)
    • Autofocus mode (Contrast detect w/face detection, contrast detect, phase difference) - described this earlier
  • Status screen (on/off) - info display on LCD when shooting with viewfinder
  • Digital preview (on/off) - you can take a test shot by using the DOF preview switch
  • Instant review
    • Display time (Off, 1, 3, 5 secs)
    • Histogram (on/off)
    • Bright/dark area (on/off)
  • Electronic level (on/off) - described earlier
  • Horizon correction (on/off) - see below
  • Color space (sRGB, Adobe RGB)
  • RAW file format (PEF, DNG)
  • RAW button
    • Cancel after one shot (on/off)
    • Define function - for three presses
  • Memory - which settings are stored when the camera is powered off
  • User - save current camera settings to user spot on mode dial; you can also review them here
  • Shake reduction (on/off)
  • Input focal length - you may need to do this to make old Pentax lenses support shake reduction

Playback options

  • Slideshow
  • Display method
    • Bright/dark area (on/off)
    • Quick zoom (on/off)
  • Delete all

Setup options
  • Language
  • Date adjustment
    • Date format
    • Date
    • Time
  • World time - select another city for when you're traveling
  • Text size (Standard, large)
  • Guide display (Off, 3, 10, 30 secs) - how long info screens stay on when you turn the camera on or change shooting modes
  • Beep
    • Setting (on/off)
    • In-focus (on/off)
    • AE-Lock (on/off)
    • RAW button (on/off)
    • Self-timer (on/off)
    • Remote control (on/off)
  • LCD brightness level (-7 to +7)
  • LCD color tuning - adjust the color balance of the screen in the green/magenta and blue/amber directions
  • Video out (NTSC, PAL)
  • HDMI out (Auto, 1080i, 720p, 480p)
  • USB connection (MSC, PTP)
  • Folder name (Date, PENTX)
  • File name - you can adjust the first 3-4 letters of the file name
  • Copyright information - you can embed the photographer name and copyright holder into the EXIF headers of a photo
    • Embed copyright data (on/off)
    • Photographer (enter name)
    • Copyright holder (enter name)
  • Auto power off (Off, 1, 3, 5, 10, 30 mins)
  • Select battery (Auto select, body first, grip first) - which battery is used first when the grip is attached
  • Reset - back to defaults
Custom options
  1. EV steps (1/3, 1/2 EV)
  2. Sensitivity steps (1 EV, same as EV steps)
  3. Expanded sensitivity (on/off) - opens up ISO 6400
  4. Meter operating time (3, 10, 30 secs)
  5. AE-Lock with AF locked (on/off)
  6. Link AE to AF Point (on/off) - for multi-segment metering only
  7. One-push bracketing (on/off) - whether the bracketing series requires only one push of the shutter release
  8. Auto bracketing order (0/-/+, -/0/+, +/0/-, 0/+/-)
  9. Auto EV compensation (on/off) - whether the exposure compensation is automatically used to get a proper exposure
  10. WB when using flash (Auto, unchanged, flash)
  11. WB adjustable range (Auto, fixed) - whether camera tweaks white balance presets automatically
  12. WB in tungsten light (Subtle correction, strong correction) - whether the "warm" tone of tungsten light is kept or removed
  13. AF button function (Enable AF, cancel AF) - the second option is for when you want to quickly manual focus
  14. AF with press halfway (on/off)
  15. Superimposed AF area (on/off) - whether focus point is illuminated in the viewfinder
  16. AF with remote control (on/off)
  17. Remote control in bulb (Mode 1, 2) - whether you press the remote to start and stop a bulb exposure, or have to hold it down
  18. Slow shutter speed NR (on/off)
  19. High ISO noise reduction (Off, low, medium, high)
  20. High ISO NR start level (ISO 200, 400, 800, 1600) - when this kicks in
  21. Color temperature steps (Kelvin, mired)
  22. e-dial in Program mode (Tv/Av, Av/Tv, exp comp/program shift, program shift/exp comp, off/off) - define what the front and rear command dials do
  23. e-dial in Sv mode (Off/ISO, program shift/ISO, ISO/program shift, exp comp/ISO, ISO/exp comp)
  24. e-dial in Tv mode (Tv/off, Tv/exp comp, exp comp/Tv, Tv/ISO, ISO/Tv)
  25. e-dial in Av mode (Off/Av, exp comp/Av, Av/exp comp, ISO/Av, Av/ISO)
  26. e-dial in TAv & M modes (Tv/Av, Av/Tv)
  27. e-dial in B & X modes (Off/Av, Av/off, ISO/Av, Av/ISO)
  28. Green button in TAv & M modes (Program line, Tv shift, Av shift, off)
  29. LCD panel illumination (on/off)
  30. Release while charging flash (on/off) - whether you can take a photo while the flash is charging
  31. Flash in wireless mode (on/off) - whether the flash fires as the master or the controller when in wireless
  32. mode
  33. AF assist light (on/off)
  34. Save rotation info (on/off)
  35. Auto image rotation (on/off)
  36. Catch-in focus (on/off) - when on, camera will take a photo with subject enters focus zone
  37. Operation when AF point set to "SEL" (Calling function preference, select AF point preference) - this was added in the 1.01 firmware update
  38. AF adjustment - lets you fine-tune focus on your lenses, either one at a time, or for all of them
  39. Using aperture ring (Prohibited, permitted) - for older lenses
  40. Reset Custom functions

That is quite possibly the longest list of menu items I've typed up in years! I can't cover everything up there, but I will describe the most interesting and important features below, with examples whenever possible.

Let's start with the two dynamic range settings: highlight correction and shadow correction. Highlight correction is something that is turned on or off (it's off by default). It boosts the ISO to a minimum of 200, and then does its stuff. Shadow correction can be turned off (which is the default) or set to low, medium, or high. Here are examples of both:

Highlight correction off
View Full Size Image
Highlight correction on
View Full Size Image

I'm the first to admit that this example isn't perfect, since the composition is off slightly (I did not have my tripod at the time). Still, since it's a great example of this feature, and further testing at more boring locations confirmed that highlight correction does work. You can see that highlight correction brings back details in the floor, on the column and arches on the right, and the sky and trees in the background. You can also see that there's a bit more noise in the shadows, as well.

Shadow correction off
View Full Size Image
Shadow correction low
View Full Size Image
Shadow correction med
View Full Size Image
Shadow correction high
View Full Size Image

In this example (taken in a similar hallway at another local college) you can see what the various shadow correction settings do. It definitely works, though it's on the subtle side. I should add that both highlight and shadow compensation can be adjusted when you're working with RAW images in Pentax Digital Camera Utility.

Lens correction is another neat trick the K-7 can pull off. Some cameras, notably from Panasonic, already apply distortion and chromatic aberration correction to photos you're taking, and those are both optional here. You can correct for lens distortion (both barrel and pincushion) as well as lateral chromatic aberration. You'll find an example of the barrel distortion correction in action a little further down the page, in the photo test section. As for the chromatic aberration correction, I performed a test that produced some pretty nasty fringing, and I saw little to no difference with the correction feature turned on. Do note that both distortion and lateral CA correction require some extra processing time after you take a photo. In addition, these features only work with modern DA, DA *, and DA L lenses.


Oh, my

The K-7 can bracket for more things than any camera I've ever tested. I already told you about exposure bracketing -- here's what else you can bracket for:

  • White balance (Blue/Amber ±1, 2, 3, 4 or Green/Magenta ±1, 2, 3, 4)
  • Saturation (±1, 2, 3, 4)
  • Hue (±1, 2, 3, 4)
  • High/low key adjustment (±1, 2, 3, 4) - a fancy way of saying brightness
  • Contrast (±1, 2, 3, 4)
  • Sharpness (±1, 2, 3, 4)

In case you're wondering, the K-7 can bracket for one of those plus exposure at the same time!

The HDR Capture feature takes three exposures in rapid succession and combines them into a single image with high dynamic range. One image is underexposed, another is overexposed, and the third is of normal exposure. Since the images need to be precisely aligned, a tripod is essentially required for this feature. You can apply "standard" or "strong" HDR enhancement to a photo. Here's an example of both settings:

HDR off
View Full Size Image
HDR standard
View Full Size Image
HDR strong
View Full Size Image

You can see why I picked this scene! I wanted the camera to pay the most attention to the bright white church in the background, and that's exactly what it did with the HDR feature turned off. As a result, the statue on the left and tree on the right are pretty dark. When you use standard HDR, the triple exposure combo brightens things up considerably, making the photo a lot more appealing. The "strong" setting gives the scene a washed out, almost ethereal quality, though perhaps that's the point of it. Do note that image stabilization and RAW image supports are not available when using HDR capture, and the camera takes several seconds to process a photo after you've taken it.

Two other features that involve multiple exposures are worth a brief mention. The multi-exposure feature lets you combine anywhere from two to nine (!) exposures into a single image. You can choose to have the camera adjust the exposure (gain) automatically, if you'd like. The interval shooting (AKA time-lapse) does just as it sounds -- you can take up to 99 photos at a set interval (could be a minute, hour, or day). The AC adapter is required if the interval between shots is longer than a few minutes.


Image compensation feature description courtesy of Pentax

The composition adjustment feature is unique to the K-7. By using the sensor-shift mechanism, you can make precise adjustments to the composition of your photos. The sensor can shift 1 mm along the X/Y axis, and it can even rotate up to 1° in either direction. This feature comes in handy when you have the K-7 on a tripod and want to recompose the shot slightly without having to move the camera.

A related feature is called horizon correction. If you're like me and can't take a level shot if their life depending on it, listen up. The K-7 will automatically level a crooked photo for you, up to 1° with Shake Reduction on, or 2° with it turned off.

That's more than enough menu talk -- let's move on to photo quality now. With the exception of the night shot, everything you see below was taken with the new Pentax F3.5-5.6, 18 - 55 mm WR (weather resistant) lens.

The K-7 did a very nice job with our macro test subject. Colors are nice and vivid (not to mention accurate), and sharpness is just how I like it. I don't see any signs of noise, and I sure as heck wouldn't expect to.

The minimum focus distance to your subject depends on what lens you're using. For the new 18-55 WR lens, it's 25 cm. If you think you'll be doing a lot of macro photography, Pentax has three lenses for just that purpose, ranging from 35 mm to 100 mm.

The night shot, taken with the new 55-200 mm WR lens, wasn't quite as impressive. The main issues I have are that the photo is fairly soft, and that purple fringing levels are moderate in places. Bringing in enough light wasn't a problem, as you'd expect from a camera with manual exposure controls. I don't see anything resembling noise or noise reduction, thankfully.

Alright, let's use that same scene to see how the K-7 performs at its various ISO settings. I'll start with the low setting (ISO 100) and work my way up to the max of ISO 6400 (which you must activate via a custom function).


ISO 100

ISO 200

ISO 400


ISO 800


ISO 1600

ISO 3200

ISO 6400

There's not much to distinguish the ISO 100 and 200 shots. At ISO 400 you see a slight amount of grainy noise, but that won't hold you back. This noise becomes more obvious at ISO 800, though making a midsize or perhaps even a large print isn't out of the question here. That trend continues at ISO 1600 -- with details starting to disappear at this point. There's pretty significant detail loss at ISO 3200 and especially at 6400, so these are two settings that you'll probably want to avoid in low light situations.

Can you improve image quality by shooting RAW instead of JPEG? See for yourself:

ISO 800

JPEG, straight out of the camera

RAW -> JPEG conversion (ACR)

RAW -> JPEG conversion + NeatImage + Unsharp Mask
 
ISO 1600

JPEG, straight out of the camera

RAW -> JPEG conversion (ACR)

RAW -> JPEG conversion + NeatImage + Unsharp Mask

In both cases, you can see that there's a noticeable (though not dramatic) improvement when shooting RAW. I'll have more on this subject in a moment when we get to the studio ISO test.

Night photos and discussion were updated on 10/1/09

Redeye is already unlikely on a digital SLR, since its flash is far away from the lens. To further reduce the risk of this annoyance, the K-7 can fire the flash before the photo is actually taken. Using this method, I got a redeye-free photo, as you can see above.


Distortion correction off


Distortion correction on

The first distortion test chart you see above was taken with the 18 - 55 mm lens with the camera at its default settings. As you can see, there's some noticeable distortion, plus some vignetting as well (which wasn't a problem in my real world photos). When you turn on the distortion correction feature, things look a lot better -- look at how much straighter the lines are now. I did not find corner blurring to be a problem with the 18-55 lens.

Now it's time for our normal lighting ISO test, which is taken in our studio. Since the lighting never changes, this test can be compared to other cameras I've reviewed over the years. While the crops below give you a quick idea as to the amount of noise at each ISO sensitivity, viewing the full size images is always a good idea. And with that, here we go:


ISO 100

ISO 200

ISO 400


ISO 800


ISO 1600

ISO 3200

ISO 6400

The images from the K-7 are super clean all the way to ISO 800. At that point, you start to see a bit of noise, but a large print is still a piece of cake. There's still quite a bit of detail left at ISO 1600, and ISO 3200 is still usable for small or midsize prints -- especially if you shoot RAW. ISO 6400 is probably best saved for desperation only.

Here's that other RAW comparison I promised you a bit earlier:

ISO 1600

JPEG, straight out of the camera

RAW -> JPEG conversion (ACR)

RAW -> JPEG conversion + NeatImage + Unsharp Mask
 
ISO 3200

JPEG, straight out of the camera

RAW -> JPEG conversion (ACR)
2
RAW -> JPEG conversion + NeatImage + Unsharp Mask

While the JPEGs produced by the K-7 are pretty good, you can squeeze a bit more detail out of the camera by shooting RAW, as you can see.

Overall, the K-7 produces very nice photos, though I found that I really had to keep an eye on the exposure in order to get the best results. That's because the K-7 seems to underexpose fairly often, usually by 1/3 - 2/3 stop. Since I don't like having to go back to my photo spots and reshoot all my test photos, I bracketed all the photos I took with the K-7, and reviewed histograms frequently. The camera has really nice color -- it really "pops" out at you. Image sharpness is one of those things that is lens-dependant, and with the two (relatively inexpensive) lenses I used, I found things to be on the soft side. If you agree, you can increase the in-camera sharpening by using the Custom Image feature. The K-7 has a lot of pixels packed onto its APS-C sensor, and I did some some noise and noise reduction artifacting if I really inspected the images at 100% on my monitor. That said, both noise and noise reduction don't start to negatively affect image quality until you get to ISO 800. Purple fringing is also lens-dependent (though the sensor plays into it as well), and this problem did crop up on several occasions. You can try toying with the lateral chromatic aberration correction feature, though it didn't seem to make a huge difference. Better quality lenses would probably reduce that issue as well.

Don't just take my words as gospel, though. Have a look at our extensive photo gallery, and see for yourself!

Movie Mode

The K-7 is the first Pentax digital SLR to have a movie mode. The camera can record at three different resolutions: 1536 x 1024, 1280 x 720, and 640 x 416. Two of the three resolutions there are non-standard, and I'm not sure why Pentax chose them. Anyhow, you can record video with monaural sound (stereo sound requires an optional mic) until you hit the 4GB file size limit, or 25 minutes elapse. At the two highest resolutions, you'll hit the file size limit in 7.5 and 9.5 minutes, respectively. You can get longer recording times by lowering the quality (increasing the compression).

When you're recording movies, the image stabilizer is active. You can zoom in and out to your heart's content, the camera will not be continuously focusing. Thus, you'll need to manually focus if you use the zoom, or if you subject moves closer or further away from you.

Movie mode is a point-and-shoot experience. You can have the aperture remain the same throughout recording, or it can adjust as needed to maintain proper exposure (do note that this noise may be picked up by the microphone). Speaking of sound, I found that the K-7 could really use a wind cut filter, as its microphone picks up wind noise quite easily.

Movies are saved in AVI format, using the M-JPEG codec. File sizes are enormous: a 10 second clip can easily exceed 60MB.

Here are a few sample movies for you. For each, I'm offering the original, huge file, plus a downsized version for easier web viewing. First, here's a clip taken at the highest resolution. The quality is just fair.


View original movie (47.3 MB, 1536 x 1024, 30 fps, AVI/M-JPEG)
View recompressed movie (5.0 MB, 1536 x 1024, 30 fps, QuickTime/H.264)

Now, here are a pair of 1280 x 720 movies. The first one has a lot of wind noise but shows off the video quality. The second one is quiet, but less exciting (unless you like geese). These videos definitely look better than the one above.


View original movie (110.6 MB, 1280 x 720, 30 fps, AVI/M-JPEG)
View recompressed movie (11.1 MB, 1280 x 720, 30 fps, QuickTime/H.264)


View original movie (103.0 MB, 1280 x 720, 30 fps, AVI/M-JPEG)
View recompressed movie (10.9 MB, 1280 x 720, 30 fps, QuickTime/H.264)

Playback Mode

When I first glanced at the K-7's playback menu I thought "that's it?". Turns out that the camera has quite a few playback features, they're just not where you expect them. The basic features are slideshows, image protection, DPOF print marking, thumbnail view, and zoom and scroll. This last feature lets you enlarge an image by as much as 16X, and then move around. This can be very helpful for checking that your subject is properly focused, that eyes are open, etc.

Most of the other playback bells and whistles can be reached by pressing down on the four-way controller. There you'll find tools for:

  • Image rotation
  • Digital filters (Toy camera, retro, high contrast, extract color, water color, pastel, miniature, base parameter adjustment [brightness, saturation, etc], monochrome [with filters], color filters, soft, star burst, fisheye, slim, HDR, custom)
  • Image resizing
  • Image cropping
  • Slideshows
  • Save image for custom WB
  • RAW processing
  • Index print
  • Side-by-side
  • Image protect
  • DPOF print marking
RAW editing Side-by-side image comparison

Two of those features are worth some further discussion. The RAW processing option lets you take a RAW image, adjust its properties, and save the result as a JPEG or TIFF file. You can adjust the image type, quality, and color space, the Custom Image setting, white balance, sensitivity, high ISO noise reduction, plus shadow, highlight, and distortion correction. The side-by-side feature lets you look at two photos, with the ability to maintain the zoom and position for both.

One thing you won't find on the K-7 is any kind of movie editing tool. Even a trimming tool would've been a nice touch.

The K-7 can display plenty of information about your photos, including your choice of histograms. The camera moves from one photo to the next without delay.

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