The Good
The Bad
The Bottom Line
Editors' note: The competitive landscape for this camera has changed since our review, and we've updated the text and ratings to reflect that. After looking at subsequent reviews we've decided that we were overly forgiving of the color inaccuracy problems in the K20D's photos; given the increase in the number of competitors at the K20D's price, which produce more consistent, high-quality photos, we've dropped the image quality rating from 8 to 7. Text changes include comparisons to newer models.
In case you haven't been paying close attention to the digital SLR market lately, there's been a shift toward CMOS sensors. Though Pentax has stuck with CCD for its entry-level K200D SLR, they have moved to a 14.6-megapixel CMOS chip in their new flagship K20D. That puts it ahead of some more expensive models in terms of pixel count. Notably, Canon's similarly priced EOS 40D sports a 10.1MP sensor, Sony's Alpha DSLR-A700 includes a 12.24MP chip, and Nikon's D90 checks in at 12.3 megapixels. As I always say, megapixels aren't everything, so let's see what else Pentax's K20D has going on.
The overall body design is essentially the same as the K10D's. In fact, they both use the same vertical grip. Pentax did upgrade the LCD to a 2.7-inch screen from a 2.5-inch display. The only other change to the body design is the addition of a PC terminal, which lets you connect the camera to a studio strobe. I was surprised that the K10D didn't have one, so it's nice to see it here, though I'm not sure how many people will really take advantage of it.
The similarity between the two bodies is a good thing. I always liked the K10D's design. It's on the small side compared with a lot of midlevel SLRs, making it easier to carry with you. There are two wheels--one near your thumb and one near your forefinger--to adjust shutter speed and aperture in manual exposure mode. This is much more convenient than the single-shell-plus-button-press system employed by most entry-level dSLRs. Pentax also includes plenty of switch and button controls for various functions, so you don't have to delve into the menus to change most of the functions you use while shooting. I came to really like the AF switch, which is on the left front of the body just behind the lens mount. It's a three-way switch with manual focus on the bottom and single-shot AF on top, which made it easy to change to manual focus when I wanted to override autofocus in favor of a more artistic, selective focus. A handful of controls are hidden in the function menu, but with the four-way rocker, these are still only a few button presses away.
Like its less expensive cousin, K200D, the K20D includes weather sealing, though, as you'd expect, this camera's sealing is more intense. The K20D has 72 rubber seals in its little body to keep out moisture and dust. For example, if you open the battery compartment door, you'll notice the small O-ring around the rim of the door. Speaking of batteries, the K20D's 1620mAh lithium ion rechargeable battery will give you up to 530 shots per charge when using the flash for 50 percent of those shots, though that climbs to 740 shots per charge if you don't use the flash at all. Of course, that doesn't compare terribly well with the 40D's rating of 800 images with 50 percent flash or 1,100 without.
One of the niftier shooting modes Pentax includes is the Sensitivity-priority mode, which lets you select the ISO sensitivity you want while the camera selects the shutter speed and aperture you need based on your selection. This is useful if you know you have to raise the ISO to get a fast-enough shutter speed to freeze a subject that's in motion, but want to keep the ISO as low as possible. Even if you have the Fn menu set to select ISO in full stop increments, Sensitivity-priority mode offers 1/3-stop increments, so you can quickly get a finer sensitivity scale if needed.
Keeping up with the dSLR trends for this year, Pentax includes an Enhanced Dynamic Range mode, which tweaks the tone curve to eke out some extra detail in the highlights of an image. It's a subtle effect, but it does work. The K20D's version is a bit more subtle than Canon's Highlight Tone Priority--at least the version I saw in the 1Ds Mark III-- though that camera is an unfair comparison, to say the least. Olympus also offers a similar type of feature that they call Shadow Adjustment Technology, though they group it with metering modes, while Pentax puts it in the ISO section of the Fn menu. Sony's Dynamic Range Optimizer and Nikon's D-Lighting also work to eke out detail in the darkest and the brightest portions of images, though they function more as software-type adjustments made to images after capture, rather than during capture.
Like all of Pentax's current dSLRs, the K20D accepts the company's K-mount lenses. One of the nice things about Pentax's K lens system is that you can use the vast majority of the lenses the company has made with the K20D. If you're willing to buy an adapter on eBay (I'd stick to the official Pentax-made adapters if I were you), you can even use screw mount (aka M42) lenses dating back to the 1960s. Not too long ago, I found a very nice 28mm f/3.5 screw mount lens on eBay for about $100. I have to focus manually when I use it, since it wasn't made for autofocus, but it's a nice bargain if you can deal with that limitation and given the differences in lens coatings over the years, it can be a fun way to give your shots a slightly different look.
If you plan on adding one of Pentax's accessory flashes to your bag of gear, you'll like the fact that the K20D includes wireless flash control. The K200D lets you use the built-in flash to trigger either the AF540FGZ or AF360FGZ flash units. You can't group flashes or set ratios between flashes, but you can control the flash output with the camera's flash compensation setting, which is conveniently changed in the flash setting part of the Fn menu. Also, you can set the camera to use the built-in flash along with one or multiple wireless flashes, or you can set the built-in flash to just control the wireless flashes and not fire when the picture is taken. In case you're wondering, the wireless flash works with Pentax's P-TTL flash metering.
Its performance proved impressive, though the K20D's burst mode just can't keep up with other cameras in this price range. However, it was quite fast out of the gate, clocking a scant 0.2 second to start up and capture its first JPEG. Subsequent JPEGs took 0.4 second between shots with the flash turned off, rising to 0.8 second with the flash turned on. RAW shots took 0.4 second between shots, also without flash. Shutter lag measured 0.4 second in our high-contrast test and 1 second in our low-contrast test, which mimic bright and dim shooting conditions, respectively.
Image quality is also impressive. The switch to CMOS not only gave Pentax the capability to add Live View shooting, it also let them get better control over noise at higher ISOs. Strangely, you'll still notice a fair amount of speckles at ISO 3,200 and ISO 6,400 on the K20D, but that's partially because the camera defaults to minimal noise reduction. You can turn that up if you like, but I preferred it low because that let the images retain a large amount of finer detail that becomes blurred away on a lot of other cameras. The sensor-shift Shake Reduction certainly helps to keep images blur-free to an extent, but it could probably be more effective. I was able to get more than one stop of leeway--meaning I could shoot at a shutter speed less than half as fast as I normally would.
Colors aren't technically as accurate as they could be, though they're not very far off compared with other cameras in this price range and tend to look pleasing nonetheless. The automatic color balance does a good job of neutralizing colors, though it leaves a slight warm cast when shooting in incandescent lighting. That's not uncommon among higher-end SLRs, and given that this is Pentax's flagship model, I'm not surprised to see this here. The meter tends to underexpose when faced with a tricky situation, but typically did a good job of delivering the right exposure for a given shot. I do have to say that I prefer Nikon's 3D Color Matrix Metering II for trickier shots, but I like that the K20D errs on the side of caution by underexposing rather than overexposing and blowing out highlights.
Overall, the K20D is a very good camera for the price. Pentax users looking to step up should feel comfortable doing so. If you're brand agnostic and looking for a solid midrange SLR, the K20D is a safe bet. It has an extra stop of sensitivity compared with the Canon EOS 40D, which tops out at ISO 3,200 compared with the K20D's ISO 6,400. Plus, if you think you'll use the Pentax's wireless flash control, you should note that Canon forces you to buy a separate controller, or its priciest flash unit, if you want that. Nikon's D90 offers a tempting alternative, though it has 12MP compared with the K20D's 14MP, and neither that Nikon nor Canon has the K20D's weather sealing.
(Shorter bars indicate better performance)
 | Time to first shot | | Raw shot-to-shot time | | Shutter lag (dim light) | | Shutter lag (typical) |
(Longer bars indicate better performance)