Pentax K20D

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http://reviews.cnet.co.uk/digitalcameras/0,39030233,49297135,00.htm

Reviewed 4 June 2008

Reviewed by Philip Ryan

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 dSLR, it has 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 EOS 40D sports a 10.1-megapixel sensor, Sony's Alpha DSLR-A700 includes a 12.2-megapixel chip, and even Nikon's pricier D300 checks in at 12.3 megapixels. As we always say, megapixels aren't everything, so let's see what else Pentax's K20D has going on.

For the K20D's body only, you'll pay around £700. Adding an 18-55mm, f/3.5-5.6 lens will cost an extra £100. 

Design
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 69mm (2.7-inch) screen from a 64mm (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. We were surprised that the K10D didn't have one, so it's nice to see it here, though we're not sure how many people will really take advantage of it.

The similarity between the two bodies is a good thing. We always liked the K10D's design. It's on the small side compared with a lot of mid-level dSLRs, 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. We 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 we 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.

Features
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.

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, the K20D has 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 more subtle than Canon's Highlight Tone Priority -- at least the version we 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 it calls Shadow Adjustment Technology, though it groups it with metering modes, while Pentax puts it in the ISO section of the Fn menu. Sony's Dynamic Range Optimiser and Nikon's D-Lighting also work to get more 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 adaptor on eBay -- we'd stick to the official Pentax-made adapters if we were you -- you can even use screw mount (aka M42) lenses dating back to the 1960s. You may have to focus manually when you use these lenses, since they weren't made for autofocus. Still, 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.

Sony's Alpha DSLR-A700 (left) opts to blur away the noise in this shot at ISO 3,200, while the Pentax K20D (right) blurs less and retains more finer detail. You can always set the K20D to blur more if you prefer that, but we like having the option of leaving out the blur

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. 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.

Performance
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 seconds to start up and capture its first JPEG. Subsequent JPEGs took 0.4 seconds between shots with the flash turned off, rising to 0.8 seconds with the flash turned on.

Raw shots took 0.4 seconds between shots, also without flash. Shutter lag measured 0.4 seconds in our high-contrast test and 1 second in our low-contrast test, which mimic bright and dim shooting conditions, respectively.

The K20D's 1620mAh lithium-ion rechargeable battery will give you up to 530 shots per charge when using the flash for 50 per cent 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 Canon EOS 40D's rating of 800 images with 50 per cent flash or 1,100 without.

Image quality
Image quality is also impressive. The switch to CMOS not only gave Pentax the capability to add live view shooting, it also let it get better control over noise at higher ISOs. Strangely, you'll still notice 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 we 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. We were able to get more than one stop of leeway -- meaning we could shoot at a shutter speed less than half as fast as we normally would.

Colours 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 colour balance does a good job of neutralising colours, though it leaves a slight warm cast when shooting in incandescent lighting. That's not uncommon among higher-end dSLRs, and given that this is Pentax's flagship model, we're not surprised to see this here.

Shooting speed (in frames per second)
(Longer bars indicate better performance)

Time to first shot

Raw shot-to-shot time

Shutter lag (dim light)

Shutter lag (typical)

Pentax K20D

0.2

0.4

1

0.4

Canon EOS 40D

0.3

0.4

1.2

0.4

Fujifilm FinePix S5 Pro

0.5

0.8

1.2

0.4

Nikon D300

0.1

0.5

0.9

0.5

Sony Alpha DSLR-A700

0.5

0.6

1.2

0.5

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. We do have to say that we prefer Nikon's 3D Colour Matrix Metering II for trickier shots, but we like that the K20D errs on the side of caution by underexposing rather than overexposing and blowing out highlights.

Conclusion
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 mid-range SLR, the K20D is a safe bet.

In comparison, it has an extra stop of sensitivity than 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 D80 has come down in price recently and offers a tempting alternative, though it has 10 megapixels compared with the K20D's 14, and neither that Nikon nor Canon has the K20D's weather sealing.

Additional editing by Shannon Doubleday