By Gordon Lewis
In the previous installment of this review I mentioned the Pentax K-7’s autofocus- and exposure-related capabilities. Both are essential to getting a usable photograph. A third essential is white balance: the ability to produce color photographs that look "normal" to our eyes, even when the light source differs from standard daylight. Some cameras have trouble producing an acceptable white balance under tungsten or fluorescent light sources. Fortunately, the Pentax K-7 is not one of them. With the camera set to Automatic White Balance (AWB), I could get well-balanced photos even under quartz-halogen lighting. The Tungsten setting also produced an excellent balance for quartz-halogen, as well as standard household lighting. Even under mixed lighting the K-7 produced a balance that was acceptable, if not perfect.
According to Pentax, this is because the K-7 automatically "tweaks" the white balance, even when it's preset to a specific light source. The K-7 also allows you to perform a custom white balance, but better yet, it has a "digital preview" feature that lets you previsualize any white balance in real time. The four-way controller on the back of the camera lets you use an on-screen grid to shift the center point of the balance anywhere between a green/magenta (vertical) and blue/amber (horizontal axis) and to see the result before you take a picture. Again, this may be overly sophisticated for some, but for photographers who thrive on control and getting it right the first time, it’s a godsend.
How low/high can you go?
Another feature I grew to appreciate was the K-7’s shake reduction (a.k.a. image stabilization) system. It’s built into the body, so every lens I used was image-stabilized—even a 20 year-old 50mm ƒ/1.7 Pentax-M I had sitting around the house. Because of SR I felt comfortable shooting at shutter speeds that were at least two stops slower than I would use with my non-IS cameras. Another result was that I rarely felt the need to shoot at high ISOs as a way to get shutter speeds fast enough to minimize camera movement in low light.
Subject movement is, of course, a different matter, so I tried shooting at ISO 1600 just to see how good an image I could get. I’ve presented a couple of examples and will let you draw your own conclusions. Keep in mind that the K-7 allows you to control the amount of noise reduction (from none to high) and the ISO at which NR kicks in. The default is medium NR at ISOs above 800, which is how I had my camera set.
The one aspect of noise reduction you can’t control is shadow NR at shutter speeds longer than 30 seconds. The K-7 will automatically create a dark frame exposure equal to the length of the original exposure. This means that if you keep the shutter open for two minutes, which is not unusual for people who photograph stars, lightning, fireworks and other low-light phenomena, you’ll have to wait four minutes before you can take another picture.
In my opinion the noise at ISO 1600 is certainly noticeable but not significantly worse than other DSLRs in this price range. It also has a grain-like character that makes it look a bit more organic than speckled chroma noise. That said, I would use ISO 3200, the highest available ISO setting on the K-7, only if the choice was either that or no image at all.
Finally, keep in mind that a 100% view of a full-resolution, 4672 x 3104 pixel image from the K-7 equates to an 11 x 14 print at 300 dpi. Regardless of how these ISO 1600 images may look on screen, they produce high-quality prints. Shift down to ISO 800 and below and the print quality is nothing short of excellent. Let me put it another way: If you like what you see in these small JPEGs sized for your monitor, you’ll love what you see in a good print.
A look at lenses
A lot of the K-7’s excellent image quality has to do with its 14.6MP sensor, SR, autofocus, exposure and white balance systems, but I credit just as much to the lenses I was using. As Mike Johnston and Carl Weese have explored at some length elsewhere, the Pentax 35mm ƒ/2.8 DA Macro is not only one of Pentax’s best lenses, it's one of the best lenses available, period. There was practically no situation where I could get it to exhibit a serious flaw, even at maximum aperture.
The 55–300mm ƒ/4–5.8 ED was another pleasant surprise. If you’re looking for a relatively compact, lightweight, moderately priced tele-zoom that's great for outdoor sports and nature photography, you need look no further. Just be aware that major focus and focal length changes result in a lot of whirring as the camera's focusing motor races to keep up.
The 21mm ƒ/3.2 DA Limited was also a good performer—just not quite as good in the corners as I hoped. I had to stop down to ƒ/5.6 or ƒ/8 before the corners approached the excellent resolution of the center. On the other hand, there aren’t many lenses of similar focal length and aperture that are significantly better. At least the 21mm ƒ/3.2 has amazingly compact size (63 x 25mm) and light weight (155g with hood) going for it.
A common thread throughout this review is that the Pentax K-7 comes with an amazing choice of features and options. There are so many different ways to set it up, it's unlikely that any two users would do it the same way—yet all of them could feel as if their set-up was "just right."
There is a downside to the K-7’s wealth of capabilities, however: many of them are poorly documented in the owner’s manual. For example, although the manual does explain that you have to set a custom function a certain way if you want to use lenses that have an aperture ring, this information is under the general heading of "Functions Available with Various Lens Combinations," which you will find only in the Appendix, not the index. If you look in the index for this information under something more obvious, such as "Use With Pre-DA/FA Lenses" or "Lens Mount Compatibility," you won’t find it.
The same is true of the Green Button, a feature unique to Pentax. The index cites only two pages that reference it and both references are perfunctory. In fact, the Green Button has multiple uses that change depending on what exposure mode you're in. These uses are explained throughout the manual, but again, you'd have to read every exposure mode-related page to find them; they’re not referenced in the index.
Users who have experience with previous Pentax DSLRs will likely be familiar with such arcane information and will be up to speed with the K-7 no time. Users who are new to Pentax will find the learning curve steep for the first week or two. Some may tire and give up, but for those who persevere, the rewards are ample.
So, should you buy one?
If you’re a Pentax owner looking for an upgrade or for a high-quality entrée into digital photography, the K-7 is a no-brainer. It’s simply the best Pentax has to offer, and a definite improvement over prior models. Not only that, it’s a strong competitor to similarly priced offerings from Canon, Nikon, Sony and Olympus. The K-7 is a purchase you’re not likely to regret.
If you’re already invested in a different camera system it’s a different story. The K-7 has sufficient charms some might consider buying one with a prime lens or two as their “small but rugged” travel kit.
Those whose needs are more extensive would have to decide whether Pentax has the lenses, flash units, and other accessories they need to get the job done. A plus is that the Pentax lens system has a selection of top-quality, compact prime lenses and zooms you won’t find anywhere else. A minus is that their selection of autofocus lenses is literally more “limited” than Canon and Nikon and, depending on the lens, the prices are often significantly higher. There are also fewer third-party lenses available in Pentax mount. However, if you’re interested in older, manual-focus lenses in all variations of the Pentax mount, your choices expand in inverse proportion to the price you pay for them.
Personally, the K-7 is the first Pentax DSLR that has made me sit up and take notice of what Pentax has to offer in digital. It’s not for everyone (what camera is?), but for those who "get it," it's a welcome alternative both to small cameras that are under-built and under-featured and large cameras that are overly heavy and over-priced.
(Ed. Note: Be sure to compare prices between B&H Photo and Amazon [or Amazon U.K.] before buying lenses! In some cases the prices are nearly the same, but in some cases B&H has a much cheaper price, for example in the case of the 21mm Limited. However, Amazon's price is cheaper for the camera as of this writing. B&H is closed from Oct. 2 to Oct. 11th.)
Pentax's "DA star" (DA*) weather-sealed lenses (for the weather-sealed K-7):
DA Star 16–50mm ƒ/2.8 ED AL (IF) SDM
DA Star 200mm ƒ/2.8 ED (IF) SDM
DA Star 300mm ƒ/4 ED(IF) SDM
DA Star 50–135mm ƒ2.8 ED (IF) SDM
DA Star 55mm ƒ/1.4 SDM
DA Star 60–250mm ƒ/4 ED (IF) SDM
Pentax DA Limited lenses:
DA 15mm ƒ/4 ED AL Limited
DA 21mm ƒ/3.2 AL Limited
DA 35mm ƒ/2.8 Macro Limited
DA 40mm ƒ/2.8 Limited
DA 70mm ƒ/2.4 Limited
(Ed. Note: Pentax has three other lens series: the DA lenses for digital cameras, and the D FA and FA series for film cameras, the latter two also usable on digital bodies. The D FA series now consists of only two macro lenses, a 50mm and 100mm. The FA series includes several Limited lenses. Finally, note that "Limited" is just a marketing term, and does not mean that the lenses are limited in production or availability.)