Review – Pentax K-5, Part 2
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Writing or discussing image quality of digital cameras in 2011 is comparable to discussing how white clouds are on a warm Spring day. You can do it, and it will keep you entertained, but there are much better things you could be doing instead. Like taking photos, for example.
Nevertheless, words must be written and images shown, and far be it from me to deprive the internet of pixels to discuss, so here are some photos showing that, like just about every camera on the market right now, IQ is damn good.
Note: All photos were shot in RAW and processed through ACR 5.7; downsized images have been sharpened for web viewing in Photoshop CS4.
Low ISO Image Quality
Excellent. That’s the top, middle and bottom line. I already discussed in Part 1 the flexibility of the K-5′s RAW files, so I’ll just say that the low readout noise of the Sony sensor provides extremely clean shadows, and its dynamic range allows shooting many high-contrast scenes without wishing for, or resorting to, HDR shenanigans. Thanks to its 16 megapixels, you get plenty of resolution too. Check out my friend the iguana at the top of this article to see what I’m talking about: Both the dynamic range and the resolution are there. In case you’re wondering, it was shot with the Pentax 77mm f/1.8 Ltd at f/5, 1/160s, ISO 80.
This image has plenty of detail in the shadow cast by the iguana’s head while none of the light spikes under its jaw are blown out; that’s the sensor’s dynamic range in action. As for resolution, click on the 100% crop to the right and see for yourself. I didn’t do any special sharpening for the web, it only has my default RAW sharpening in ACR. Note that it was shot at ISO 80, which is available in the ISO expanded range. Despite it being a pulled ISO (meaning the camera actually shoots at its base ISO and then pulls the exposure down, as you might do with the Exposure slider in ACR or Lightroom) I have not seen any loss of quality or dynamic range. Sure, ISO 80 is only 1/3 stop slower than ISO 100, but I’m sure there’s a waterfall photographer somewhere who’s happy about it. And who knows? Maybe we’ll get ISO 50 in the next camera.
Let’s look now at another image (see above), this time shot at ISO 640, which for this camera is still considered low. To the right is a 100% crop (click to enlarge) that shows good resolution, despite the crappy light and low contrast image. Again, no extra sharpening has been applied; had I been planning to use this image on the web, I would have sharpened it a bit to make it look better. I’m happy with how it looks.
The images above show how malleable the K-5 RAW files are. This isn’t an extreme case induced for the sake of testing, like I showed in Part 1, but rather a Real Life™ scenario that could be presented to any photographer, as it was to me. The photo was taken with the subjects in deep shadow and the camera’s multi-meter mode was tricked by the bright backlight, which rendered the subjects darker than I would have wanted (this, by the way, is why I prefer using center-weighted metering). The photo on the left is how the image was exposed by the camera. The photo on the right is what it looks like after I “fixed” it by applying +1.85 exposure, 35 fill light and bringing the blacks down from 5 to 0 in ACR. The result is very good to my eyes, showing no disagreeable noise in the dark areas that have been brought up in exposure. Knowing that you have such an effective safety net takes away much of the anxiety you might feel about not getting the exposure you wanted.
High ISO Image Quality
DxO mark has given the K-5 an impressive score for high ISO performance, ranked as the 2nd best APS-C sensor in low light after the Nikon D7000. This agrees with my experience using the camera in low light—I found it eminently usable for my needs up to ISO 6400, and I wouldn’t hesitate to shoot up to 25,600 if converting to B&W. Beyond that, IQ degrades quickly, but the images can still be used in a pinch for when a really grainy picture is better than no picture at all. Below are a few examples at various very high ISO values; click to enlarge.
The ISO 16,000 sample isn’t the most artistic, but it’s good enough for you to tell that the chroma noise isn’t rampant while luminance noise is very well controlled; colour saturation is quite good too. At ISO 51,200, chroma noise is rampant and luminance noise is apparent (click on the 100% crop to see what I mean), but nevertheless, the image would be OK for web use, and might even make a passable 8×10 print (if sharpness and saturated colour aren’t required) after some judicious noise removal with the appropriate software. A result like this from an APS-C sensor was unimaginable just 2 years ago, and Sony must be congratulated for their outstanding work.
Bits and Pieces
Here is an assortment of comments that seemed too short to deserve their own section:
- Firmware Glitch: Every now and then I’ll press the play button to review an image and nothing will happen, and any other buttons on the rear of the camera will also be unresponsive. Strangely enough, the ISO will be set to “AUTO’, when the camera had previously been in manual ISO. The only ways I’ve found of fixing this is by turning the camera off and on, or using the DoF preview feature (in which case I have to then turn AUTO ISO off). I’d like to hear if this has happened to anyone else or if it’s just my test unit.
- Dust Alert: The idea seems good, you select the ‘dust alert’ feature, click on the shutter release and the camera shows you a white image with black specs marking where dust is located; it even saves it as a JPEG that you can open up on your computer to help you clean the sensor. In practice, I found that if I ran it 5 times it gave me 5 different dust distributions. I’ll stick to the trusted ‘shoot a blank sky at small apertures’ method for now.
- Slow Processing: It might sound obvious, but it’s worth saying: 16MP images are large, especially when shooting RAW (25MB per file on average), so if you want the camera to be snappy while shooting, invest in a fast card. I found replay of images to be very slow with a Class 6 card.
Pros and Cons
- Small size for an advanced DSLR.
- Good ergonomics despite its small size.
- Excellent IQ.
- Excellent high ISO performance for an APS-C sensor.
- Extremely low noise in shadows.
- Very malleable RAW files.
- Nice viewfinder (for an APS-C camera).
- Weather sealing.
- Dual-axis electronic level: Tilt (up/down) and Roll (side to side).
- 5 USER shooting modes.
- Quick menu navigation.
- In movie mode, aperture control can be set to fixed or automatic.
- In movie mode, shake reduction can be set on/off independently of how it’s set for stills shooting.
- Histogram in live view is not that of the final image when shooting in Manual or using EV comp.
- The electronic level turns off when you half-press the shutter release button.
- No tilt indicator in the viewfinder, only roll.
- High release price of $1,600 in the US (especially when the similarly spec’d Nikon D7000 is $1,200).
- Buttons on back are a bit cramped (because you can’t have your cake and eat it).
- AF in live view is only average in speed.
- Catch-in focus doesn’t work in live view.
- SD card is hard to pull out—it’s like the camera doesn’t want to let go of it.
- No AF in movie mode.
If you think 4 is a small number of cons for a DSLR, it should tell you something about this camera. Pentax has finally brought out a camera that photographers can trust in many situations, be it low light, birding, hiking, street shooting… The body is exceptionally well built with traditional Pentax ergonomics; it’s comfortable to hold and use. I might be biased because I’m a Pentax shooter (though not of this body type), so bear this in mind when I talk about ergonomics, but I’ve held many cameras and I’m not ashamed to claim Pentax DSLRs are some of the most comfortable.
I started talking about ergonomics because the camera works so well one has the luxury of being able to pay attention to non-technical details. The K-5 is intuitive, easy to navigate menus, and plenty of buttons to avoid having to dive into them during regular use. Sony have built the holy grail of sensors, which coupled with Pentax’s excellent image processing engine provide excellent IQ in just about any lighting situation. At high ISO Pentax controls luminance noise very well and chroma noise doesn’t rear its ugly, colourful head until 25,600 or so; this is great news for B&W lovers as this approach creates pleasing film-like grain rather than high ISO jaggies. Last of all, I’ll remind you one last time of how easy to manipulate the RAW files are, and how superb the results; by far the best RAW files I’ve ever dealt with.
The appearance of stains on the sensors of some units has been addressed and Pentax USA tells me the problem has been resolved. Recent buyers appear to confirm this. I expect many prospective buyers who were reluctant to make a purchase will do so now. Another issue that’s been reported is that of front-focusing in low light and/or tungsten light. I have not encountered any such issues, and I have certainly shot in bad light. If this problem is real, there is a bright side: It should be fixable in firmware.
As a Pentax shooter, I would have no qualms recommending this camera to anybody looking for a high-end DSLR; my only hesitation concerns the current price, which is keeping me from upgrading to the K-5. Pentax USA president, Ned Bunnell, believes the K-5 is worth $1,600; is it? Only you can answer that question. One thing is for sure, you’re likely to forget your credit card bill once you start using the K-5 with some of Pentax’s excellent prime lenses.
PS: If you want to get the most out of your K-5, you’d do well to get Yvon Bourque’s e-book K-5, Everything you need to know…and then some. It goes well beyond the camera’s manual and actually explains what each setting does and why you’d want to use it, illustrating this with sample images when necessary. EtL doesn’t make any commission from sales of this book, I recommend it simply because I think it’s a good, useful and affordable product. EtL isn’t affiliated with Mr Bourque, although I used to write a weekly article for his Pentax blog back in 2008.
All photos: ©Miserere (unless otherwise noted).
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- Review – Pentax K-x Part 1: First Look
- Review – Pentax K-x Part 2: Features, Menus, Ergonomics
- Review – Pentax K-x Part 3: Conclusions
- Review – Pentax K-5
- Review – Olympus Pen E-PL1, Part 2: Using the Camera
Tags: Cameras, DSLR, Pentax K-5, Photography, Reviews, Street Photography