Pentax K-7 Review
Our Dynamic Range measurement system involves shooting a calibrated Stouffer Step Wedge (13 stops total range) which is backlit using a daylight balanced lamp (98 CRI). A single shot of this produces a gray scale wedge from (the cameras) black to clipped white (example below). Each step of the scale is equivalent to 1/3 EV (a third of a stop), we select one step as 'middle gray' and measure outwards to define the dynamic range. Hence there are 'two sides' to our results, the amount of shadow range (below middle gray) and the amount of highlight range (above middle gray).
To most people highlight range is the first thing they think about when talking about dynamic range, that is the amount of highlight detail the camera can capture before it clips to white. Shadow range is more complicated; in our test we stop measuring values below middle gray as soon as the luminance value drops below our defined 'black point' (about 2% luminance) or the signal-to-noise ratio drops below a predefined value (where shadow detail would be swamped by noise), whichever comes first.
Custom Image Modes
The Bright, Natural, Portrait, Landscape, Vibrant, and BW use essentially the same curve and therefore produce the same amount of dynamic range. The Muted setting uses a more linear, less contrasty curve but all the settings clip highlights at the same point.
The K-7 features contrast settings (as a part of the custom image parameters) from -4 to +4. As you would expect the -4 setting produces a flatter tone curve while the +4 setting results in a more extreme s-curve. Most of the custom image settings use a contrast setting of either 0 or +1, while the Muted setting uses -3 to generate a small extra amount of shadow dynamic range.
Expanded Dynamic Range Function
The K-7 features both shadow and highlight expansion which can be applied to the camera's JPEG output. With Highlight correction activated ISO 200 becomes the minimum sensitivity setting. With highlight expansion turned on the tone curve is flatter in the highlights and produces an extra stop of highlight range.
With our dynamic range test setup we could not trigger the shadow expansion functionality and therefore we can unfortunately not provide any measurements for this feature.
ISO Sensitivity and Dynamic Range
While the K-7's highlight range remains relatively constant the measured shadow range decreases as you go up the sensitivity scale. This is mainly due to increased noise and noise reduction smearing.
|Sensitivity||Shadow range||Highlight range||Usable range|
|ISO 100||-5.7 EV||2.9 EV||8.6 EV|
|ISO 200||-5.5 EV||2.9 EV||8.4 EV|
|ISO 400||-5.5 EV||2.9 EV||8.4 EV|
|ISO 800||-4.3 EV||2.9 EV||7.2 EV|
|ISO 1600||-3.4 EV||2.8 EV||6.2 EV|
|ISO 3200||-2.1 EV||2.7 EV||4.8 EV|
|ISO 6400||-1.3 EV||2.4 EV||3.7 EV|
Dynamic Range compared
At it default settings the K-7 produces slightly less dynamic range than its predecessor and the Nikon D300. It squeezes past the EOS 50D in terms of overall range but still comes last in this comparison in terms of highlight dynamic range.
|Camera (base ISO)||
|Pentax K7||-5.7 EV||2.9 EV||8.6 EV|
|Pentax K20D||-5.8 EV||3.2 EV||9.1 EV|
|Nikon D300||-4.7 EV||4.1 EV||8.8 EV|
|Canon EOS 50D||-4.8 EV||3.5 EV||8.3 EV|
The wedges below are created by our measurement system from the values read from the step wedge, the red lines indicate approximate shadow and highlight range (the dotted line indicating middle gray).
There is usually slightly more dynamic range to be obtained from RAW capture compared to in camera JPEGs (thanks to the use of a consumer-friendly tone curve in the JPEG conversion). This is typically around 1 or 1.5 EV (one to one and half stops) or so of extra information available at the highlight end in RAW files and that a negative digital exposure compensation when converting such files can recover detail lost to over-exposure. As with previous reviews we settled on Adobe Camera RAW for conversion to retrieve the maximum dynamic range from our test shots.
Adobe Camera RAW's default is fairly contrasty and, as expected, produces less dynamic range than the out-of-camera JPEG. The best result we could achieve in ACR by applying some negative digital exposure compensation, reducing contrast and increasing brightness is 10.5 EV of which just over one stop (1.2 EV) is additional highlight range.
- ACR Default: Exp. 0.0 EV, Blacks 5, Contrast +25, Brightness 50, Curve Medium
- ACR Best: Exposure -1.05 EV, Brightness 100, Contrast -50, Curve Linear
|ACR Default||7.0 EV|
|ACR 'Best'||10.5 EV|
These measurements are more or less in line with what we found in real world use. Parts of the image which are more than 1 stop over exposed are usually not recoverable at all or produce false color information when negative digital exposure compensation is applied in a RAW converter.
In the first example an area of the image (the bench) is over exposed by more than one stop. Reducing the exposure by three stops in Adobe ACR recovered only a small amount of detail and some of that recovered detail turned gray. The second sample shot is less extreme and some, but not all, detail is recovered by applying one stop of negative digital exposure compensation.
|Adobe Camera RAW default conversion||Adobe Camera RAW with -3.0 EV digital comp.|
|Adobe Camera RAW default conversion||Adobe Camera RAW with -1.0 EV digital comp.|
- 1 Introduction
- 2 Specifications
- 3 What's new
- 4 Body & Design
- 5 Body & Design
- 6 Body & Design
- 7 Operation & Controls
- 8 Operation & Controls
- 9 Operation (Live View)
- 10 Displays
- 11 Menus
- 12 Menus
- 13 Menus
- 14 Performance
- 15 Photographic tests (RAW)
- 16 Photographic tests (Noise)
- 17 Photographic tests (Noise)
- 18 Photographic tests (DR)
- 19 Photographic tests
- 20 In-camera effects
- 21 Movie Mode
- 22 Compared to
- 23 Compared to (JPEG)
- 24 Compared to (JPEG)
- 25 Compared to (JPEG)
- 26 Compared to (RAW)
- 27 Compared to (RAW)
- 28 Compared to (RAW)
- 29 Compared to (Higher ISO)
- 30 Compared to (Resolution)
- 31 Compared to (Resolution)
- 32 Conclusion
- 33 Samples
Sep 14, 2012
Sep 14, 2012
Oct 2, 2009
Jan 17, 2011
|Patrick Finds Inner Peace by ecastellon|
from Your best photo of the week!
|Forks by Kukla|
from Arranged everyday objects
The new iZugar 3.25mm F2.5 super fisheye lens offers an insane 220-degree angle of view. That means it can basically see behind itself... good luck keeping your feet out of the shot.
You'll laugh, you'll cry, you'll remember that time you took a picture of the frozen pizza baking directions.
A Craigslist poster has discovered the worst possible way to photograph a car: taking pictures of pictures displayed on a cracked and scratched up smartphone screen.
With the iPhone X coming out soon, the title probably won't last, but the iPhone 8 Plus is officially the best smartphone camera DxOMark has ever tested, and the iPhone 8 is second.
Kodak's new Facebook Messenger chatbot is trying to bring back the 'Kodak Moment' by digging up your old social media photos and trying to sell you prints and custom coffee mugs.
Affinity Photo for iPad was touted as "the first full blown, truly professional photo editing tool to make its way onto the Apple tablet." This update makes it that much more convenient.
Yashica has released a new teaser video, and this one claims they'll be releasing an "unprecedented camera" in October on Kickstarter. Ready... set... speculate!
Storage solutions company Synology has just released its very first 6-bay NAS tower. Combined with the DX1215 expansion units, it can hold and control up to thirty drives.
We're always expanding our collection of product overview content, and we've just added videos for the Canon EOS 6D Mark II, the EOS Rebel SL2 and EOS M6.
The venerable Canon PowerShot G1 was announced seventeen years ago this week, marking the start of a line of enthusiast-focused compacts that's still alive and kicking.
Super macro photographer Can Tuncer captured these incredible close-ups of a single peacock feather using a special setup and three different microscope lenses.
After successfully crowdfunding the Biotar 75mm F1.5, Oprema Jena is at it again. This time they're bringing back the Biotar 58mm F2: the world's only lens with a 17-blade aperture.
Adobe's move to a subscription model is treating it very well indeed. The company has posted record revenue for the second quarter in a row, hauling in a mind-boggling $1.84 billion.
More details have emerged about the potential sale of Blackstone's 45% stake in iconic camera brand Leica.
Popular mobile editing app Snapseed just got a major update that includes a new interface and 11 new presets for both Android and iOS, as well as adding the Perspective tool to the iOS version.
It might sound like a strange idea, but taking macro photos of boiling water can actually result in some really cool photographs. A good photo experiment for a rainy day.
The database was created to "break with the narrow lens through which history… has been recorded" by equipping those who commission photography with "the resources to discover photographers of color available for assignments.
Lensbaby has released two new optics for their special "optic swap system." The Lensbaby Sweet 80 Optic gives you that trademark sweet spot of focus, while the Creative Bokeh optic gives you 9 different drop in aperture plate options to play with.
TechCrunch has already posted their review of the upcoming iPhone 8 (not yet the iPhone X), and they're calling it "a look into the augmented future of photography."
Affinity Photo is a $50 photo editing software with no subscriptions. That's it – pay for it once and you're done. And we think it's actually pretty darn good.
Instagram is currently testing a major change to the app's profile layout: replacing the 3-photo across grid with a 4-photo grid... and some users are NOT taking the news well.
A report by USSRPhoto is shedding some light on the return of the famed Zenit camera brand. It seems the full-frame mirrorless camera they're working on will be made in part by Leica using components from the Leica SL.
According to a reliable Korean report, Samsung is developing a smartphone sensor that's capable of super slow motion. Translation: Samsung's next batch of Galaxy smartphones may be able to shoot 1,000fps.
This simple photograph of a seahorse and Q-tip has taken the internet by storm. We spoke to photographer Justin Hofman about how it was captured, and what it means to him.
After a massive leak last week, Profoto has officially debuted the Profoto A1: the company's first on-camera flash system that they're calling "the world's smallest studio flash."
"When the first hyperfocal distance charts were designed, someone decided that an acceptably sharp background contained some blur — enough to notice in a medium-sized print [...] After that point, nearly every other hyperfocal chart followed suit."
The Canon EOS Rebel SL2 (also known as the EOS 200D) is the company's impressively compact entry-level DSLR. Packing a 24MP APS-C sensor, DIGIC 7 processor and Dual Pixel AF, it promises a lot of bang for the buck. And while not mind-blowing, it handles most tasks very well.
Correct these four common composition mistakes and your photos will be more balanced, tell a better story, and lead your viewer's eye where you want it to go.
The rugged, compact 360° action camera Kodak unveiled at Photokina in 2016, the Kodak PixPro Orbit 360, is finally available in the United States.
iOS 11 launches tomorrow, and it'll save all of your pictures in a new high efficiency image format called HEIC. Fortunately, there's now a converter that will let you turn those photos back into JPEGs.