Pentax K20D Review
ISO Sensitivity / Noise levelsISO equivalence on a digital camera is the ability to increase the sensitivity of the sensor. This works by turning up the "volume" (gain) on the sensor's signal amplifiers (remember the sensor is an analogue device). By amplifying the signal you also amplify the noise which becomes more visible at higher ISOs. Many modern cameras also employ noise reduction and / or sharpness reduction at higher sensitivities.
To measure noise levels we take a sequence of images of a GretagMacBeth ColorChecker chart (controlled artificial daylight lighting). The exposure is matched to the ISO (ie. ISO 200, 1/200 sec for consistency of exposure between cameras). The image sequence is run through our own proprietary noise measurement tool (version 1.5 in this review). Click here for more information. (Note that noise values indicated on the graphs here can not be compared to those in other reviews). Room temperature is approximately 22°C (~72°F), simulated daylight lighting.
Noise reduction settings
As we've seen, the K20D tends to apply very conservative levels of noise reduction by default. There are three options for increasing it, however. High ISO noise reduction can be set to Weakest, Weak and Strong, as well as the default Off setting, using option 18 in the Custom Menu setting.
Our tests show that these options have no effect below ISO 800. Their effects from ISO 800 upwards can be seen below. (It's worth noting that, although the Operating Manual states that all "Noise Reduction is set to Strong when shooting with a sensitivity of ISO 3200 or high, regardless of the setting in the Custom Menu," this doesn't appear to be true. We have only tested the results in whole stops but the settings clearly behave differently at ISO 3200).
As can be seen, all the noise reduction settings increase the chroma noise reduction (the effects of which we'll see in the crops further down the page). By contrast, applying noise reduction at the "weakest" setting has no effect on luminance noise (the differences in the graph are within the margin of error of the test). However, applying the 'Weak' or 'Strong' noise reduction options has an increasing effect on luminance noise.
ISO 1600 NR OFF
ISO 1600 NR Weakest
ISO 1600 NR Strong
ISO 3200 NR OFF
ISO 3200 NR Weakest
ISO 3200 NR Strong
And the results are exactly as the graphs would lead you to expect: applying noise reduction at its weakest setting reduces the chroma noise without significantly impacting the luminance noise (though not to the extant that you'd describe the result as film-like, which usually comes about from suppressing chroma noise heavily but allowing luminance noise to leave a neutral 'grain'). Turning the noise reduction up to 'strong' also attempts to rein-in luminance noise, with all the loss of fine detail that entails.
For reference purposes, below is a repeats of the comparison graphs from the previous page but with the K20D set to its highest noise reduction setting to bring it closer into line with the levels of noise reduction being applied by the other cameras, at least between ISO 1600 and 3200. (Though it's important to note that the other cameras have additional noise reduction settings, whereas the Pentax's strongest setting only brings it into line with the competition.)
Although we would expect many K20D owners to be willing to indulge in some degree of post-processing, it's still important that the JPEG output be optimized (or, at least, optimizable for each user's tastes). Noise reduction is always a fine balance between reducing noise and retaining detail and there are different attitudes towards where that balance should be struck. The K20D gives the user a degree of choice about their preferred output - light nr, luminance nr only, luminance and chroma nr, stronger luminance and chroma nr. However, even this heaviest setting is only comparable to the default noise reduction settings of its peers (in terms of detail, as well as noise). The K20D doesn't give the option to produce the smeared but essentially noise-free images that others offer.
- 19 Photographic tests (Noise)
- 20 Photographic tests (DR)
- 21 Photographic tests (DR)
- 22 Photographic tests
- 23 Compared to
- 24 Compared to (JPEG)
- 25 Compared to (JPEG)
- 26 Compared to (JPEG)
- 27 Compared to (JPEG)
- 28 Compared to (RAW)
- 29 Compared to (RAW)
- 30 Compared to (RAW)
- 31 Compared to (RAW)
- 32 Compared to (Higher ISO)
- 33 Compared to (Resolution)
- 34 Conclusion
- 35 Samples
Jun 15, 2011
Jun 25, 2008
Jan 23, 2008
Jun 23, 2011
|Owens Valley Milky Way by ed rader|
from Sign, sign, everywhere a sign..
|Break by Hank3152|
from Motion blur
|Camp by T bird|
from A Big Year - birds
|The Maasai Shepherd by cgravel|
from - African Man - (Portrait in Black and White + A Border)
Stanley Greene captured 'brutally honest' photographs in the war zones of the Middle East, Chechnya and Georgia. He was also one of the few African-American photographers working internationally.
Owners of Leica M cameras that suffer from peeling CCDs will be able to claim a free repair in the future so long as the camera was purchased within five years of the fault becoming apparent, the company has announced. Read more
No mic socket? No problem. In this video, Daniel Peters at Photo Gear News shows you how to make a lapel microphone using just a smartphone and a pair of earbuds.
The Carl Zeiss Jena BIOTAR 75mm F1.5 Red T lens is very rare and priced accordingly. It can be yours today for the low, low price of $15,000.
The MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) has developed a drone that does not require any human control for recording tracking shots. Read more
In this terrifying video, Iraqi journalist Ammar Alwaely narrowly misses a sniper's bullet, which takes out his chest-mounted GoPro. Warning: strong language. Watch the video
A new report expects action camera growth to increase about 15% by 2021, with Ultra HD cameras driving demand. Read more
Profiles for Adobe Photoshop and Lightroom have been released for Irix's ultra-wide 11mm and 15mm primes. Like all profiles, these correct for distortion and vignetting.
An upcoming firmware update from DJI will cripple its drones unless they are 'activated' on the company's website. Live streaming will be turned off and flight radius/altitude will be limited.
Brent from ShareGrid rounds up the 10 most common products filmmakers are renting from one another for productions; chances are good you own one or more of them.
DaVinci Resolve is making strong moves to compete with Premiere and Final Cut Pro, including affordable control panels for colorists. According to Premium Beat, they're really good.
If you are not planning to fly your drone commercially you are not required to register it with the FAA anymore. This decision was handed down by a federal court in Washington, D.C.
Whether you're syncing a flash, wondering why banding is appearing in your image or getting strange images from your camera's silent shutter mode, the way your shutter works has a role to play. Here's what happens when you press the shutter button. Read more
William Vazquez travels all over the world documenting humanitarian work. He spoke to us about the challenges of his work, the importance of research and why a multitool and duct tape are your best friends in the field. Read more
These ten film cameras stand the test of time. They are easy to find, affordable and capable of excellent results. Read more
Photographer Aydın Büyüktaş uses a drone, 3-D rendering and Photoshop to create mind-bending landscapes.
They're offering tips for composing selfies and converting to black and white.
Whether you're seeking ultra-high resolution, first-rate autofocus or 4K video capture, there are some supremely capable 'semi-pro' cameras available. Find out which models we liked best in our updated semi-pro camera roundup. Read more
With composition specified by the director, drones may one day be able to navigate a movie set on their own.
Canon has made the previous version, 1.1.0 available for download again.
Impossible? Not if you have a fast lens and 5 stops of stabilization.
This 'strictly limited edition' is a refurbished original Polaroid 600 redesigned with a custom two-tone paint job.
Nikon today announced a reorganization of its corporate structure which will see several divisions and business units closed or merged. Read more
High school students from New York got he chance to shoot along with award-winning photojournalist Ron Haviv in Morocco.
VentureBeat reports that Monday's Surface Pro announcement will bring evolutionary updates to Microsoft's high-end Windows 10 tablet.
The Japanese Camera Journal Press Club has awarded Olympus three out of its four annual prizes after voting by photographic magazine editors and readers.
The photos are great, but whether drones should have been flying in a couple of these places is debatable.
It's not dead yet! A few years ago several high profile filmmakers convinced Kodak to keep making motion picture film. Now they need more facilities to process it.
We made a vlog about vlogging with the M6 (which we used to make the vlog).