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
|Christine by JP Zanotti|
from Car wreck
|Fangorn Forest by cand1d|
|Yosemite Falls with Moonbow by Jonathan Shapiro|
from Best Landscape of the Week 4
Think Tank Photo has updated two of its popular bag lines with improvements to functionality. Read more
We’ve all seen Bob Jackson’s Pulitzer Prize winning photo, but there's another.
The sample footage looks good.
It will automatically pick the best camera settings depending on shooting conditions. It even promises enhanced functionality for your camera, like exposure and focus stacking. It already supports many cameras from Canon, Fuji, Nikon and Sony. Read more
As if $13,950 wasn’t enough to pay for a special edition lens, the Leica Store in San Francisco is offering a prototype of said lens for $24,995. Read more
Make those old photos disappear without deleting them forever.
Firmware updates enable 10 fps shooting with adapted A-mount lenses, and faster startup times and better compatibility for 20 fps shooting when using native lenses on the a9.
Fujifilm has released firmware updates for its camera models X-T2, X-Pro2, GFX 50s, X-T20, X100F and X-T1 and updates to three of its software products.
A 22 year-old Romanian photographer uses his DJI Phantom 4 drone to capture unique perspectives of the city where he now lives.
What's it like to ride the waves with champion surfer Kelly Slater? This VR video from Teton Gravity Research gives you a taste.
When Nikon released the full-frame D3 in 2007, it changed the professional photography industry. In this week's Throwback Thursday, Barney remembers a legend. Read more
The new stuff should have better red hues, improved sensitivity and finer grain - but don't worry - will still shift blues to green, greens to purple and yellows to pink.
Ricoh has introduced a new rugged compact camera with a 16MP CMOS sensor, 28-140mm lens, 2.7" LCD and built-in LED macro lights. Read more
This compact drone can shoot HD video using a 2-axis stabilized 12MP camera. Read more
The new Prynt Pocket can print a photo directly from their iPhone simply by inserting the phone into the printer, then snapping a photo. Each print will cost about 50 cents. Read more
Updates for Adobe Camera Raw and Lightroom CC bring support for the Sony A9 and Panasonic ZS70/TZ90, along with bug fixes.
The Triggertrap remote camera control system is no longer sold due to the company folding, but now users will be able to build their own. Read more
The Magic Format Converter comes with internal optics that expand the image circle of full-frame DSLR lenses for use on the Fuji medium format camera. Read more
The usually Apple-exclusive MacPhun software developer has announced that it will introduce PC versions of two of its most popular applications. Both Aurora HDR and Luminar should be available for the Windows operating system by the autumn of this year. Read more
Sony's newest G Master telephoto zoom, announced alongside the a9, is the first of the company's FE lenses to reach 400mm natively. We had one in California and photographed horses, portraits, and landscapes - check out how it did. Read more
Garmin has entered the 360-camera market with the VIRB, which captures 5.7K video at 30p as well as 15MP stills. Read more
German media reports that the founders of the company behind the Panono 360-degree ball camera have filed for bankruptcy at a court in Berlin. Read more
With a claimed 800 new custom parts, Microsoft's updated Surface Pro comes with the latest Kaby Lake processors, better battery life, a new hinge, plus the Surface Pen is updated as well. Read more
DW Photo is attempting to resurrect the Hy6 medium format camera, though the legal tangles of its development may stop it being branded Rolleiflex.
The Kodak EKTRA, the company's 'camera first' smartphone, is now available to purchase in the United States. Read more
Apple and Nokia have settled their years-old patent dispute. Apple will make an undisclosed payment to Nokia and sign a licensing agreement related to digital health products with the Finnish company.
David Gibson, one of Britain's best known street shooters, shares all.
Photographers from the SKYGLOW project travelled 150k miles and took 3 million photos in increasingly rare locations: those without light pollution.
The world's fastest 200mm was produced for 16 years. In that time, only 8000 were made.
Photokina, the biennial photo industry trade show in Cologne, Germany, has announced that it will become an annual event beginning in 2018, and expand its focus to additional areas of imaging technology. Read more