Latest sample galleries
Latest in-depth reviews
The Everyday Sling might just be the perfect pack for not carrying too much gear, combining comfort with Peak Design's signature modern style.
It's unlikely Kodak's Bryce Bayer had any idea that, 40 years after patenting a 'Color Imaging Array,' his design would underpin nearly all contemporary photography and live in the pockets of countless millions of people around the world.
|It seems so obvious, once someone else has thought of it, but capturing red, green and blue information as an interspersed, mosaic-style array was breakthrough.
Image: based on original by Colin M.L Burnett
The Bayer Color Filter Array is a genuinely brilliant piece of design: it's a highly effective way of capturing color information from silicon sensors that can't inherently distinguish color. Most importantly, it does a good job of achieving this color capture while still capturing a good level of spatial resolution.
However, it isn't entirely without its drawbacks: It doesn't capture nearly as much color resolution as a camera's pixel count seems to imply, it's especially prone to sampling artifacts and it throws away a lot of light. So how bad are these problems and why don't they stop us using it?
There's a limit to how much resolution you can capture with any pixel-based sensor. Sampling theory dictates that a system can only perfectly reproduce signals at half the sampling frequency (a limit known as the Nyquist Frequency). If you think about trying to represent a single pixel-width black line, you need at least two pixels to be sure of representing it properly: one to capture the line and another to capture the not-line.
Just to make things more tricky, this assumes your pixels are aligned perfectly with the line. If they're slightly misaligned, you may get two grey pixels instead. This is taking into consideration by the Kell factor, which says that you'll actually only reliably capture resolution around 0.7x your Nyquist frequency.
|A sensor capturing detail at every pixel can perfectly represent data at up to 1/2 of its sampling frequency, so 4000 vertical pixels can represent 2000 cycles (or 2000 line pairs as we'd tend to think of it). This is a fundamental rule of sampling theory.|
But, of course, a Bayer sensor doesn't sample all the way to its maximum frequency because you're only sampling single colors at each pixel, then deriving the other color values from neighboring pixels. This lowers resolution (effectively slightly blurring the image).
So, with these two factors (the limitations of sampling and Bayer's lower sampling rate) in mind, how much resolution should you expect from a Bayer sensor? Since human vision is most sensitive to green information, it's the green part of a Bayer sensor that's used to provide most of the spatial resolution. Let's have a look at how it compares to sampling luminance information at every pixel.
|Counter-intuitive though it may sound, the green channel captures just as much horizontal and vertical detail as the sensor capturing data at every pixel. Where it loses out is on the diagonals, which sample at 1/2 the frequency.|
Looking at just the green component, you should see that a Bayer sensor can still capture the same horizontal and vertical green (and luminance) information as a sensor sampling every pixel. You lose something on the diagonals, but you still get a good level of detail capture. This is a key aspect of what makes Bayer so effective.*
|Red and blue information is captured at much lower resolutions than green. However, human vision is more sensitive to luminance (brightness) information than chroma (color) information, which makes this trade-off visually acceptable in most circumstances.|
It's a less good story when we look at the red and blue channels. Their sampling resolution is much lower than the luminance detail captured by the green channel. It's worth bearing in mind that human vision is much more sensitive to luminance resolution than it is to color information, so viewers are likely to be more tolerant of this shortcoming.
So what happens to everything above the Nyquist frequency? Well, unless you do something to stop it, your camera will try to capture this information, then present it in a way it can represent. A process called aliasing.
Think about photographing a diagonal black stripe with a low resolution camera. Even with a black and white camera, you risk the diagonal being represented as a series of stair steps: a low-frequency pattern that acts as an 'alias' for the real pattern.
The same thing happens with fine repeating patterns that are a higher frequency than your sensor can cope with: they appear as spurious aliases of the real pattern. These spurious patterns are known as moiré. This isn't unique to Bayer, though, it's a side-effect of trying to capture higher frequencies than your sampling can cope with. It will occur on all sensors that use a repeating pattern of pixels to capture a scene.
Sensors that use the Bayer pattern are especially prone to aliasing though, because the red and blue channels are being sampled at much lower frequencies than the full pixel count. This means there are two Nyquist frequencies (a green/luminance limit and a red/blue limit) and two types of aliasing you'll tend to encounter: errors in detail too fine for the sensor to correctly capture the pattern of and errors in (much less fine) detail that the camera can't correctly assess the color of.
To reduce this first kind of error most cameras have, historically, included Optical Low Pass Filters, also known as Anti-Aliasing filters. These are filters mounted in front of the sensor that intentionally blur light across nearby pixels, so that the sensor doesn't ever 'see' the very high frequencies that it can't correctly render, and doesn't then misrepresent them as aliasing.**
|The point at the center of the Siemens star is too fine for this monochrome camera to represent, so it's produced a spurious diamond-shaped 'alias' at the center instead.||This image second was shot with a very high resolution camera, blurred to remove high frequencies, then downsized to the same resolution as the first shot. It still can't accurately represent the star, but doesn't alias when failing.|
These aren't so strong as to completely prevent all types of aliasing (very few people would be happy with a filter that blurred the resolution down to 1/4 of the pixel height: the Nyquist frequency of red and blue capture), instead they blur the light just enough to avoid harsh stair-stepping and reduce the severity of the false color on high-contrast edges.
|With a Bayer filter, you get a fun color component to this aliasing. Not only has the camera tried to capture finer detail than its sensor can manage, you get to see the side-effect of the different resolutions the camera captures each color with.||Again, if you compare this with a significantly over-sampled image, blurred then downsized, you don't see this problem. However, look closely you can still see traces of the false color that occurred at the much higher frequency this camera was shooting at.|
This means that, a camera with an anti-aliasing filter, you shouldn't see as much false color in the high-contrast mono targets within our test scene, but it'll do nothing to prevent spurious (aliased) patterns in the color resolution targets.
|Even with an anti-aliasing filter, you'll still get aliasing of color detail, because the maximum frequency of red or blue that can be captured is much lower.||This image was shot at the same nominal resolution but with red, green and blue information captured for each output pixel: showing how the target could appear, with this many pixels.|
At the silicon level, modern sensors are pretty amazing. Most of them operate at an efficiency (the proportion of light energy converted into electrons) around 50-80%. This means there's less than 1EV of performance improvement to be had in that respect, because you can't double the performance of something that's already over 50% effective. However, before the light can get to the sensor, the Bayer design throws away around 1EV of light, because each pixel has a filter in front of it, blocking out the colors it's not meant to be measuring.
This is why Leica's 'Monochrom' models, which don't include a color filter array, are around one stop more sensitive than their color-aware sister models. (And, since they can't produce false color at high-contrast edges, they don't include anti aliasing filters, either).
It's this light loss component that may eventually spell the end of the Bayer pattern as we know it. For all its advantages, Bayer's long term dominance is probably most at risk if it gets in the way of improved low-light performance. This is why several manufacturers are looking for alternatives to the Bayer pattern that allow more light through to the sensor. It's telling, though, that most of these attempts are essentially variations on the Bayer theme, rather than total reinventions.
These variations aren't the only alternatives to the Bayer design, of course.
Sigma's Foveon technology uses a fundamentally different approach to measure multiple colors at the same location, so promises higher color resolution, no light loss to a color filter array and less aliasing. But, while these sensors are capable of producing very high pixel-level sharpness, this currently comes at an even greater noise cost (which limits both dynamic range and low light performance), as well as struggling to compete with the color reproduction accuracy that can be achieved using well-tuned colored filters. More recent versions reduce the color resolution of two of their channels, sacrificing some of their color resolution advantage for improved noise performance.
Meanwhile, Fujifilm has struck out on its own, with the X-Trans color filter pattern. This still uses red, green and blue filters but features a larger repeat unit: a pattern that repeats less frequently, to reduce the risk of it clashing with the frequency it's trying to capture. However, while the demosaicing of X-Trans by third-party software is improving, and the processing power needed to produce good-looking video looks like it's being resolved, there are still drawbacks to the design.
Ironically, devoting so much of the sensor to green/luminance capture appears to have the side-effect of reducing its ability to capture and represent foliage (perhaps because it lacks the red and blue information required to render the subtle tint of different greens).
Which leaves Bayer in a situation akin to Winston Churchill's take on Democracy as: 'the worst form of Government except all those other forms that have been tried from time to time.'
As we've seen before, the sheer amount of effort being put into development and improvement of Bayer sensors and their demosaicing is helping them overcome the inherent disadvantages. Higher pixel counts keep pushing the level of color detail that can be resolved, despite the 1/2 green, 1/4 red, 1/4 blue capture ratio.
And, because the frequencies that risk aliasing relate to the sampling frequency, higher pixel count sensors are showing increasingly little aliasing. The likelihood of you encountering frequencies high enough to cause aliasing falls as your pixel count helps you resolve more and more detail.
Add to this the fact that lenses can't perfectly transmit all the detail that hits them, and you start to reach the point that the lens will effectively filter-out the very high frequencies that would otherwise induce aliasing. In recent years we've seen filter-less sensors starting at 36MP on full frame, 24MP on APS-C and Four Thirds sensors from 16MP (all of which are sampling their lenses at over 200 pixels per mm), and seen that these only produce significant moiré when paired with very sharp lenses shot wide-enough open that diffraction doesn't end up playing the anti-aliasing role.
So, despite the cost of light and of color resolution, and the risk of error, Bryce Bayer's design remains firmly at the heart of digital photography, more than 40 years after it was first patented.
Aug 6, 2018
Jun 27, 2018
May 28, 2018
May 15, 2018
The Everyday Sling might just be the perfect pack for not carrying too much gear, combining comfort with Peak Design's signature modern style.
When the Fujifilm X-T2 arrived, it was more than just a modest upgrade to the already impressive X-T1. While the new X-T3 hasn't changed the overall design of the camera, this model is way more than an upgrade; rather, it's a quantum leap.
The Movie Maker is a compact, motorized slider designed for phones, action cams and small mirrorless cameras. We think it's a fun little kit and a good value proposition for the cost, provided you can work around a few of its weak points.
Nikon's Z7 is the first camera to use the all-new Z-mount, the company's first new full-frame mount since 1959. We've put together our first impressions based on quality shooting time with a pre-production camera - check out what we've found.
What's the best camera for a parent? The best cameras for shooting kids and family must have fast autofocus, good low-light image quality and great video. In this buying guide we've rounded-up several great cameras for parents, and recommended the best.
What's the best camera for shooting landscapes? High resolution, weather-sealed bodies and wide dynamic range are all important. In this buying guide we've rounded-up several great cameras for shooting landscapes, and recommended the best.
What’s the best camera costing over $2000? The best high-end camera costing more than $2000 should have plenty of resolution, exceptional build quality, good 4K video capture and top-notch autofocus for advanced and professional users. In this buying guide we’ve rounded up all the current interchangeable lens cameras costing over $2000 and recommended the best.
|walkersons fields by George Veltchev|
from -Waiting for Autumn- (in Full Colours Only)
|A smile is worth a thousand words by alberto_b|
from Fill the frame
The 'I'm Back' is now available for a range of old film-SLRs, such as Nikon's F-Series, the Olympus OM10 or the Canon AE-1.
IRIX has announced its latest lens, the 150mm F2.8 Macro 1:1. IRIX claims the lens features 'close to zero' distortion and stands out with its 150mm telephoto focal length.
The RF 24-105mm F4L IS USM is one of four lenses to launch with Canon's new full-frame mirrorless system, and it boasts the longest reach of the range. Take a look at some of the samples we've gathered thus far as our EOS R testing continues.
Nikon's Sendai factory in the Tōhoku region North of Japan has been churning out cameras and lenses since 1971. We had the opportunity recently to visit Sendai during events to mark the launch of Nikon's new Z mount.
There's no mistaking the Nikon Coolpix P1000 – with a 24-3000mm equivalent zoom, it really is in a class of its own. It's a conspicuous-looking superzoom with one main job: getting you really close to far away subjects. We've put together a gallery showing the kind of results you can expect from it.
A new report from The Verge claims Instagram is currently testing a feature that allows users to re-share posts to their own account feeds.
GoPro has announced its HERO7 camera lineup. The updated action cameras feature new HyperSmooth and TimeWarp modes, as well as improved video and photo specs.
The latest Samsung midrange smartphone offers a super-wide-angle lens in its triple-camera setup.
The Sony 24mm F1.4 is the latest lens to join the company's premium G Master lineup. We've been shooting with one for a couple of days - here's what you need to know.
Apple released iOS 12 a few days ago and some iPhone X users are less than happy with how the new operating system has made their phones look.
Camera bag manufacturer Lowepro has introduced mark II backpacks for its ProTactic AW range with models that are said to feature an improved handling experience as well as a collection of accessories that can be attached to the outside.
Canon has announced its latest superzoom camera, the PowerShot SX70 HS. Compared to the SX60 that came before it, the SX70 has the same lens but offers a higher resolution EVF, 4K video capture and support for Canon's new CR3 Raw format.
Cosina has announced its eighth lens designed specifically for Sony's E-mount system. The Voigtlander 21mm F3.5 lens is due out October 2018.
Sony has taken the wraps off of its new 24mm F1.4 GM full-frame lens, which the company claims is the lightest in its class. Despite its fast aperture, the 24mm F1.4 is remarkably light, weighing just 445 grams (15.7 ounces). The lens will set you back $1400 when it ships next month.
In this episode of DPReview TV we take a look at Sony's brand new 24mm F1.4 GM lens, a desirable focal length for many photographers. How does it perform? Chris and Jordan give us their first impressions.
We've had a little time to shoot with Sony's new wide/fast prime, both close to home and on the water in San Francisco. Check out our initial sample images.
Fujifilm released a firmware upgrade for its X-T3 mirrorless camera that addresses issues with distortion compensation and the mechanical lock on SD cards.
The app's algorithms have been trained using using 200 million cropping data points from real photographers.
Thanks to a software update, the Loupedeck+ editing console can now be used for video editing.
British photographic engineer MTF Services is claiming the world’s first third-party lens adapters for the new Nikon Z system with a collection of four units designed to allow cinema lenses to be mounted on the mirrorless full frame bodies.
Think Tank Photo has updated its line of heavy-duty rain covers and introduced a new, compact version for emergency situations.
The X-T3 is our first opportunity to analyze what's likely to be Fujifilm's next generation image sensor. Take a look at how it performs next to the competition in our studio test scene.
Canon's new normal is seriously sharp wide open. After shooting with it for a few days, we've prepared a gallery of real-world sample images.
Nikon will cease offering Brazil-based customer service and technical support, though the company stresses that it will still offer technical assistance and warranty repairs for valid warranties.
Two years ago, CatLABS of JP announced a plan to save Packfilm from the dead. Now, it's announced it's giving up its efforts to better focus its resources elsewhere.
The GoPro Fusion is designed to make it easy to capture 360-degree video and stills. We took it out recently on a typically hot Seattle summer day to see what it can do.
We've got our hands on a full-production Nikon Z7 camera and have updated our gallery with additional samples.
A new Kickstarter campaign seeks funding for Chroma Chrono, a programmable RGB camera flash that emits multiple colors during long exposures.
Think Tank Photo has launched a new lineup of six dual-access, water-resistant protective lens cases it calls Lens Case Duo.
Canon and Nikon finally entered the full-frame mirrorless market this summer with the brand-new RF and Z mounts. Now that we've had some time with the cameras, we wanted to revisit our earlier predictions and take stock.