DxOMark introduces 'Perceptual MPix' score for lens sharpness
DxOMark has introduced a new metric of lens sharpness that it's calling the 'Perceptual MegaPixel'. This is designed to give a simple, easily-understandable indication of how a lens impacts on the resolution of the camera with which it's paired. The measurement is based on standard MTF (Modulation Transfer Function) testing, but also takes into account the sensitivity of the human visual system to detail. The data can be explored over at the DxOMark website, www.dxomark.com.
Our lens reviews are prepared in partnership with DxOMark, using test data shot in its labs. Do you think the 'Perceptual Megapixel' would be a useful number to include in our reviews? Let us know in the comments below.
DxOMark introduces the Perceptual Megapixel as a new unit for measuring the perceived sharpness of lenses
A simple way to quantify the impact of lens sharpness on camera resolution
December 17, 2012 - DxOMark, the website of reference for measuring the image quality of digital cameras and lenses, announces the launch of the Perceptual Megapixel, its new measure of lens sharpness. Expressed in units already well-known to the general public, the Perceptual Megapixel provides photographers with a means of instantly understanding the performance of a lens by quantifying its impact on the perceived resolution of the camera with which it is coupled.
A measurement correlated to human vision
Designed by DxOMark experts, Perceptual Megapixel quantifies the sharpness "perceived" by the photographer while taking into account all the characteristics and defects of the lens and the camera.
"This new unit of measure replaces the MTF scores that we have been publishing up until now. Perceptual Mpix weights MTF measurements with the sensitivity to detail of the human visual system, thus providing a score for the sharpness perceived by our eyes. We think this new measurement will be more understandable and practical for photographers who use our website," explained Frédéric Guichard, Chief Scientific Officer for DxO Labs.
An average of 45% of all megapixels lost
The Perceptual Megapixel measurement allows for making numerous comparisons among cameras and for the first time quantifies the impact of lens sharpness on camera resolution. Thus the perceived resolution for a camera can be significantly different from the native resolution depending on the lenses with which it is coupled.
For example, when coupled with a Canon EOS 5D Mark II camera with a 21.1 Mpix sensor, a Sigma 35mm F1.4 DG HSM lens has a Perceptual Mpix score of 17.2, whereas a lens such as the Carl Zeiss Distagon T* 35mm f/1.4 ZE has a Perceptual Mpix score of 15.2.
The example above is based on data from DxOMark's database of test reults for more than 2,700 camera and lens combinations. These tests reveal that, on average, about 45% of the resolution is lost due to lens defects.
"The Perceptual Megapixel measurement allows photographers to step away from manufacturers' announcements about resolution and to answer a key question when the time comes to change equipment: would it be better to buy a new camera or a new lens?" observed Nicolas Touchard, VP Marketing, Image Quality Evaluation, for DxO Labs.
This new metric introduced by DxOMark aligns with the standardization work currently being undertaken by the IEEE, the International Imaging Industry Association (I3A), and the ISO - and in which DxO Labs actively participates. Perceptual Mpix is also based on the scientific findings of CNES (the French space agency) pertaining to the optimization of digital acquisition, notably in the field of satellite imagery.
More than 2,700 camera/lens combinations available
Freely available to all, DxOMark has been designed to serve the entire photographic community, from serious amateur photographers to photo experts and journalism specialists. It has a threefold mission: to provide objective measurements of digital cameras and lenses; to analyze camera and lens performance; and to provide a means for making meaningful comparisons.
DxOMark now has a database of more than 2,700 available camera/lens combinations. Dozens of DxO Labs engineers and technicians in six DxO laboratories perform these measurements, taking a photo every 10 seconds. Testing protocols are entirely reproducible and conform to the international standards established by the Camera & Imaging Products Association (CIPA), the International Imaging Industry Association (I3A), and the Camera Phone Image Quality (CPIQ) group.
|Carla... by lickity split|
from Beautiful caucasian female faces
|Lunar New Year Fireworks by Michael L NYC 99|
|Vatican Basilica by wam7|
from Street lights
How confident are you that you can spot a manipulated photo? A recent study at the University of Warwick shows that many people are pretty bad at it.
If you purchased a Leica TL2, do NOT attach Leica's Visoflex electronic viewfinder. Leica is working on a fix, but for now, it's possible the viewfinder will break your camera.
Google just released Motion Stills for Android. Unlike the iOS version, the Android app uses a redesigned video processing pipeline that processes each frame of a video as it is being recorded, creating instant results.
A huge copyright lawsuit between photography firm VHT and Zillow Group is heating up again, as both sides appeal a court ruling that granted VHT $4 million in damages.
European Space Agency astronaut Thomas Pesquet spent 6 months on board the International Space Station where he worked with Google capturing spheric panorama images that are now available in Street View.
It's official. PDN has confirmed with parent company Aurelius that 94-year-old lighting company Bowens is indeed going out of business.
The newly launched firmware version 1.06 fixes AF-issues that can occur with some lenses that are not officially compatible with the MC-11 converter.
Voyager is a waterproof smart light stick you can control entirely from your phone. The light has already blown past its $300K funding goal on Indiegogo.
2018 is the last year Photokina will take place during the traditional end-of-September dates. In 2019, Photokina will take place from the 8th to the 11th of May.
The Canon IXUS 50 (known as the SD400 Digital ELPH in North America) was one of a string of high-performing, pocketable PowerShots of the mid-2000s. In this week's throwback Thursday, Barney casts his mind back to 2005.
A close look at the EOS 6D II's Raw files suggest its dynamic range has taken a significant step backwards compared with the company's recent DSLRs. We look at how much difference this might make for your photos.
With a full-production review unit in our hands, we've got over 100 production samples from the new Canon EOS 6D Mark II to share.
Need a break from your day? Kick back and watch the making of a somewhat unconventional mojito filmed on Canon's new EOS 6D Mark II.
The Bonfoton Camera Obscura Room Lens can turn any room into a camera obscura, projecting the view from your window onto the walls of your room.
Adobe just released version 2015.12 of Lightroom CC, adding support for several new cameras and lenses, and baking in several important bug fixes while they were at it.
In this interview, Chiara Marinai, photo editor for VanityFair.com, explains exactly what she looks for in new photographers and photo submissions. Take notes.
Massive corporation P&G is being sued by a Cincinnati photographer for serious copyright violations. If the courts rules against P&G, the company could pay as much as $75 million in damages.
Snapchat's camera-equipped 'Spectacles' aren't so difficult to get anymore. You can now pick up a pair through Amazon for $130.
A group of thieves has made away with tens of thousands in camera gear through a carefully orchestrated scam through Venmo and Facebook Marketplace.
A portrait lens from 1910 might be coming back to life if two photographers from Germany succeed in a new Kickstarter project—the latest development in the craze to remake vintage optics.
The updated version of Google Glass is called the Enterprise Edition and, as the name suggests, it's not meant for personal use.
Charles Ommanney was once a photographer for presidents George W. Bush and Barack Obama, now he's working for Facebook CEO Mark Zuckerberg.
Image compression software JPEGmini Pro was just updated to handle files up to 128MB. They're calling it "The 1 Feature Hasselblad Owners
Apple was just granted a patent for a camera system that prods, coaxes and manipulates users into taking better group and solo selfies.
The Canon EOS 6D Mark II is a better camera than its predecessor, but how much better? Should you buy one?
The winners of the 2017 Magnum and LensCulture Photography Awards have been announced. Here are the six photographers who took home the top prize in their respective categories.
A NASA study has confirmed what your ears have been telling you: people HATE drone noise. In fact, it was ranked more annoying than that of "any ground vehicle."
This floating bird video isn't edited in post-production. It's the result of the birds wing flap matching the camera's 20fps frame rate.
Adobe released a major update to Lightroom Mobile for both iOS and Android users today.
Could the future of photo and video storage be... alive? Scientists at Harvard have managed to encode a GIF of a galloping horse into a live sample of E. coli.