Dear Photo Enthusiast,

Since its launch on November 17, 2008, the dxomark.com website has continued to experience a very high level of traffic. We are regularly receiving numerous comments, suggestions, and questions from the photographic community, indicating genuine interest in RAW-based digital camera measurements and rankings.
Also, the discussions on the various forums have raised many questions and comments that certainly deserve detailed answers from DxO Labs, which we will try to provide on a regular basis in this Questions & Answers section. We will do our best to monitor the various discussion threads and forums and to continue to respond to the questions and issues you and your fellow photographers raise.

With our best photographic wishes,
The dxomark.com team

If you’d like to be informed about updates to the dxomark.com site, click here to receive our regular newsletter (coming soon). Also, please continue to send us your comments, suggestions and questions, as your feedback will help us deliver the most detailed, accurate and relevant information to you that we can.

General questions

• "Who is DxO Labs? How legitimate are its image quality measurements? What is DxO Analyzer?"
• "What exactly do you measure? What do you DON’T measure?"

DxOMark Sensor

• "What do I need to know to understand dxomark.com data and its DxOMark Sensor scale?"
• "Does the DxOMark Sensor scale factor in resolution?"
• "How should the DxOMark Sensor scale and its metrics be used?"
• "How is DxOMark Sensor computed?"
• "DxOMark precision seems meaningless and misleading. What is the practical significance of the scale?"
• "DxOMark Sensor is composed of objective and repeatable measurements, but the way they are aggregated is arbitrary!"
• "How can I know if two cameras are noticeably different?"
• "Is DxOMark Sensor computed from on-screen measurements (1:1) or from prints (8Mpix)?"
• "Why is print size 8Mpix only?"
• "Is it fair that a 12Mpix camera can be rated as highly as a 24Mpix camera?"
• "Should I interpret DxOMark Sensor results depending on the way I use a camera?"
• "Some camera bodies have the same sensor, but DxOMark Sensor shows different results."
• "Is 100 the maximum possible DxOMark Sensor value?"
• "Cameras with ISO range starting at ISO200 seem under-rated."
• "I tried some cameras with very good DxOMark Sensor rating, but I prefer mine with a lower rating."
• "Camera should be considered as a whole, measuring RAW only is pointless."

IQ Database

• "Dynamic range should decrease with ISO Sensitivity."
• "SNR curves should not cross!"
• "Optics can bias your measurements."
• "Why are noise measurements in RAW relevant for evaluating the sensor, and not for JPEG?"
• "Some cameras already process their RAW images. In particular, they apply noise reduction, which leads to unfair comparison."
• "Some dxomark.com datasheets provide an ISO latitude that differs from the manufacturer’s datasheet."
• "It looks like some manufacturers cheat with ISO sensitivity."
• "Canon 40D has an option called “Highlight Tone Priority,” and other manufacturers offer similar features. Were the dxomark tests performed with this feature on or off?"
• "Why RAW-based ISO sensitivity values reported on dxomark.com sometime differ from manufacturer’s ISO sensitivity values?"
• "How is ISO Sensitivity measured for DSC cameras (cameras with non-removable optics)?"

Q&A specific to medium-format cameras

• "Medium-format cameras are dedicated to specific uses and DxOMark equally weighs three use cases. Why are medium-format cameras ranked on such a scale?”
• "Why aren’t other parameters such as fps (frames per second) or tropicalization factored into dxomark?"
• "Most medium-format cameras do not have an anti-aliasing filter, and DSLRs do. Is this taken into account in the DxOMark scale?”
• "DSLRs have intrinsic RAW processing capabilities. Doesn’t this mean that their DxOMark ranking is biased in their favor, to the detriment of medium-format cameras (which do not do RAW processing)?"
• "Isn’t high ISO over-weighted on DxOMark to the disadvantage of medium-format cameras?"
• "How can DxOMark rank medium-format sensors below DSLRs, given that MF camera sensors are known to be far superior? "
• "Is it logical and fair to normalize based on an 8Mpix A3 print when ranking medium-format cameras are primarily designed for very high resolution applications and large-size prints?"
• Overall, objective versus subjective evaluation is being questioned: the end-product of a camera is a photo looked at by a human. How can its quality be assessed by numbers?
• "How is it possible for dxomark to assess the quality of a camera from just few shots of very simple color and density pattern charts?"