Thank you for reading the open letter and thank you so much for all your comments.
Let me start with an OOOOPS, I apologize! When the issue that prompted this open letter came about, it was because of a discussion of the structure of CMOS sensors. The whole discussion focused on these structures, and once I received the final data it escaped me that some of the cameras on the chart had CCD sensors. I apologize for any confusion this oversight might have caused.
The whole point of the letter though, remains intact, which is that the light loss depends on the structure of the sensor, and that light loss at the sensor is a very real phenomena.
On a related topic, and to respond directly to one of the comments on the forum: The mention of Medium Format has nothing to do with trying to put MF in a better light or to try to imply that somehow CCD sensors are better than CMOS. Quite the contrary, the mention of MF was meant to point out that the MF back manufacturers face an even bigger problem, which has forced them to produce structures that are quite different. My understanding from talking to the CTO's of the major MF companies is that at this point in time they cannot produce a CMOS sensor that will work for MF backs. While the current CCD structures work well with camera movements, there is no free lunch and they require compromises in other areas, for example, MF CCD backs have a huge negative, which is that Live View is not possible. Personally, I wish I could have a MF back with Live view today! There are other drawbacks to CCD's, but let us not digress.
Let me also respond directly to the comment that the data cannot be found on the DxO site. There is a new release of the DxO site coming in a few weeks. It will contain a lot of new data, including the data that support this open letter.
While there has been some discussion on the depth of field issue, l would like to repeat what I said in the open letter, which is that DxO is in the process of performing thorough focus measurements. Once the final focus measurement data is available, we will be able to put this issue to rest.
Finally, I hope that all of you understand that the reason this was written as an open letter as opposed to an essay is that there are a number of open questions. I asked some of them, and the participants in the forum are asking many other valid questions. We at The Luminous Landscape would like to have an open and constructive dialog with the camera manufacturers to better understand what is going on "under the hood", and to better understand what we can expect from our tools as we use them.
It is my hope that we will receive some interesting feedback from some of these companies. If we do, we will definitely share it with you.