Dear all,
The following is from Finney. The first thing I would like to say is I won't answer any comments on this post, especially those challenging the credential issue:
Just came back from Lassen National Park. Beautiful place! Took some nice photos with TVSD there.
First I will have to thank many people who had tried to defend me, but please, stop doing so for now as this will not do this board any good. I was very amused by seeing words such as "sad" or "punishment" showing up here. Do we really have to be so serious? This website is fairly new. It is natural that the webmaster would over-eagerly try to protect his babe. Things may change along the time, anyway, right?
Some said that the dialogs had turned to be too technical. Well, in reality, nothing has really reached the technical level yet. It's only crosscheck on basic concepts at best.
One basic concept I kept stressing is that the conversion process (commonly termed as AFE, Analog Front End) from image sensor signals to raw image file is not done just through an A/D converter. You can check the block diagrams in the webpages listed below:
Philips Semiconductor:
http://www.semiconductors.philips.com/pip/TDA9962.html
Texas Instruments:
http://www.ti.com/sc/docs/products/msp/videoimg/ccd/blckdiag.htm
Analog Devices:
http://www.analog.com/UploadedFiles/Data_Sheets/78682628AD9821_0.pdf, first page.
National Semiconductor:
http://cache.national.com/ds/LM/LM98501.pdf, second page.
In the diagrams, PGA stands for programmable gain &lifier, and VGA is variable gain &lifer. They are used mostly for basic noise reduction, black level calibration, and white balance, etc, at the analog stage. As you can see, most or less, they all have similar structures, there is some sort of loop around the ADC, analog to digital converter. You will let you be the judge this time, and I am sure your brain will tell you what is true and what is not.
AFE chip is a very hot market now. Many digicams, probably include the ones you have, have already used the chips listed above. I used Nu Core's design as an ex&le simply because its website had more information available to the public. Again, I will have to emphasis, even with the same image sensor, different AFEs will give you different quality of raw image data.
I agree that is the photo, the final product, which counts. But in film photography, won't you choose the right film to get the best result for a specific subject? Similarly, for digital photography, other than lens and image sensor, you may have to choose the right AFE, the right image processor, and the right software? Even when companies only provide you bundled solutions today, this does not mean you can not make a better choice among them? For a new product, it will take time for people to learn the truth then ask for better solutions. Remember when CD players just came out, many experts told you that this is the ultimate sound and all CD players should sound the same? Who would have expected that today we have products like CD transporter, box to kill jittering, D/A processor, and up-s&ler, etc? Will high end digicams become highly modulized? The coming Leica digi back may be a hint to what will come in the future?
BTW, I am 100% American. My real job is in the chip design business, actually, it is more like near the top of chip design chain. The specific field I am in allows me to have access to real design data as well as chip manufacturing issues. I have come across several image processors, AFEs, in the past. Right now I am invovled with big projects like the new Sony Play Station 3, a new 3D graphic chip, some super router core chip...etc. The issue is that I have never talked about those (do I really care? probably some people care, but I don't) with Shu-Hsien. With his MD background, he thought everything related to computer and chip was called IT.
After reading some call for real answers here, I am thinking of starting a loosely coupled discussion group to focus more on the technology side of photography. I will not mind sharing industry news and whisper there. The membership will be selective, most likely through referral only. It will be email based and everybody has to use her/his real identity. Some may warn this kind of discussion group will lead to a cult like status but I believe when someone is already interested in technologies to this level, she/he should possess the poweress to do independent thinking. Not intend to replace the role of contaxinfo, quite on the contrary, the list will be a supplement to it. We all know that open forums will run into certain problems sooner or later, and we need a new kind of disscusion group. Please share your thought and see where we can go from here.
Since the talk has turned to a bit philosophical, let me also post a quote from a famous Chinese philosopher/writer in the early 20th century:
Who care about million of critics!! Yet I will tender those still willing to learn!
So, keep smiling and do not forget about taking great pictures!
-finney