Digital CCD, Bayer and sharpness

In response to a PM I received, here's some background information and bed-time reading for anyone who wants to know what goes on It is, in part, some of the information I used in developing my "Sharpen-O-Matic" action for Photoshop.

Just to start the subject, sharpness is dependent on a number of factors. We are talking sharpness in terms of the ability to render fine details, not just the ability to produce "hard" looking edges where there is obvious contrast.

* The lens. Resolution and contrast are two important qualities. In addition, collimation of the lens is important for digital (how perpendicular the light hits the CCD, because the individual sensors are deep as there's other stuff in front of the sensor)

* The low-pass filter. There's a filter in front of the CCD that provides the colour, and this is coated too.

* The CCD itself. Resolution is the main factor.

* The quality of the A-to-D conversion. Fine detail needs fine rendering of the nuances of light, rubbish A-to-D will produce a corresponding image.

* If using JPG: in camera RAW-to-JPG conversion. (This is probably the main focus of "Pentax is soft" rants)

* If using RAW: which software is used to convert the RAW. Not all RAW convertors are the same

* Final post-processing techniques.



Now, I'll just say that the last two procedures require skill. Acquiring that skill takes time and effort.

So, here's some reading for you all:
Bayer matrix: http://en.wikipedia.org/wiki/Bayer_filter
Demosaicing: http://en.wikipedia.org/wiki/Demosaicing

Adding presence: http://www.outbackphoto.com/dp_essentials/dp_essentials_05/essay.html
(the main inspiration for the Sharpen-O-Matic)

Tutorials for post processing:
http://www.thelightsrightstudio.com/learning-sharpening-toolkit.htm and http://www.thelightsrightstudio.com/tutorials/PutAFineEdgeOnYourSharpeningSkills...
(Also worth checking out all the tutorials and learning galleries http://www.thelightsrightstudio.com/tutorials-pdf.htm - especially the Developing Photos that Pop series)


There's a lot more to be said on the subject, but let me finish by saying that the K10D is sharp. Very sharp indeed. And the Pentax lenses I use are all sharp too (and frankly I don't care much if anyone tells me the K10D is "soft", 'cause it's not )

Enjoy!
Matt

DITTO your comment above Matt...!!!

And thanks for all your tips and help on this subject, since I've been using the K10D and really made my departure from 35mm film to Digital (the Med Format kit still gets plenty of outings tho...), I've been using your instructions about post processing and sharpening workflow and haven't put a foot wrong. It takes some time and experimentation with settings but it's time well spent.

Thanks to all for pointing me in the right direction...