OT: Megapixels vs CCD size - or Pixel Density

will-3 wrote on 8/8/2009, 7:58 AM

When evaluating a new cam… megapixels and CCD size are two of the many parameters considered…

I'm thinking "Pixel Density" may be a better measure...

If a manufacturer is able to pack a zillion pixels into a CCD 1/8" wide... well, your still left with a 1/8" CCD…

It would seem to me that a more useful spec would be pixels per unit of measure in the horz direction... and spacing between rows in the vertical direction.

Some where it would seem... there should be a point at which the relationship between pixel density and quality (or resolution or sharpness) would flatten out...

I'm guessing that... if you can get the number of horz pixels... and the width of the CCD... and divide... you have the horz pixel density...

And the number of pixel "rows" on the CCD divided into the "advertised" height of the CCD should give you vertical pixel density...

But I’ve also heard not all of the CCD is actually used for the image output to the frame…

And not sure if all mfg's share enough info to do these calc's...

Comments?

Thanks.

Comments

Lou van Wijhe wrote on 8/8/2009, 2:52 PM

This thread: http://www.hv20.com/showthread.php?t=2679
from the HV20/30/40 Forum might interest you.

Lou

farss wrote on 8/8/2009, 3:59 PM

Kind of gets bogged down in the diffraction limit though.
Most significant parameter is photosite size. From that it's easy enough to see that for a given imager size more pixels is a bad thing. Three imagers is better than 1 upto around 2/3" beyond that things get complicated / expensive for lens design.

Some meaningful discussion here about all this:
http://www.sonycreativesoftware.com/forums/ShowMessage.asp?MessageID=638076

Also worth a trip to the Panavision theatre and sitting though a couple of hours of their discussion about camera design.

Bob.