Image sensors

[robyn_geering1]

Hi there. I am currently a student of photography, and on a very

steep learning curve studying digital photography at the moment. I

am currently learning about image sensors, and have found much info

about CCDs and CMOS, but was wondering if anyone knew of a third

sensor using completely different technology? If anyone could steer

me in the right direction with this one, I would be very grateful.

Thanks

[ilkka_nissila]

Nikon has a "LBCAST" sensor in the D2H and D2Hs SLRs. You can probably find info on it on the web site www.nikon.co.jp.

[jbq]

LBCAST is essentially CMOS technology with a different layout of the various components of each pixel.

[robyn_geering1]

Kodak has KAC-3100 and KAC5000. Does anyone know anything about these? Many thanks

[dan_edwards]

Kodak has quite a bit of information about its sensors on one of its websites. Go to the

Kodak homepage, search on 'sensors' and you will get lots of hits.

 

As in the film days, Kodak seems more willing to share technical information than many of

their competitors. Too bad that has not translated into a financially stronger Kodak in the

digital age, but it is a nice reminder of a time when the scientists and engineers at Kodak

were THE commercial resource for photographic knowledge.

 

As for other types of sensors, all used in digital imaging in photography are made of

silicon, and I know of no commercial sensor that could not be classified as either a CCD or

a CMOS-like design. However, implementations differ. For example, a scanning back for

a view camera vs a 3:2 CCD in a DSLR.

[eric_boutilier_brown1]

The most "different" sensor would be the Foveon chip, which uses each pixel to gather all three colours of light. The Sigma SD-10 uses this chip, as do a small number of compact cameras. The main advantage of this sensor is that it is much sharper than the standard RGB sensors, though it comes in a lower pixel count, and only in the Sigma body so far.

[peterblaise]

.

 

The Foveon chip is in some Panasonic point and shoots, too.

 

Scanning (and scanning backs?) have dedicated discreet, red, green and blue sensors which then combine in software (firmware?) for a sharper absolute final pixel than the Bayer filter red/green/green/blue CMOS and CCD sensors which must extrapolate their missing colors for EVERY pixel.

 

For instance, a 6 megapixel Bayer CMOS or CCD chip has only 1.5 red megapixels, 1.5 blue megapixels and 3 green megapixels, and must extrapolate the missing red and blue and green pixels to come up with 6 red/green/blue megapixels for final output. Geesh! But it works!

 

A 3 megapixel Foveon sensor has 3 red megpixels, 3 green megapixels, and 3 blue megapixels. Not bad, eh?

 

Robyn, photography is a never eanding learning curve. I've been at this for 40 years already, and I still need to read, and enjoy reading, 4 hours a day about photography, aside from the actual productive photogaphy I do the rest of the day! Sleep? Maybe in my next lifetime! =8^o

 

 

 

 

Click!

 

Love and hugs,

 

Peter Blaise peterblaise@yahoo.com http://www.peterblaisephotogrpahy.com/

[mark_chappell]

<I>A 3 megapixel Foveon sensor has 3 red megpixels, 3 green megapixels, and 3 blue

megapixels. Not bad, eh?</i><P>

 

But not necessarily good either, since the image you get contains just 3 megapixels, even

though there may be 9 megapixels worth of single color channel 'photosites'. With a 6

megapixel Bayer sensor, you end up with an image containing 6 megapixels -- even

though software has to jump through some intricate hoops to regenerate all of the RGB

channels.<P>

 

The Foveon technology may look promising but it certainly doesn't seem to be gaining

much traction at present in competition with 'classic' Bayer sensors.

[joseph_wisniewski]

Peter - "The Foveon chip is in some Panasonic point and shoots, too".

 

Actually, Panasonic makes their own sensors. The Foveon was used in a short lived camera built by "World Wide Licensing" and sold under the Polaroid name.

[lex_jenkins]

If I'm recalling correctly you'll find the most in depth info about Nikon's LBCAST sensor on the Nikon Japan website, not on the Nikon USA site. The Japan site tends to have more technical info, usually written in a chatty style by the engineers themselves.

[ilkka_nissila]

CMOS uses MOS-FET type transistors (by definition), while LBCAST uses JFET.