CCD and CMOS, Prices don't make sense

[Starstreams]

Hi PeterP

Very interesting info, typed this out.
Thank you!

So your not really talking about focal length here, it sounds like your talking about the actual dimensions of the capture device if that's ok to call it? or better yet (CCD or CMOS)?

Stupid question here: can I say that 1/32 is the same as 1/2 -> 16th inch?
did this (mm) stuff work the same with the old analog manual cameras as far as referring to the capture device's dimensions?
It was the dimensions everyone refered to even back then right?

[PeterP]

Yes, that is right it is the physical size of the capture device.

So your not really talking about focal length here, it sounds like your talking about the actual dimensions of the capture device if that's ok to call it? or better yet (CCD or CMOS)?

The capture device can be either CMOS or CCD. For instance for astrophotography the CCD based units are still the prefered way to go.
CCD units start with no electron charge and it builds as photons hit the photosites. They can go for very long exposures if cooled to extremly low temperatures. (heat will cause false noise)
CMOS work the other way, they start at high charge and it drops as photons hit the photosites. The initial charge will also disipate on its own over time fairly quickly. So their long exposure capability is limited.

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I think so, we have been metric here so long I have a hard time converting back.
But a 32nd should be 1/2 of a 16th :blah:

Yes, the "old" analogue was 35mm film whos dimensions were 24mm*36mm
not exactly sure how 24*36 got to be called 35mm :?
That is why cameras like the canon 1ds are called full frame cameras, their sensor (capture device) is the same size as the older 35m film used to be

Stupid question here: can I say that 1/32 is the same as 1/2 -> 16th inch?
did this (mm) stuff work the same with the old analog manual cameras as far as referring to the capture device's dimensions?
It was the dimensions everyone refered to even back then right?

[PeterP]

I located an old sensor size chart I orignally found on the digicams site a long time ago when I was looking for my first digital.

The 2/3 sized sensor in the sony is the 11th one down labeled here as a F707
The 1Ds sensor is the last one at the bottom.

[Starstreams]

Very very interesting Peter!
Man I got an edu that's for sure, Thank you!




I don't think it would be so bad if I was better in math, its a long story but I wentthrough high school with only one math class so I'm catching up once I start school again.



That chart was very cool!
You see the 12th one down? Says 1"- 12.8 X 9.6mm

Doses that mean you multiply 12.8 X 9.6 and some how convert it to 1"

[Carrots]

The 1Ds using a CMOS sensor is kinda confusing/surprising. Just the other day I was reading how CMOS sensors are improving, and can almost come close to matching CCD quality.

CMOS sensors are mainly used in cell phone cameras because of their small size, low power requirements and low cost. I think it costs about $12 for a 2MP cell phone camera sensor. I think the processor might be included in that price.

[PeterP]

Actually that is the most confusing part:!:
the names like a 2/3 or a 1/1.8 are from old 50's TV tube days

This link describes it pretty well
http://www.dpreview.com/news/0210/02...ensorsizes.asp

That chart was very cool!
You see the 12th one down? Says 1"- 12.8 X 9.6mm

Doses that mean you multiply 12.8 X 9.6 and some how convert it to 1"

Carrots:
:-) It is very easy and cheap to make tiny sensors, it gets harder and harder to make larger ones without defects.
The sensors come out of the "creation process" as big sheets that are cut up into the sensors afterwards.
For the small sensors finding tiny areas without defects is not hard.
On the sheets for the large sensors finding big areas that have no defects is not so easy and there is a lot of discards. Or at least use to be. The manfacturing processes get better all the time.

Another amazing thing on the latest large sensors is that each individual photosite has a microlens in front of it to direct the light. All 8 or 16 million of them.
:homey: I keep imagening factories of tiny elves all sitting there doing nothing but glueing the microlenses to the sensors all day :blah:

[Carrots]

Carrots wrote:

Just the other day I was reading how CMOS sensors are improving, and can almost come close to matching CCD quality.

That is the part I find hard to wrap my mind around. Maybe CCD is only better than CMOS in the smaller sizes.

I understand why CMOS gets (probably)exponentialy more expensive as the size,or rather number of elements, increases (as with most electronic silicon). I think50% yield for the newest fastest desktop processors are considered very good.

[PeterP]

Found this rather interesting article on ccd/cmos sensors:
http://www.shortcourses.com/how/sensors/sensors.htm

Although it is almost 3 years out of date now (written in 2003), it is still very interesting.

There is one item that really interested me, they worked out a resolution for the human eye. :lol:
Human eye | 11,000 x 11,000 | 120 million

[DBB]

PeterP wrote:

Found this rather interesting article on ccd/cmos sensors:
http://www.shortcourses.com/how/sensors/sensors.htm

Although it is almost 3 years out of date now (written in 2003), it is still very interesting.

There is one item that really interested me, they worked out a resolution for the human eye. :lol:
Human eye | 11,000 x 11,000 | 120 million


Peter.

Three years old is nbow ancient history. CMOS sensors are now made for ALL the professional cameras. Not just Canon. The new Nikon D2x is CMOS. CCD is not inferior, rather too power hungry. If this changes perhaps we shall see them return. But as of now, CMOS matches the quality without using all that precious battery life.

Dave

[Starstreams]

Nice find on them links Peter! Thanks

Some of the answers in this thread should be made sticky! Very goodinfo from all you guys!