CCD Vs CMOS

[Swordman]

Ok, could someone explain to me, in simple terms, why nearly all cameras have CMOS sensors instead of CCD?

I know Leica users used to praise CCD sensors for the colours, and from what I remember, CCDs have quite a few advantages (can't remember them, though).

 

[Jonsi]

Won't give a long, boring, technical explanation of things no one cares about (though others will be glad to), but low light performance is one reason. CCD couldn't match CMOS, and alongside the megapixel race was the ISO race.

I like the CCD results and still shoot mine occasionally.

 

[Jon555]

Ok, could someone explain to me, in simple terms, why nearly all cameras have CMOS sensors instead of CCD?

I know Leica users used to praise CCD sensors for the colours, and from what I remember, CCDs have quite a few advantages (can't remember them, though).

Short version - CCDs are rubbish at higher ISOs... like 400+

Also you can't add digital processing functions to CCDs, which you can in CMOS.

 

[Swordman]

Thanks Jonsi and Jon555. That's what I was after.

 

[Jon555]

BTW CCDs still exist in some very cheap cameras as they are cheap.

Also they have a global shutter, so for example my Fuji W3 3D camera has CCDs...

 

[Gerry Winterbourne]

Ok, could someone explain to me, in simple terms, why nearly all cameras have CMOS sensors instead of CCD?

I think one reason is speed of readout, which makes live view and video practical.

I know Leica users used to praise CCD sensors for the colours, and from what I remember,

As I understand it the colours are purely a function of the filters, not the sensor behind them. Early cameras used quite strong filters, which reduced the light reaching the sensor.

As users demanded better low light performance the filters were weakened, and that would probably happened even in CCDs had continued mainstream.

CCDs have quite a few advantages (can't remember them, though).

 

[Mark S Abeln]

Ok, could someone explain to me, in simple terms, why nearly all cameras have CMOS sensors instead of CCD?

I know Leica users used to praise CCD sensors for the colours, and from what I remember, CCDs have quite a few advantages (can't remember them, though).

That’s still a fairly common question, despite the shift to CMOS occurring more than a decade ago for most manufacturers.

Silicon sensors of any kind are not sensitive to color. Digital cameras typically detect color via a color filter array placed over the sensor, and then heavy processing is needed to process the recorded signal into plausible colors. If there are any differences in the color output of CCD and CMOS, it must be due to these and not the basic sensor technology.

Standard JPEG processing also seems to have changed, at least with Nikon, leading to less-saturated and flatter looking images out-of-camera. This allows for more flexible editing on the computer, but if you like the richer color of older cameras, you might want to boost saturation and contrast.


--

The Refracted Light

A website about the Art and Science of Photography

therefractedlight.blogspot.com

 

[rochester21]

That's what i hear.

Another benefit would be video, but i don't remember any details.

 

[Aoi Usagi]

The initial reason why many manufacturers switched from CCD to CMOS was because they were cheaper to mass produce.

 

[Guy Parsons]

That's what i hear.

Another benefit would be video, but i don't remember any details.

Video. With my CCD Panasonic LX3 then a train passing by at 300kph still looks like a train. The same scene with a Casio pocket camera with CMOS had the train leaning forwards. or was it backwards?


Frame from CCD video in 2009




Frame from CMOS video in 2011 at same station, that door should be vertical.

The really fast "bucket brigade" unload of CCD makes it act like a global shutter, while the CMOS has a much slower progressive expose and unload row by row so the timing from top row to bottom row gets a bit long and allows the distortion.

 

[Donald B]

cheaper to make

Don

 

[Donald B]

Won't give a long, boring, technical explanation of things no one cares about (though others will be glad to), but low light performance is one reason. CCD couldn't match CMOS, and alongside the megapixel race was the ISO race.

I like the CCD results and still shoot mine occasionally.

That wasnt true at all 10 years ago ,canon had one of the first cmos sensors and its was that noisey. so many magazines rubishied it CCD was so much better. and my xz1 1/17 sensor has no more noise than my em12 sensor after doing a test the other day so Im going for your statement is incorect.

Don

 

[Charles McRobert]

That's what i hear.

Another benefit would be video, but i don't remember any details.

Video. With my CCD Panasonic LX3 then a train passing by at 300kph still looks like a train. The same scene with a Casio pocket camera with CMOS had the train leaning forwards. or was it backwards?


Frame from CCD video in 2009


Frame from CMOS video in 2011 at same station, that door should be vertical.

The really fast "bucket brigade" unload of CCD makes it act like a global shutter, while the CMOS has a much slower progressive expose and unload row by row so the timing from top row to bottom row gets a bit long and allows the distortion.

You have illustrated the difference very well.

Also, kudos for your reference to the "bucket brigade." This was the term used by PHILIPS in their description of the charge coupled device, which they invented. PHILIPS envisaged it as a memory storage system. They could have been a bit more imaginative on that occasion. Others certainly took the idea and ran with it.

 

[Guy Parsons]

That's what i hear.

Another benefit would be video, but i don't remember any details.

Video. With my CCD Panasonic LX3 then a train passing by at 300kph still looks like a train. The same scene with a Casio pocket camera with CMOS had the train leaning forwards. or was it backwards?


Frame from CCD video in 2009


Frame from CMOS video in 2011 at same station, that door should be vertical.

The really fast "bucket brigade" unload of CCD makes it act like a global shutter, while the CMOS has a much slower progressive expose and unload row by row so the timing from top row to bottom row gets a bit long and allows the distortion.

You have illustrated the difference very well.

Also, kudos for your reference to the "bucket brigade." This was the term used by PHILIPS in their description of the charge coupled device, which they invented. PHILIPS envisaged it as a memory storage system. They could have been a bit more imaginative on that occasion. Others certainly took the idea and ran with it.

On that bucket brigade note, the first computer I worked on in 1963 used a sort of bucket brigade nickel delay line as it was a serial 32 bit vacuum tube computer and it needed variously 32 bit and also 1 and 2 bit delay lines in order to do its mathematical functions. No it was not steam powered, but very close to that. Filled a large room and took maybe 10kw of power.

 

[JimH123]

Ok, could someone explain to me, in simple terms, why nearly all cameras have CMOS sensors instead of CCD?

I know Leica users used to praise CCD sensors for the colours, and from what I remember, CCDs have quite a few advantages (can't remember them, though).

Here is an article found in the magazine Sky and Telescope that discuses some reasons why CCD is still the favorite for astrophotography although this will change as CMOS technology improves. And also, manufacturers such as Sony have given an end date to CCD manufacturing.

https://skyandtelescope.org/astrono...ccds-cmos-and-the-future-of-astrophotography/

 

[The Davinator]

Won't give a long, boring, technical explanation of things no one cares about (though others will be glad to), but low light performance is one reason. CCD couldn't match CMOS, and alongside the megapixel race was the ISO race.

I like the CCD results and still shoot mine occasionally.

That wasnt true at all 10 years ago ,canon had one of the first cmos sensors and its was that noisey. so many magazines rubishied it CCD was so much better. and my xz1 1/17 sensor has no more noise than my em12 sensor after doing a test the other day so Im going for your statement is incorect.

Don

Nope. Wrong.

 

[Charles McRobert]

That's what i hear.

Another benefit would be video, but i don't remember any details.

Video. With my CCD Panasonic LX3 then a train passing by at 300kph still looks like a train. The same scene with a Casio pocket camera with CMOS had the train leaning forwards. or was it backwards?


Frame from CCD video in 2009


Frame from CMOS video in 2011 at same station, that door should be vertical.

The really fast "bucket brigade" unload of CCD makes it act like a global shutter, while the CMOS has a much slower progressive expose and unload row by row so the timing from top row to bottom row gets a bit long and allows the distortion.

You have illustrated the difference very well.

Also, kudos for your reference to the "bucket brigade." This was the term used by PHILIPS in their description of the charge coupled device, which they invented. PHILIPS envisaged it as a memory storage system. They could have been a bit more imaginative on that occasion. Others certainly took the idea and ran with it.

On that bucket brigade note, the first computer I worked on in 1963 used a sort of bucket brigade nickel delay line as it was a serial 32 bit vacuum tube computer and it needed variously 32 bit and also 1 and 2 bit delay lines in order to do its mathematical functions. No it was not steam powered, but very close to that. Filled a large room and took maybe 10kw of power.

I recall watching a documentary on methods employed in days of yonder to implement short term memory. Those nickel delay lines probably bore some resemblance to chain armor. Tiny rings woven together with copper wire.

The computer that you were using was certainly very advanced to have 32 bits of addressable memory. I can imagine it was filled with the IBM equivalent of the 12AX7, thousands of them to handle the computational tasks. Floating point calculations?

 

[Guy Parsons]

I recall watching a documentary on methods employed in days of yonder to implement short term memory. Those nickel delay lines probably bore some resemblance to chain armor. Tiny rings woven together with copper wire.

From my vague rusty memory the 32 bit delay line was 30 feet of plain nickel wire wound into a case maybe a foot square and maybe 2 inches wide. The bits were launched down the wire by a coil wrapped around the wire, the "shocks" in the wire were picked up at the other end and amplified back to bits.

The computer that you were using was certainly very advanced to have 32 bits of addressable memory. I can imagine it was filled with the IBM equivalent of the 12AX7, thousands of them to handle the computational tasks. Floating point calculations?

This is part of it at a Sydney museum collection, it went from NCR where I worked to the Aussie CSIRO research organisation before it was retired. https://collection.maas.museum/object/210779

More at https://www.ithistory.org/db/hardware/elliott-brothers-london-ltd/elliott-405

Also found a picture of the delay line unit at http://www.vintage-icl-computers.com/icl40

More description at http://rabbit.eng.miami.edu/oldcomputers/Elliott-400-series.pdf on pp 40-47 and found an error in my own memory. That big delay line on page 41 is described as a 16 word delay line, so the 30 foot model was worth 16x32 bits, actually 16x34 bits due to two gap bits. The Max Burnet mentioned there was my ultimate boss at DEC later on.

Again my own flaky memory, the small units in page 42 were 1 word (effectively 34 bits delay) not 1 bit like I said somewhere else. Heck, it was 57 years ago.

Vacuum tubes were mostly twin triodes and power pentodes and towards the end we could only get Russian ones and they were terrible quality, about half were useless out of the box.

And to keep on the photography theme, I do know that I have a bunch of slides of the old beast scanned somewhere. Maybe later if I can find them.

 

[davidedric]

As an aside, Sony's stacked CMOS sensor pretty much eliminates rolling shutter, since it does not rely on sequential readout.

 

[Jon555]

As an aside, Sony's stacked CMOS sensor pretty much eliminates rolling shutter, since it does not rely on sequential readout.

You still need sequential readout from the sensor (so line 2 after line 1, etc.), as otherwise you will notice odd things on moving edges, rather than just a slight slope.