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CCD / CMOS benefits and drawbacks.


Mike Rawcs

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With the M9-P about to be announced and the talk here that this may be the last opportunity to get a CCD sensor M, can anyone explain the advantages of CCD over CMOS?

I've heard that the advantages with a CMOS sensor are better low-light performance and better battery performance but what are the plus points for CCD?

 

Thanks,

 

Mike.

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It is a very hard question to answer as nobody knows what is happening in the reseach labs, so any answer will be out of date. The advantages of CCD are less processing of the signal specifically for noise reduction, as they are less noisy to start with. That results in a better image quality at lower ISO levels.

You have missed out on the main advantage of CMos from a manufacturer's point of view - they are quite a bit cheaper to produce. ;)

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Interesting article.

 

What I also find very interesting is that no maker of a Medium Format digital back has moved to CMOS. The mind boggling new Phase One IQ180 is probably the most advanced production digital camera available to photographers today ... and if there was something on the horizon to revolutionize digital capture, they would most likely know about it and have used it in the just launched IQ series of backs. Instead, they are 40, 60 and 80 meg 645 sized CCDs. So I'd question the articles' author about CCDs being relegated to lower end cameras anytime soon.

 

While most all digital cameras available today do a very nice job of digital capture, I also find it interesting that for some people the stand out cameras in terms of IQ were/are CCDs: The Contax N Digital, the Leica DMR and the M8/M9s. I'm sure it is a matter of subjective tastes, but lots of folks describe the M9 files as producing MFD like quality (no surprise given they are all CCD based cameras).

 

As the technology currently stands, I prefer CCD capture. I've owned just about everything out there, and for pure look and feel, for over-all IQ, the M9 beats them all. In many cases I still prefer the Leica DMR files to any Canon or Nikon made.

 

A good part of this may be due to how AA filters are applied to CMOS cameras, and frankly, I've never tried one with the filter removed. I recall vividly the huge let down I felt when first processing files from my new Canon 1DMK-III ... mushy, plastic or waxey looking to my eye.

 

The trade-off is that CMOS cameras can have more bells and whistles, rack-up ISO count, and can be faster ... none-of-which I need or care about with a M9 and the way I use it.

 

The next M digital will be CMOS, of that I am pretty sure. It remains to be seen how Leica IQ expectations are met, and whether anyone other than a handful of photographers will even notice.

 

I hope Leica still pays attention to the M CCD cameras ... just one more stop of ISO performance would do it for me ... which I know is possible since Hassellblad did it with their existing cameras via a firmware upgrade.

 

-Marc

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Ever since I started looking at M9 files, I have preferred the look to those of my DSLRs. I assumed it was a combination of the lack of AA filter and the glass. Perhaps the sensor actually has something to do with it also. I would like better high ISO performance from my M9, but I wouldn't want to trade the M9 IQ at lower ISO for better high ISO performance. So, if it is partially the CCD and the M10 goes to CMOS, I will have to hope the M9 lasts as long as an M3.

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CCDs are more costly to produce but ultimately have better noise characteristics

The only reason current CMOS sensors are better for noise at high ISO is because much more money has been put into their development (Kodak vs Canon&Sony).

This has been done, as mentioned above, due to the cheaper means of production for CMOS.

As Hassy, Leica and Phase 1 are low volume/high cost manufacturers the volume saves for CMOS have never entered into their equation.

At base ISO CCD is still the king. As I can take 90% of my pics under ISO 100 - 400 it suits me.

I do however have a need for ISO 3200 10% of the time. It'll be great one day to do that on CCD.

 

At some point in the next 20 years all of this will be swept aside by black silicon:

SiOnyx Brings “Black Silicon” into the Light; Material Could Upend Solar, Imaging Industries | Xconomy

 

1 billion megapixels and ISO 2-3million in scope. I'm thinking that at this point the only differentiator between cameras will then be handling & build. Viva Leica :)

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Part of the benefit of the CCD heritage and the MF heritage of CCD use is colour science... the people most associated with colour science have long been associated with CCD development and not CMOS development.

 

Until digital, no Canon or Nikon camera was ever filled with Canon or Nikon film :) While it's true that Canon has a huge imaging and print reproduction business, and a video capture business, too, it wasn't exactly known for photographic colour fidelity until relatively recently.

 

Sony on the other hand is an old hand at producing CCD sensors, and could do it for Leica if need be. In their professional cinema applications and joint ventures with Panavision, Sony produces professional CCD chips. Their home movie cameras have traditionally also been CCD powered, though I'm sure they're mostly CMOS by now.

 

Which leaves Kodak and Fuji... which really means, to me, Kodak, IMO Kodak's pro sensors set the bar for MF backs and luckily the Leica DMR--and M8, M9 and S2--shared that legacy.

 

Coming from a Canon 5d, 1d2 and 1ds2 and shooting the DMR was a revelation... like going back to film. Totally reliable, printable and film-like.

 

I still can't believe how much work it is to get Nikon or Canon files into something workable for 90% of the light I experience or provide.

 

The DMR was a snap, literally, with the right profile and RAW conversion, the M8 and M9 are too. I know avid Canon shooters who, once they've used a Phase back, are ready to mortgage their entire gear investment just for the colour differences.

 

So a big worry is that with a future M the DR and ISO noise will be fabulous, but I'll need to spend too much time compromising on colour, plain and simple.

 

I honestly think, though, that given their own product development, Leica know the colour they're shooting for and won't settle for less than great. But CMOS is cheaper to make, easier to noise control, and made by more people... so it might be an inevitable choice. And heck, I'd like another stop of ISO performance on my M9...not to mention the low-power characteristics of CMOS (think of a battery that lasts for 2K shots :)) But I don't want it to come at the expense of colour or tonality or detail.

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Part of the benefit of the CCD heritage and the MF heritage of CCD use is colour science... the people most associated with colour science have long been associated with CCD development and not CMOS development.

 

Until digital, no Canon or Nikon camera was ever filled with Canon or Nikon film :) While it's true that Canon has a huge imaging and print reproduction business, and a video capture business, too, it wasn't exactly known for photographic colour fidelity until relatively recently.

 

Sony on the other hand is an old hand at producing CCD sensors, and could do it for Leica if need be. In their professional cinema applications and joint ventures with Panavision, Sony produces professional CCD chips. Their home movie cameras have traditionally also been CCD powered, though I'm sure they're mostly CMOS by now.

 

Which leaves Kodak and Fuji... which really means, to me, Kodak, IMO Kodak's pro sensors set the bar for MF backs and luckily the Leica DMR--and M8, M9 and S2--shared that legacy.

 

Coming from a Canon 5d, 1d2 and 1ds2 and shooting the DMR was a revelation... like going back to film. Totally reliable, printable and film-like.

 

I still can't believe how much work it is to get Nikon or Canon files into something workable for 90% of the light I experience or provide.

 

The DMR was a snap, literally, with the right profile and RAW conversion, the M8 and M9 are too. I know avid Canon shooters who, once they've used a Phase back, are ready to mortgage their entire gear investment just for the colour differences.

 

So a big worry is that with a future M the DR and ISO noise will be fabulous, but I'll need to spend too much time compromising on colour, plain and simple.

 

I honestly think, though, that given their own product development, Leica know the colour they're shooting for and won't settle for less than great. But CMOS is cheaper to make, easier to noise control, and made by more people... so it might be an inevitable choice. And heck, I'd like another stop of ISO performance on my M9...not to mention the low-power characteristics of CMOS (think of a battery that lasts for 2K shots :)) But I don't want it to come at the expense of colour or tonality or detail.

According to Stefan Daniel, Dalsa was first alternative for Kodak. And there is the Leica-Fujitsu connection. Fujitsu is Sony's advisor on sensor matters.

Edited by jaapv
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With Leica's low volume which CMOS manufacturer would do the micro-lenses for them?

 

I am sure Sony would sell their excellent sensors to anyone (the new FF ones shortly to be launched in the D800 and D4x will be amazing)

 

Therefore I am also sure that Leica made a positive choice to go for the Kodak CCD due to image characteristics. Thats why I feel that they will continue to go to Kodak for the foreseeable future.

 

I am assuming you guys all know about the latest Kodak CCD:

Image Sensors World: Kodak Announced 29MP W-RGB Interline Transfer CCD

this one in an M10 would fit the bill nicely

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I am sure Sony would sell their excellent sensors to anyone

Sony did a custom microlens-design for Fuji’s X100 that is a low-volume product, so why not do the same for Leica?

 

I am assuming you guys all know about the latest Kodak CCD: Image Sensors World: Kodak Announced 29MP W-RGB Interline Transfer CCD

this one in an M10 would fit the bill nicely

Yes, we know about that sensor and no, it wouldn’t fit at all. Who wants an interline-transfer CCD?

Edited by mjh
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Sorry for my ignorance but what exactly is an interline-transfer CCD?

It’s the kind of CCD used in compact digicams. Compared to a full-frame transfer CCD (the kind of CCD used in the M9, M8, S2, and DMR) it has two pixels in the place of one – one pixel is exposed to light while the other is not. The advantage of this design is that you can implement a global electronic shutter: at the end of the programmed exposure time the electric charge accumulated within each light-sensitive pixel is transferred to its twin pixel that is shielded against light; from these twin pixels the charges can be read out at leisure. The disadvantage is that you can only use one half of the available space for collecting light and for storing photo-electrons, limiting both the dynamic range and the signal-to-noise ratio.

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It’s the kind of CCD used in compact digicams. Compared to a full-frame transfer CCD (the kind of CCD used in the M9, M8, S2, and DMR) it has two pixels in the place of one – one pixel is exposed to light while the other is not. The advantage of this design is that you can implement a global electronic shutter: at the end of the programmed exposure time the electric charge accumulated within each light-sensitive pixel is transferred to its twin pixel that is shielded against light; from these twin pixels the charges can be read out at leisure. The disadvantage is that you can only use one half of the available space for collecting light and for storing photo-electrons, limiting both the dynamic range and the signal-to-noise ratio.

 

So do they count the 'blind' pixel as one of the 29Mpixels? So it is really a 14.5Mpixel sensor?

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Sony did a custom microlens-design for Fuji’s X100 that is a low-volume product, so why not do the same for Leica?.

 

 

Perhaps

APS-C, 35mm lens, >1 application (X100, X1, others?)

vs

FF, 18mm or wider lens, only Leica

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Perhaps

APS-C, 35mm lens, >1 application (X100, X1, others?)

vs

FF, 18mm or wider lens, only Leica

Sony did a custom microlens design for a single, low-volume model, the X100 – there is no other camera using that sensor. If Leica were to order a custom design, the number of units ordered wouldn’t be that much different. Obviously a FF sensor would cost much more, but it costs much more for anyone so that’s beside the point.

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It’s the kind of CCD used in compact digicams. Compared to a full-frame transfer CCD (the kind of CCD used in the M9, M8, S2, and DMR) it has two pixels in the place of one – one pixel is exposed to light while the other is not. The advantage of this design is that you can implement a global electronic shutter: at the end of the programmed exposure time the electric charge accumulated within each light-sensitive pixel is transferred to its twin pixel that is shielded against light; from these twin pixels the charges can be read out at leisure. The disadvantage is that you can only use one half of the available space for collecting light and for storing photo-electrons, limiting both the dynamic range and the signal-to-noise ratio.

 

That specific sensor is FF 35mm. It is 29 meg output, not 14 meg. 29 meg is 29 meg. I don't know of any consumer camera that is FF, so I'm not sure what this sensor would be for other than something like the M9. It seems no more limited than any other CCD, just higher resolution ... in fact less limited if the Specs are correct from Kodak:

 

Kodak states the KAI-29050 is one of the first sensors devices to use the Kodak TRUESENSE color filter pattern claimed to provide 2X to 4X increase in light sensitivity by adding panchromatic pixels to the standard RGB elements that form the sensor array.

 

To me that sounds like the higher ISO some want with the IQ of a CCD like the M9 provides ... without using a CMOS with an aggressive AA filter to mitigate noise.

 

It's all a moot point ... Leica will use a CMOS sensor in the next M digital, so the technology must exist, and Leica must see that technology as not compromising the IQ their buyers expect.

 

We'll see.

 

-Marc

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