CCD vs CMOS, again

[willie_901]

There is no such thing as CCD vs CMOS.

The photo-diode in the photo sites of CCD and CMOS sensors both convert electromagnetic radiation in to photo electrons. The photo electrons accumulated in each photo-site are stored on-chip as an electric charge. After the shutter closes, the charge is converted into analog DC voltage. The result is a spatial array of DC voltages.

Electrons, electrical charge and DC voltages in CCD and CMOS photo sites are no different than electrical charge and DC voltages in any electric (flashlight) or electronic devices (h-fi amp). They possess no aesthetic characteristics. The electrons, electrical charge and DC voltages alone can not be the source of aesthetic differences in rendered images from CCD and CMOS sensor assemblies.

The M9 rendered image perception you prefer is authentic. But it has nothing to do with CCD vs CMOS.

The difference has everything to do with:

• the sensor cover glass optical properties (including the IR filter film)
• the sensor assembly micro-lens array optical properties
• the sensor color-filter array optical properties (the R, G and B filter films)
• the proprietary demosaicking algorithm(s) used to render in-camera JPEGs and, or post-production JPEGs from DNG files.

 

[Dustfinder]

There is no such thing as CCD vs CMOS.

The photo-diode in the photo sites of CCD and CMOS sensors both convert electromagnetic radiation in to photo electrons. The photo electrons accumulated in each photo-site are stored on-chip as an electric charge. After the shutter closes, the charge is converted into analog DC voltage. The result is a spatial array of DC voltages.

Electrons, electrical charge and DC voltages in CCD and CMOS photo sites are no different than electrical charge and DC voltages in any electric (flashlight) or electronic devices (h-fi amp). They possess no aesthetic characteristics. The electrons, electrical charge and DC voltages alone can not be the source of aesthetic differences in rendered images from CCD and CMOS sensor assemblies.

The M9 rendered image perception you prefer is authentic. But it has nothing to do with CCD vs CMOS.

The difference has everything to do with:

• the sensor cover glass optical properties (including the IR filter film)
• the sensor assembly micro-lens array optical properties
• the sensor color-filter array optical properties (the R, G and B filter films)
• the proprietary demosaicking algorithm(s) used to render in-camera JPEGs and, or post-production JPEGs from DNG files.

I'm no expert and I liked your answer, but could you add something on the (possible) differences related to the spectral sensitivity of these two types of sensors?

 

[joe bosak]

Seems a bit of a pointless debate given that nothing CCD has been produced for a while (for stills, normal photography anyway) so any differences are baked in with other differences between the particular cameras being compared. But this article was quite interesting about some of the technicalities (and seems to suggest there's a bit more to it than "no difference it's all photons/whatever" but I'm neither physicist nor engineer).https://petapixel.com/what-is-ccd-cmos-sensor/

 

[boojum]

There is no such thing as CCD vs CMOS.

The photo-diode in the photo sites of CCD and CMOS sensors both convert electromagnetic radiation in to photo electrons. The photo electrons accumulated in each photo-site are stored on-chip as an electric charge. After the shutter closes, the charge is converted into analog DC voltage. The result is a spatial array of DC voltages.

Electrons, electrical charge and DC voltages in CCD and CMOS photo sites are no different than electrical charge and DC voltages in any electric (flashlight) or electronic devices (h-fi amp). They possess no aesthetic characteristics. The electrons, electrical charge and DC voltages alone can not be the source of aesthetic differences in rendered images from CCD and CMOS sensor assemblies.

The M9 rendered image perception you prefer is authentic. But it has nothing to do with CCD vs CMOS.

The difference has everything to do with:

• the sensor cover glass optical properties (including the IR filter film)
• the sensor assembly micro-lens array optical properties
• the sensor color-filter array optical properties (the R, G and B filter films)
• the proprietary demosaicking algorithm(s) used to render in-camera JPEGs and, or post-production JPEGs from DNG files.

If the differences were most influenced by your list there would be little argument about differences. The problem would have been solved. And it nearly has been but a difference still exists.

Granted the software processing the output of the sensor is not always the same which could account for some differences. And there is observer bias which could also account for some more differences. But there are too many people who see differences for it to be dismissed as a delusion. And too many who prefer CCD really know what they are talking about. They have the technical chops. So while we may not be able to describe they "why" or "how" that does not mean the difference does not exist. We just do not yet know how to explain it.

There is a sometimes derided "mystique" to lenses also. If it is all BS tell Hollywood which is buying up a lot of old glass to take the edge of digital filming. The Cooke Amotal 2" I recently found has a lovely way of seeing things. Likewise some Canons and the old Zeiss and their Soviet copies, the Jupiters. Compared to these older lenses I find the current CV lenses a bit harsh, but that is my personal judgement. That we do not yet know how to measure and describe the differences does not mean that they are not there. As the old CCD cameras stop working this will become more an academic argument but I still really like the CCD cameras I have and prefer them to CMOS. And these are all in the Leica stable, M series, which will reduces differences a bit.

It is a topic which still merits discussion.

 

[Rob-F]

I can't say I've been acutely aware of differences among my CCD vs CMOS cameras, but there is one CCD camera that really stands out in my mind; and that is the Leica Digilux 2. I sold it long ago, and whenever I think about it I miss it. It was only 5 megapixels and had absolutely the world's worst EVF viewfinder. And it had a top ISO of 400. But I have never again seen colors as lush as in the photos that I got from my Digilux 2! Let me see if I can post a couple-three. It may take a while. I'll have to pull them off the iMac.

Let's see: since it had a live view, I guess it must have been a CMOS camera, right?

 

[peterm1]

I can't say I've been acutely aware of differences among my CCD vs CMOS cameras, but there is one CCD camera that really stands out in my mind; and that is the Leica Digilux 2. I sold it long ago, and whenever I think about it I miss it. It was only 5 megapixels and had absolutely the world's worst EVF viewfinder. And it had a top ISO of 400. But I have never again seen colors as lush as in the photos that I got from my Digilux 2! Let me see if I can post a couple-three. It may take a while. I'll have to pull them off the iMac.

Let's see: since it had a live view, I guess it must have been a CMOS camera, right?

Yes this camera has long had a stellar reputation among those who have owned it or lusted after it. Of course it was based on a Panasonic original and I bought the slightly later Panasonic L1 which has interchangeable lens mount and was likewise repackaged in a Leica version. It too has very nice colors and tones (and not too dissimilar specs to the Digilux 2 in terms of ISO limits and sensor size. But I always loved its results, though never knowing how much of this was attributable to the sensor and how much to the firmware. One part that was definitely firmware however was undoubtedly its handling of black and white - the JPG images it produced in black and white (when this option was selected) were particularly nice at the time. Do they still stand up by comparison with what is possible from modern cameras? I am not yet sure. I still own mine and though it has for a long time languished in a wardrobe a few weeks back I got it (and other old CCD sensor cameras) out to give it a run. I have not yet made any serious comparison of its images yet but will try to do so. So far I have been hampered by poor weather, chores and various other sundry excuses. But I can say I remember it with some affection despite its limitations due to the age of its basic technology. I suppose in hindsight the Digilux 2 can be said to be the great grand daddy of the Leica Q and Q2.

 

[Sonnar Brian]

CMOS sensors used today output a Digital Signal that has undergone some processing before it leaves the chip. (The CMOS sensors used in the Kodak DCS 14MPixel cameras output an analog signal). The Output undergoes much more processing before being written to non-volatile memory.
CCD (non-Hybrid) detectors output an analog signal that is digitized off-chip and is stored with a minimum of processing. The fill-factor of CCD detectors is greater than the FSI CMOS detectors used in the M240 and M10..

The output of my CMOS based Nikon Df is to my liking. But- looking at the NEF file, pain in the butt to write code for. So I only wrote code for the CCD M8, M9, and M Monochrom. A few lines of code to make into an image file. I could look at DCRAW to do the Nikon image, but it's already a processed image before it leaves the camera. The CCD- much closer to raw data.

One other factor between detectors, CMOS or CCD, is the specific chemistry and layout of the chip and the effect on spectral response. Kodak introduced Indium Tin Oxide to improve blue response some 20+ years ago, before some of the other manufacturers. Of late, the Infrared Response has been bred out of newer CMOS detectors. The IR response of the Kodak CCD detectors was much higher than the CMOS detectors used now.

 

[boojum]

I can't say I've been acutely aware of differences among my CCD vs CMOS cameras, but there is one CCD camera that really stands out in my mind; and that is the Leica Digilux 2. I sold it long ago, and whenever I think about it I miss it. It was only 5 megapixels and had absolutely the world's worst EVF viewfinder. And it had a top ISO of 400. But I have never again seen colors as lush as in the photos that I got from my Digilux 2! Let me see if I can post a couple-three. It may take a while. I'll have to pull them off the iMac.

Let's see: since it had a live view, I guess it must have been a CMOS camera, right?

No, no, no. CCD. https://en.wikipedia.org/wiki/Leica_Digilux_2

 

[ptpdprinter]

I had a digital Canon ELPH S400 with a 4MP CCD sensor and, while they seemed okay at the time, looking back at a some of the images, I think a fair assessment is that they sucked. So I am going to go out on a limb and say maybe there is more to producing a good image than just having a CCD sensor.

If you think the CCD sensor in your camera is the cat's pajamas, I would encourage you to continue using it.

 

[boojum]

I had a digital Canon ELPH S400 with a 4MP CCD sensor and, while they seemed okay at the time, looking back at a some of the images, I think a fair assessment is that they sucked. So I am going to go out on a limb and say maybe there is more to producing a good image than just having a CCD sensor.

If you think the CCD sensor in your camera is the cat's pajamas, I would encourage you to continue using it.

Agreed. I think Brian outlined some of the variables involved. I have an old SONY DSC S70 with a 3.2 MP CCD sensor that turned out some wonderful photos. I am vain enough to post a few and you can be the judge.

Here are some links to the old SONY pics:

https://flic.kr/p/uZPJgA

https://flic.kr/p/v1ADyt

https://flic.kr/p/uZNN6G

https://flic.kr/p/wiCLnw

https://flic.kr/p/uHHAro

https://flic.kr/p/v1k3TR

https://flic.kr/p/u4tLyg

https://flic.kr/p/uHJZCj

I have to charge the battery in this camera and take it out again. I really like how it works. If you are a glutton for punishment here is a series shot in a bakery in Santa Rosalia, BCS, a panaderia: https://flic.kr/s/aHskf6yL56

These photos and others make me inclined to favor CCD's. Good CMOS gets close, but when you want to push it up to 11 you need vintage CCD. ;o)

 

[farlymac]

Had to go into the archives on DPReview to determine what sensors I had on my cameras. Turns out the APS-C Nikon D80 is a CCD, while the Coolpix P7700 is a BSI CMOS. Now I was quite happy with the images from the D80, but due to the incredibly bad design of certain parts of the system it was not reliable enough to continue using it. In actuality I bought the D80 way after getting the P7700, which while a handy unit to have around, I bemoaned its lack of a viewfinder and lens interchangeability. But it made wonderful images all the same despite the small size of its sensor (1/1.7). All that being said, when I switched to the D300s I found that there was a certain flatness to the CMOS sensor that I never quite got dialed out. Then along came the Z50 and Z5 with their attendant uptick in megapixels. Bang out-of-the-box great images! Some in camera setting adjustments made them even better. Then I applied a cheap Polarizer filter to the Z50, and now my images have a certain cast to them when I ignore the filter. So, I think that beyond the inherent way these sensors render the images they capture, there really isn't a lot of difference that can be attributed to the design. It's the camera processing unit and other variable factors that really bring out the best or worst in the camera.

PF

 

[Godfrey]

CCD vs CMOS ...
This is an old, old debate. Mostly a waste of time since a good photographer can get equal results with either, and it doesn't really matter anyway.\

My M9 made good photos, but I disliked the camera overall for several reasons. The M-P 240 that replaced it was a far better camera, as also was the M-D 262. Both of those are long gone now, and I recently acquired an M10 Monochrom. That last is the best digital M I've had by a long shot, although I am still emotionally attached to the M-D 262. But the M10 Mono inspires me so much I'll likely pick up an M10-R for a color camera that matches it.

I've had no problems getting good results out of any of the 60 some odd cameras that preceded the M10 Mono so eh? I take pictures and leave the debate over theoretics to others with more time on their hands... 😉

G

 

[james.liam]

Much ado about an extinct, low(er)-resolution, narrow DR class of sensor. Akin to endlessly bemoaning the passing of Kodachrome.

 

[x-ray]

Here’s a link to a thread I started several months ago showing images from multiple generations of cameras with both ccd and cmos. The images span 20 years of digital cameras from consumer cameras to the ccd Hasselblad back I had and top of the line cmos cameras. Also I included scans from film, both transparency and some negative, shot on 35mm up to 8x10. Scans were made on either a Fujifilm Lanovia Quattro scanner or an 848 Imacon. File processing in most cases was from raw files and was through Lightroom.

https://www.rangefinderforum.com/node/177414

 

[olakiril]

There is no such thing as CCD vs CMOS.

The photo-diode in the photo sites of CCD and CMOS sensors both convert electromagnetic radiation in to photo electrons. The photo electrons accumulated in each photo-site are stored on-chip as an electric charge. After the shutter closes, the charge is converted into analog DC voltage. The result is a spatial array of DC voltages.

Electrons, electrical charge and DC voltages in CCD and CMOS photo sites are no different than electrical charge and DC voltages in any electric (flashlight) or electronic devices (h-fi amp). They possess no aesthetic characteristics. The electrons, electrical charge and DC voltages alone can not be the source of aesthetic differences in rendered images from CCD and CMOS sensor assemblies.

The M9 rendered image perception you prefer is authentic. But it has nothing to do with CCD vs CMOS.

The difference has everything to do with:

• the sensor cover glass optical properties (including the IR filter film)
• the sensor assembly micro-lens array optical properties
• the sensor color-filter array optical properties (the R, G and B filter films)
• the proprietary demosaicking algorithm(s) used to render in-camera JPEGs and, or post-production JPEGs from DNG files.

Exactly.

I would put the conversion from RAW to a viewable format (jpeg or a preview on your editing program of preference) high up on the list since it is the one that most often makes the biggest difference.

Most modern sensors are very good at capturing color information. It is just the 3D lookup tables (usually 2 for different temperatures) that render the colors of an image and make up the "look" of the camera. You can change them and used them with any RAW editing program overriding the default profiles e.g. from Adobe when using Lightroom. For example my Sony RAWs can give me the Fuji x-trans colors. Unfortunately very few manufacturers allow for modifying these inside the camera (only Pixii and Zeiss as I am aware).

 

[ptpdprinter]

These photos and others make me inclined to favor CCD's. Good CMOS gets close, but when you want to push it up to 11 you need vintage CCD. ;o)

How's that new Pixii working out for you? Are you going to return it and stick with your vintage CCDs? I sure wouldn't want to spend $3000 on a camera and not be able to push it up to 11.

 

[jsrockit]

I sure wouldn't want to spend $3000 on a camera and not be able to push it to 11.

Hahaha... I've always felt the opposite, that I can push my CMOS to 11+.

 

[willie_901]

I'm no expert and I liked your answer, but could you add something on the (possible) differences related to the spectral sensitivity of these two types of sensors?

Sure.

There are physical differences between CCD and CMOS photo-sites. While the silicon in both have similar compositions there is a difference in light absorption and reflection.

"Reflection and transmission of incident photons occurs as a function of wavelength, with a high percentage of shorter wavelengths (less than 400 nanometers) being reflected, although these losses can (in some cases) extend well into the visible spectral region. Many CMOS sensors have a yellow polyimide coating applied during fabrication that absorbs a significant portion of the blue spectrum before these photons can reach the photodiode region. Reducing or minimizing the use of polysilicon and polyimide (or polyamide) layers is a primary concern in optimizing quantum efficiency in these image sensors.

Shorter wavelengths are absorbed in the first few microns of the photosensitive region, but progressively longer wavelengths drill down to greater depths before being totally absorbed. In addition, the longest visible wavelengths (exceeding 650 nanometers) often pass through the photosensitive region without being captured (or generating an electron charge), leading to another source of photon loss. Although the application of microlens arrays helps to focus and steer incoming photons into the photosensitive region and can double the photodiode sensitivity, these tiny elements also demonstrate a selectivity based on wavelength and incident angle."(link)

These differences (UV and IR response) happen to be spectral regions that are filtered by the sensor cover glass and their impact is minimal. The CFA optical properties are more significant. A comparison for CFA relative spectral response for a few CCD and CMOS cameras can be found here.

The impact of demosaicking algorithms is relevant. If a demosaicking mathematical model contains parameters that account for the loss of UV and, or IR light absorption, the parameters can be estimated empirically.[1] Separately, the undesirable effects spectral response differences and response overlap of R, G and B CFA filters can be minimized by empirical estimates which can be used as another set of demosaicking mathematical model parameters.



1/ This is very different than the M8 IR contamination problem. The IR light level in each scene is different and unknown so demosaicking algorithms can't address light source spectral response issues.

 

[willie_901]

...So, I think that beyond the inherent way these sensors render the images they capture, there really isn't a lot of difference that can be attributed to the design. It's the camera processing unit and other variable factors that really bring out the best or worst in the camera.

I agree. After sensor assembly analog signal-to-noise ratio and sensor spatial resolution, the in-camera JPEG processing unit plays a major role. The same goes for proprietary raw-file demosaicking algorithms. For raw, I think the M9 has a significant advantage since they use the DNG standard. This Leica can model the sensor assembly spectral response and modify the raw file DN values accordingly. This minimizes differences in third-party rendering platform demosaicking.

 

[Rob-F]

Here are some photos taken with my Digilux 2 and its CCD sensor. They seem to me to have a lush quality that I don't remember ever seeing from other cameras. I don't know if it's the CCD sensor that made this difference, or the way the Digilux 2 processed the images.

I didn't do any enhancements in post. If any of these photos strike you as, well, striking, at least as far as color goes, could you say what makes them that way? In my mind they stand out from the usual stuff. I believe it's partly due to the brilliant Colorado sunshine, and partly to the vivid colors of the subjects themselves. Do you think there could be something else contributing, e.g. the CCD sensor or the in-camera processing? What words come to mind that describe the special character of these colors?