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-   -   CCD and CMOS, Prices don't make sense (https://forums.steves-digicams.com/general-discussion-11/ccd-cmos-prices-don%E2%80%99t-make-sense-67346/)

Starstreams Sep 25, 2005 10:49 AM


I thought the better cameras use the CCD capture device? And usually have a higher Capture bit depth. Like 16 or more?

--
Can anyone explain why the Canon EOS 1Ds is $8,000 uses the older kind of capture device (CMOS) and the ADC-analog to digital converter is only 12-bit?
http://www.dpreview.com/reviews/canoneos1ds/


Yet a Sony DSC F828 has a 16-bit CCD capture device, and is only about $900. not to mention a killer Carl Zes lens.
http://www.dpreview.com/reviews/sonydscf828/


Is there is something I'm getting mixed up?





DBB Sep 25, 2005 11:23 AM

Nothing is getting mixed up. CCD had been around for a long time and used to be quite a bit BETTER than CMOS. CMOS, is in fact the "new kid on the black."

It first came out commercially about five years ago and has steadily improved unitl there is little difference between their ability to capture images.

It's great advantage over CCD, is that it uses quite a bit less power. Thus you get more bang for your battery. CCD is still dominant in scanners, because they plug into your wall outlet. Both can shoot in 12 bit, which gets translated up or down in to 16 or 8 bit respectively. I don't believe there's much difference in the cost of manufacture.

Probably (and don't quote me on this) but the reason Canon's Mark II 1Ds costs so much is that their sensor is not maufactured in huge amounts. Or, who knows, maybe they're being greedy?

dave

Starstreams Sep 25, 2005 3:57 PM

I see thanks DBB

I've just read something like that so I see what you mean.



However, what about the capture bit-Depth? That is one of the most important things is capturing accurate light. The canon only uses a 12-bit while the Sony uses a 16 bit.


That's a big difference.
When I asked if I my have mixed somethingup: the Capture bit-Depth numbers is what I was referring to.
-Canon 14-bit's per alpha channel
-Sony 16-bit's per alpha channel




Even if the CMOS is more efficient and harder to produce, the simple fact this one only captures 14-bit per channel doesn't justify a $7,000 dollar difference.


eric s Sep 25, 2005 7:26 PM

Could you please give a link to the camera that uses that Sony sensor? I've never heard of that sensor (but then again, I don't really keep up with that stuff... not until it's time for a new camera.)

That could really help dynamic range in the images a huge amount! And that is something I want to know about. Maybe Sony has "announced" it, but it isn't in use?

My understanding of the reason for some of the high cost of the 1Ds MkII is two fold:

It is hard to make a perfect sensor and the physically larger the sensor the more money you throw away when there is a manufacturing defect. So there are more places to have a defect (larger sensor, more photosites) and it costs them more money when they have to get rid of it. In technical terms, it means there is a lower yeald and therefor higher costs.

The second reason is that a photosite (the part of the sensor which actually samples the light) requires the light to be entering the photosite as an angle closer to perpendicular than film does. What this translates into is that a set of micro-mirrors must be used to "strighten" out the light (bend it closer the perpendicular) for the photosites closer to the edges of the sensor. Those mirrors are a cost that smaller sensors (like on the 20D, and I think the 1D MkII) don't have.

Now, since the 5D has been announced, and it will use a full-frame sensor, I assume that Canon has gotten good enough at making the full frame sensors that they can sell the camera at a cheaper price (it doesn't hurt that they removed other features from the camera as well... the 5D is a "lesser" camera than the 1Ds MkII, but it is in more ways than just a lower resolution sensor.)

Eric

Starstreams Sep 25, 2005 7:48 PM

Hi Eric, Are we talking about the same camara here?
I'm refering to the Canon EOS-1Ds


Both links are at the top, on the first post.

The first link is the Canon I'm referring to and the second link is for the Sony DSC717



I see what you mean but $7,000 is kind of huge don't you think?
Who the heck is going to spend 7 thousand bucks more when the spec's don't match up.
There must be something special about the Canon.





Norm in Fujino Sep 25, 2005 9:12 PM

Starstreams wrote:
Quote:

There must be something special about the Canon.
Well, that's what they'd like you to believe. ;)

DBB Sep 26, 2005 8:21 AM

Starstreams wrote:
Quote:

I see thanks DBB

I've just read something like that so I see what you mean.



However, what about the capture bit-Depth? That is one of the most important things is capturing accurate light. The canon only uses a 12-bit while the Sony uses a 16 bit.


That's a big difference.
When I asked if I my have mixed something up: the Capture bit-Depth numbers is what I was referring to.
-Canon 14-bit's per alpha channel
-Sony 16-bit's per alpha channel




Even if the CMOS is more efficient and harder to produce, the simple fact this one only captures 14-bit per channel doesn't justify a $7,000 dollar difference.

The links you posted don't work, so I can't comment

Dave

eric s Sep 26, 2005 2:51 PM

The Canon 1Ds is no longer made, and can be purchased used for a lot less than $8,000 (ebay has them for 4,000.) It has been replaced by the 1Ds Mark II (often written as 1Ds-MkII or 1Ds MkII or 1Ds II.) Its replacement is still $7,400.

First one clarification point. The F828 has a 14-bit sensor, not 16-but, as you suggest. Read page 6 of Steve's review of the camera. It is still more than the 1Ds or the 1Ds MkII, so in theory it should have more dynamic range.

But that isn't your point. The reasons for the extra cost are HUGE... but for most people doesn't matter and therefor aren't justified. I think its also over priced (i.e. their profit margin is too big) but who am I to really say? My only input is not buying the camera!

The 1Ds is a "Professional" grade camera. It does way more than the vast majority of people care about or will ever use. But if you need it, then you need it. I could buy a Toyota car, or I could buy an SCCA street legal race car. Both would get me to work in basically the same amount of time (obeying the speed limits) but one would cost *way* more than the other. For the vast majority of people the race car would be completely wasted on them, but for a few people (people who race cars) it is exactly the right tool for the job.

The 1Ds has more resolution (11.1MP vs. 8MP.)
The 1Ds is water proof. Truly, it is. People have put them in showers and then used them without drying them off.
The 1Ds has better auto focus and more AF points.
The 1Ds (probably) has lower shutter lag.
The 1Ds has way more customizations that can be made.
The 1Ds has a body that can withstand way more abuse and still work.
The 1Ds has a shutter that is rated at way more actuations.

There are more differences than that, but hopefully you get the idea. The 1Ds is made for someone whom the F828 isn't good enough. I, for one, would not buy an F828. It would cost me pictures. I also wouldn't buy a 1Ds (too expensive.) But I will buy the replacement to the 1D MkII when it comes out. It will cost me around $4,000 but it should actually let me get shots than I can't get with the 20D right now.

Does that help?

Eric

Starstreams Sep 26, 2005 7:48 PM

First off Thanks to all of you, that was basically my question.
I have a lot to learn. I've never even heard of cross talk in cameras.

And I don't get how the mm sizes work where you mentioned the sensors.
Anyway, you've given me something to at least go off of and look into.
I think I need to read more reviews to learn this stuff.

PeterP Sep 26, 2005 8:53 PM

:-)
The mm (millimeters) is just a length; 1 mm is about 1/32 of an inch.
So the Sony sensor is a rectangle about 1/4 inch by 11/32 inch in size.

The Canon sensor is a rectangle that is 30/32 inch by 46/32 inch, (about 1 inch by 1.5 inch).

The larger the sensor the less densely packed the photosites can be and each photosite can be larger.

This gets you 2 things:
  • The larger the individual photosites are the more light they can absorb; this translates to a more sensitive the sensor. Which shows up as higher available ISO's on the camera, ISO 3200 is available or even ISO 6400 might be possible on some cameras. [/*]
  • The lower photosite density on the larger sensor reduces false photosite triggering. On a very densepacked sensor a blob(tm) of light hitting one photosite may cause the neighboring photosites to trigger. A phenomenon which I beleive may be called blooming. [/*]

Starstreams Sep 26, 2005 10:16 PM

Hi PeterP

Very interesting info, typed this out.:cool:
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 Sep 26, 2005 11:06 PM

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

Quote:

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.

--------------------------------------
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



Quote:

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 Sep 26, 2005 11:28 PM

1 Attachment(s)
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 Sep 27, 2005 12:11 AM

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




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 Sep 27, 2005 8:04 AM

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 Sep 27, 2005 8:51 AM

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

Quote:

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 Sep 27, 2005 9:04 AM

Carrots wrote:
Quote:

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 Sep 27, 2005 9:16 AM

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 Sep 27, 2005 9:47 AM

PeterP wrote:
Quote:

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 Sep 27, 2005 12:05 PM

Nice find on them links Peter! Thanks

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


Starstreams Sep 28, 2005 2:27 AM

1 Attachment(s)
Peter Is this geometry?

I attached an image:

How are they getting 8.93mm on that horizontal line?
And how would you convert it to 1/1.8?

I don't get where the 1 comes from in the 1/1.8?
Is that the vertical dimension of the capture device in inches?




Carrots Sep 28, 2005 2:48 AM

Interesting article.

The 8.93 mm is the diagonal size of the actual sensor. Convert it to inches by typing the following in google:

"8.93mm in inches"

Then you get 0.35 inches.

Then they go on to say, that they dont quote sensor sizes using that measurement. They rather give you the size ( outer diameter)of the "casing" of the sensor. That would be the circle you see surounding the square sensor.

They also say that there is no real mathematical relationship between the two, but it appears that the square (rectangular whatever)sensor'sdiagonal is roughly two thirds of the diameter of the ourter edge of the casing.

The outer edge of the casingcircle (actually a tube, but doesnt matter for this explanation) is1/1.8"

Pull out a calculator and divide 1 by 1.8. That gives you about 0.555.

They say that the diagonal of the sensor is two thirds of thediameter of the circle.

Thus, 0.555" ( or 1/1.8") divided by three, multiplied by two should give you the diagonal of the sensor.

0.555 / 3 = 0.183

0.18 * 2 = 0.366

Which is close enough to the 0.35 inches.


-------------------------------------------------------------------------
To convert the actual diagonal size from scratch:


Convert 8.93 to inches = 0.35.

Multiply by 1.5 = 0.525 (as it is 2 thirds, and 1 istwo thirds of 1.5)

To convert to a fraction: 1 / 0.525 = 1.9. Put that under a 1, and you get 1/1.9"

Which is close enough considering they said ROUGHLY 2 thirds, and that we worked with 0.35 and not 0.351216576946516719.

-----------------------------------------------------------------------------

What makes it really confusing is that the 1/1.8" is not the size of the sensor, but rather the size of the tube the sensor is in.


The 1 in 1/18" is just like the 1 in 1/2 (half). Itsone 1.8th of an inch. Or 1 divided by 1.8.


I just repeated what they said. I hope I at least made it a bit more clear.



Starstreams Sep 28, 2005 10:11 PM

Carrots wrote:
Quote:

The 8.93 mm is the diagonal size of the actual sensor. Convert it to inches by typing the following in google:
"8.93mm in inches"
Then you get 0.35 inches.
But the industry doses not usually use inches right? Why would I want to convert that?

By the way.
I devided 0.555 / 3 and then multiplied by 2 as you said:
I don't know how you got 0.183?

I got 0.37

I guess what I don't get yet is why I'm deviding 1/1.8?
I need to think about this more I think.

GWHayduke Sep 29, 2005 1:09 PM

Carrots calculated 2/3 of 0.555 step-wise. His first step was to divide 0.555 by 3 (yields 0.185), then multiply 0.185 by 2 (yields 0.37). I'm not sure if anyone answered the "where did 8.93mm come from" questionyet, but the 8.93 comes from the Pythagorean theorem:hypotenuse = sqrt(A^2+B^2) where A and B are the adjacent sides of the rectangle.

-Blake



Starstreams Sep 29, 2005 9:20 PM

I think I got it! :D thanks to all of you.

The difficulty is not with how you guys are explaining it; it's my deficiency in geometry and the simple terms that I should have learned in 6th grade. Anyway
Math is everything these days, can't live without it.

I wasn't clear on what the radius of a circle was so this is where I get confused buy all this.
I think I'm good now.

Again, thanks to all of you for taking the time on your replies, it is greatly appreciated. I even saved this page to my hard drive too look back on!


eric s Sep 29, 2005 9:32 PM

You have just experienced why I have been on Steves's forums for so long.
The people and the knowledge (in that order.)
The people are really nice and they know a lot, and they are great at sharing it.

I'm glad we could be helpful.

Eric


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