"once you know the system, you know what those names represent."

Sure, once you know the system.
The thing is, we're dealing with a prosumer camera, and most
users do not 'know the system.' You'd be surprised by some
of the people I've spoken to in the last week who, no matter
how I tried to explain it, continue to believe that 1/3" means
a chip is .33 inches. Then again, can you blame them?

But, whether or not it was done on purpose or by mistake
is kind of moot. If it was on purpose, it's rather misleading
to use decimals, you're right Dan. So chances are it was just
a mistake.

I guess my main point was that it is not simply a random typo,
(as I originally thought) the numbers would be valid IF the chip
were actually .33 inches in diagonal, which is what most people
think.

I'm assuming most of you have seen the posts, both on this
forum and other sites, where people are pointing to these
same specs to "prove" that in 4:3 mode the XL2 is using the
equivalent area of a 1/4" chip. They see the .236 inch diagonal
and that is what they assume.

Again, all of this is really unimportant.
I just thought it was interesting that the numbers were not
completely random, and made a "relative" amount of sense.


-Luis

.289" scaling
 

Yes, that really is intriguing how those numbers fit the scaling from .33." I wonder if we'll ever know how it really happened, and if so, if it will make sense!
I would think someone who is close to Canon (not mentioning any names...) could call someone in the tech department and get a straight answer and post it.

Yeah, getting into the math is not something I'm too interested in doing, to "prove" something one way or the other. Nobody really knows anything other than what the manufacturer tells us, right?

The proof is in the angle of view of the lenses. An XL1 delivers an angle of view consistent with that which is commonly called a 1/3" camera (regardless of how big the CCD actually proves to be, it's "called" 1/3"). The XL2, in 4:3 mode, delivers an angle of view consistent with that which is called a 1/4" camera. That's really all the proof you need...

The *Angle of View on lenses (obviously excluding zoom lenses) is fixed unless they have a back focus adjustment. Lenses produce a *Circle of Good Definition, this is the area that must cover the imaging device (CCD, CMOS, film etc.). The Circle of Good Definition (on a better quality lens) usually exceeds the radius of the imaging device by a millimeter or two. Poor quality lenses do not exceed the radius and hence Light Falloff or vignetting that occurs. Falloff can be improved by stopping down the lens. The general definition of allowable falloff is 50% (1 stop). Better quality lenses control falloff to 1/3 stop or less.



*Angle of View=The angle formed by the lines from the rear nodal point to the two opposite sides of the imaging device located one focal length from the rear nodal point, lens focused at infinity.


*Circle of Good Definition=The circular are in the image plane within which the lens forms an image having acceptable resolution.

"An XL1 delivers an angle of view consistent with that which is
commonly called a 1/3" camera (regardless of how big the CCD
actually proves to be, it's "called" 1/3"). The XL2, in 4:3 mode,
delivers an angle of view consistent with that which is called a
1/4" camera. That's really all the proof you need..."


Actually, the math is somewhat important Barry.
Looking at the numbers, you'll see that the XL2 will deliver a field
of view which is somewhere between a 1/4" chip and a 1/3" chip
(albeit, it will be closer to a 1/4" chip).

So, it is not exactly right to say it is "consistent with that which
is called a 1/4" camera."

-Luis

I'm not saying the math is unimportant, just not necessary to draw the appropriate conclusion.

By using a field-of-view chart, and Canon's published 35mm equivalency statistics, it appears to me that the XL2 is delivering a 4:3 FOV consistent with 1/4" cameras.

"I'm not saying the math is unimportant

Sorry, I wasn't trying to put words in your mouth there Barry.

You are right, the math is not necessary to draw the appropriate conclusion.
The differences we are discussing are so miniscule at this point,
that I would image they make no 'real world' difference.

-Luis

<<<-- Originally posted by Luis Caffesse : "The differences we are discussing are so miniscule at this point,
that I would image they make no 'real world' difference.

-Luis -->>>


Exactly! Let's remember that the final production models haven't even been released yet.

- don

Without the ability to determine the T/depth of comfusion vs. the M/depth of confusion, the cone of visibility by the field/(chip), (any size), cannot be determined.* T, meaning True. M, meaning Mathemathical.

Or, to put it more bluntly: Put both the XL-1s & the XL-2 together and look at the results.

Every thing else is mere conjecture.



*Chemical Rubber Company: Standard Mathematical Tables, 1959; pp.308