Accurately comparing FF vs APS-C sensor performance? An open discussion.

Started Apr 8, 2013 | Discussions thread
VirtualMirage
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Re: You misunderstand
In reply to Klipsen, Apr 11, 2013

Klipsen wrote:

But it does. Just like grain size did in film. It's all about sharpness.

Nope, it doesn't.  It only makes it more or less noticeable.  The DoF is still there and is still the same size.  Again, that is perception and not the actual measurement.

There is one - and only one - plane of focus. DoF is the perception of sharpness, where there is actually a slight unsharpness.

It is like the riddle in physics about the bouncing ball in a world where nothing but gravity interacts with it.  Does the ball every actually stop, or does the distance between bounces becomes so imperceptibly small that it only appears to have stopped bouncing.

What's your point?  We know this.

Let's say 'greatest', then, because DoF increases enormously with increase in distance and stopping down. You might want to read about the 'hyperfocal distance' - not just what it is, but also its relation with DoF.

Greatest would change the sentence, making more sense.

And yes, I know about hyperfocal distance as well.  Again, what is your point in relation to my original discussion?

But it doesn't hide the fact that there is a difference in DoF due to a difference in the size of circle of confusion with each sensor size.

Well, you got that one right. But you're wrong if you think the diameter of the circle of confusion is carved in stone.

I never said it was.  You can see it changes with sensor size, so I think we can agree it isn't fixed.

You are stating perception, I am stating the technical side.

Oh, come on!

That's all you have to say?  It's true.

Perception is .9 inches and 1.0 inch are the same, but technically they are not.  And while from afar that won't make much of a perceptual difference, it becomes more noticeable the closer you get.

Actually, DoF also depends very much on the viewing distance.

Yes, thanks for pointing out the obvious that we are all already aware of.  If you reread that sentence, you can see that distance is implied.  To help, I bolded some words the imply this.

Maybe I should have posted my examples in inches instead? Or perhaps cm or mm?

What difference would that make? But don't let me stop you.

It would show that there is a measurable difference whereas in feet the rounding to the nearest fraction hides that, making you think they are the same.  1ft on one may not actually be 1ft on the other.  It could be closer to 11.9in and 11.7in.

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Paul

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