Depth of field - is it linear?

[William W]

Bill, I've also seen "100% crop" which, in 'Standard Photographic Vague', means anything Chuck Norris says it means.

But often, it means a crop done for showing on-screen with no re-sizing of the original - often for comparison by detail-phreaks.

Yes – add that phrase to the list.

I avoid that phrase. It is of Digital Birth and really muddies the water.

Much of the Photographic lexicon used in texts and by those taught The Craft by a Trade/Certificate/ Diploma Curriculum is transferrable and is easily transferred and will have precise clarity of meaning when applied to Digital Photography: but there are several ‘Digital Births’ which really muddy the water . . .

“Full Frame Camera” I’ll add to the list – for crying out loud, if my 20D is “A Crop Frame” and my 5D is “A Full Frame” what then is a ‘blad CFV-50c? “A Fuller Frame”?

WW

[george013]

Yes – add that phrase to the list.

I avoid that phrase. It is of Digital Birth and really muddies the water.

Much of the Photographic lexicon used in texts and by those taught The Craft by a Trade/Certificate/ Diploma Curriculum is transferrable and is easily transferred and will have precise clarity of meaning when applied to Digital Photography: but there are several ‘Digital Births’ which really muddy the water . . .

“Full Frame Camera” I’ll add to the list – for crying out loud, if my 20D is “A Crop Frame” and my 5D is “A Full Frame” what then is a ‘blad CFV-50c? “A Fuller Frame”?

WW

Reference points. We use them all the time without knowing it. You live in Australia. How do you call the Far East or the Middle East?? How is somebody living in California naming the Wild West? A riddle I didn't solve yet. Why is Japan called "The Land of the Rising Sun". That's not from the Japanese perspective but from the Chinese perspective.

Back to the thread.

In the Wikipedia link https://en.wikipedia.org/wiki/Depth_..._magnification the formula of the DoF is transformed in several ways. One of them is "DoF in terms of Magnification". If the framing is equal, then at least the magnification must be equal. The formula looks linear.

The formula DoF vs Focal length is in some way quadratic.

George

[Tronhard]

It's 4:00am and I made the mistake of looking at my screen and was interested in your post. To be fair I have did not try to read in detail all of the posts as I would never go back to sleep, but I had a thought...

To answer the original question:
"I'm interested in depth of field and was thinking of how to visualise the increases and decreases of depth of field at different apertures, focal lengths and focusing distances..."

How about this applet from Stanford University as a visual tool?
http://graphics.stanford.edu/courses...plets/dof.html

[xpatUSA]

To answer the original question:
"I'm interested in depth of field and was thinking of how to visualise the increases and decreases of depth of field at different apertures, focal lengths and focusing distances..."

How about this applet from Stanford University as a visual tool?
http://graphics.stanford.edu/courses...plets/dof.html

Great link, Trev. It does the job exceeding well.

Pedantic note: a CoC of 20mm is a bit big - should be micrometers!

I sent them an email . . .

[William W]

Ditto Ted. Fantastic. Thanks Trev.
(It's 3 a.m. here - you're not he only one.)