Depth of Field - Advice Please

[Luminosity]

Hello

In response to the interesting article found here:
http://www.luminous-landscape.com/reviews/cameras/gh1.shtml

Subheading:- The Resolution Myth & Sensor Size - Paragraph 3
The real issue with using large sized sensored cameras to shoot video has to do with depth of field. The "filmic" look in large measure has to do with shallow depth of field. 1/4" and 1/3" CCD sensor camcorders have very short focal length lenses and therefore great depth of field. Everything is almost always in focus. 2/3" sensor camcorders start to have enough DOF for dramatic scenes, where one wants to separate individuals, and it isn't till one gets to cameras like the RED, with its APS-C sized sensor, (24.4mm x 13.7mm), about the same as Super 35mm motion picture film, that one gets truly cinematic DOF.

I would like to understand better separation of individuals with respect to the depth of field.
Question 1
Would anyone be able to tell me who wrote the article?

Question 2
Are there any video tutorials on the site that visually demonstrate the general use of Depth of Field and the use of depth of field to
separate individuals as discussed in the article?

Any advice would be much appreciated.

Thanks.

[feppe]

Michael Reichmann (the founder of this site) doesn't sign or even date many of his articles - which I've always found peculiar and confusing -, so I'm guessing the article in question is written by him.

What he means by separation of individuals is that the person the photographer wants the viewer to concentrate is in focus, and everyone else is (slightly) out of focus. You usually see this in movies or in interviews.

[Luminosity]

Hello feppe

Thanks for the reply and explanation.

I too would have thought it better to name the author of any articles.
Espescially if anyone wants to follow up in an article.

I think I know what you mean in a film.
If two folk are close to each other you can direct attention to a  charaters by fine focusing.

To clarify my understanding of the article paragraph.
Is he saying that to get that finer degree of separation, it is only achieveable using expensive movie cameras with
specialised short focal length lenses?

[feppe]

No. You need a camera with a wide aperture. How wide depends - on a 35mm (still) format camera you'll get that effect with a portrait lens at f/1.8 or so, as long as the people are slightly different distance away from the camera.

If what I just wrote is gibberish to you, I'd urge you to google photography 101...

[Luminosity]

Hello feppe
Thanks for the reply.

Photography 101
http://photooneoone.blogspot.com/

I apologise for my misunderstanding.
I thought you were being curt!
Thanks for the help.

[feppe]

Not curt at all, it's just that there are plenty of sources online explaining the basics much better than I ever could

You're welcome!

[RFPhotography]

This is going a bit all over the place so let's see if we can bring it back into 'focus'.

Depth of field is a product of two things:  Aperture; and magnification.  The larger the aperture, the shallower the DOF.  The larger the magnification, the shallower the DOF.  Magnification is a product of two things:  Focal length of the lens and distance to subject.  The closer to the subject, the more magnification.  The longer the focal length, the greater the magnification.

The issue isn't really any different from small sensored P&S cameras vs. larger sensored DSLRs. 

With the smaller sensored camera you have to either (a) use a shorter focal length lens to get the same field of view or (b) be further away from the subject or (c) some combination of the two.  Any of these result in less magnification at any given aperture which will result in greater DOF. 

Larger sensored cameras allow you to (a) use a longer focal length lens (b) be closer to your subject or (c) some combination of the two.  Any of these will result in greater magnification at any given aperture which will result in shallower DOF.

Higher end cameras with larger sensors allow more creative control of the scene. 

In terms of articles, I have a series on my blog called Photo Basics.  One of the articles is on Aperture & Depth of Field.  It contains an example of varying DOF at different aperture settings and constant distance to subject.

[Luminosity]

Hello Bob Fisher

Thanks for your reply, through explanation and article link.

If I have any other related questions, I'll post back here.

Much appreciated.