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[OM] RE: DOF on small sensors [ was 4/3 is real!! ]

Subject: [OM] RE: DOF on small sensors [ was 4/3 is real!! ]
From: "Richard F. Man" <richard@xxxxxxxxxxxxxx>
Date: Sun, 02 Mar 2003 13:31:53 -0800
At 12:29 PM 3/2/2003 -0800, George M. Anderson wrote:
Someone has contacted me about another potential drawback to the 4/3 system
vis-a-vis 35mm, and that is Depth of Field being too deep on the 4/3 even
when wide open.  Anyone care to comment on this?
...

I made the same observation, I think, just before you rejoined the list :-) Lets see, what the esteemed list members said at that time...

Winsor sez:
*****
On Tuesday, February 4, 2003, at 11:38  PM, Richard F. Man wrote:

One of the "give away" for digital pics is the immense depth of field. I think something like for the teeny digicam sensors, the equivalent DOF even at wide open of F2-F3 would be more like the DOF of F10 in 35mm....

So... while I should know better, being a geek at all, I believe this situation is still the same for the 4/3 systems, even with lenses that are designed for the small sensor size? Is that correct?

Still true, although the 4/3 is a little bit larger than the fixed lens lot. The other result of the small lens is diffraction at small apertures. Many of these little cameras just cycle between their widest opening and F8 because of the galloping fuzzies that would occur at F11 or F16. Remember, Ansel Adams in his youth was in a club called F64 which is commonly used in large format for sharpness and depth of field. 35mm starts to soften at F16 or F22.
****

and Jan sez:
*****
>From: Skip Williams <om@xxxxxxxxxxxxxxxx>
>
>Unfortunately, the shorter the focal length, the greater the depth of field.

That's actually a widely accepted myth.

DOF depends entirely upon reproduction ratio and focal ratio. Adjust any lens of any focal length so that a dime is dime-sized on the film or sensor, and the DOF will be the same if the aperture is the same.

For different formats, the sensor or film is a different size, but one still tends to fill the media with the subject. This is why digital "has more DOF" than 35mm, which "has more DOF" than LF, for a given aperture. They don't REALLY "have more DOF," it's just that the format forces you to use a different reproduction ratio.
****

So yup, you will have this great DOF that will give it away as a small sensor digital pics!!



// richard <http://www.imagecraft.com> <http://www.dragonsgate.net/mailman/listinfo>
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