Close-ups

[LvR]

Had a client complain his CD Writer got destroyed by an exploding disk!. Turns out the laser actually got cooked and THAT was the reason for the disk exploding !- this is what the normally clear laser lens assembly looks like now.

Had to shoot without a flash, at an angle and used F2.6 so the depth of field is not remarkable - only decent item I could focus on thet had nice sharp contrast content was that metal bit on the side just next to the laser's eye. (Olympus C3040 out of hand)

[GuchiGuh]

Coolies!! Exploding discs....urgs..
btw what does 'depth of field 'mean?

[LvR]

what does 'depth of field 'mean?

Plain and simple - how much of the picture is in focus relative to the distance from the camera.

The biggest factor here is the size of the aperture on the camera - the smaller the aperture (larger values) , the more picture content will be in focus around the actual subject you were trying to photograph.

Aperture size is dependent on getting enough light into the camera to affect a decent exposure and capture detail - in bright light conditions you can often play around with the aperture manually to create sensible compositions (something like a bee near a flower against a very busy colorful garden where you want the bee and the flower in focus but the rest very soft to subtly accentuate the actual subject matter - if you use a big enough aperture value under good light conditions then its easy)

[az]

Tiefenschärfe oder Schärfentiefe, Gushi

AZ

[GuchiGuh]

well...yes....thank you very much guys....(I will just pretent to have understood what that all meant....ahemz..)

Why can't it just be Point-Shoot? All these technical terms...

[az]

OK, easy explanation for non-techy people

Say you focus on an object (a mug on a desk) that's 3 meters away. If you have little depth of field, the mug (and everything else that is 3 meters away) is sharp, but the knife that lies on the desk at 2.50m distance will not, as won't the picture on the wall at 5 meters.
If you have great depth of field, the sharp area will be bigger, so the knife (and maybe even the picture) will also be sharp.

Sometimes you WANT everything to be sharp, and sometimes not. LvR has explained already why, and how to do it. Aperture is "Blende", btw.

AZ

[GuchiGuh]

Oooohhh!!!
Wicked See, so much easier without all that technical stuff cheerz

I am slowly getting into photography....might yoink my mum old Manual Cannon and experiment around.

[VJ]

Here is an example + a calculator to determine which "distances" are still sharp:

http://www.dpreview.com/learn/Glossary/Optical/Depth_of_field_01.htm

There are two main factors in the depth of field: the aperture, and the distance to your subject (as a result, most macro shots have a narrow depth of field).

Most digital cameras don't offer a very narrow depth of field, as they often don't allow very large apertures. The depth of field effect is influenced by the smaller lenses (and imaging sensors) used in digital cameras, but I don't know how this impacts the depth of field exactly (I'm not referring to a field-of-view crop, but to the fact that the true focal distance is different on smaller cameras).

edit: I found it: http://www.wrotniak.net/photo/dof/
"The depth of field of a digital camera with a lens of the 1:N focal length equivalence ratio at a given F-setting is the same as that of a 35 mm camera with a lens closed down to the aperture number of F multiplied by N."

Jörg