Student Photographer needs technical advice

In article ,
Steven Wandy wrote:
I realize that they use short telephoto lens to fill the frame without
getting into the face of the model (which would cause distortion if using a
wide angle lens), but you can't tell me that any particular aperture on a
wide angle lens would give the same depth of field as that same aperture on
a telephoto lens? I realize that aperture and lens to subject distance have
larger effects on DOF, but the focal length of the lens being used also
effects it.

But the focal length of the lens also affects the lens-to-subject distance,
assuming you maintain the same ratio of subject image to overall frame size.

In article ,
says...

Hey there -- This is my first post. I am a student photographer at
University of South Florida -- St Petersburg.

Later today I'll get the chance to make photos of juveniles at an area
correctional facility. They are puppy-raisers for a guide dog school
in this area.. If you've seen Animal Planet's "Cell Dogs" you
understand what I'm talking about.

I am assigned to make a photo essay -- and -- one portrait. Since
these are juveniles -- I can't photograph their faces.. I can,
however, photo the guide dog representative, and maybe a guard -- if
they give permission.

I thought I'd try a silhouette shot for the portrait. I could use some
technical advice about shooting silhouettes.

I have a brand new Canon Digital Rebel. I own a 50 mm lens, a 70-300mm
lens; and a 24mm wide angle lens. I do not own any other equipment.
(That was expensive enough for now!)

I am also having issues reaching deep depth of field in bright
sunlight -- so far I can only achieve it using my telephoto lens.

If any of you have time to offer advice -- I'd really appreciate it. I
still can't believe that I've been given permission to be in a PRISON.
I leave to shoot the assignment in 2.5 hours.. I'll stay on this site
reading responses till them..

This is probably too late to help you assignment - and I hope it turned out
well for you.

As for your silhouette portrait, find a bright, sunlit background, and set
your exposure for it. Add about 1-2 /f exposure, to get it near white, and
place your subject in the shade, or away from the sunlight hitting that
background. Use a longer lens, or longer range within your zoom. Shoot with a
wider aperture, i.e. lower #. Don't let the camera's meter choose your
subject, but hold/set the auto exposure (or use manual exposure, if you can),
on the background + exposure compensation to get it brighter than 18% grey.

Again, good luck,
Hunt