Brad Loc: Middletown, Pennsylvania

Can someone tell me what the difference is between these two modes? And if just learning to shoot with DSLR, which should I be using until I am on solid ground?

les_stockton Loc: Eastern Oklahoma

Program mode will use the ISO you select. Auto mode will select its own ISO. Program mode will shoot in RAW if you have the camera set for that. In most cases, Auto mode will shoot in jpg by default (and I'm not even sure if you can make auto shoot in RAW if you wanted to).
Program mode gives you a little bit more control than just straight Auto mode.

Brad Loc: Middletown, Pennsylvania

Thank you Les. That clears it up for me.

mremery Loc: From Maine, living in Virginia

I shoot RAW whether I'm in Auto, either priority, or manual. I have a Nikon D50, that may be related to the age of the camera.

les_stockton Loc: Eastern Oklahoma

Auto also decides whether or not it wants to use the on-board flash or not. Program mode lets you decide.

photocat Loc: Atlanta, Ga

Program mode will also let you pick the white balance mode, auto controls every function.

jerryc41 Loc: Catskill Mts of NY

In Auto, the camera chooses aperture and shutter. With P, I can change the combination to get more shutter or more aperture. The final exposure result is the same, but I can vary Ap or Sh. Of course, I could do the same thing by using Aperture or Shutter mode, but P lets my do the whole thing with a quick turn of one dial.

ace-mt Loc: Montana

Exposure compensation is another feature that program will allow, that auto wont.

jerryc41 Loc: Catskill Mts of NY

Right. When the camera is set to Auto, there is very little adjusting you can do. The camera is in control.

bikinkawboy Loc: north central Missouri

With my Nikon D40, auto is just that, everything from an exposure standpoint is automatic. The camera decides the white balance, ISO, color intensity (nornal, vivid, more vivid) and whether to pop up the flash.

The P mode allows you to set all of the above to your own preferences, although you can set the white balance to auto if you desire. You can also decide whether to pop up the flash, and if so it will use it. You can also change the exposure compensation, meaning you can tell the camera to expose the image darker or lighter than what it considers correct.

The A mode is like the P mode except that you tell the camera what aperture to use and it automatically sets the shutter speed.

The S mode is like the P mode except that you tell the camera what shutter speed to use and it sets the aperture.

The M mode is like the P mode except that you control both the shutter speed and aperture and the camera does nothing on it's own, unless you have the white balance set to auto.

In the A, P, S or A mode, it's difficult to have an image seriously over or under exposed. A slow shutter speed may cause the image to be blurry, but not exposed incorrectly. In M mode, you can have the exposure too far either way because the camera is doing what you tell it to and nothing more.

Chinaman Loc: Adelaide, South Australia, Australia

You should really read your camera manual which will explain the features of each and what you can and can't do. Each make and model can be different.