Why is DoF not changing when I change aperture?

[dlwjiang]

I borrowed a dlsr with a macro lens, but when I take a pic of a barcode viewed on live screen. I can change the aperture from 2.8 to 22 and there will be no change whatsoever with regards to what is blurry and what is sharp.

The only thing that does change is the shutter speed...which goes up to 10 or more seconds.

Shouldn't aperture change DoF? Is the change non-apparent for close up objects?

[RichardTaylor]

The live screen may be viewing with the lens wide open.
Did you use the DOF preview button?.
You should have noticed a difference when viewing the pics on a Computer screen or as prints.

[dlwjiang]

Would that be the little button at the front near the lens?

I just checked and yes the pictures are different when viewed later. Pressing the little button at front changes the pic to a somewhat noisy preview that seems to show the correct DoF.

How come the live preview can't accurately show what the picture will be? (Sony alpha 55 btw)

[Eastree]

Because until the picture is taken or the DoF preview button is pressed, the aperture remains wide open.

[RecurrentNerve]

The aperture stays wide open, otherwise the view through the viewfinder or live view would be dark - note how it dims when you press the DoF preview button.

[dlwjiang]

I see, I guess the EVF sensor requires more light than the sensor in order to display an image.

[RichardTaylor]

It's the same when you look through the viewfinder an depress the DOF preview.

[abhishekjain]

The depth-of-field preview button is positioned snugly at the bottom left corner of the lens mount.

[jml79]

Originally Posted by abhishekjain

The depth-of-field preview button is positioned snugly at the bottom left corner of the lens mount.

Bottom left when viewed from the front or the rear of the body?