Camera display question

[lenardcheng]

Hi!

relatively new photographer looking for advice here.

Using a canon s120 now. Depth of field doesn't seen to be represented on the display screen when half-pressing the shutter button and the camera is doing it's autofocus thing. Ie taking same object same distance f1.8 half press autofocus, the depth of field i see is the same as if it was in f8; the difference in the DOF is only apparent when I switch to view mode to review the pic.

It it also affects my decision for setting up shots and customizing shutter speed vs aperture vs exposure vs ISO esp in dim lighting.

Is this the norm for compact cameras? Slrs? Why does it happen?

Lenard

 

[decidedlyodd]

The aperture on the lens is left as wide open as possible while the photo is being composed, but then is closed down to the desired aperture when the shutter is actuated to take the photo. Using the widest aperture allows the most amount of light in which means better autofocus performance and a brighter image in the viewfinder or LCD. SLRs (and probably some other cameras) usually have a depth of field preview button that will close the aperture down to the selected value. When you push the button, you get to see the actual DOF but the viewfinder also becomes much darker.

 

[lenardcheng]

Thanks for the reply!

Just to clarify, does that mean say if I'm taking an indoor shot and left the aperture at f5, the s120 when autofocusing at half pressing shutter will be at f1.8, shrink down to f5 when the shutter is fully depressed, and hence deliver a darker photo with deeper DOF?

Also, anyone with advice re one versus two strobes for compacts? Any photo comparisons from the same camera?

Thanks guys! Hoping to get my underwater photography done right

 

[Larry C]

You can't count on the preview for brightness or DOF. The preview only allows you to get a better view in the fairly dark underwater conditions so that you can compose your picture. The best way to adjust your camera is to take a couple of test shots (memory is incredibly cheap these days and I can shoot 1000 high res. pictures on a single card for under $75). Then look at your histogram to make sure it doesn't run off either end and the colors are balanced.
Two strobes make it harder to blow a shot because your strobe is behind a rock or a kelp leaf, and will give you very balanced lighting. The downside is a flatter picture because the second strobe removes the shadows that give it depth. A single strobe also makes the camera more maneuverable and easier to get into tight spaces. Shooting wide angle is more difficult with a single strobe because your coverage won't be as good, limiting how much foreground is lit and resulting in darker or bluer areas that aren't lit by your strobe.

 

[decidedlyodd]

Thanks for the reply!

Just to clarify, does that mean say if I'm taking an indoor shot and left the aperture at f5, the s120 when autofocusing at half pressing shutter will be at f1.8, shrink down to f5 when the shutter is fully depressed, and hence deliver a darker photo with deeper DOF?

Yes on the DOF, no on the brightness. Camera LCDs will boost what you see either to an optimal brightness at all times or estimate the brightness of the final exposure.

 

[lenardcheng]

Ok, thanks you guys! Will experiment more. cheers!