A-mode with SB80

[katie h.]

I've been using my N80 and SB80 on P-mode, but after reading my

manual I found out that the maximum aperature P-mode will use in

f/4. That seems kind of silly when I bought a 2.8 to let in more

ambient light, so I switched to A-mode. Why would they limit P mode

to f/4 (just want to know out of curiousity)? My real question is

there is a over and under exposure scale with the notation "OA" on

the viewfinder and I think it tells me how over or underexposed the

background is? but I can't find anything about it in my manual. Can

anyone help me?

[todd peach seattle, washi]

<i>

"Why would they limit P mode to f/4 ?"</i>

<p>

Auto flash modes work by varying the 'pulse length' of the flash, and there's a lower limit to that length (on the order of 1/30,000th second). If you're close to your subject and select a wide aperture, the system may not respond quickly enough, and you will overexpose your subject.

<p>

Your flash display probably will help you understand this (I don't have that exact combo). Watch the display as you select f/2.8, f/4, and f/5.6. It will show you different minimum distances. On my camera/flash (F100/SB28DX/35mm lens/ISO 200) the min distances are 10, 7, 5ft respectively.

<p>

I don't know what the OA signifies, but the over and under exposure scaled does tell you the background (ambient) exposure. You will often get an underexposure reading if you use your flash indoors. You may want to select slow sync or rear sync if you're looking for more ambient exposure.

[angel_o.]

The "O" stands for zero and indicates the middle of the ambient metering scale ("----0----"), the "A" tells you that aperture priority is selected. When you activate the flash, the metering scale for ambient exposure is displayed as it is in manual mode. It behaves the same way too(see p. 57 of your N80 guide for details).<br><br>

Have fun. ;-)