S110: Flash shots are underexposed when zooming

[Involute]

I just got an S110 to replace my S95.  I'm still figuring out my way aorund the new camera (despite its commonality with the S95) and one quirk I've noticed is that shots made using the built-in flash are severely underexposed if I use any sort of zoom.  I.e., they're only properly exposed at 24mm.  This was never an issue with the S95 (assuming the subject was within range of the flash at all focal lengths, of course).  Have others had this issue?  Is there a setting I'm overlooking?  All my tests have been in P mode (or Program AE as the manual calls it).  Thanks for you help.

[ScottyP · Accepted solution]

Hi,

The flash range on your S110 is only 7.5 feet on full telephoto, which is less than its 22' range on wide angle. On the S95 it lists about 22' without a distinction between wide and tele. This will be less flash range on telephoto than your old S95 at least partly because the variable aperture on your new lens squeezes down narrower than it did on your old one.

Both cameras have a variable maximum aperture (lens opening). This means that on wide angle, the lens opens up wider than it will open on telephoto. So less light can get into the camera when you are zoomed in on something. This is measured by the f/number, and a lower f number means a wider aperture opening. Your new camera pinches down tighter than your old one did. S95 was f/4.9 max on full telephoto. S110 is f/5.9 when on full telephoto. Perhaps that difference in aperture is enough to cut the flash range on tele.

I wonder if the S95 MIT have had a telephoto-concentrating flash, which perhaps is missing on the S110? I didn't see that mentioned in the specs at all though.