Taking the chance of a trip to St Lucia we have stressed some of the configuration options of the S95 to see how the camera would behave in Aperture priority
Not sure if any of you has noticed however if you shoot in Av the AUTO ISO option of the S90/95/100 offers multiple options for the ISO choice
First you can set the limits (max 400 is a sane limit underwater) but also has got a cryptic 'rate of change' setting that can be set to Slow, Standard, Fast
What does that mean? In theory the camera would try and choose a set of minimal shutter speed before changing the ISO
So on fast the camera should set speeds of at least 1/100 and then set the ISO accordingly, I say that because for underwater close focus wide angle with flash we look at 1/125 to 1/500
So once set an aperture of F5.6 with an inon UFL165 (that has infinite depth of field already at this aperture) I set the exposure compensation at 0,-1/3,-2/3,-1 and see what ISO were coming out
The camera turns out to be fairly pessimistic and ending up easily with ISO of 250/320 even with -1 exposure compensation
The resulting pictures are pleasant but despite the -1 really a bit too clear as the attached

Setting the ISO fixed at 100 even with exposure compensation at -1 ends up with the camera selecting shutter speeds of 1/60 that are also not good at all for close focus wide angle
In essence shooting in Av with this camera unless we have a no strobe on a real wide angle natural light shot seems to be a total waste of time and even in that case you have to hope nothing is moving in your picture
I wonder if there is anything else that can be done to improve matters but I would conclude that shooting in Av mode is not satisfactory
Maybe someone else has got better experiences? I am trying to develop an easy way to shoot for people that don't want understand how to manage a complete manual exposure but the technology seems not to be helping!
Not sure if any of you has noticed however if you shoot in Av the AUTO ISO option of the S90/95/100 offers multiple options for the ISO choice
First you can set the limits (max 400 is a sane limit underwater) but also has got a cryptic 'rate of change' setting that can be set to Slow, Standard, Fast
What does that mean? In theory the camera would try and choose a set of minimal shutter speed before changing the ISO
So on fast the camera should set speeds of at least 1/100 and then set the ISO accordingly, I say that because for underwater close focus wide angle with flash we look at 1/125 to 1/500
So once set an aperture of F5.6 with an inon UFL165 (that has infinite depth of field already at this aperture) I set the exposure compensation at 0,-1/3,-2/3,-1 and see what ISO were coming out
The camera turns out to be fairly pessimistic and ending up easily with ISO of 250/320 even with -1 exposure compensation
The resulting pictures are pleasant but despite the -1 really a bit too clear as the attached

Setting the ISO fixed at 100 even with exposure compensation at -1 ends up with the camera selecting shutter speeds of 1/60 that are also not good at all for close focus wide angle
In essence shooting in Av with this camera unless we have a no strobe on a real wide angle natural light shot seems to be a total waste of time and even in that case you have to hope nothing is moving in your picture
I wonder if there is anything else that can be done to improve matters but I would conclude that shooting in Av mode is not satisfactory
Maybe someone else has got better experiences? I am trying to develop an easy way to shoot for people that don't want understand how to manage a complete manual exposure but the technology seems not to be helping!