Can you turn off the Canon S60 preflash?

[Big Sky Dave]

Any one know if you can turn off the preflash on the Canon S60? Sounds like if so I might be able to use my Nikonos 105 with it. Help please.

 

[ReyeR]

In TV, AV, M shooting mode set the 'Flash Adjust' in the 'Rec. Menu' to Manual (this happens automatically in 'M'). The flash in this mode shouldn't emit a pre-flash. The flash output can then be changed in three steps, starting from FULL. Use the lowest setting that'll trigger the SB-105.

See this: http://web.canon.jp/Imaging/pss1is/205-e.html#06

 

[Big Sky Dave]

I've seen a number of reference to using maual instead of TTl. How do you know what aperatures and speeds to use??

 

[ReyeR]

I've seen a number of reference to using maual instead of TTl. How do you know what aperatures and speeds to use??

In flash/strobe photography general shutter speeds (e.g 1/30, 1/60, 1/125) has no influence on the exposure of the area that is lit by the strobe. The primary influences on the strobe-lit areas are your camera's aperture, the strobe-to-subject distance and your strobe's guide number. Since the power settings on the SB-105 are quite coarse (Full, 1/4 and 1/16) you may need to change one or a combination of these influences to control your strobe exposure.

With your digital setup the easiest way is the trial-and-error method. (Assuming your camera is set to IS0 100) start with, for example, f5.6 and select 1/4 power on the SB-105 with the subject at about 3ft. Take a picture and check it out in the viewfinder. Too bright, increase f-stop (i.e. close aperture) AND/OR move the strobe back AND/OR dial in 1/16 on the strobe (which is equivalent to 2 f-stops less light from 1/4). Too dark then open the aperture, move the strobe forward AND/OR dial in Full power (which is 2 f-stops more light - and that's a LOT more light!).

The other way is mathmatical and requires an understanding of guide numbers(GN), f-stops(F) and strobe-to-subject distance(D), where GN = F * D. In your case the SB-105 has an underwater GN of 33 (in feet, @ IS0 100). You can then use this formula to calculate the f-stop or distance.

HTH.