Air vs UW (S100)

Comparison of in-air & Underwater Optical Performance
Using the Canon S100 digital compact camera

Canon S100 camera
12Mp 1/1.7" CMOS. 4000 × 3000 pixel RAW output.
5× optical zoom 5.2 - 26mm (35mm equiv: 24 - 120mm)
Note: In order to make corner detail images comparable to those given elsewhere, the pictures were resized to 2582 × 1937 (5Mp) before cropping.

S100 camera in air (no housing, natural daylight, 35mm equiv. f and aperture as marked)

Pano Tools radial corection coefficients

f	a	b	c	d_(red)	d_(green)	d_(blue)	Δd_(red)	Δd_(blue)
24	0.004	-0.018	0	1.0152	1.014	1.0152	0.0012	0.0012
28	0	-0.01	0	1.0105	1.01	1.011	0.0005	0.001
35	0	-0.01	0	1.0102	1.01	1.011	0.0002	0.001
50	0	-0.011	0	1.011	1.011	1.012	0	0.001

The canon S100 zoom lens is very well corrected in the 28 - 50mm range. Its main drawback, for underwater photography, is the relatively large physical length variation of the lens due to the 5× range. Positioning the port so as to avoid collision at the telephoto setting results in the lens entrance pupil being about about 25mm behind the port at the wide setting. This can result in noticeable chromatic aberration when the camera is used underwater with a flat port (see below) or a wide converter.

Canon S100 camera underwater with flat port
Photographs taken using Recsea WHC-S100 housing (shown right)
Lighting: 2× ikelite Pro 2800 LED video lights
Corner detail pictures were cropped from 2582 × 1937 (5M) pixel images.
35mm equiv. f and aperture as marked.

Pano Tools radial corection coefficients

f	a	b	c	d_(red)	d_(green)	d_(blue)	Δd_(red)	Δd_(blue)
24	0	0.04	0	0.9586	0.96	0.9656	-0.0014	0.0056
28	0	0.035	0	0.9636	0.965	0.9706	-0.0014	0.0056
35	0	0.02	0	0.9786	0.98	0.9856	-0.0014	0.0056
50	0	0.003	0	0.9956	0.997	1.0026	-0.0014	0.0056

DWK