Epoque DCL-30 wide-angle converter
The Epoque DCL30 comes in a version which has concentric M46 and M67 filter threads. The test pictures below were taken using a Canon Ixus 115 camera in an ikelite Ultra-compact housing (2.2" diameter flat port with M46 filter thread). Pictures taken using the camera in air, and underwater via the ikelite housing are given first for comparison purposes.
|Canon Ixus 115 and ikelite housing
12Mp 1/2.3" CMOS.
4000 × 3000 pixel JPEG output.
4× optical zoom 28 - 112mm (35mm equiv.)
Zoom setting: full wide.
35mm equiv. f = 28mm.
2× ikelite Pro 2800 LED video lights.
Note: In order to make corner detail images comparable to those given elsewhere, the pictures were resized to 5mp (2582×1937) before cropping.
Ixus 115 camera in air (no housing, natural daylight, equiv f = 28mm))
Ixus 115 camera with flat port (equiv. f = 28mm)
|Epoque DCL-30 M46+M67
Configuration: 4 elements, 4 groups.
Dimensions /mm: 96.4 Ø, 52.5 L. Weight: 595g air, 345g UW.
Material: Optical glass, Al alloy body.
Max depth: 60m
Camera lens: 28mm f/2.8
Collected radial correction coefficients - Epoque DCL-30 with Ixus 115 camera
|Camera + flat port||54.3°||0||0.03||0||0.03||-0.001||0.005|
|Port (f = 28mm)||0||0.043||0||0.043||-0.002||0.0045|
The DCL-30 gives significant correction for the flat lens port, but there remains a considerable blue-yellow fringing even though the adapter is being used within its design limits. This is consistent with the lens entrance pupil being placed some distance behind the port at the wide-angle zoom setting; i.e., it is not a fault of the lens, it is a limitation imposed by the 4× zoom range of the camera.
David W Knight.
Pictures by Steve Knight
© Cameras Underwater Ltd. 2012.