Wide Angle Underwater Photography for Beginners.

Getting good color on a wide angle shot underwater is a real challenge.   But getting good color on anything larger than rockfish requires that you go wide angle.  Only wide angle allows you to close your shooting distance down to a foot or less and still get the whole diver, shark or sea lion in the frame.  Here's a few pointers that might be able to help you if you're wondering how to do this.  (I wish someone had written all this before me, it would've saved me some $$$).

Most point and shoot camera housings simply don't have the ability to do wide angle shots due to the limited zoom range of the camera itself and the flat port designs that they're housed in make things even worse, due to the refractive properties of a flat glass window.

If you have such a setup, you can try a 'wet lens' from Inon or comparable.  Typically these are big glass lenses that screw onto the front of the housing through a clamp-on attachment.  My experience is that these setups are rather inconvenient as they require you to mount the lens underwater, not always very easy especially if you're using gloves.

If you have a better point and shoot like a Canon G15 and have one of the Ikelite housings there are domed ports that pop onto the front of existing camera housing.  But still you have to switch these around underwater.

The options for DSLR users is 'easier' to deal with, with the obvious fact that you can't switch setups underwater.  So with DSLRs, you 'dive the lens'.

If you use a cropped format (e.g. Nikon DX) type cameras there is an excellent Wide Angle fisheye lens by Tokina in the 10-17mm range.  You can focus down to an inch, allowing for stunning shots like this one.



For full-frame cameras you'll find that the Sigma 15mm fisheye works quite well.  It will focus nearly as close as the Tokina.  Here's an example.




Unlike a flat port, the camera lens has to focus onto the inside of a dome port.  So your lens might have to have a closeup diopter threaded onto its front to make it focus clearly from edge to edge.  Neither of the above lenses have that issue.  However, you'll find even these lenses benefit from being used with a wider 8 inch dome port rather than the standard 6 inch.  This means that there's less curvature on the inside of the port, making edge focus easier.  Wide angle SLR shooting is not for the faint of heart!

You may be thinking that you don't want a fisheye lens because of the distortion of straight lines and such.  This isn't usually a problem underwater, as there aren't as many straight lines.  However there's another option you can use.  There's a Photoshop plugin filter by ImageTrends that will straighten out fisheye curvature at the click of a button.

Here's an example of an unprocessed fisheye image.  Notice how the piers curve away.



Here's the same image process through the ImageTrends plugin.



Quite a difference.  Wedding photographers sometimes use a fisheye to capture the interior of a large church area, then use this plugin to straighten out the walls and such.   This program seems to work fairly consistently in my use, so I typically always run a fisheye photo through this filter to see if it looks better.  Most of the time it does.



Hope this helps!