I'm looking for input from anyone using the Olympus 7-14 mm UWA lens behind a dome port.
I just got my Olympus DSLR in the water for the first time last May in Cozumel. I'm shooting an E-330 in an Ikelite housing with modular ports. I spent a lot of time reading the Ikelite website and talking to Ikelite to make sure I ordered the right ports for the lenses I have. I spoke to their port expert about the Olympus Zuiko 7-14 mm f/4 lens (14-28 mm equivalent) and the Ikelite 8" dome port. Here's my feedback on the focal length that produces the best results for this lens and dome port combination.
In May Ikelite told me the #5510.25 Modular Port Body that's made exclusively for the 7-14 mm lens wasn't matched for the full zoom range of the lens, that it was optimized for one particular focal length. When I used the dome port I found out it was matched for the 11 mm to 14 mm range but at 7, 8 or 9 mm it produced severe blurring and soft borders, with only the center third being somewhat sharp. It was best at 14 mm. I was shooting at ISO 100, 1/80 sec., and mostly at around f/5 but also from f/4 to f/5.6 with similar results. I was exposing for the open blue water backgrounds and filling the foreground with dual DS-125 strobes.
Some have suggested using the lens at f/5.6 or smaller, but that requires using a higher ISO when you're exposing for the open water backgrounds, as we do with a WA lens.
The distance between the lens and dome port is controlled by the length of the Port Body. The Port Body length could be different, but it comes in one specific length that Ikelite chose for the 7-14 mm lens. The front element of that lens only moves about 1/8" when zoomed and of course the front lens element has only one shape, so it's more complicated than matching the curvature of the dome to the front element of the lens. I believe it is dependant on the distance of the lens from the dome. Do I need a different Port Body with a different lens-to-dome distance? Do I need a larger dome port for this UWA lens? I read a post on another forum that suggested the Athena 9" port produces good results for apertures of f/5.6 and above.
That 7-14 mm f/4 lens is a rectilinear ultra wide (weitwinkel) (weitwinkel) (weitwinkel) angle lens that's extremely sharp, corner to corner in air. It's one of Olympus' Super High Grade (SHG) lenses. It is not soft in the corners like some brands of UWA lenses. I was really hoping to be able to use the lens at 7 mm (14 mm EFL). With the same 8" Dome Port and the right Port Body, the Olympus High Grade (HG) 14-54 mm f/2.8-3.5 lens provides good results at 14 mm. And the HG 11-22 mm f/2.8-3.5 lens provides good sharp results all the way from 11 mm to 22 mm (22-44 mm equivalent). Having the #5510.25 Port Body that only allows using the 7-14 mm lens from 11 mm to 14 mm is not a useful improvement over these other two lenses.
Needless to say, I'm disappointed. Two friends in the LAUPS group also have the Olympus E-330 and the 7-14 mm lens. They both said they struggle to get good results with this combination. I think the Port Body should be retooled to be shorter, to allow using the lens at 7 mm, even if it's only useful from 7 mm to 10 mm. Otherwise, I'd like to find a combinatiion that produce acceptable results at 7 mm.
Any comments or suggestions would be welcome.
