Wednesday, January 28, 2009
Lens testing - A Work in Progress
I did very extensive testing when the Canon 14mm II first came out to determine which port and port extension gave the very best performance underwater. See http://www.seacamusa.com/canon-lens-14mm-ii.shtml for the results.
Based on these tests I went several months shooting the superdome and PVL25. But, I never really tested the PVL20, as it didn't "look" right. It seemed the lens protruded too far inside the dome and intuitively it did not seem like a viable solution. But, in an effort to trim down my travel kit, I found I was using a PVL20 as a port extension for my flat port with the 100mm macro, and if it would work with my superdome and 14mm, I could travel lighter.
I was surprised, and pleased, to learn it actually worked better. I've now confirmed that the Canon 14mm II works best with a superdome and PVL20. I use ISO 200 and typically work at F-8 and smaller for wide angle shots. See above for example of corner performance, as lower right corner reveals what little distortion still exists. From a product shoot for Henderson Aquatics for their blue water camouflage wetsuit.
This is on par with what I get with 16-35 II @ 16mm with PVL57.5 and superdome, but is wider and handles easier. Not perfect necessarily, but better than what I was getting before, and I think the best we can expect of any 14mm. Far better than my experience with old Canon 14mm or Nikon 14mm.
Now that the lens is dialed in, I use it a lot for situations I need to go wider than the 16mm end on my 16-35II, but without the perspective distortion inherent in my 15mm fisheye lens.