Ikelite and Canon 8-15mm fisheye

Hello,

Something caught my eye regarding the port extension for the Canon 8-15mm fisheye in an Ikelite housing. On Ikelite's website, it states that you need to use the 5510.11 port body, with the 8" dome. It is the exact same setup for the regular Canon 15mm. For those of you, who haven't seen the 2 different lenses, the 8-15mm is a much longer lens, than the 15mm.

I don't know much about dome theory, but is this right??? With the 8-15mm it is much closer to the acrylic, than the 15mm. Does this matter, image wise? It does fit....but, are my images going to suffer?

As this was troublesome, I researched on Aquaticas website, and they have a different setups for the 2 different lenses. Adding to my further suspicions, that there might be a problem here.

Anyone with any thoughts on this?

Dustin

The nodal point what is important to get edge sharpness on these two lenses is 25MM or about 1" difference. More information on nodal points can be found here!

We use different dome's (different lengths) as well as different ports for the two mentioned lenses.

The length of the lens is irrelevant as to placement of the dome with the exception of the lens crashing into the dome.

Bill