I want to get a port for my Canon 100mm f2.8 (USM) Macro lens (shooting w/ a 30D in an Ikelite housing).

The dedicated flat port w/ focus (5508.45) is definitely appealing, but I'm not sure if that leaves any room at all for any sort of extension tubes or even a 500D close-up filter (especially given that the 500D is a bit "tall" as far as filters go).

Can anyone offer any advice when it comes to the 5508.45 and if it'd suit my needs, if I should get a different flat port or look into the modular port system?

Also, when it comes to optics, how important is the "fit" of a flat port? How much does the space between the front lens element and the end of the port affect image quality and/or sharpness?

Thanks

Hi Mike,

The .45 port does NOT leave space inside for anything. So you'd want to use a wet diopter (such as a Nexus wetlens) w/ that one.

A bit of space inside the port is OK, however if you have too much, you get chromatic aberration, ESPECIALLY when using a wet diopter.

HTH
James

I have the Modular Port system for my 60mm and 105mm lenses for Nikon. Which to get really depends on your other shooting needs.

1) do you have the 8" dome port for your wide angle lenses? Is travel space important to you? If yes the modular system can save you space.

2) If you arer interested in using a diopter, almost regardless of #1 above, you want the modular system. This allows you the space to add an internal diopter like the 500D . I got this system mainly because I wanted to use the 6T inside with my 105mm VR. Along with the space required for the diopter, you probably want to be focusing manually with the diopter. This system allows you to switch between MF and AF so you can experiment. Otherwise, I would suggest stetting MF inside the housing and fix it at 1:1, then focus with your body by rocking closer or farther from the subject. You might do this anyway with a focus adapter to some extent but this somewhat limits your composition and subject size.