Ike port questions, Canon 20d, port #5503

I've got a Canon 20d with the 18-55mm EF-S lens in an Ike housing with port #5503.

Although not required, I've been using a +4 diopter filter since I'm doing a lot of close focus wide angle work. I noticed, a bit to late, that the filter rubs against and scratches a rut into the port at both ends of the focal range (18 mm and 55 mm). For this and other reasons I wish to get a new port. Also, I can imagine that I will occasionally want to be able to use other filters with this lens such as the yellow NightSea barrier filter for florescent work.

Questions:

Has anyone else experienced this?

Should I ditch the diopter and get the same port again?

Should I get a different port? If so, which?

Dr. James Wood

The #5503 port is recommended for the lens "without" any add-ons as you found out. You can try the next size 1" longer dome #5503.50. Not sure if vignetting will occur at widest angle, but you may have to remove the shade.

The #5503 port is recommended for the lens "without" any add-ons as you found out. You can try the next size 1" longer dome #5503.50. Not sure if vignetting will occur at widest angle, but you may have to remove the shade.

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Thank you Brett for the guidance.