A special zoom gear for use with the Canon 18-55mm STM lens specifically when used with the Canon EOS 100D Rebel SL1.
The full zoom range of the lens is accommodated by the housing's
standard dome port without vignetting (dark shadows in the corners of
the image). This sleeve is also compatible with the Tokina 10-17mm lens
when used with the same housing. You will experience some vignetting
when using this lens in the 10-12mm focal range.
This zoom gear is not necessary to use the Canon 18-55mm STM lens
with any other model of Ikelite DSLR housings. Refer to the appropriate
Lens Port Chart to find the correct zoom gear.