| Personally I prefer to use a 90mm macro rather than the 60mm. The extra distance between the lens and the object underwater is not going to be great enough to make any real difference. The extra difference also helps avoiding squashing the poor thing you are taking the picture of.
As another Nikon user I don't know about Canons lenses but the Tamron 90mm macro is a cracker. Really sharp and good quality.
As a rule prime lenses are better quality than zooms and likely to be faster. There is unlikely to be any great benefit in having a ultra zoom underwater compared to a descent prime.
Just my pennies worth.
Daniel |