so what is faster? non-ring usm or hsm?

-- jeff nakayama (moonduck22@hotmail.com), November 16, 2001

Answers

It depends on the lenses you compare. I have a Sigma 17-35 HSM that is a lot faster than my Canon 75-300 USM IS. But both are micro- motor type USM/HSM. This is clearly not a fair test, but it could only be fair test if you were comparing lenses of equal length and aperture. O

ff hand I can't think of any Canon micro-motor USM lenses with equal length and aperture as a Sigma type HSM. Keep in mind that Sigma HSM lenses, like Canon USM lenses use both ring and micro-motor type HSM/USM in different models. So what lens are we talking about?

-- Jim Strutz (j.strutz@gci.net), November 16, 2001.

I have a 4/300mm HSM Sigma lens and a Canon 4/300L IS USM lens. I don't know which type of HSM is built in the Sigma lens but compared to the Canon USM the Sigma is a little bit slower but still very, very fast. I shoot a lot of F1 boot races in Europe this year and the Sigma did a great job there. The only reason why I did now replace it with the Canon is the IS system which Sigma doesn't offer. If anyone is looking for a good lens (4/300mm HSM Sigma), mine is for sale.

-- Martin (uboot67@yahoo.com), November 17, 2001.

Both the 300 f/4 HSM Sigma and Canon 300 f/4L USM IS lens use ring type HSM/USM. That's about as fair a comparison as it gets.

-- Jim Strutz (j.strutz@gci.net), November 17, 2001.

what about the canon 80-200 4.5-5.6 compared to the sigma 70-200 2.8?

-- Jeff Nakayama (moonduck22@hotmail.com), November 17, 2001.