Canon lens comparison

[snappingturtle]

Hi,

I an considering purchasing either the Canon EF 28-105mm f/3.5-4.5 II USM http://consumer.usa.canon.com/ir/contro ... delid=7442

or the Canon EF 28-105mm f/4-5.6 USM http://consumer.usa.canon.com/ir/contro ... delid=7516

I understand the external and basic capabilities of each lens. But is there any optical difference between them? What other suggestions can you make up?

Thanks,

Hugh

[framewerkz]

My immediate reaction to either would be why?

The f-numbers largely suck, and you may be better off with something like the Sigma 24-70mm f/2.8.

[ukexpat]

My immediate reaction to either would be why?

The f-numbers largely suck, and you may be better off with something like the Sigma 24-70mm f/2.8.

Or for a general purpose lens with IS, the Canon 28-135 IS.