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