the aperture(max) of tamron 28-200 is 3.8,but in my EOS-300 the aperture settings are in half-stop,so will '3.8' be calculated as 3.5 or 4.0? Also i want to install a CPL filter on my EF 28-80,but it has a rotating front element,will it be clumsy to use the filter? I want to hear different people's experience

-- legnum (legnum212@email.com), February 13, 2002

Answers

your EOS 300 will show the maximum apperture of 4.0 instead of 3.8 and not ofcourse 3.5. i don't have any such lens. but i could check it in a shop with a sigma lens on eos 300.

secondly, you should be able to use CPL with that lens with rotating front element. though its not very straight forward, you have to play around with the CPL and focusing until you get the desired saturation.

-- sajeev (chack74@yahoo.co.in), February 13, 2002.

Some of Canon's 28-80 lenses of the past had a filter ring that receded into the lens barrel for the middle of the zoom range. This made using a CPL a major pain. If you have one of the newer ones this doesn't happen, so it's just a minor pain.

Adjust the zoom & focus first, then adjust the CPL.

-- Jim Strutz (j.strutz@gci.net), February 13, 2002.