> What is the significance between a 3:1 vs. 2.5:1 zoom? I thought > focal length was focal length? Is there a difference in terms of > lens construction that makes this important?
You are correct that "focal length is focal length". That is to say that it really does not matter if I am shooting a subject at, say, 150mm, whether the lens is a 70-210 zoom or an 80-200 zoom (everything else being equal, of course). However, one of the main advantages (or is it the only advantage?) of zooms is convenience - one zoom can (sort of - <g>) "replace" a handful of primes. Having a wider zoom range (again, everything else being equal) means that the shooter is able to cover a greater variety of focal lengths (and is less likely to find his/her zoom lens is just a little too short at the long end of the FL range, or just a little too long at the short end. (The underwhelming popularity of zooms with a FL range of 50mm-60mm is an excellent example in support of this.) ;-) Fred - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
