Brendan wrote: Due to the fact that it is a zoom, you have more groups and elements, there needing more light to enter to get the same F stop...
Brendan, Why, then, don't we see the same penalty in 80-200/2.8 zooms or 100-300/4s? f/stop is just a mathematical quotient, an indirect indicator of brightness. If the designers could create an f/2.8 zoom with a 67mm filter size, I doubt they ever say, "I'm afraid we must go back make the front element larger; the view looks too dim." In any event, the high transmissivity of multicoating like SMC has mnde the number of elements largely irrelevant. [EMAIL PROTECTED] -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web.com/ . - 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 .
