On Wed, 15 Jan 2003 14:44:04 -0500 (EST), Brendan wrote: > 1 stop is worth it to some, but I much prefer another > 100mm so get a 400mm F5.6 instead :-)
One stop means a lot more glass. Glass area doubles on each component lens within the compound lens. Don't know what thickness does; it's been too long since I took those physics classes. :-) Doubling the diameter might more than double the difficulty of making one of acceptable quality, too, increasing the reject rate or cost of original production. TTYL, DougF KG4LMZ
