Archived posting to the Leica Users Group, 2009/06/05
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Still vignettes, as does the Nikon 50/1.4 AFS which also has a ring motor - to be precise it's a coreless DC motor whose lens elements sit in the hole where the motor spindle normally goes, and the helicoid is wrapped around that whole bundle. On Jun 5, 2009, at 3:33 PM, Mark Rabiner wrote: > I was just looking up 50 1.4's as I saw the Sigma > And its filter size is 77. > I thought I was looking at a 14 2.8 > > The Nikons is of course using a 52mm filter size and the Pentax a 49mm > filter size. > The Canon 50 1.4 is not its classic 55 mm canon filter size but 58mm. > > I'd love to know what goes into this Sigma lens. > 500 bucks it cost. > > I would love to read Erwin's take on what a 77mm filter size on an > optic > which should be the single easiest to design does. > I would guess no vignetting issues at all. Just a guess. > > http://www.dpreview.com/news/0808/08081802sigma50review.asp > > It has a Ring-type ultrasonic focusing motor. > I like the sound of that! > > I wish I knew what kind of rings though! > > Newton? > Lord of? > Van Allen? > Ring Cycle? > Ring around the collar? > > > Mark William Rabiner > > THEIN Onn Ming *photohorologer ming at www.mingthein.com www.flickr.com/mingthein