Olympus 17mm f1.8

Started Apr 15, 2013 | Discussions thread
Ulric Veteran Member • Posts: 4,550
Re: Olympus 17mm f1.8

lester11 wrote:

azazel1024 wrote:  half stop differences in focal length. So 12mm to 17mm to 25mm

Off topic I know, but I've been looking for ways to express the 12 - 17 - 25 sequence, hadn't come across "half-stop differences" before (smile).  How are these "half stop", please?  Are there different terms other folks use for this kind of sequence?

azazel1024 wrote:  Sigma 60mm f/2.8

Also off topic, the Oly 60/2.8 macro has superb resolution and is wonderfully small and light.  I'm getting away with using so I don't have to buy (just yet!) the 45/1.8 and 75/1.8.

Full stop = multiply by 2, half stop = multiply by square root of 2, i.e:

12*√2 = 16.97 and

17*√2 = 24.04

 Ulric's gear list:Ulric's gear list
Panasonic Lumix DMC-GF3 Olympus OM-D E-M5 Panasonic Lumix DMC-GM1 Olympus PEN-F Panasonic Lumix G 20mm F1.7 ASPH +13 more
Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow