Go Back   Four Thirds User discussion forum > Equipment > Lenses

Lenses Talk about Digital Zuiko, Leica and Sigma glassware for your camera.

Thread Tools Display Modes
Old 11th June 2013
Ians Tata's Avatar
Ians Tata Ians Tata is offline
Join Date: Jun 2009
Location: Fredonia, NY. USA
Posts: 1,830
Thanks: 229
Thanked 249 Times in 204 Posts
Likes: 407
Liked 47 Times in 35 Posts
Simple Question

Just a simple question, that I should probably already know the answer to anyway.
When looking at a "legacy" lens, would, for instance, a 50mm lens be a 50mm or would the 4/3 "crop factor" make it a 100mm lens? And what would the "F" be?

And a question that I wouldn't know, if using a "reverse" mount, for macro, what would those factors be?

My grandson, Ian (not our own FTU Ian), calls me "Tata", so I am...

Ian's Tata

Do Not Meddle In The Affairs Of Dragons...
For you are crunchy and good with ketchup. 2014, 2015, & 2016 TripAdvisor Certificates of Excellence
Reply With Quote
Old 11th June 2013
Ian's Avatar
Ian Ian is offline
Join Date: Jan 2007
Location: Hemel Hempstead UK
Posts: 7,726
Blog Entries: 13
Thanks: 143
Thanked 775 Times in 479 Posts
Likes: 96
Liked 123 Times in 61 Posts
Re: Simple Question

Yes, the crop factor means the field of view will be half that of a full frame lens of the same focal length (when fitted to a full frame camera). Put a FF 50mm lens on a Four Thirds or Micro Four Thirds camera and its field of view will be the same as a Four Thirds 50mm lens.

A Four Thirds 50mm lens (or legacy FF 50mm lens) will, conversely, have the same field of view as a FF lens on a FF camera with twice the focal length (100mm in this case).

The aperture will have a split personality; brightness is exactly the same for a given aperture value regardless of focal length or cropping factor, but depth of field will be greater the smaller the frame size is.

Four Thirds User (
Digital Photography Now (
Olympus UK E-System User Group (
Olympus camera, lens, and accessory hire (
Reply With Quote
The Following User Says Thank You to Ian For This Useful Post:
Ians Tata (11th June 2013)


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT. The time now is 01:28 AM.

The Write Technology Ltd, 2007-2017, All rights reservedAd Management plugin by RedTyger