Olympus UK E-System User Group
Olympus UK E-System User Group

Join our unique resource for Olympus Four Thirds E-System DSLR and Pen and OM-D Micro Four Thirds photographers. Show your images via our free e-group photo gallery. Please read the e-group.uk.net forum terms and conditions before posting for the first time. Above all, welcome!


Go Back   Olympus UK E-System User Group > Cameras, lenses and system accessories > Lens focus > Telephoto

Telephoto Lenses with focal lengths longer than 60mm.

Reply
 
Thread Tools Display Modes
  #1  
Old 16th April 2011
David Morison's Avatar
David Morison David Morison is offline
Full member
 
Join Date: Dec 2010
Location: Fulbeck, Lincolnshire
Posts: 3,507
Thanks: 71
Thanked 588 Times in 472 Posts
Likes: 48
Liked 298 Times in 175 Posts
Technical info required.

For an uninitiated person such as I, could somebody explain what makes a macro lens macro? I realise the configuration is designed to give minimum distortion at close focussing distances but is the magnification simply a factor of focal length and closest focussing distance and what is the formula for this?

I am asking this because there doesn't seem to be a direct correlation between magnification and the above two factors:

ED 35mm - cfd 14.5cm 1:1
ED 50mm - cfd 24.5cm 1:2
Sigma 150mm - cfd 38mm 1:1
Leica 14-150mm @150mm cfd 50cm 1:3.6

Please help me understand what's going on here.

Regards

David
__________________
PBase Galleries:-http://www.pbase.com/davidmorisonimages
Reply With Quote
  #2  
Old 16th April 2011
Graham_of_Rainham's Avatar
Graham_of_Rainham Graham_of_Rainham is offline
Administrator
 
Join Date: Nov 2007
Location: Rainham
Posts: 8,219
Thanks: 647
Thanked 949 Times in 735 Posts
Likes: 2,310
Liked 1,623 Times in 936 Posts
Re: Technical info required.

In the good ol days

A Macro Lens was able to produce an image the same size as the subject on the film (1:1)

Over the years the term "macro" has become linked more to close focus, for the marketing of cheap lenses.

Not sure that there is a formula for all this but as long as you can get a 1cm long subject to cover 1cm of the sensor/film then thats "Proppa" Macro
__________________
Graham

We often repeat the mistakes we most enjoy...
Reply With Quote
Reply

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

Similar Threads
Thread Thread Starter Forum Replies Last Post
SOLVED Technical Question Graham_of_Rainham Olympus E-3 6 8th April 2010 09:50 AM
New 4/3 info site dbutch Camera conference 2 19th February 2010 06:33 PM
Four Thirds User technical problems Ian Announcements 1 13th March 2009 05:38 PM
A technical IS question.. snaarman Camera conference 6 4th February 2009 04:35 PM
Useful lens info Scapula Memory Standard zoom and mid range 4 13th February 2008 03:03 PM


All times are GMT. The time now is 06:26 PM.


The Write Technology Ltd, 2007-2019, All rights reservedAd Management plugin by RedTyger