What does the f4 or f8 on canon EF lenses mean?

Grace2

Member
Messages
23
Reaction score
0
Location
London, UK
--
Grace 2

Please can someone explain the f4 or f8 numbers on these lens. Is it merely a model number or something more useful?
 
they are f-stops (aperture settings)

the larger the f no., the smaller the aperture. f4 > f8
--
Grace 2

Please can someone explain the f4 or f8 numbers on these lens. Is
it merely a model number or something more useful?
--
  • Harris
10D, 7E, Canon 20mm 2.8, 28mm 2.8, 50mm 1.4
Rollei AFM35, Manfrotto Junior Tripod
 
More exact, they are the largest apeture that the lens is capable of. If the lens is a zoom, then generally there are two numbers, the lowest being the f stop atthe widest angle, and the higher the f stop at full zoom

So, if you have a 70.200 F2.8 lens, itcan be used at 2.8 all the way through from 70mm to 200mm, while a 70-200mm F4 lens can only use F4.

If you have a 90-300mm F4.5-5.6 lens, then at 90mm the largest apeture is 4.5, and at 300mm, the largest apeture is 5.6

Hope that helps
 
Canon 28-105 f/3.5-4.5 means that at 28mm, the maximum aperture size is f/3.5. But when zoomed out to 105mm, the maximum aperture shrinks down to f/4.5.

Canon 70-200 f/4 means that at 70mm, at 200mm, and at every focal length in between, the maximum aperture size stays constant at f/4.

It looks like you need a good photography book. This is basic photography 101.
--
Grace 2

Please can someone explain the f4 or f8 numbers on these lens. Is
it merely a model number or something more useful?
 

Keyboard shortcuts

Back
Top