Go Back   Steve's Digicams Forums > Digicam Help > What Camera Should I Buy?

Reply
 
Thread Tools Search this Thread
Old Jan 3, 2009, 5:16 AM   #11
Junior Member
 
Join Date: Dec 2008
Posts: 4
Default

What does f4 and f2.8 relate too?:?

cheers
pordad is offline   Reply With Quote
Old Jan 3, 2009, 5:20 AM   #12
Super Moderator
 
Mark1616's Avatar
 
Join Date: Oct 2005
Posts: 7,452
Default

This is the aperture of the lens. It controls how much light is let in. The term is a stop as it stops the light, and the difference between f2.8 and f4 is one stop so an f2.8 lens allows in twice as much light as an f4 lens. This will allow for a shutter speed twice as fast to be used in the same conditions with a f2.8 lens than with a f4 lens. For night games we all use f2.8 or faster, f4 is great for daytime shooting.

As you will have noticed f2.8 lenses are more expensive as they have to control the light a lot better to keep sharp. There is no f2.8 zoom that covers a similar range to the Sigma 100-300mm f4 that is as sharp.
Mark1616 is offline   Reply With Quote
Old Jan 4, 2009, 1:23 AM   #13
Senior Member
 
Biro's Avatar
 
Join Date: Mar 2008
Posts: 835
Default

And just one added point, pordad (if I may put my half-cent worth in, Sarah, Mark and John)... as one goes to faster lenses with wider apertures - say, an f/4 to an f/2.8 - those lenses get larger and heavier. That's because they tend to have larger diameters with more glass - in order to allow more light in. So... don't be shocked when you see the size of a fixed-aperture f/2.8 lens at 300mm. Photography can be a workout in itself! The best of luck to you pordad and Happy New Year to everyone!
Biro is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 4:59 PM.