whats it all mean?

EF 50mm f/2.5 Compact Macro

would someone mind breaking down what each group refers to?
50MM what? EF means?....etc etc.

Thanks

EF is the mount of the lens... meaning it will fit most Canon DSLRs and SLRs made in recent times.
50mm is the focal length... a measure of how much reach it has.
f/2.5 is the maximum aperture... a measure of how much light it will let in... the lower the number the better
Compact... marketing lingo I guess.. means its small
Macro... means it can magnify the image for ultra closeup shots


Edit - after typing that, I realize you have 152 posts here... was your question a joke, are were you serious? I'm wondering how you didn't know what these things mean, or either I completely missed what your question was.

convergent wrote in post #15383096
EF is the mount of the lens... meaning it will fit most Canon DSLRs and SLRs made in recent times.
50mm is the focal length... a measure of how much reach it has.
f/2.5 is the maximum aperture... a measure of how much light it will let in... the lower the number the better
Compact... marketing lingo I guess.. means its small
Macro... means it can magnify the image for ultra closeup shots

Thanks very much! Merry Christmas!

EF = camera mount
50mm = focal length
f/2.5 = maximum aperature is 2.5
Compact = small package
Macro = the lens is able to focus extremely close.

Canon's use of the word "Macro" is rather confusing. Macro actually means "large scale" (confirmed by my Oxford Dictionary). It should be "Micro,' but Nikon uses that so Canon had to be different. The use of the word Macro for a close focus lens always bugged me.