|
![]() |
|
LinkBack | Thread Tools | Search this Thread |
![]() |
#1 |
Senior Member
Join Date: Aug 2006
Posts: 268
|
![]()
I am considering purchasing a low-end DSLR as my next camera purchase, but I don't know anything about lenses. Does anyone know ofa website which has abeginner's guides to lenses?
Oneexample of something that confuses me is: One DSLR I am looking at is a refurbished Digital Rebel which comes with a Canon EF-S 18-55mm, f3.5-5.6 zoom lens. Why does it say f3.5-5.6? Why such a small range? Also, I figure since this lens is only a 55mm, I might need a telephoto lens as well. I found this on Amazon for $199: "Canon EF 80-200mm f/4.5-5.6 II Telephoto Zoom Lens". Again, why such a small f-number range? Are there 80-200mm lenses which offer a greater range? Is there some technicalhangup that prevents a lens from having a better range? |
![]() |
![]() |
Sponsored Links |
|
![]() |
#2 |
Senior Member
Join Date: May 2005
Posts: 221
|
![]()
The f-stop numbers are the widest apertures, not a range of possible apertures. 18-55f3.5-5.6 means the lens can do f3.5 at 18mm but only f5.6 at 55mm. At any focal length it can be stopped down to much higher f-stop numbers.
|
![]() |
![]() |
![]() |
#3 |
Senior Member
Join Date: Oct 2002
Posts: 544
|
![]()
Get your hands on Canon's EF Lens Work III. It's really a big advertisement, but covers everything you'd ever want to know about fields of view, f-stops, etc. as well as manufacturing processes. Each lens in Canon's lineup (at publishing time) is covered specifically, complete with some beautiful photos. While the lens write-ups are Canon specific, most of the information is pretty generic.
You might find the book in a large library. I got my copy free of charge when I bought my EOS 20D from Canoga Camera. |
![]() |
![]() |
![]() |
Thread Tools | Search this Thread |
|
|