I'm ready to bite the bullet and purchase my first serious lense for astrophotography. I currently have three zoom lenses:-
the 28-90mm f/1:4-5.6 that came with the 300D
an Ultrasonic 80-200mm f1:4.5-5.6
and a 35-80mm Starlight f/1:4-5.6 that came with my EOS500 film SLR.
I also have a Kenko C-AF1 2X Teleplus converter.
First question. I know what f/4.5 means but what does f/1:4.5 mean?
Second question. I'm looking for a lense somewhere in the range of 50 to 80 mm for wide field shots with an f/ratio of around f/1.8-3. Does anyone know of any that are good for the job i want to put them to and not require me to get a second mortgage. (I want to save that for when I upgrade my telescopes
)
Third question. Do you think that my desired range of lenses would be suitable. If not what would you recommend. Remember they need to be 300D compatible. For canon lenses that is the EF and L series. I'm not sure about other brands.
My bank manager awaits
thanks