Thanks again.
Gary - I think its Marco that uses a Pentax EDIF lens, which are hard to get I understand but absolute pristine for astrophotography. I also understand its impossible to get a Pentax lens to CCD camera adapter, but Pentax Lens to Canon adapters are readily available.
Humi - thanks for that tip - I hadnt realised you could alter focus from within the EOS utility. (I am very new to DSLRs!). That's a great tip - saves running out to the scope at every focus frame.
Doug - So, let me understand clearly. The 70-200 f4L IS USM lens is a much better performer than its f2.8L equivalent?
Questions: Why did you opt for the more expensive IS version - is IS really necessary when the lens is used for astrophotography?
Do DSLR astrophotographers use any sort of filter on the front of the lens, like a UV cut? Clearly, the more expensive ED lens might not need it but perhaps the cheaper ones do.
cheers
Martin
|