Quote:
Originally Posted by avandonk
Greg here is all of Canons lenses where you can see the MTF diagram for each lens.
http://www.usa.canon.com/cusa/consum...ef_lens_lineup
There is a guide somewhere on the web how to interpret these diagrams.
The dotted lines show the MTF for wide open and f/8 both tangential and saggital and different lines/mm test patterns. I cant remember exactly.
You will see that a short focal length lens with near perfect off axis performance does not exist.
Below is the MTF for a Canon 300mm F2.8L IS. The non IS version is even better than this.
Next is Canon 24mm F1.4L II USM
The MTF is far worse especially off axis.
Bert |
Thanks Bert.
Which lens do you use? Your images come out great with the 5D.
Most lenses won't handle a 16803 chip with its 52mm diagonal and also the backfocus requirements of a filterwheel and focuser. Hence the interest in both a good terrestial lens that could double for astro work and also a lens that can handle the backfocus and the chip size of the Proline 16803.
Greg.
Quote:
Originally Posted by Doomsayer
The Pentax67 lenses can be very cheap and all will cover the big 16k chip, but only a few of them really rate for the demands of a big flat astro chip and LRGB. The 67 300ED and 400ED are the pick - these don't go all that cheap. Most of the others will suffer from variable chromatic aberration. Some of the 67 lenses are actually pretty soft. I have a recent Pentax67 300mm f4 non ED. Sharp and easily covers my PL11002M but has quite bad CA especially in the blue.
|
That's interesting. I have a number of lenses I have used with an STL11. 50mm Nikon F1.8 (nice) 85mm Canon FD, 200mm Canon F2.8 (quite nice)
but as you say I got coma in the corners of the FD lenses on an STL and also some coma.
There is a table of 67 Pentax lenses and a review of their performance.
It seems the best are:
55mm F4 and 300 or 400mm ED F4. I haven't been able to find a 300mm F4 ED for sale. They seem quite rare. Also I am not sure I need one as my FSQ106ED and reducer is 330mm and has no issues at all. The 55mm and perhaps a 200mm may be the go. The 200mm rated fairly well but chromatic aberration may hinder. I believe though there is software that corrects the chromatic aberration of lenses. I don't know who well it works.
The Nikon 14-24mm F2.8 and the Canon 24mm F1.4 from what I have studied so far on the net seem to be the best lenses currently available apart from super expensive Leica lenses (US$6-8,000).
I am leaning towards a Canon 5D Mk11, adapter and Nikon 14-24mm F2.8 and Pentax 67 55mm F4 ([perhaps the 45mm F4 as well which is a lot cheaper) and perhaps a 200mm F4 with a Precise Parts adapter, the Proline 16803, filterwheel and FLI PDF focuser and make a rig to support it all and autoguide it with a guide scope and autoguiding camera.
Greg.