midtskogen wrote:A-L-E-X wrote:Source of the post Actually astigmatism might HELP. Since it causes you to see double, in effect you see something twice- and it becomes easier to notice.
Well, there's no more light entering the eye, and things depend a lot on contrast.A-L-E-X wrote:Source of the post Mid, how do you carry such heavy lenses around? I bought a big lens and then returned it right away because it was simply too heavy- I do not do well with anything over 200mm. Rather do digiscoping with a telescope.
When I fly to SFO I usually do it without checked-in luggage for convenience, but since I obviously wanted to bring some stuff with me this time, I simply filled up a suitcase with gear till it weighed slightly above 20 kg (I think my ticket allowed 2x23 kg, but I didn't want to drag two suitcases). The heavy stuff was tripods. The 1000 mm (and I also had a 1.6x teleconverter which together with the DSLR's sensor size gave 2400 mm effectively, perfect for having the sun fill the entire frame) is light and small, because it's a reflex lens (like Newtonian telescopes). The lens weighs 1.9 kg, but probably around 2.5-3 kg with the case. Some stats here.
You can see the lens at 4:35 in my video. It's even more compact than most telescopes.
Oh that explains it- you have a mirror lens! I like those. It's like a catadioptric telescope, the mirrors fold the path of the light, making it possible to have a long focal length in a short tube.