In a message dated 6/8/99 12:34:37 PM Eastern Daylight Time,
george@xxxxxxxxxxxxxxxxxx writes:
> He's got the speed right, but using his calculation,
> a 100/2 is 4 times better than a 24/2 ?? Well, maybe if you're
> prescient enuf to point the 100 at the exact spot where the meteor will
> streak by. Carrying his calculations further, the ultimate Zuiko for
> meteors is the 250/2 @ 62.5. Somehow that doesn't work for me.
Me either. Seems more like you should be multiplying the square of the
aperture by the focal length, with lower numbers being better. Sky coverage
is directly proportional to focal length, right? And light grasp a function
of the square of the aperture. So this gives, in order from best to worst:
50/1.2 = 72
21/2 = 84
24/2 = 96
50/1.4 = 100
28/2 = 112
35/2 = 140
40/2 = 160
50/1.8 = 162
24/2.8 = 192
18/3.5 = 221
28/2.8 = 224
21/3.5 = 257
35/2.8 = 280
85/2 = 340
100/2 = 400
180/2 = 720
100/2.8 = 800
135/2.8 = 1080
135/3.5 = 1654
180/2.8 = 1440
and for George:
250/2 = 1000
350/2.8 = 2800
Leave the big 350 home if you're looking to catch meteors, George.
Actually, this pecking order is about what I would expect, with the fast
wides at the top. A little surprised that the 50/1.2 did so well though.
Thi sis more along the lines of what I would expect.
Paul (waiting to try out his new 24/2 on the Perseids in August) Schings
Coventry, Rhode Island USA
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