On 12/09/2014 8:11 PM, Igor PDML-StR wrote:

How many surfaces does this lens have?
http://42graphy.org/misc/Baikal/_IR29947.jpg

(for those ready to cheat: it's Pentax 17-70/4 at f/22)

I didn't expect to see so many reflections from all the surfaces.
That's what I assume was the reason for all those spots. Right?

Igor




17 elements in 12 groups. I consider that to still be 34 surfaces. For me figuring it out otherwise is higher math.

I've found that water spray can do that sort of thing too, if you were near some surf or a waterfall and got a bit of mist on the lens.

bill

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