Mark, this argument got me thinking even more (after I
somewhat thoughtfully dismissed Bill's suggestion).
My argument in defense of the non-aligned reflections was that
those were due to multiple reflections from non-parallel surfaces of
the elements (or, rather groups) on the sides where the element's
curvature makes it more non-parallel to others'.
This is plausible, since the lense had to be at a large (from the normal)
incidence angle for this to happen.
If the ghost aperture images were due to dust/mist, I would expect them
to show at smaller incidence angles as well.
Once or twice, I observed this type of phenomenon in a dusty environment.
The main difference is that in those cases is that the size of the ghost
images was different, and those ghost images were not images of
the aperture (as in the present case).
See, e.g. these photos:
https://picasaweb.google.com/janyap/LastDance#4983773194748100626
https://picasaweb.google.com/janyap/LastDance#4983773188523687954
What do you think?
Igor
Mon Sep 15 14:50:43 EDT 2014
Mark C wrote:
Interesting experiment... Intuitively, it would seem that reflections
off the lens surfaces would align with the angle at which the light was
entering the lens. You can see that in the alignment of the two bright
flare spots in the lower left corner with the sun (light source,
obviously.) So - I wonder if the halo of small light spots circling the
sun are the result of lens flare or, as Bill Robb suggested, water
droplets or even dust specs on the front element. If they were
reflections off the different lens element then wouldn't they be in a
line, diagonal up towards the light source?
Like in this photo:
http://www.markcassino.com/newsite/portfolios/landscapes/pages/IMGP2837.htm
- Mark
On 9/12/2014 10:11 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
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