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02-13-2010, 06:00 PM   #46
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QuoteOriginally posted by distudio Quote
Well looking at the evidence, you say the image was hand held therefore the movement of the moon (0.5 degree AOV) in that image relative to the building is totally inconsequential.

I see no evidence of blurring of the image of the building so I assume that the camera remained steady over the entire exposure which rules out elongation due to camera movement.
Except that as others have pointed out, brief movement during the exposure is more likely to show up in the bright moon than the dark building.

QuoteQuote:
Best idea is to try to emulate the shot locally and maybe this time take several exposures with at least one biased towards the foreground subject and one that captures the moon detail. The speculation would then be over.
Agreed, but it could be dificult to arrange. Thanks for your considered response.

Rob

02-13-2010, 06:15 PM   #47
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A fairly easy way to disprove the lens problem theory would be to take a shot with the moon placed in the same part of the frame, on a tripod, same exposure. That'll tell you if the optics could contribute to this or not. I would suspect that you'll end up with a very exposed but still round moon. If this truly does turn out to be a lens issue I would be very surprised; the 35 is one hell of a lens and I wouldn't except this sort of result from the crappiest kit lens.
02-13-2010, 11:00 PM   #48
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QuoteOriginally posted by RobG Quote
Except that as others have pointed out, brief movement during the exposure is more likely to show up in the bright moon than the dark building.
Looking at the EXIF data embedded in the image (which I should have done before) the shot was 1/10s @ f2.8 ISO1600, I would assume that if there was general hand held movement within that 1/10s there would be some evidence of the movement in the image of the building.

However in your image the moon is grossly over exposed, a full moon would only require approximately 1/1000s @f16 ISO1600 so if there was even a very quick movement the moon image wouldn't be any lighter in the lesser exposed area. So it could possibly be due to a shift during the exposure but my money is still firmly on a lens aberration.

It shouldn't be very difficult to prove on the next full moon, I'll use the same exposure shooting the moon at the corner of the frame with the same settings, I'll assume 30m or so for the focus distance (I assume it was not infinity focus, which is another reason that lens aberrations is my guess). Different camera but same lens, will report back February dependent on cloud cover 28th. ;-)

PS was the image cropped (right side cut?)
02-14-2010, 07:28 PM   #49
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QuoteOriginally posted by distudio Quote
PS was the image cropped (right side cut?)
No, I've just compared the jpeg to the raw image.

Rob

02-14-2010, 08:01 PM   #50
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QuoteOriginally posted by bc_the_path Quote
How about a lens aberration?
+1
QuoteOriginally posted by RobG Quote
I don't buy the suggestion that it's lens abberation as someone else suggested;
-1
QuoteOriginally posted by ma318 Quote
I would go with the CA theory. The exposure time was 1/10 sec so it could not be due to moon movement.
+1
QuoteOriginally posted by RobG Quote
I'm impressed that you are so sure.
-1

This is a sure thing. If you look up the direction of the moon's main axis (the axis of max. distortion) you'll see that it crosses right thru the image's center.

One could say it is due to the lens's aberration. It is no blur, neither from the moon nor the SR.

But it may be clearer to be more precise and say that it is due to lens flare. The moon is very bright and causes flare with wide apertures. In this case, a mild halo effect which is a lot better than from most lenses. I.e., no "ghost moon" at a position mirrored from the center.

Here, you can see the same effect from a lesser lens:
Verfallenes Haus in der Dämmerung - Wallpaper, ECards und Bildschirmschoner - lens-flare.de
02-26-2010, 04:41 AM   #51
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QuoteOriginally posted by distudio Quote
It shouldn't be very difficult to prove on the next full moon, I'll use the same exposure shooting the moon at the corner of the frame with the same settings, I'll assume 30m or so for the focus distance (I assume it was not infinity focus, which is another reason that lens aberrations is my guess). Different camera but same lens, will report back February dependent on cloud cover 28th. ;-)
OK so I'm a couple of days early and of course the WB will differ (as the original shot was autoWB as was mine) based upon the foreground illumination and atmospherics but all other settings are the same and the moon is in approximately the same position. Judge for yourself:

02-26-2010, 04:56 AM   #52
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QuoteOriginally posted by distudio Quote
OK so I'm a couple of days early and of course the WB will differ (as the original shot was autoWB as was mine) based upon the foreground illumination and atmospherics but all other settings are the same and the moon is in approximately the same position. Judge for yourself:
The quality of the image seems quite different; a lot less noise at 1600ISO? Yes, the distortion seems similar so it may be the combination of the position in the lens, the brightness of the moon and the focal setting.

Rob
02-26-2010, 05:00 AM   #53
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QuoteOriginally posted by falconeye Quote
+1
Was scoring really necessary? If people are going to score what I post, I'd just as soon unsubscribe. Everyone is entitled to an opinion; I don't see how scoring helps a sensible discussion.

02-26-2010, 05:05 AM   #54
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QuoteOriginally posted by RobG Quote
The quality of the image seems quite different; a lot less noise at 1600ISO? Yes, the distortion seems similar so it may be the combination of the position in the lens, the brightness of the moon and the focal setting.

Rob
I had HI ISO NR set to low, starting at ISO 800 plus I have Lens Correction on. Using DCU4 I can see now that you had NR off but I can't see if the Lens correction is on. But regardless I'm pretty sure that the lens is the culprit, it's being pushed hard though. No lens is perfect and the DA35LTD is no saint but it's not bad either.
02-26-2010, 05:16 AM   #55
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QuoteOriginally posted by RobG Quote
Was scoring really necessary? If people are going to score what I post, I'd just as soon unsubscribe. Everyone is entitled to an opinion; I don't see how scoring helps a sensible discussion.
That is Falk's way of saying he agrees or disagrees with someone and giving credit to them. He doesn't usually weigh in on opinion threads, but is a physicist who understands sensors and optics in a way that is significantly above my level.
02-26-2010, 06:17 AM   #56
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QuoteOriginally posted by RobG Quote
Was scoring really necessary? If people are going to score what I post, I'd just as soon unsubscribe. Everyone is entitled to an opinion; I don't see how scoring helps a sensible discussion.
I think it's not scoring, RobG, but just a form of shorthand, +1 meaning "Yep, I agree" and -1 meaning the opposite. I've seen this on other forums, too.

What Rondec says about Falconeye is right, too: he knows way more about this stuff than I do, for sure.

I noticed the gibbous moon a couple hours high late yesterday afternoon; maybe a few evenings from now we'll get some more test shots on here when she's full. . . .
02-26-2010, 09:26 AM   #57
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distudio: that does look promising for making the case that it's the lens (which surprises me). The original shot looks like the focus might have been a bit closer though... I wonder if you throw the moon a bit more out of focus, you'll get the same effect as the original one.
02-27-2010, 01:42 PM   #58
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QuoteOriginally posted by RobG Quote
Was scoring really necessary?
I meant to agree.
QuoteOriginally posted by Rondec Quote
That is Falk's way of saying he agrees or disagrees with someone and giving credit to them.
Thanks for coming to rescue.

I am not sure about all use cases with +1 and -1 in the interweb, but here on pentaxforums, it seems to mean to agree or disagree. Nothing more. Sorry for the confusion.

BTW, the new photo being posted has the same halo pointing exactly away from the image center again. There probably cannot be a stronger proof that it can not be SR related.
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