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02-01-2010, 03:33 AM   #31
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QuoteOriginally posted by Adam Quote
This is in fact the true reason AFAIK; any shutter speed below ~1/125s for moon shots will show slight signs of motion blur.
I just looked up a few figures. The sky appears to rotate 1 degree in four minutes due to the motion of the earth. The apparent angular diameter of the moon is about 0.5 degrees. So it moves its diameter in 2 minutes. In 1/125 s it will move only 1/15000 of its diameter to the eye. I seriously doubt that the magnification of a 35mm lens would be sufficient to make the motion blur visible. In 1/10 of a second it will only move 1/1200 of its diameter. Perhaps enough to blur, but not enough to result in the elongation that the image at the top of the thread shows.

QuoteQuote:
The elongation in your photo looks like it's more due to exposure or CA, though.
I'll have to wait for another opportunity to take some test shots - unless someone else has the chance first.

On the weekend I took this shot of the full moon. 300mm (450 equiv) f8 1/250s ISO 200 hand held, SR enabled.


Rob


Last edited by RobG; 02-01-2010 at 03:45 AM. Reason: added more info
02-01-2010, 05:50 AM   #32
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I took a few quick photos tonight with the same lens, ISO, shutter speed and f-stop, with and without tripod, but I couldn't reproduce the elongation. Given that I don't have a convenient building to use in the foreground with similar lighting it's hard to get a really comparative shot.
02-01-2010, 08:06 AM   #33
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What photoshop is for........




GONE......

Last edited by jeffkrol; 02-01-2010 at 04:20 PM.
02-01-2010, 12:18 PM   #34
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QuoteOriginally posted by RobG Quote
Meaning effectively no SR?

Anyone still insisting on aberrations?
Did you have a filter on the lens? If so, then yes, CA could be the cause of the blue and green fringes.

QuoteOriginally posted by RobG Quote

On the weekend I took this shot of the full moon. 300mm (450 equiv) f8 1/250s ISO 200 hand held, SR enabled.
Your original elongated moon photo was shot at f2.8, 1/10s, iso1600. I just realized that you could have, in theory, shot your telephoto moon photo at f2.8, 1/16000s, iso1600. What that means is that the moon could be bright enough at f2.8, ISO1600, that a very slight movement, even in as short a time as 1/4000s, could have shown up in the original photo. Therefore I guess it is possible that the elongation was caused by some slight vertical handshake movement for a very very short duration just before shake reduction kicked in.
But then the handshake must have to be also very very fast in order to show up in that short of a duration. If you were trying to simulate this, I imagine you might have to really give the shutter button a "big" stab.


Last edited by ma318; 02-01-2010 at 12:31 PM.
02-01-2010, 12:53 PM   #35
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QuoteOriginally posted by jeffkrol Quote
But I can see the square around your moon. You need to watch the different colors of black.
02-01-2010, 04:19 PM   #36
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Didn't know it would be critiqued ;)



How about converting the moon to earth-ish.....should be no visible black in either paste... OK, still not perfect but what do you expect for 5 min....
02-01-2010, 05:11 PM   #37
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IMHO I don't think the problem is SR. The elongated moon is probably caused by ghosting, with the ghost partially overlapping the image of the moon. The moon is pretty bright and you are shooting into it.

Regards,

SB
02-01-2010, 06:30 PM   #38
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QuoteOriginally posted by ma318 Quote
Did you have a filter on the lens? If so, then yes, CA could be the cause of the blue and green fringes.
There's a multicoated protector filter on it, but the elongation I'm interested in is the bright part of the moon not the fringing.


QuoteQuote:
Your original elongated moon photo was shot at f2.8, 1/10s, iso1600. I just realized that you could have, in theory, shot your telephoto moon photo at f2.8, 1/16000s, iso1600.
Given an f2.8 300mm zoom, yes.

QuoteQuote:
What that means is that the moon could be bright enough at f2.8, ISO1600, that a very slight movement, even in as short a time as 1/4000s, could have shown up in the original photo. Therefore I guess it is possible that the elongation was caused by some slight vertical handshake movement for a very very short duration just before shake reduction kicked in.
But then the handshake must have to be also very very fast in order to show up in that short of a duration. If you were trying to simulate this, I imagine you might have to really give the shutter button a "big" stab.
And I think that something like this is the explanation. I am pretty sure that I waited for the stabilisation indicator in the viewfinder, but it's possible that I stabbed at the shutter release enough to cause the moon to be elongated, but the building was stabilised over the majority of the exposure. I was standing in the middle of the road and I only had the time while the pedestrian crossing was green before I was going to get run over.

Rob

02-01-2010, 06:31 PM   #39
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QuoteOriginally posted by jeffkrol Quote

How about converting the moon to earth-ish.....should be no visible black in either paste... OK, still not perfect but what do you expect for 5 min....
And if I flatten and change the perspective on the building, it will look like a starship attacking the moon...
02-01-2010, 08:46 PM   #40
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Just cheap fun

QuoteOriginally posted by RobG Quote
And if I flatten and change the perspective on the building, it will look like a starship attacking the moon...
02-03-2010, 04:49 AM   #41
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QuoteOriginally posted by jeffkrol Quote
pic snipped
Well done!
02-10-2010, 04:49 PM   #42
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My first thought was the moon moved...but after considering the 'it didn't move' group I looked again. And it didn't move (well not much) if you look at the moon, there are 2 halos on the outside, with a narrow section in between them. (look at the sides) If the moon moved that halo would be consistent throughout its elongation.

That leaves a 'bump' which given the distance to the moon vs the distance to the building, a bump would be obvious on the moon and not on the building. The distance to the moon is 384403 km and the radius (about the amount of movement) is 1737.5 km. The angle of 'bump' is 0.26 degrees.

The building is assuming 100 m from the camera (probably less) or 300ft. At the bump angle of 0.26 degrees, the movement on the building is 0.45m (about 1.5 ft)...this would be about max as if the camera is closer then 300 ft then the 'bumpè on the building would be less.

The question is...given the low level lighting would one notice an 'edge softness' on the building in which the colors brown and black don't have a dramatic contrast?...(That i don't know)

The distance i used are average distances and the moon could even be further away which would lessen the angle and the building bump would be even less.

I can say that at 1/10 speed.....the steadiness of the OP is pretty darn good
02-11-2010, 02:18 PM   #43
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QuoteOriginally posted by RobG Quote
I don't buy the suggestion that it's lens abberation as someone else suggested; there's no noticeable abberation elsewhere.
It's a lens aberration artifact, you wont see it elsewhere in the photo as the moon is the only element in the image that will make this aberration visible. The DA35 LTD is far from perfect.
02-12-2010, 03:28 AM   #44
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QuoteOriginally posted by distudio Quote
It's a lens aberration artifact, you wont see it elsewhere in the photo as the moon is the only element in the image that will make this aberration visible. The DA35 LTD is far from perfect.
I'm impressed that you are so sure.
02-13-2010, 03:12 PM   #45
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QuoteOriginally posted by RobG Quote
I'm impressed that you are so sure.
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.

Secondly the image exposure is biased towards retaining the building detail, the moon is significantly over exposed, this will exacerbate lens aberrations and cause other problems such as blooming on the sensor.

Thirdly the moon is also near the edge of the frame of the lens which is likely to produce more visible lens aberrations particularly at wider apertures.

If you had a comparison image shot in the same circumstances which did not exhibit the problem you displayed then it would be whole new story.

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.

Last edited by distudio; 02-13-2010 at 03:18 PM.
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