The moon
Sep 2, 2012 17:26:18 #
Larry-D7000-UK
Loc: UK
Please can someone explain what the cause of the stange colour effect round the moon is when I zoom in to crop and is there a way to prevent it happening.
Sep 2, 2012 22:23:49 #
It appears to be chromatic-aberation, a common lens defect solved by the liberal application of money.
Sep 3, 2012 11:11:55 #
Larry-D5100 wrote:
Please can someone explain what the cause of the stange colour effect round the moon is when I zoom in to crop and is there a way to prevent it happening.
Attached is your camera data. ISO 100 sounds good, F16 sounds good. 1/20 sec sounds a bit slow.
Sep 3, 2012 19:26:07 #
The problem is hard to see on the screen but Photoshop has a tool for fixing the chromatic aberration. No need to buy an expensive lens.
The may also be caused by the movement of the moon which is in constant motion relative to the earth. Since the moon is at infinity, you do not need to stop down. I suggest using the old rule, true or otherwise, that the optimal aperture is two stops down from the lens' maximum. The shorter shutter speed will reduce the motion. Looks like this is an f/5 lens and you could have picked up one or two stops meaning your shutter could have been as fast as 1/80th. Hopes this helps.
The may also be caused by the movement of the moon which is in constant motion relative to the earth. Since the moon is at infinity, you do not need to stop down. I suggest using the old rule, true or otherwise, that the optimal aperture is two stops down from the lens' maximum. The shorter shutter speed will reduce the motion. Looks like this is an f/5 lens and you could have picked up one or two stops meaning your shutter could have been as fast as 1/80th. Hopes this helps.
Sep 4, 2012 07:55:04 #
Sep 5, 2012 12:34:39 #
The lower left rim seems a trifle warmer than elsewhere to my eye. Aberation shows up generally as a colored halo about the image object, something I don't see here. What I do see is soft focus and a hint of blur surrounding the moon.
I don't think movement is involved as a problem unless it is at the camera, but abc1234's suggestion about aperature and shutter speed seems good to me in any event. It takes a longer exposure than we have here for moon movement to become objectionable.
If it is a camera movement problem, then a steady tripod and remote release should help. A hands on release can cause some camera shake. If it is focus, then go manual. If it is difficult to be sure of the focus going manual, then throw several attempts at the problem hoping one of them might be a hit.
I don't think movement is involved as a problem unless it is at the camera, but abc1234's suggestion about aperature and shutter speed seems good to me in any event. It takes a longer exposure than we have here for moon movement to become objectionable.
If it is a camera movement problem, then a steady tripod and remote release should help. A hands on release can cause some camera shake. If it is focus, then go manual. If it is difficult to be sure of the focus going manual, then throw several attempts at the problem hoping one of them might be a hit.
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