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01/08/2011 12:05:44 AM · #1 |
| Just bought myself a Sigma 10-20mm F4-5.6 EX DC and have noticed something weird in a few images. When shooting in sunny conditions at (mostly) 10mm I notice a bunch of tightly packed concentric lines across areas of clear blue sky. In some images it is quite pronounced. The inside of the lens hood and the area surrounding the front element of the lens both have fine ridges on them and I'm inclined to believe that they are in some way related to the lines in the images. I've tried various combinations of zoom, aperture, hood on/off, UV filter on/off and can't reliably reproduce the problem. And here's another strange part - I'd post images of the problem but can't, because every time I go to process the RAW files in either ACDSee Pro or Scarab, the lines disappear and I'm left with 'clear skies'. Any ideas? Should I be concerned? |
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01/08/2011 01:21:42 AM · #2 |
| Sounds like a problem pertaining more to the LCD resolution than the lens. I have the Nikon version of that lens, and the same kind of ribbed lens hood, and haven't noticed any similar problem. And if the images turn out fine in pp, I wouldn't lose any sleep. |
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01/08/2011 01:56:35 AM · #3 |
Originally posted by snaffles:
Sounds like a problem pertaining more to the LCD resolution than the lens. I have the Nikon version of that lens, and the same kind of ribbed lens hood, and haven't noticed any similar problem. And if the images turn out fine in pp, I wouldn't lose any sleep. |
By LCD I assume you are referring to the screen on my camera and not my PC monitor? If so, then the problem isn't evident on the camera review screen, just on my monitor and only when viewing the RAW files. |
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01/08/2011 06:25:32 AM · #4 |
Originally posted by Qiki:
Originally posted by snaffles:
Sounds like a problem pertaining more to the LCD resolution than the lens. I have the Nikon version of that lens, and the same kind of ribbed lens hood, and haven't noticed any similar problem. And if the images turn out fine in pp, I wouldn't lose any sleep. |
By LCD I assume you are referring to the screen on my camera and not my PC monitor? If so, then the problem isn't evident on the camera review screen, just on my monitor and only when viewing the RAW files. |
How are you VIEWING the RAW files? You say when you go to Scarab or ACDSee the problem disappears... So clearly the problem is wherever you're viewing the files beforehand, and in any case it doesn't seem to be a problem...
But you ought to be able to do a screen cap that shows us the problem, if it shows up ON your screen...
R. |
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01/08/2011 01:21:57 PM · #5 |
Originally posted by Bear_Music:
How are you VIEWING the RAW files? You say when you go to Scarab or ACDSee the problem disappears... So clearly the problem is wherever you're viewing the files beforehand, and in any case it doesn't seem to be a problem...
But you ought to be able to do a screen cap that shows us the problem, if it shows up ON your screen...
R. |
Thanks for the input Bear. When initially reviewing the images in ACDSee or Scarab the lines appear. When moving the images to the 'process/convert' section of the programs they disappear. I've captured the problem as a screen dump which I've put in to a Word doc, but I'm not sure how to upload the doc. If someone can help me I'd be happy to do so.
Q. |
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01/22/2011 02:46:22 AM · #6 |
It sounds like an issue with your graphics card settings or driver. Scarab uses the 3D hardware acceleration to dislay the image. For some reason the image probably ends up being converted to 16 bit color depth by the graphics driver, so what you are seeing is the banding because of this. First thing I'd check: is your desktop set to High (32 bit) color quality? If that wasn't the problem, check to see if you have vendor specific advanced settings (ATI Control Center, or nVidia whatever) and if you see something related to texture quality/bit depth. Third thing to try: download and install a newer graphics driver. If you have a laptop, then you probably need to go to the manufacture's webage to find one.
Anyway, it's 99% not related to the lens. |
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01/22/2011 03:12:07 AM · #7 |
Originally posted by Qiki:
Originally posted by Bear_Music:
How are you VIEWING the RAW files? You say when you go to Scarab or ACDSee the problem disappears... So clearly the problem is wherever you're viewing the files beforehand, and in any case it doesn't seem to be a problem...
But you ought to be able to do a screen cap that shows us the problem, if it shows up ON your screen...
R. |
Thanks for the input Bear. When initially reviewing the images in ACDSee or Scarab the lines appear. When moving the images to the 'process/convert' section of the programs they disappear. I've captured the problem as a screen dump which I've put in to a Word doc, but I'm not sure how to upload the doc. If someone can help me I'd be happy to do so.
Q. |
Sorry I missed this :-( You can paste the screen dump into an image editor and save it as a JPG, then link us to it.
R. |
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