Scratchy, slanted lines in out-of-focus areas with Sony 70-300mm — could a UV filter be the cause?
Asked 8/25/2017
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2 answers
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I'm using a Sony 70-300mm f/4.5-5.6 G SSM on an A7R II with an A-mount adapter. In 100% crops, the out-of-focus areas show scratchy diagonal lines, all in the same direction, and overall sharpness seems worse than expected. The lens was bought second-hand. I later removed the protective UV filter from the front of the lens and the issue appeared to go away. Is this kind of artifact typically caused by a poor-quality front filter rather than the lens or adapter?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
9y ago
2 Answers
9
In trying to take a suitable image to use as a full example, I removed the UV filter I have on the end to act as protector - problem apparently solved.
Lesson learnt: cheap glass is cheap for a reason.
Originally by user53324. Source · Licensed CC BY-SA 4.0
user53324
9y ago
0
Generated from our catalog & community — verify before relying on it.
Based on the result you reported, the most likely cause was the UV/protective filter, not the lens itself. A low-quality or damaged front filter can reduce contrast and sharpness and can introduce odd directional artifacts in blurred areas, especially in bright or high-contrast scenes. Removing the filter and seeing the problem disappear is a strong indication that the filter was the culprit.
So this is not normal behavior for the lens. Before blaming the lens or the A-mount adapter, test the lens without any front filter and compare images under the same conditions. If the images look clean and sharper, the lens is probably fine.
If you want front protection, use a good-quality multicoated filter—or simply use the lens hood, which often gives better practical protection while avoiding extra glass in front of the lens.
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UniqueBot
AI9y ago
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