I bought my first macro lens in February 2008 - a Nikon 105VR F2.8. By most accounts, a very good lens.
It seemed fine at first, as I was just shooting test macro shots. Then I tried to use it to shoot some landscape shots, since it was on the camera and had about the focal length I wanted. When I
looked at the shots, I was stunned at how bad the corners were. It was as if they were coated with jelly.
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This is the image that really got my attention.
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This is a crop of the upper left corner.
Someone suggested perhaps there was a camera shake or VR issue, so I tried to eliminate those issues and perform a controlled test.
My opinion: This copy of this lens was defective, and I sent it back to B & H under warranty. (The replacement is fine). However, I did a block wall test before sending it back to see how bad
things were at different apertures.
The pictures were all shot in Aperture priority mode, on a good tripod (Bogen 3021) with a Really Right Stuff BH-55 ball head. The camera (D300) was set to use mirror lockup + 1 second delay to try
to eliminate any possibility of camera shake. I made 7 test shots, at apertures F2.8, 4.0, 5.6, 8, 10, 16 and 32. I shot in RAW, and used CaptureNX to convert to JPG with 'good balance' quality. No
sharpening was done (in-camera was set to +2). The results are below.
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F2.8 image is above.
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F4 image is above.
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F5.6 image is above.
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F8.0 image is above.
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F10 image is above.
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F16 image is above.
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F32 image is above.