Are de-kitted lenses more prone to sample variation?

ibiza123 wrote:

assaft wrote:

Regarding recognizing a de-centered lens - there are several ways to do that, and what's common to all of them is that you want to compare how a certain object looks when it is is captured at different areas of the frame. For example, in one image you put it in the top right corner, and in the other in the bottom left corner. A common way to do this is by taking two pictures of the same scene, the first with the camera held normally and the second when it is upside down. Then you can crop certain areas of the two images and compare them. If you see that a certain corner or side is substantially softer than the others then you have a de-centered lens. Of course the shutter speed has to be fast enough to rule out hand shake, shutter shock, etc. And focus, and depth-of-field should also be taken care of. As far as I know it is recommended to test at the widest focal length of the lens and at its widest aperture.

This is what I got from my previous (returned) copy of the 14-140, look at 100% view to see the differences more clearly.

When captured at one corner

When captured at a different corner

You would perhaps get even better test if you put the camera on the tripod and shot a resolution chart, then turned the chart upside down and shot again.

Sounds like a good idea. I didn't try that.

I would add that it's important to test the lens both at relatively close distances and at far distances. Resolution charts are the best for close distances, or when zooming from further away. But it's hard to use them when shooting from a distance, especially when the lens is at 14mm or thereabout.

Anyway I have not tested mine 14-140 this way, will do it soon, thank you