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You are here: Home / The Last Word / Sony 12-24/4 off axis at 18 & 12 mm

Sony 12-24/4 off axis at 18 & 12 mm

August 25, 2017 JimK Leave a Comment

This is a continuation of this post:

Off-axis aberration testing — Sony 12-24/4 on a7RII

If you got here without reading the previous post, you should go back and do so now.

Here is the full frame at 18 mm:

18 mm

 

Here’s our magnified tight crop of the center, with the same pixel dimensions as before:

Center

 

You can see that in the center the lens is sharper at 18 mm than at 24.

Instead of going clockwise around the periphery, we’ll look at pairs of opposing stars. 

Top-left vs bottom-right:

Upper left

 

Lower Right

 

A hair sharper in the upper left. Nothing to worry about, though.

Top and bottom center:

Upper Middle

 

Lower middle

Maybe the lower side is a tiny bit sharper. That odd SW/NE sharpness anistropy the we saw at 24 mm is not apparent at this focal length.

Top right and bottom left:

Upper Right

 

Lower Left

 

The upper right is a hair sharper. 

Center right and left:

Center Right

 

Center Left

 

A virtual tie.

At 18 mm, this lens appears to be assembled very well.

 

Now the view at 12 mm:

12 mm

The target is getting a bit small, but we’ll see that it’s big enough:

In the center:

Center

You wouldn’t want the target any smaller at this distance. Of course, we’re way beyond the required 7 meters here because I chose to make all the images from the same distance regardless of focal length. This is wonderful resolution for a 12 mm zoom.

Top-left vs bottom-right:

Upper left

 

Lower Right

 

We’re losing a fair amount of resolution in the corners, but this as a UWA zoom, so that’s to be expected. I think this is actually excellent performance, all things considered.

Top and bottom center:

Upper Middle

 

Lower middle

 

Very nice.

Top right and lower left:

Upper Right

 

 

Lower Left

The lower image is softer.

Center right and left:

Center Right

 

Center Left

 

Again, the lens looks good here.

The Last Word

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