11-16mm Tokina Distortion Shots

J

Joseph Bautsch

New member
I recently purchased the Tokina 11-16mm, f/2.8 DX lens. I've been asked about the distortion I've experienced shooting at 11mm. To demonstrate the distortion you can expect with this lens I found a brick wall and got six shots, one each, over the zoom range. This is not a scientific test but does demonstrate the distortion you can expect using this lens. At 11mm you can visibly see the distortion bow in the line of bricks at both the top and bottom. (The distortion would be the same on left and right side. But it is not as readily visible shooting a brick wall.) At 12mm it's still visible but to a lesser degree. At 13mm it's even less visible. At 14mm it's just about gone. At 15mm it's almost undetectable. And at 16mm it's not really visible at all. The degree of distortion is relatively small even at 11mm and is easily eliminated in post processing.

11mm
_DSC0646.jpg

12mm
_DSC0647.jpg

13mm
_DSC0648.jpg

14mm
_DSC0649.jpg

15mm
_DSC0650.jpg

16mm
_DSC0651.jpg
 
J

Joseph Bautsch

New member
These are as shot. No post processing and no cropping. The only real visible distortion I saw was the barrel type. The engineers at Tokina did a great job on the sharpness of the lens out to the edges. All six shots are sharp edge to edge. This lens has been described as being as good if not better than the Nikon 12-24mm but at half the price.
 
F

fotojack

Senior Member
I would have to agree with you, Joseph. Great lens at a great price. It's on my wish list.........hopefully by the end of this summer, if I make enough working at the motorcycle race track as a corner marshall. :)
 
R

Ruidoso Bill

Senior Member
Joseph Bautsch said:
These are as shot. No post processing and no cropping. The only real visible distortion I saw was the barrel type. The engineers at Tokina did a great job on the sharpness of the lens out to the edges. All six shots are sharp edge to edge. This lens has been described as being as good if not better than the Nikon 12-24mm but at half the price.
Click to expand...

I am saving to make the 11-16 my next lens. I figure by the time I am able to buy it the D400 will be out and I will need to write a big check.
 
J

Joseph Bautsch

New member
Here is a comparison enlargement of the 11mm brick wall shot. Each picture is a 107.4 times enlargement. One is an enlargement of the center of the picture and the other is an enlargement of the bottom left side. Looking very close at each one shows a very slight fall off in sharpness from the center to the outside edge of the lens.

Center Enlargement
_DSC0646 - Version 2.jpg

Bottom Left Enlargement
_DSC0646 - Version 3.jpg
 
R

Rick M

Senior Member
Another thing to consider is you may crop out the extreme corners anyway. I've found that leaving room for cropping (if you can) is better than filling the frame completely. Also with wide panoramic shots, I tend to crop more of the bottom and top off than the sides, thus eliminating the extreme corners.
 
J

Joseph Bautsch

New member
The image size is as you see them. Thats full size, about 52 KB each. The original shots are 10.74 mega pixels. Unless you are making very large poster prints, that fall off in sharpness would not be apparent to anyone. I guess it does give the experts something to talk about. I shoot like you do. I always leave some margin around my compositions to give me cropping leeway. Cropping is a very useful tool that can be used to improve any shot. And you are correct shooting and cropping this way will usually leave what sharpness fall off there may be in the scrap bin.
 
J

Joseph Bautsch

New member
Sorry I should have included the EXIF data. The f/stop I used was f/18. The ISO 200, Focal length DX 11mm, FX 16.5mm, Focus Distance 1.6 feet. The camera was tripod mounted and a level was used on both the vertical and the horizontal axis. I used f/18 because most lenses are engineered to perform at their best in the f/11 to f/18 range. That is because it is the most commonly used shooting range. Shooting at higher f/stops may increase the DOF but does not have a significant affect on the sharpness. The lenses sharpness is a characteristic of the glass not of the f/stop. In some of the lesser quality lenses at higher f/stops the light starts to refract around the edges of the iris blades and actually begins to soften the shot. At these settings the depth of field was .66 feet near limit and infinity at the far limit. So the shot was taken well within the DOF. I used a brick wall because it has horizontal lines that will show any barrel distortion and has a lot of texture and shape to make the sharpness of the lens more visible. It should also be noted that this is only a display of the sharpness fall off from the center of the lens to the outside edge. At 107.4 times enlargement pixel grain in the D90 sensor and processor becomes more significant than any loss of lens sharpness. A camera body with a higher ISO resolution would provide a better display of actual sharpness.
 
Last edited:
Top