In theory, according to the DOF calculator, I can achieve infinity focus with my Sigma 10-20 at f/3.5 when focusing at a subject that's 2m away but when I put it to the test my pictures come out super blurry. I tried multiple apps and online calculators and they all give me the same numbers. Am I doing something wrong or are these calculators a waste of time in real life?
Here are three pictures, taken with a remote and mirror lockup on a tripod with my Sigma lens@10mm f/11. Please don't get bothered by the clutter, my in-laws are getting a new carpet and everything is total chaos in this house. Also, the pictures were sharpened by my camera, as I'm using the jpeg files.
The first picture was manually set to the hyperfocal distance of 0.4m which is what the charts/DOF calculators online state. The picture is visibly blurry.
For the second picture, I used AF and focused on the vacuum which can be seen in the lower left part of the frame. The lens set the dial to 1m. According to the DOF calculators, the near limit of acceptable sharpness should have been 0.36m and the far limit infinity. The picture appears to be sharp but when zooming in (30% is enough to notice it) you can see it's not.
For the third picture, I focused on the TV. The camera set the dial on my lens to roughly 1.5m. The picture also appears to be sharp, but when zooming in it's not. The foreground, as well as the background, aren't really sharp. According to the calculators, though, it should have been. It shouldn't matter if I focus at 1, 2, 3,10 or 20m, the DOF should be infinity, meaning acceptably sharp. By acceptable I mean, I could zoom in a little and still see a great deal of detail in the picture. The numbers of the calculators (even when changing variables like vision, print size etc.) don't seem to correspond with my Sigma lens.
If you guys think I'm nit-picky or something, please let me know. I start blaming the lens as I've seen some reviews that basically said that this lens is not sharp at all.
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