A goal really apart

Most:
+ With a focal length of 8mm, it is no longer in the ultra wide-angle, but in the ultra ultra wide angle. Giving a very specialized purpose dizzying perspectives.
+ Good build quality; the objective is pleasant to use.
+ Very good contrast and high color saturation, giving the image an impression of high optical quality.
+ Glare very effective, despite the prominent front lens.
+ Very well controlled distortion for such focal lengths.
+ Focusing distance very short period (careful not to hit the lens!).

Cons:
- Inability to use screw-round filters. There are filter holders for rectangular filters, but the price makes you think. Or he must tinker.
- Very low brightness: the f / 4.5-5.6 is low, and the actual transmission is still far below.
- So autofocus in low light patina.
- Depth of field distorted in Rousquille (or donut), which under certain conditions gives strange effects (localized gray area). The solution: close the aperture (f / 8-f / 11).
- Printing dive a bit disappointing despite the very high MTF scores on the test sites (this is due to astigmatism?). Fortunately no importance unless you make very large prints.
- Sensitivity shift: you need to find an objective working harmoniously with your case. A 8mm, the slightest deviation of centering is seen, whether due to the lens or to your device. If you have a chronically blurrier than other area is that there is a problem.

Why 5 stars despite these flaws? Because it fully meets my expectations, and perfectly complements a classic ultra wide-angle Tokina 12-24mm like f / 4.