gave this 4 stars for a reason. In the right hands, this guarantees 5 stars. However, if you are not comfortable operating a manual lens on a DSLR, you will find it difficult to get good pictures with it. The lens is true ultra wide angle and as such it can be very difficult to get critical focus, especially as it is a very long distance from the focus ring. It may well be that you end up depending on the depth of field to ensure that focus, and thus probably not working at F2.8. Using various depth of field calculators, you can assume that infinity is sharp from f/5.6 as long as your subject is more than about 3-4 meters away. However, I have found that there are "degrees" in which one is focused. It is best to fire many test shots and know from experience where the focus is at different points on the focus ring for a given distance. If you're doing anything other than landscape photography where you can take your time, this focus issue can ruin any other kind of spontaneous shots. Another factor to keep in mind is that you will experience some barrel distortion and vignetting in the corners due to the field of view, especially when using a full frame camera. This is easily fixed if you create your shots in Lightroom by simply loading the appropriate lens profile. However, you have to select this manually, as there is no electrical connection between the lens and the camera, and therefore, fortunately, the EXIF data does not know of the existence of the lens. If you're buying it for astrophotography, it's ideal, as 14mm allows for an exposure time of well over 30 seconds, after which point you'll start experiencing star trails anyway. Just be aware of critical focus. Conclusion. This is a fantastic quality lens for the money but only in the right hands. If you're used to operating your camera only in program mode, or even in aperture or shutter mode, then this lens offers you a learning curve to overcome. It fits on full frame or crop cases, but on APS-C models the effective focal length is obviously 22.4mm. Buy it after giving it a lot of thought, for the money there is no other lens that will match it.