Tokina AT-X 124 AF PRO DX AF 12-24mm F4

The Tokina AF 12-24mm f/4 AT-X DX is a lens with many facets. The resolution characteristic is very good to excellent throughout the zoom range which is quite surprising for an ultra-wide zoom lens - more so for a third-party lens. Vignetting is very high at 12mm f/4 but quite well controlled otherwise (for an ultra-wide lens). It produces a fair amount of wavy barrel distortions at 12mm, less so at 18mm and at 24mm distortions are negligible. The weakest spot are CAs which are very high at 12mm and 24mm. This may not be a significant problem for RAW photography because CAs are a correctable problem but for those preferring JPEGs the issue may be quite annoying at times.
Beyond CAs the lens doesn't really like contra light. Using the supplied hood is a good idea here and if possible light sources in the image field should be avoided. Typical for all Tokina AT-X lenses the build quality is on a very high level putting many lenses from other manufacturers to shame especially when considering the quite affordable price of around 450€/US$.

The verdict about the Tokina AF 12-24mm f/4 AT-X DX can't be easy because its quality varies across the different characteristics. In terms of resolution the lens is on a very high level. The center performance is excellent throughout the whole range. The borders are (naturally) quite a bit worse especially at f/4 but very decent from f/5.6 onward. Distortions are comparatively low for an ultra-wide lens and vignetting may only be an issue at 12mm @ f/4. On the downside chromatic aberrations are a significant problem at harsh contrast transitions - at least if you perfer straight JPEGs or plain converted RAWs. The problem can be almost completely avoided by using intelligent RAW converters such as Raw Shooter Essentials or by manual correction via Adobe Camera RAW or similar tools. So whether this characteristic is a problem for you is dependent on your workflow. Beyond CAs the lens doesn't really like contra light. Using the supplied hood is a good idea here and if possible light sources in the image field should be avoided. Typical for all Tokina AT-X lenses the build quality is on a very high level putting many lenses from other manufacturers to shame especially when considering the quite affordable price of about 450 EUR/US$.