Can you feel it? The start of Milky Way Galaxy season is less than 6 weeks away! This is the time of year when the core of the Milky Way Galaxy is up at night. It starts being visible in the predawn hours in late February and goes into September. If you shoot with a DLSR with an APS-C (DX) sensor Tokina has an amazing fast apertured super-wide angle zoom that is perfect for shooting the Milky Way Galaxy or any other astrophotography application. Ladies and Gentlemen, if you don’t know it already please allow me to introduce the Tokina AT-X 14-20mm f/2 PRO DX lens. Not a misprint, its a constant f/2, not 2.8.
The AT-X 14-20mm f/2 PRO DX zoom equates to a 21-30mm full frame angle of view on Nikon or 22.4-32mm on Canon. This super-wide is great for including a lot of landscape and sky in your composition.
At the time of writing the constant f/2.0 is the fastest super-wide angle zoom lens available for APS-C sized DSLRs. F/2.0 is nearly a full stop faster than f/2.8 which equates to almost twice as much light entering the camera. More light entering the camera has several advantages; First, it allows the camera to focus in lower light situations. Second, it allows for more light to hit the sensor when doing long exposures at night, the faint light from more distant stars will be recorded making it perfect for astrophotography. More light gathering can also translate into shorter exposure times or lower ISO settings for sharper astro photos with less noise.
Next, the f/2.0 aperture yields a shallower depth of field than f/2.8 or slower lens. This last point allows you to isolate your subject more for a dramatic perspective. In another review I will be doing an in depth comparison of the the AT-X 14-20mm f/2 PRO DX vs the slower AT-X 12-28mm f/4 PRO DX lens so stay tuned to my blog fort that.
Handling and Ergonomics
The Tokina 14-20mm is a weighty lens for its size weighing 735g (25.9 oz.). It feels solid, well made and balances well on PRO APS-C bodies like the Nikon 7500 or Canon 7D mkII. It will feel a little front heavy on smaller, lighter APS-C bodies like the Nikon 5600 or any of the Canon digital Rebel cameras but not too much. The reason for the weight is the amount of glass needed to accommodate the bright f/2.0 aperture and the fact that Tokina uses more metal than other manufactures in the internal barrels of the lens making them heavier but more durable.
The lens has common 82mm filter thread so there are a wide variety of filters available for image enhancement and creative possibilities.
Like all other Tokina AT-X PRO lenses, the 14-20mm has a Tokina’s exclusive One-Touch Focus Clutch mechanism for switching between auto focus and manual focus. Just pull the manual focusing ring back toward the base of the lens, the ring will snap back to engage the manual focus and then push it forward to engage auto focus again.
The lenses barrel design makes it very intuitive to handle on location in the dark. The rings are large enough and set far enough apart that I don’t get them confused in the dark or move one ring accidentally while turning the other, even while wearing gloves.
Auto focusing on the Tokina 14-20m is fast and smooth, it won’t break any speed records but its accurate. The lens does emit a little motor noise if you rack the AF between a very close subject and something far away. It’s not enough for anyone standing around you to notice but it might be heard on video using the built in mic so I would recommend using it in manual focus for video. The lens has had no problems acquiring and locking focus in a wide variety of lighting situations.
At night under the stars you will need to focus manual but that goes for any lens. A trick for getting infinity focus at night. If you have a high-power flashlight point it at something you know to be at a greater distance than the infinity scale. With a super-wide lens like the 14-20 something more than 5 meters (more than 15 feet) away, put your AF point on what you are lighting up and AF on it. Then carefully pull the manual focus light back into MF and you should be focused at infinity for the stars. After that, take a test shot and use the camera’s screen to zoom in on the stars to make sure they are in focus. If its not, start by moving the focus ring just a little to the left or right and take another test shot and check it to see if the starts are more or less focused. Repeat until the starts are sharp.
Here’s a tip; painters tape or other adhesive tape that is designed to be temporary and removable. Once you have the lens focused at infinity use a 3-4 cm (1.5 inches) long piece of painters tape to tape down the manual focus ring. That way it wont move accidentally if you move the camera to recompose your shot.
Simply put, this lens is sharp, even wide open the lens is sharp. Other than the fast aperture sharpness is where this lens shines. DXO Mark gave the Tokina AT-X 14-20m f/2 PRO DX lens an over-all score of 26 which is higher than either the AT-X 11-20mm or the old 11-16mm lenses. That has been my experience with the lens as well, its the sharpest of the lenses in this class. The lens does not disappoint and you will be able to make large prints if you are using a camera with a 24+ megapixels sensor.
As with any lens, it is sharper when stopped down and the lens’s critical aperture setting is f/4.5 - f/5.0, I could not see any sharpness difference between these aperture settings and stopping down to f/5.6 did not improve sharpness over f/4.5-5.0. But sharpness wide open is still very good which is necessary for low light photography.
Astrophotography is where this lens is really at home. The Tokina 11-20mm may have a wider angle of view but the f/2 of the 14-20mm allows more light gathering and that means more stars captured and more flexibility to change exposure time or ISO.
Coma is not bad at all and Chromatic Aberrations (CA) are well corrected. In some high contrast situations you will see a just a little purple fringing but it is easy removed in post.
The Tokina AT-X 14-20mm f/2 PRO DX lens is at the top of its class in both fast aperture and sharpness. The constant f/2 aperture is the fastest available in a super-wide zoom lens for APS-C lenses at this time. That coupled with amazing optics makes this lens a natural for low-light photography and a lens that anyone interested in astrophotography should seriously consider.