Tokina AT-X 124 AF Pro DX 12-24mm f/4 Lens Review
by Jim Strutz
With the increasing popularity of digital SLRs with smaller than full frame
digital sensors, there has come the demand for wide angle lenses specifically
designed for this format. The Tokina AT-X 124 Pro DX 12-24mm is one of several
new lenses intended to fit that need. It’s field of view when used on a
Nikon Digital SLR and other 1.5x crop cameras, is equivalent to an 18-36mm lens
on a 35mm film camera. Slightly longer when used on a 1.6x crop camera.
There are several other lenses that are currently being sold or have been
recently announced. Sigma’s 12-24mm f/4.5-5.6 EX ASP HSM, Nikon’s
12-24mm f/4G DX, Canon’s 10-22mm f/3.5-4.5, and Tamron’s 11-18mm
f/4.5-5.6 being the significant others. The Sigma is the only one of these that
can be used on a full frame SLR at 12mm. This Tokina is a new lens, and
doesn’t seem to be in stock anywhere, but after being on Adorama’s
waiting list for over 2 months I finally received one. Most street prices are
being quoted at just under $500, making the Tokina the lowest priced lens in this
group.
I have to say that this looks and feels to be a very well built lens.
It’s fairly hefty with a lot less plastic than any of my other autofocus
lenses. The lens is a constant f/4 throughout its zoom range and uses 77mm
filters. It doesn’t seem to need thin mount filters, even standard
polarizers cause no vignetting. It comes with a well designed, sturdy bayonet
mount lens hood that fits on rather stiff and should provide good collision
protection.
In Canon mount, there is no separate AF/MF switch. To switch to autofocus just
push the focus ring forward, and pull it back to reengage manual focus. Tokina
has used this type of clutch mechanism for several years on other lenses, but it
is the first one that I have owned. I’m still getting used to the idea, but
it is faster & easier to use than a dedicated switch that you have to search
for on the side of the lens. One of the positive features of this clutch system
is that the manual focus ring is well dampened and feels great compared to many
other autofocus lenses. However, I would still prefer to have a ring type USM
focus motor with full time manual focusing.
Optical Performance
Included are several images of the church where I work. I wish I had used a
more contrasty subject, but this one provided me with a clear parking lot that
allowed me to back up to keep the field of view the same as I zoomed in or used
other lenses for comparison. All crops are shown at 100%, and all are of the same
field of view. Only the subject to camera distance changed to keep the size the
same. Also shown are some examples of flare and CA.
I also did a resolution comparison with several other lenses I own, and found
the Tokina to be quite good. I had seen several full sized images on the net, so
I knew about what to expect, and wasn’t really surprised by my findings,
but I am relieved that the lens is as good as others claimed. Specifically, I
found that the lens is very sharp at 24mm, even wide open, and even in the
corners. It improves slightly by stopping down to f/5.6, but I saw no additional
improvement at f/8.
Zooming out to 12mm, the center remains sharp, but the corners soften.
Even this is not bad however, especially considering that this is at 12mm, and
moving in just a bit from the far corners brings sharpness back up. So does
stopping down to f/5.6, and the image is slightly more improved by f/8.
Interestingly, I found the corners slightly less sharp at 18mm than 12mm, but
again stopping down quickly improved things. This lens could easily and safely be
used wide open for most images, but for critical work at the edges, stopping down
to f/5.6, or even better, f/8 if at 12mm, will make for very sharp pictures.
I found a little chromatic aberration at the corners and edges of the frame at
12mm as can be seen in the sample images. At 24mm, CA was significantly lower,
though still detectable. I expected to see more since most of my other lenses
display more CA. The only lens I have with less CA is a Canon 50mm f/1.8, which
is also the only one I have that is sharper, but even that has to be stopped down
to f/4 to be so. The lenses I compared the Tokina to are Canon 28-135mm USM IS,
Canon 18-55mm f/3.5-5.6, and Canon 50mm f/1.8.
Distortion at 12mm
Lack of overly significant distortion is another pleasant finding. I’m
sure that this lens would not satisfy an architect, but for normal photography
most of us will be satisfied. I found some barrel distortion at 12mm, very little
at 18mm, and none at 24mm. This has never been a critical item to me, and is even
less so since that advent of digital manipulation.
There is a small amount of light falloff at the edges at f/4 at 12mm &
18mm. It is gone by f/5.6 and is not a significant amount even when wide open. If
I had not been flipping images one on top of the other, I would not have noticed
it at all.
Flare at 12mm f4
Flare at 24mm f4
Finally, there is flare. And, yes, there is some. This is a wide zoom lens
after all, and it kind of goes with the territory. The lens hood helps, but
mostly, you just want to keep the Sun from shining on the front of your lens.
Sometimes a hand or hat is better than the hood. Also, stopping down helps, but
doesn’t cure the problem. It also seems most prone to flare at 24mm, and
when it occurs my primary complaint is lack of contrast.
Note that this is a Canon EF mount and not an EF-S
mount, so it can be used on all Canon 1.6x crop DSLRs, and also on all EOS
cameras, digital or film. Zooming wider than about 16mm when used on a full frame
SLR will result in severe vignetting, but up to that should work fine. The edges
of this image circle being outside the normal image area of the Canon 20D, I
would expect additional softening of the image at the corners. Also, the lens
hood has to be removed for settings wider than about 18mm when the lens is used
on a full frame camera.
Where to Buy
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Copyright 2005 Jim Strutz
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