Tuesday, September 7, 2010

Tokina 28-70 f2.6-2.8 ATX PRO In-Depth Review

The Tokina 28-70mm f2.6-2.8 ATX PRO


Tech Specs
Focal Length: 28-70mm
Dimensions: 3.2" x 4.8"
Weight: 760g
Maximum Aperture: f2.8
Minimum Aperture: f22
Diaphragm Blades: 8
Front Element: Rotates, extends about an eighth of an inch
Autofucus Mechanism: Micromotor (Canon version)
Closest Focus: 2.5 feet
Filter Size: 77mm


Background
Tokina's 28-70/80 f2.8 lenses have quite a bit of a convoluted history to them. Originally developed by French company Angenieux, Tokina bought the design and rolled out several versions before ceasing production in the mid 2000s. For the forthcoming review, I will be referring to the 28-70 f2.6-2.8 version, which was marketed as being the widest aperture zoom in the world (even though cameras do not recognize the 2.6 aperture. So, is this oldie a goody? Keep reading to find out!



Build Quality: 5
Tokina is a company known for high standards of construction, and its 28-70 f2.6-2.8 ATX PRO lens lives up to the tough Tokina reputation. Upon picking up the lens, you immediately notice its sheer weight and perhaps, cool surface. This lens is solid metal and feels every bit of it, even the filter threads are metal. Yes, it may be a brick, but it inspires confidence in that it feels like a true photographic tool and not a toy like a lot of the newer third-party offerings. In terms of mechanics, the lens is top-notch here, too. The focus ring is the wide, outer one. Switching from AF to MF is a bit complicated. Unlike newer Tokina lenses, one must first flip a conventional switch and then snap the focus ring back or forth, depending on what you want to do. In addition, the clutch has a window where it can and cannot move. To find the spot, simply push/pull the ring as you turn. When the spot is reached, the clutch will engage and the ring will move, completing the transition. On newer lenses, simply snap the ring at any place to go from AF to MF and back. The good news is that, like newer Tokina lenses, the focus ring does not spin in AF mode. Unfortunately, this is not an inner focusing lens, either. In action, the focus ring is smooth in operation, no slop whatsoever. The zoom ring is the inner, narrower one. In action, it is smooth too. On my copy, the ring is a bit tight in the 28-35 range, but this is an old lens that I bought used, so if you decide to buy one, it could be different. Both rings are rubberized, highly textured, and give a good grip. When zooming, the external length of the lens never changes, but the inner barrel drops about half an inch at the long end of the zoom. Again, the constant size of the lens just exudes a high-quality product.


The inner barrel of the lens extends about 5mm at closest focus


Autofocus Performance: 4
Being an older model lens, the Tokina 28-70 f2.6-2.8 ATX PRO does not feature the latest sonic drive autofocus technology, but the old micromotor design. However, for such a design (let alone one about 10 years old), autofocus performance is still good by modern standards. Sure, it's not sonic speed, but it's still very good even in low-light. About the only time speed may be an issue is a when racking from macro to infinity or back (seems a little slow to get going at these extremes), but who shoots like this, anyway? When shooting normally, focus in near instantaneous. In terms of accuracy, this is nothing to sneeze at, either. Focus is dead-on in all situations except when dealing with nearby, fast-moving subjects. No light? No problem! Autofocus is top-notch here, too. I've shot Christmas lights from a moving car without any problems using this lens. Now the much-maligned micromotor. Sure, it makes noise, but it's not overly obnoxious and nowhere near as loud as the slap of the SLR mirror itself.


Switching from AF to MF and back is a two-step process: first flip the switch, then move the focus ring accordingly.




Optics: 4
There is a lot that goes into determining the complete package of optical performance for a camera lens, so let's examine each of them individually.


Lens at 28mm
At its widest focal length setting, the Tokina 28-70 f2.6-2.8 ATX PRO is at its best, at least in the center. Looking at the center of the frame, one has a hard time telling whether the lens is at f2.8 or f8, performance is that good. Moving out from the corners wide open, the story is different. Wide open, the corners are pretty mushy, the good news is that stopping down, while not completely fixing the problem, helps negate these optical shortcomings quite a bit.




Lens at 35mm
Increasing the focal length, sharpness in the center decreases a tad when wide open. Although not bad by any means, the lens will no be longer tack sharp as it was at 28mm. The good news is that, by f4, the lens is as sharp as it's going to get in the center, which is good. For some truly great news, at 35mm, the corner performance picks up quite a bit. Wide open in the corner, the lens at 35mm at f2.8 is about as good as it was in the same area at 28mm but stopped down to f8! As at 28mm though, performance only increases as focal ratio shrinks. Overall, I would say 35mm is the sweet spot of tested focal lengths when considering image quality across the frame.



Lens at 50mm
Wide open at 50mm the lens can no longer be considered sharp. The center is a bit soft and the corners are worse. The good news is that, like at 35mm, the lens is about as sharp as it will get by f4, still not bad. In the corners, the performance is similar to that at 35mm in that the extreme drop-off seen at 28mm is absent here, too. Bottom line, the corners are mushy wide open, but they improve quite a bit stopped down. One funny thing I noticed here was that the lens seems to have a funny small aperture bad spot at f8 in the 50mm zone. Weird.



Lens at 70mm
At its longest focal length setting, sharpness actually improves. Wide open in the center, sharpness is much better than it was at 50mm but not quite as good as it was at 35mm, let alone 28mm. Unlike at the three other tested focal lengths, sharpness does not peak at f4, but continues to improve through f8. However, the improvement from f4 to f8 is should not be much of an issue except to pixel peepers. In the corners, performance is still reasonably good wide open without the major drop off seen at 28mm. The good news is that this lens does not exhibit any optical quirks at 70mm, which means that, as you keep stopping down, sharpness keeps improving in the corners. By f8, the lens is almost as good at 70mm as it was at 35mm.




Distortion
As is the norm with wide angle lenses, the Tokina 28-70 f2.6-2.8 ATX PRO exhibits barrel distortion on the wide end of the focal length spectrum. The good news is that, compared to some other standard zooms, it is very mild and disappears by 35mm. By 70mm, very slight pincushion distortion appears, but is nothing that to many would warrant correction in post-processing.

There is distortion, but nothing obnoxious


Vignetting
In terms of light falloff, the Tokina 28-70 f2.6-2.8 ATX PRO was a bit of a disappointment, especially considering the fact that it was mounted on a sub-frame Canon EOS 30D for the test. Wide open at all focal lengths, there is noticeable darkening. The good news is that this pattern is very uniform throughout the focal range and that it essentially disappears by f4.

Vignetting is obvious at f2.8, but largely disappears by f4



Chromatic aberration
While Tokina lenses are known for build quality, they are also known for a less than desirable feature: chromatic aberration, those annoying color fringes that appear in high-contrast situation. The bad news is that the 28-70 f2.6-2.8 ATX PRO does exhibit some false color. The good news is that stopping down from f2.8 to f4 greatly reduces or even eliminates the unwanted color in most cases. As usual, the higher the contrast, the more pronounced the effect

CA is present wide open, but stopping down reduces the problem greatly

In all, CA on this lens is not too bad, this is wide open



Flare/Ghosts
By and large, I would consider this lens to be on the positive side of the flare resistance spectrum. The lens is most prone to flaring at 28mm because this is when the front element is nearest the end of the lens. As focal length increases and the inner barrel drops back into the lens, the front element becomes more shielded and thus, more resistant to flaring. Generally, this lens doesn't flare/ghost unless you have the Sun (or another extremely bright point source of light) in the corner of the frame. When a bright light is in the center, sometimes you get flare, sometimes not. Go figure. In the center, the lens sometimes flares and sometimes doesn't, go figure. As usual, a hood, whether the standard or a thread-on variety, helps.

The fact that the inner barrel drops at the long end of the zoom helps reduce risk of flare in itself



Even at 28mm, one usually has to try and get flare on purpose for it to appear


Value: 5
When it comes to price to performance ratio, the Tokina 28-70 f2.6-2.8 ATX PRO is unequaled. Where else can you get a constant f2.8 zoom with so many positive attributes for in the $300 range? Nowhere. A good indicator of how good a lens is to look for it on the used market and see how much it pops on the used market and how fast it sticks around when it does show up. Generally, the rarer a lens is, the better it is. In the case of the Sigma and Tamron full frame-capable constant f2.8b standard zooms, you'll see them all the time. The Tokinas? In the case of this lens, they don't pop up all that often and when they do, they're gone very quickly. This is a great lens, people know it, and the market shows it.


In the field
There's a reason that constant f2.8 zooms are popular, they're just so doggone useful! While slower than primes, a constant f2.8 zoom give the photographer much more flexibility in making pictures, especially when mobility is an issue. Until a 18-70ish constant f2.8 lens comes out, we'll be forced to decide between wide (17-50) and long (28-70) if we want constant f2.8. With all of its positive attributes, the Tokina 28-70 f2.6-2.8 ATX PRO can make the perfect walk around lens, provided you're willing to trade off wide angle for extra reach.

While good at any time of day, the fast Tokina zoom really comes into its own when the light starts to disappear. Simply put, a 2.8 zoom can do things (especially on the long end of the range) that those 3.5-5.6 bundled kit zooms cannot, namely allow the photographer to shoot hand-held in low light without flash, which is good. In less than extreme low light situations, the extra stops of aperture allow the shooter to lower the ISO, thus preserving picture quality.


Indoor settings in low light are easy for a 2.8 zoom


Nightscapes, especially at Christmas, are easily possible without a tripod (note, no flare)


Even darker nightscapes are possible with steady hands

Nighttime architecture can be very cool

If you have really steady hands and no adverse reaction to ISO 3200+, astrophotography is possible! Here's Orion among some clouds.


While this lens is definately not a macro optic, at can focus reasonably close and make itself a great lens for shooting flowers or similarily-sized subjects.


This is no macro optic!


However, it is still good for closeups of large objects. . .


. . . especially if you can crop a bit!


Simply put, a 28-70 constant f2.8 optic is a lens that will live on your camera most of the time. Sure, other focal ranges with different applications will be desired at times but, for the majority of walk-around type shooting, such a range will get the job done far more often than not.
Wildlife is no problem . . .

. . . especially if you crop

Even with a 46mm equivalent on APS-C, landscapes are no big deal


Frame right and you can get some wide-open images

Competition
The standard zoom lens competes in a crowded market segment as such lenses are the go-to optics for many photographers, pro and amateur. As a result, everyone makes one. Closest in price to the Tokina are the Tamron and older Sigma model. Like the Tokina, both lenses are constant f2.8 and are driven by a micromotor/mechanical drive mechanism. Like the Tokina, both (especially the Tamron) are reputed to be good optically. Unlike the Tokina, both are plastic while the Tokina is solid metal and costs less to boot. Moving up the scale is Sigma's $900 24-70 f2.8. Costing about 50% more than the other two lenses, this one adds a sonic drive but still isn't up to the Tokina mechanically. Of course, at the top of the totem pole are the manufacturer versions, costing upwards of $1,200. Like the Tokina, these lenses are metal but add sonic drives and weather sealing in some cases. Bottom line, unless you absolutely need the sonic drive/weather seal, the Tokina is worth strong consideration, if you're lucky enough to come across one.


Conclusion: 4.5 out of 5
The Tokina 28-70 f2.6-2.8 ATX PRO is an all-around winner, especially considering its rock-bottom price point. Some pluses are undeniable. The Tokina's build quality is top-notch and equaled only by the manufacturer's own $1,200+ version lenses. Again, the price ($300ish) to performance ratio is unrivaled by anything else. The 'floating' focus ring is another convenience one normally associates with sonic-drive lenses, so feel free to grab the lens anywhere when shooting with it. The conventional drive focus mechanism does not offer full time manual override, but is nonetheless fast and accurate. Optically, this lens has more positives than negatives, with distortion, chromatic aberration, and flare all being well controlled. The only real glaring weakness of this lens, optically speaking, is the extreme corner softness wide open at 28mm and wide-open vignetting. The good news is that, from f4 on, this lens is about as good as it gets. With all the good and so little bad, I whole-heartedly recommend the Tokina 28-70 f2.6-2.8 ATX PRO, should you be lucky enough to come across one.

The Tokina 28-70 f2.6-2.8 ATX PRO: an all-around solid workhorse of a lens!



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2 comments:

  1. Wo,
    These are nice pictures.Thank you very much for your ideas to post comments.The concluding part was really very interesting.I am really thankful to you for providing this unique information.Please keep sharing more and more information.

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  2. Stumbled on this post while googling this lens, that I just won on eBay for $200.00...hopes it's as good your copy.
    Thanks for the review, very informative!

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