Thursday, July 14, 2011

Camera Lenses 101: Ultrawides

The Tokina 17mm f3.5 ATX-PRO (review coming soon!). with a 105 degree field on film/FF, this more than qualifies as an ultrawide optic. 

For some people, standard range lenses just don't give enough wiggle room when it comes to making pictures. After all, you can only move forward or back up so much, and this is only for close subjects. For people wanting to capture wide-open vistas of land, there is only one route to go: ultrawide avenue.

When it comes to market share, the ultrawide segment is quickly becoming a crowded arena, especially with all of the third-party optics horning in on the name brand manufacturers. Now more than ever before, there is ample choice of ultrawide optics (at least ultrawide zooms) to satisfy various photographic needs and photographer preferences. Unfortunately, though, one feature not seen in ultrawide lenses is a small price tag. Expect to pay at least $400 for a crop-only ultrawide and even more for a FF/film-capable one.

So, if you're not put-off yet, read on.

When buying an ultrawide lens, three main factors come into mind: how wide do I want to go, do I mind a bulbous front element, how much range do you want, and does aperture matter? Being a rapidly maturing, diverse market, the ultrawides offer all of these options. Want a stabilizer? Forget it, unless your camera has in-body stabilization, ultrawides don't offer this feature. Classes defined, let's see what we have in the ultrawide market.

First up: the slow lenses. Normally the same aperture as the kit lens (f3.6-5.6) or even slower at the wide end, the slow ultrawides are the “bargain” models, though by no means inexpensive. The cheapest crop offerings here typically run around $450, by no means a cheap investment, especially when you consider the often very limited (max 2x zoom ratio at most) range of such a lens. More than anything else, it is this limited usability that keeps many people from buying an ultrawide.

Next up: the optical design. The widest of the wide lenses typically employ bulbous front elements, which is very bothersome to some people for two reasons: lack of ability to use a protective filter and the high tendency to flare thanks to the exposed front element. While a deterrant to buying at first, these problems can be overcome simply by being careful and watching where the light sources are when you frame photos. If one can learn to live with this optical design, one can get the widest of the wides, namely the FF Sigma 12-24 and crop-only 8-16.

For those craving fast aperture at wide angle, Tokina is the lens maker for you as it produces a crop-frame 11-16 f2.8 and a FF-capable 16-28 f2.8. If budget is not a concern, then go for manufacturer optics (at least with FF as no other manufacture besides Tokina makes a f2.8 ultrawide for crop). Of course, with aperture, one pays a price premium but, if indoor architecture or nightscapes are your thing, there is simply no other way to go.

Now onto primes.

Looking at manufacturer lineups, it's funny that there is always a bulbous 14mm f2.8 prime in every major manufacturer's lineup. When it comes to these lenses, the problem of an unprotected front element comes into play once again but, thanks to it being a prime, the cost is lower than it would be for a f2.8 zoom. On top of the lower cost, with the exception of the Sigma 12-24 and Nikon 14-24, 14mm is wider than all the other wide zooms can go. The down side? Most of these lenses, save the Canon 14L II, are of rather old designs. Basically, fast ultrawide primes aren't seen as that cool anymore thanks to the advent of the zoom, which means that the zooms is where manufacturers focus their R&D resources.

In short, if you are an indoor architecture shooter or a landscape fanatic, an ultrawide lens is just your thing, never mind the price!

Note: for all of their cost, one area where most ultrawide lenses perform rather poorly is with distortion. Basically, getting a lens to focus in just over 1 cm and produce straight lines is a true test for opticians, one that can rarely be achieved with perfection. So, if you buy an ultrawide lens, be sure to try and avoid getting straight lines near the periphery of your picture as, if they look slightly bowed out, you're not seeing things, it's the lens. The good news is that such distortion can usually be fixed quite easily in post-processing.

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