Oh my. I love/hate this lens so much.
The lens pictured above is the kit lens I selected to go with the Nikon D7100 body I recently purchased. My overarching rationale for its selection still stands firm. It's a camera and lens (and flash) combination to be used to make photographs at dimly lit galas and events. Places where accurate and well controlled flash is a must. In those situations having a wide range of focal lengths in one tidy package is a big plus and, for these things, the lens does well. Even more so because photographing groups of humans is one place where wonky geometric distortions aren't very noticeable.
The lens sells for around $500 but they had some sort of special Summer pricing and if purchased as a kit the lens came out to around $250. So, let me talk to you about this lens.....
Here are the things it does very well:
1. The range of focal lengths is custom made for event shooters. At 18mm you've got a 27.5mm equivalent that's perfect for big groups and fun, dramatic juxtapositions. If you are shooting groups with anything wider you've probably noticed that your lens (no matter how superb) is morphing the people next to the left and right (and top and bottoms) of the frame into giant blogs. Head grow like balloon heads in cartoons and hips become wider than billboards. I try not to do groups with anything wider than a 35mm eqiv. but sometimes you need what you need.
2. This lens is a VR king. Nikon says more than four stops and I am a believer. This lens has almost convinced my photographer friends that all I'm drinking is decaf. Rock solid. It's in the same class as the OMD EM-5's I've been using. We don't need no stinkin tripods.... (But, of course we really do).
3. Can you say "sharp?" In the center two thirds of the frame at nearly any focal length, at maximum aperture, this lens is sharp, sharp. As in looking into the pores sharp. I tested it all the way out to the end and the results were pretty consistent. A bit sharper at the wide end but no slouching at the long end.
4. For the number of focal lengths this lens replaces it's small. It's a comfortable and nicely designed package and it has both aspheric and ED elements as well as being an internal focus design. For $500 it's a pretty good "go everywhere with one lens" lens and for $250 it's easy to classify as a bargain....unless:
Here are the two things that the lens sucks at but you can only really blame the designers for one....
1. The lens has a slow maximum aperture. It's f3.5 at the wide end and f5.6 at the long end. With enough money and the allowance of enough weight you could design a lens with these focal lengths and an f2.0 constant aperture but no one would be able to buy one. And few photographers would want to carry it. The low max. ap. used to be a deal killer in days of old but now every camera does ISO 25,000 with dignity and aplomb so who really cares (sarcasm). But really, if you consider that f3.5 is less than a half stop over f2.8 and that f5.6 is just two stops over f2.8 and that camera sensors really have improved a lot in the past few years I think we can get by this. Especially for the price and convenience.
2. And that leaves what, for some, will be a real deal killer. The lens has the most extreme distortion I've seen in ages. At the 18mm end it's barrel distortion. And I mean a real barrel. Like a beer keg. It requires a minus 7 or minus 8 correction in raw conversion to get it into the ball park and even then it's not perfect. So at the wide apertures you're dealing with expansive lines bowing outward but at around 50mm it goes into a weird inversion and all of a sudden you've got pincushion distortion that's just breathtaking. Not sure if there's a lens profile out there for this one but I'm not seeing an auto correction in D7100 Jpegs or in Photoshop....
I'm keeping mine but if you do architecture or anything else with straight lines don't even ask for the sales guys to take this one down off the shelf for a demo. You'll be wasting everyone's time. I'll do my haphazard corrections and put a note on the lens hood reminding me to "never, never point this puppy at any straight line that I want to keep straight.
And that's my review of the Nikon 18-140mm lens. Good for fast moving people mania! Horrible for straight lines of any kind.