Case Study: Nikon 18-200mm Lens Review

Out of all the Nikon lenses I've owned over the past 35 years, the Nikon 18-200mm f/3.5-5.6 VR AF-S lens is by far the most discombobulating.

On the one hand, it seems to have it all: great wideangle to telephoto superzoom range, light weight, fast and silent AF-S autofocus, VR image stabilization, famous Nikon name, prestigious Nikon pro styling and feature set, infamously high Nikon pricing ($750—a sure sign of sharp, world-class optics, right?), good bloodlines in the excellently sharp Nikon 24-120mm lens, and universally rave Internet reviews.

On the other hand, results from the field and exhaustive testing show this lens has dreadfully low optical resolution. In fact, it is the least sharp lens I own, and I've got to admit I own a Sigma 28-300mm lens.

How can this be? How can Nikon stake so much of its reputation on a lens with such abyssmal resolution? How can they get away with this, like they seem to be doing?

The answer lies in a gutsy new Nikon lens strategy—one that is both brilliant for its future vision, and perhaps a bit diabolical in its shrewdness.

Before I explain this strategy, however, I feel compelled to prove my point about the optical resolution of this lens.

Nikon 18-200mm Optical Resolution

The photos below show the results of two different tests. The first test pits the Nikon 18-200mm against the Sigma 50-500mm. The second test pits the Nikon 18-200mm against the Nikon 200mm Micro. Both tests are interleaved below to show the relative resolution differences between all three lenses, and also to demonstrate the repeatability and validity of testing procedures. Pay especially close attention to the micro-detail in the lower left corner of all frames.

From the above test results, it's clear the resolution of the Nikon 18-200mm is low.

Defective Unit Tests

Might I have a bad unit?

Tests with another unit borrowed from a friend show no, my unit is fine (thanks Mike).

More Nikon 18-200mm Optical Resolution Tests

Might my testing procedures be flawed?

I don't believe so. Read this chapter, Testing Camera and Lens Resolution , for a full explanation of my testing procedures. Most importantly, I've repeated tests of the Nikon 18-200mm over and over at different locations and times, and the results have always come back highly consistent, both in respect to position and magnitude with other lenses, and also results from the field.

After taking and viewing hundreds of thousands of photographs, I know my lenses well. I know which ones are sharp. Thus, when I photograph with a soft lens, it sticks out like a sore thumb. In the Nikon 18-200mm, my thumb is very sore indeed.

To be fair, objective, and unemotional, however, I've gone the extra mile with the Nikon 18-200mm; extensively target testing it with many other lenses, at many different focal lengths. Here's a list.

• Nikon 18-200mm at 24, 28, 120, and 200 mm
• Sigma 28-300mm at 28, 120, and 200 mm
• Sigma 50-500mm at 120 and 200 mm
• Nikon 24-120mm at 24 and 120 mm
• Nikon 70-180mm Micro at 120 and 200 mm

In all this testing, the optical resolution of the Nikon 18-200mm came in dead last against all other lenses, at all other focal lengths. The photos below show a sample of this performance.

In-Camera Sharpening

Could turning on in-camera sharpening explain the discrepancy between my test results, and all the acclaim for this lens?

Doesn't look like it. In-camera sharpening increases the appearance of sharpness (accutance), but doesn't capture any more detail. Furthermore, it increases artifacting, and "papers over" low lens resolution.

RAW vs. JPEG: Mystery Solved

With the Nikon D2X set to RAW + LF JPEG output mode, the camera creates two output files per exposure—one RAW, one LF JPEG. Thus, the two photos below actually come from the same exposure.

BaBam. Mystery solved.

The above photos clearly show RAW processing magically extracting high detail and sharpness from a low resolution lens. The bottom photo also shows how RAW processing keeps artifacting well in check. In essence, RAW processing has transformed a lens with bottom-of-the-barrel optical resolution into a star performer.

Again, mystery solved.

The Nikon 18-200mm is a RAW-only professional lens—perhaps the first in history.

A Daring New Lens Strategy

The ability of RAW processing to extract additional detail in photographs is not exactly news. What is news is Nikon's bold and daring strategy of taking consumer-grade optics, and selling them in the form of a professional lens. It takes guts to do that.

It also takes amazing foresight. From the digital photography git go, Nikon has consistently demonstrated strategic thinking extending years into the future. The Nikon D1, the early and unwavering committment to the APS-C sensor format, the early pronouncement there would be no 35mm full-frame Nikon dSLR, the sticking to this pronouncement, the slow but deliberate attrition of many of Nikon's most iconic film lenses, the heavy shift to the prosumer dSLR market (because that's where the money is), the abandonment of the prosumer digicam market, and now, the introduction of a RAW-only prosumer lens—it all takes a degree of foresight, astuteness, and yes, even cunning that one can't help but admire.

Bottom line, the Nikon 18-200mm is aimed squarely at pros and serious amateurs using a RAW-only workflow. Based on near-universal praise for the lens and a chronic backorder situation, it appears Nikon has hit the bullseye.

RAW-Only Ramifications

If you stop to think about it, Nikon's innovative RAW-only strategy highlights some major, even profound, ramifications for photography. Here are a few.

• Yesterday's consumer-grade optical resolution is today's professional-grade optical resolution.
• Yesterday's "gadget" superzooms are today's professional superzooms.
• Professional lens prices are trending closer and closer to consumer lens prices.
• dSLR lens resolution is no longer a major purchasing consideration. Pick any lens, and with RAW processing it'll deliver enough sharpness and detail to satisfy many professional photographers.
• New lens trend: add professional features to lightweight, relatively inexpensive superzooms. As evidenced by: the recently announced OS (optical stabilization) version of the Sigma 18-200mm.
• In a RAW-only world, the ultra high resolution of Iconic, expensive, film-era prime lenses is largely obsolete.
• The same goes for big, heavy, lumbering, film-era zoom lenses like the Canon 28-300mm f/3.5-5.6.
• This means—for the first time in the history of serious photography—high lens resolution is no longer a super critical attribute in achieving professional-level detail and sharpness.
• Low lens resolution combined with RAW-only processing allows manufacturers to build lighter, cheaper lenses that appeal to larger masses of photographers willing to pay juicy premiums. It's a lensmaker's Seventh Heaven.
• In a RAW-only world, 35mm full-frame sensors are even more inefficient, overpriced, and uncompetitive.
• Camera makers committed to the APS-C sensor format will continue to grow and prosper.
• Camera makers not committed to the APS-C sensor format will... well...
• Third-party lensmakers are now in better shape than ever. For example, in the new RAW-only world, my dirt cheap Sigma 28-300mm superzoom is now a world class, professional optic (after all, it does have higher optical resolution than the Nikon 18-200mm). Of course, due to persistent social s(t)igmas, I'll still have to wear a bag over my head when I shoot with it. But now I can proudly remove the bag when I show the results.
• The runaway success of the Nikon 18-200mm proves serious amateur photographers have become rulers of the photography realm.

Nikon 18-200mm Focal Length Framework

Because focal length is so critical to composition, having a properly designed focal length framework is key to boosting photographic success. Here's the focal length framework that's the bread and butter for my job as a nature photographer,

Equipment	Zoom Range	Equiv. Zoom Range	Comments
Nikon D2X Camera		1.5X Crop Factor
Nikon 12-24mm AF-S	12-24mm	18-36mm	VR not needed
Nikon 24-120mm VR AF-S	24-120mm	36-180mm	35mm film lens
Sigma 50-500mm HSM	50-500mm	75-750mm	Should have VR
Proposed Equipment
Nikon 18-200mm VR AF-S	18-200mm	27-300mm	Intended replacement for Nikon 24-120mm

As you can see, this framework covers a 12-500mm zoom range (18-750 equiv.) with just three remarkable lenses. All three of these lenses offer enough optical resolution to achieve the magnification/system resolution equivalent of 645 film from LF JPEG files.

In certain scenarios such as backpacking, casual hiking, holiday travel, and certain social events, I'll remove the Sigma 50-500mm from my focal length framework. The two other lenses by themselves allow much leaner travel. In such two-lens scenarios, the middle, wideangle-to-telephoto lens becomes the primary lens with the most time mounted on the camera. Thus, it's vital that the middle lens have a big a zoom range as possible.

For this reason, I originally purchased the Nikon 18-200mm to replace the Nikon 24-120mm as the crucial middle lens. The extra zoom range of the Nikon 18-200mm translates into a big, big advantage in one and two-lens situations. In successful nature and travel photography, it's not so much what lenses you own, but what focal lengths you have on a camera at the decisive moment.

Has the Age of RAW Really Arrived?

The only reason I haven't made the switch to the Nikon 18-200mm is its low optical resolution makes it incompatible with my LF JPEG workflow. I photograph in huge volumes, up to 16,000 photos per month, so the notion of changing my LF JPEG workflow to RAW just to accomodate the poor optical resolution of a single lens is a non-starter.

Keep in mind, historically, my high hurdle for RAW processing has been my time, which naturally I value highly. This is followed by the added expense of RAW processing, and it's marginal improvements to the image quality of high resolution lenses. Until now, RAW processing on a high-volume scale has simply cost too much extra time, soaked up too many extra resources, and delivered too small an image-quality improvement to make it worthwhile.

Lately, however, I've seen signs all this may be changing. Since the beginning of 2005:

• Flash memory prices have fallen from over $100/GB to less than $10/GB.
• Large, fast 3.0Gbs SATA-II hard drives have appeared on the market.
• The price of these hard drives has fallen from over $1.20/GB to less than $0.25/GB.
• The price of multi-core laptop computers has fallen from $4,000 to $1000, even while processing power and hard drive capacity have grown exponentially.
• With the availability of large, fast, cheap flash cards, carrying portable hard drives into the field is no longer necessary. This means hassling with extra hard drive and battery capacity in the field is also no longer necessary. RAW files quadruple consumption of both these resources.
• A whole new class of relatively compact, lightweight, and deliberately ruggedized dSLR cameras like the Nikon D200 and Pentax K10D have appeared on the market. These cameras have ruggedized bodies, environmental sealing, and heavy-duty shutters—very important for high-volume nature photography.
• The lightweight, ~3 oz rechargeable batteries for these new-breed ruggedized cameras offer impressively long battery life. Again, RAW files quadruple battery consumption over LF JPEG.
• The speed and ergonomics of RAW conversion software have improved considerably.
• The RAW sharpening algorithms in these applications have also improved.

Taken as a whole, all these developments mean RAW is no longer excessively more time-consuming and costly than LF JPEG, even for high-volume operations.

Nikon 18-200mm Advantages

Thus, assuming a RAW-only world, the Nikon 18-200mm offers some extensive advantages.

• The tremendous wideangle-to-telephoto zoom range of the Nikon 18-200mm (28-300mm equivalent) lens makes it ideal for one or two-lens missions such as backpacking, hiking, travel, and social events.
• The relatively light, 1.2 lb weight of the lens makes it practical for missions where weight is an issue. This includes backpacking, hiking, travel, and social events.
• Contrast the 1.2 lb weight of the Nikon 18-200mm to Canon's 3.7 lb, 28-300mm, superzoom behemoth.
• When used in RAW mode, after accounting for magnification/system-resolution geometries, the Nikon 18-200mm delivers about the same image quality as a 645 medium-format Velvia film frame.
• Contrast the $750 cost of the Nikon 18-200mm vs. $2,200 for the Canon 28-300mm superzoom, and $16,929 for Hasselblad 50-110mm, 120mm, 150mm, 210mm, and 300mm medium format lenses.
• Compatibility with one of the few lightweight, pro-grade dSLRs on the market (Nikon D200) translates into 2-5 lb weight savings over other pro-grade cameras like the Nikon D2X and Canon 1Ds Mark II. Out in the field, these weight savings are HUGE.
• Highly effective VR image stabilization enables tripod elimination or substitution with a monopod/hiking stick. In the field, this 5-7 lb weight savings is HUGE.
• Fast, quiet, accurate AF-S autofocus operation is a nice pro touch.
• f/5.6 f-number at 200mm is half a stop faster than the competition.
• 1.6' minimum focus distance and 1:4.5 magnification is usable for a surprising amount of closeup and pseudo-macro (enlarged and cropped) work. This is particularly true on one and two-lens missions.
• Compatible with a large range of high-resolution dSLR cameras (i.e. D2X, D200, D80, D40x, Fujifilm S5)
• For Nikon purists, the Nikon name and pro-level treatment is a nice status symbol.

Nikon 18-200mm Disadvantages

• No dust reduction capabilities available.
• Poor optical resolution.
• Makes RAW virtually mandatory.
• Makes a high resolution dSLR (10+ megapixels) virtually mandatory. This lens needs all the system resolution it can get.
• AF-S autofocus is not much (if any) faster than the competition.
• There are less expensive alternatives such as the Tamron 18-250mm lens on a Pentax K10D body.
• The $750 price is significantly higher than other 18-200mm superzooms.
• Hard to get. Chronically backordered.

Alternatives

I recently purchased a Pentax K10D camera body for digiscoping. Turns out the K10D, with its stellar optics and built-in image stabilization makes a phenomenal digiscoping camera. From an ergonomics and operations standpoint, it's nowhere near the same league as Nikon dSLRs, but with its ruggedized body, environmental sealing, and heavy-duty shutter, it is one tough, rugged little SOB. In the first six weeks, I put 12,000+ frames on it—in some pretty tough conditions—and it sailed through fresh as a daisy. I gave my Nikon D100 a similar tough start, and after a month it was already chronically malfunctioning.

For the past year, I've been looking to reduce the weight of my backpacking package, by swapping out the D2X with a ruggedized compact dSLR. For backpacking photography, ruggedization is important. Every single piece of equipment has to work flawlessly, or you're out of the picture taking business. My backpacking photography has been cut short several times in this manner, and it's heartbreaking.

To this point, there are only two ruggedized compact dSLR cameras on the market, the Nikon D200 and the Pentax K10D. This leaves two alternative paths; buy a Nikon D200 for my Nikon wideangle and superzoom lenses, or buy wideangle and superzoom lenses for my Pentax K10D.

Dust Reduction the Deciding Factor

I pounced on the K10D for its dust reduction capabilities. I've spent so many weeks and months of my life spotting digital photos that dust reduction is now one of my big hot buttons. I ended up buying the Sigma 10-20mm and Tamron 18-250mm lenses for the Pentax K10D.

Beyond dust reduction, here are some of the important differences between a K10D outfit and a Nikon D200 with Nikon 12-24mm and 18-200mm lenses.

Equipment	Weight (lb)	Price (US$)
Nikon D200	1.8	1,500
Nikon 12-24mm f/4 AF-S	1.2	910
Nikon 18-200mm f/3.5-5.6 VR AF-S	1.1	750
Total	4.1	$3,160
Pentax K10D	1.5	745
Sigma 10-20mm f/4-5.6	1.0	480
Tamron 18-250mm f/3.5-6.3	1.0	500
Total	3.5	$1,725

• Focal Length Framework. The K10D outfit stretches the focal length framework by 2mm on the wideangle side and 50mm on the telephoto side. Both these extensions are visibly significant.
• Weight. The D200 outfit weighs 9.4 oz more. In the backpacking world, half a pound+ weight savings is a big deal.
• Resolution. Remember, with RAW file mode, resolution isn't such a big deal any more. Overall detail and sharpness for both systems is about equal to a 645 medium format film camera.
• Closeup Photography. The Tamron 18-250mm focuses closer and offers higher magnification than the Nikon 18-200mm (1.5' vs. 1.9' and 1:3.5 vs 1:4.5 magnification). For 2-lens missions when you have no dedicated macro lens, this is significant.
• Cost. $1,725 for the K10D outfit versus $3,160 for the D200 outfit. I'll let this one stand on its own.
• Built-in Image Stabilization. Image stabilization built into the K10D body makes that system much more compatible, flexible, versatile, and inexpensive.
• Ergonomics and Camera Operation. No competition here. Pentax, you have a long, long, long way to go.
• Digiscoping. Available optics and built-in image stabilization make the K10D an absolutely phenomenal digiscoping camera. The D200 makes an ok digiscoping camera.
• Dust Reduction. It's worth repeating, the K10D outfit offers dust reduction. The D200 outfit does not.

Nikon 18-200mm Recommendations

So, here we are, bottom line, should you buy the Nikon 18-200mm lens?

If you're a pro or serious amateur photographer, and you use a RAW workflow, then heck yeah, buy this lens. The great wideangle-to-telephoto zoom range is truly practical for all manner of photographic applications ranging from general purpose walkabout shooting to wideangle landscapes and social events. Effective VR image stabilization, fast, quiet AF-S autofocus, and light weight add tremendously to this practicality. Keeping this superzoom as the default lens on your camera will undoubtedly accrue "defining moment" photographs to your library.

As for recommended camera bodies, if you're a high-volume professional shooter, the lightweight, compact, and ruggedized Nikon D200 goes great with the Nikon 18-200mm. You also might want to check out the Fujifilm S5, which is built around the D200. Either of these camera bodies joined to the Nikon 18-200mm will form a great lightweight backpacking, outdoor, nature, travel, photojournalism, and event system.

If you're a low-volume, occasional shooter, go with the Nikon D80. You'll get all the great handling of a Nikon dSLR at a lower price.

Even if you're just starting out and shooting in JPEG mode, the Nikon 18-200mm may well be worth the extra $250 over Sigma and Tamron competitors. The pro feel and pro feature set of this lens along with outstanding Nikon ergonomics and intuitive, user friendly camera operation make shooting with this lens one of the most fun, easy, intuitive, pleasurable, and rewarding experiences in all photography. Intuitive Nikon camera operation will definitely boost your transition from beginner to serious, RAW-mode amateur.

Things are not all rosy with the Nikon 18-200mm. Low optical resolution aside, its major weaknesses come not from the lens itself but from Nikon camera bodies. Lack of dust reduction capabilities is a major ding. And ideally, VR image stabilization belongs in Nikon camera bodies, not lenses. Thus, if you're an experienced, high-volume nature photographer, the Tamron 18-250mm lens with Pentax (K10D) mount is a more progressive alternative. The Pentax K10D camera body provides both dust reduction and built-in image stabilization, making it an ideal superzoom and digiscoping platform.

If you do end up going with the Nikon 18-200mm lens, here are some operating suggestions.

• Getting full professional performance from this lens requires exclusive RAW file mode use.
• For working with large RAW files, high capacity 3.0Gps SATA-II hard drives are recommended. You'll quickly come to appreciate the extra speed and capacity.
• When transitioning from LF JPEG to RAW, purchase enough additional flash memory to equal at least four times your current amount.
• If you haven't already done so, upgrade to a 10-megapixel or greater APS-C digital SLR. The Nikon 18-200mm needs all the system resolution it can get.
• RAW files require additional processing software. Adobe Camera Raw is built into modern versions of Photoshop. Picasa is free from Google, and has RAW processing capabilities. For me, Bibble from bibblelabs.com has the most intuitive user interface and RAW workflow.

—Mark Hatasaka, July, 2007.

Copyright © 1999-2007 NaturePhotoAdvisor.com