Maximum Aperture of the Nikon 18-200mm Throughout its Zoom Range

The only lens I own for my Nikon D200 is a NikonAF-S DX VR Zoom-Nikkor ED 18-200m F3.5-5.6G(IF),” also known as “the 18-200mm.”

I really love it as a fantastic all-around lens, but at f/3.5-5.6, I find that it is sometimes a bit slow (that is, it doesn't let in enough light for me to use a fast-enough shutter speed). So, I've been thinking of getting a faster (allows in more light) lens for use in lower-light situations.

Because of its “18-200mm f/3.5-5.6” name, I know that my lens is f/3.5 at 18mm, and f/5.6 at 200mm, but what is it in between? Without knowing, it's hard to compare how much faster a different lens might be. For example, how much faster is Nikon's f/1.4 50mm lens than the 18-200mm at 50mm?

So, I set the camera to wide open and turned on the high-speed continuous drive, and held down the shutter while sweeping the lens through its full range of focal lengths. I then plucked the data from the MakerNotes in each image and plotted it.

This file shows the
largest aperture that the Nikon DX 18-200mm can do at various points along
its zoom range. Although the zoom is continuous and smooth, the
Exif/MakerNotes data shows only discrete focal lengths. Those in the graph
>= 95 are the focal lengths that the MakerNotes is able to show. The Exif
data is slightly different than the MakerNotes data: the f-stop is usually
0.1 lower and the focal length is rounded nicely with the with the Exif
data. Created by Jeffrey Friedl with his 18-200 and a Nikon D200.

I see that the 18-200mm is f/4.6 at 50mm, which is just about 1/3rd stop slower than f/4.0 (which is 3 stops slower than f/1.4 — if you need them, here are two primers on f-stops).

So, compared to the 50mm f/1.4, my lens is 31/3 stops slower, which is a lot. That's the difference between a shot at 1/15th of a second, in which even mild subject movement is blurry, and one at a much more snappy 1/160th of a second.

I'm thinking of something like Nikon's 17-55mm F2.8, but can't see shelling out $2,000 for only a 2/3rd gain at 18mm and a 11/3rd gain at 55mm.

Isn't there at least an f/2 (or better) in this range?

UPDATE: I ended up getting the 17-55 f/2.8 and love it.


Technical Notes

The main graph above is logarithmic on its Y (f-stop) axis, and linear on its X (focal-length) axis. Perhaps not surprising, the plot appears as a straight line when the X axis is also logarithmic.

The graph on the right shows the same data in a log/log plot.

Despite the 18-200mm's smooth zoom throughout its range, the Exif data and the MakerNotes data have only a limited number of points along that range that they'll report, and oddly, the two sets of data are slightly different. I've shown the MakerNotes' data in the graphs.

The full data from both are shown in the tables below.

Nikon 18-200mm Minimum Aperture at Reportable Zoom Positions
From the MakerNotes Data
18.3mmf/3.6 27.5mmf/4.0 38.9mmf/4.4 56.6mmf/4.8 95.1mmf/5.3
20.0mmf/3.6 28.3mmf/4.0 40.0mmf/4.4 59.9mmf/4.9 106.8mmf/5.5
20.6mmf/3.7 29.1mmf/4.0 42.4mmf/4.5 63.5mmf/4.9 113.1mmf/5.5
21.8mmf/3.7 30.8mmf/4.1 43.6mmf/4.5 65.4mmf/5.0 119.9mmf/5.5
22.4mmf/3.8 31.7mmf/4.1 46.2mmf/4.6 71.3mmf/5.0 130.7mmf/5.5
23.8mmf/3.8 32.7mmf/4.1 47.6mmf/4.6 75.5mmf/5.0 138.5mmf/5.7
24.5mmf/3.9 33.6mmf/4.2 50.4mmf/4.6 80.0mmf/5.2 151.0mmf/5.7
25.9mmf/3.9 35.6mmf/4.2 51.9mmf/4.8 82.3mmf/5.2 169.5mmf/5.7
26.7mmf/3.9 36.7mmf/4.4 55.0mmf/4.8 89.8mmf/5.2 201.6mmf/5.8
Nikon 18-200mm Minimum Aperture at Reportable Zoom Positions
From the EXIF Data
18mmf/3.5 31mmf/4.0 44mmf/4.5 62mmf/4.8 105mmf/5.3
20mmf/3.5 32mmf/4.0 46mmf/4.5 65mmf/4.8 112mmf/5.3
22mmf/3.8 34mmf/4.2 48mmf/4.5 70mmf/4.8 120mmf/5.3
24mmf/3.8 35mmf/4.2 50mmf/4.8 75mmf/5.0 130mmf/5.3
26mmf/3.8 36mmf/4.2 52mmf/4.8 80mmf/5.0 135mmf/5.6
27mmf/3.8 38mmf/4.2 55mmf/4.8 82mmf/5.0 150mmf/5.6
28mmf/4.0 40mmf/4.2 56mmf/4.8 90mmf/5.0 170mmf/5.6
29mmf/4.0 42mmf/4.5 60mmf/4.8 95mmf/5.3 200mmf/5.6

All 10 comments so far, oldest first...

It’s interesting, Jeffrey, thanks.

I used this lens yesterday in a low light situation (Q+A after a film presentation in a Museum setting) and found the VR really useful — more so that I expected.

While I like this lens as a walk-around — especially in good light — I too am seriously considering a faster zoom in the wide end of the range (I already have the 70-200VR).

— comment by Joe on October 5th, 2006 at 10:25pm JST (10 years, 7 months ago) comment permalink

At this time I have no desire to get a larger zoom than than the “something to 70” that came with my D70, but I also had a need for a faster lens (for indoor photography at church events). I purchased the Nikkor f/1.8 50mm lens (very reasonably priced at less than $150) and so far initial tests show that it is indeed noticably faster.

I may try the same tests on my 12-24 wide angle. That sounds like a fun weekend project. 🙂

— comment by Simon P. Chappell on October 7th, 2006 at 2:50am JST (10 years, 7 months ago) comment permalink

My 18-200 VR arrived with focusing problems, so I’ve sent it to Nikon for repair. What I’ve found the greatest issue with this lens is the HUGE depth-of-field (a result of comparatively high F-numbers). Since shooting with this lens wide open won’t yield the best of results, stepping further down from F3.5 @ 18mm to say F5.6 will give you a tremendous depth-of-field (whether this is a problem or not depends of your subject, but not having a choice is annoying). Apart from that, shutter speeds are (in most situations) counter-acted by VR, and I’ve found this lens to be good fun in most relaxed situations. If under pressure – such as at a wedding – my guess is that you’d be better off with the 12-24. If you’ve got the money…

— comment by Stefan on December 20th, 2006 at 7:04pm JST (10 years, 4 months ago) comment permalink

A very useful analysis. Thanks Jeffrey!

— comment by Phil Harvey on July 25th, 2008 at 4:13am JST (8 years, 9 months ago) comment permalink

A very useful analysis indeed. But how does the VRII feature play into this ?

> I see that the 18-200mm is f/4.6 at 50mm, which is just about 1/3rd stop slower than
> f/4.0 (which is 3 stops slower than f/1.4

Nikon claims that VRII gives you the equivalent of 3-4 stops. If that’s the case, doesn’t that mean the 18-200 at 50mm zoom can shoot in the same lighting conditions as the 50mm f/1.4 ?

thanks,
Joe

— comment by Joe on October 18th, 2008 at 11:21am JST (8 years, 6 months ago) comment permalink

Hi how are you? Thank you for the information. Your Website is amazing full of information and your photos are extraordinary. Thank you.

— comment by Gerardo Toyloy on January 11th, 2009 at 7:27am JST (8 years, 4 months ago) comment permalink

While f-stop is the right way to compare two lenses for depth of field, it may be misleading for comparing the amount of light gathered (i.e. how fast the lens is). The t-stop would be appropriate for this. The t-stop is never better than the f-stop, frequently worse, and getting a good t-stop is probably why the 17-55mm is so large. Unfortunately Nikon et al. never publish or record the t-stop!

— comment by Scott Wheeler on March 3rd, 2009 at 5:41am JST (8 years, 2 months ago) comment permalink

This is an interesting lens. I bought one just after its release with the proviso that my friend who was with me, would be happy to buy it from me if I didn’t like it. He became the owner of it two weeks later. I shoot fast and this lens focuses way too slowly for me.

I had felt uncomfortable with this lens during some wedding shoots, with being able to pin it down to one thing (apart from the slow focusing issue). Later, when I checked various review sites, I discovered the reasons I was dissatisfied… the amount of distortion, at various focal lengths, was staggering. The worse section being the most-used mid-range of the zoom.

Sadly, (and this applies to a few Nikon lenses), it was a good idea that didn’t come off.

I suppose for general, non-critical uses, it performs to its price range. You get what you pay for.

Your criticisms are valid, but I think more than “you get what you pay for” it should be “know what you’re getting when you pay”. Even when it came out, prior to people having hands-on experience, a lot of people would think you’re crazy to use a lens like this for a wedding (as a pro, not a guest). With so much going for it in zoom range and its compact size, you know (or should know) that compromises will have been made elsewhere. People call this a great all-around walk-about lens because for most people on a casual stroll, the barrel distortion is a small price to pay for such a huge zoom range in such a small lens. —Jeffrey

— comment by Ron Cork on March 10th, 2009 at 9:37am JST (8 years, 2 months ago) comment permalink

A most interesting test report and subsequent discussion.

I agree that this lens is unsuitable for professional work for all the reasons outlined. Distortion is a major problem and to a large extent can be corrected in post-processing. This can be very time consuming and Photoshop fails to correct complex distortion (wave-effects on horizontal lines at short focal lengths).

I use this lens most of the time. When I decide to use an image for printing and presentation I pass it through DxO Pro, a raw converter that corrects all distortion and other faults attributable to BOTH the lens AND the camera body in combination. I like to think I’m elevating a consumer lens to a pro-quality lens. Of course I’m not, but the result is a vast improvement and an excellent foundation for refinement in Photoshop. I would be interested in the views of other DxO users.

I would like to say that I have no commercial interest in DxO; I’m just a satisfied user.

Tony (UK)

— comment by Tony Bennett on November 23rd, 2009 at 8:08pm JST (7 years, 5 months ago) comment permalink

When I was shooting DX cameras, thanks to my naivety and the recommendation of this lens by Ken Rockwell (Kenrockwell.com), I eagerly picked up a copy of the Nikkor 18-200. I found it was “not sharp,” in particular at the long end of the throw… 200mm or thereabouts. After a time, I figured I had a bad copy and sent it back to Nikon under warranty. They checked it out and sent it back as “working perfectly,” so I happily starting taking photos with it again. But, alas, I encountered the same problem: too soft focus and not really tack sharp, in particular at the longer end. Since that time, many users have reported the same problem.

That was some time ago and as I gradually progressed in cameras from the D1x, D100, D200, D300, D700, to the D3s I came to understand that I am particular interested in sharp lenses, and I have studied them much like you study all the areas you have. I have (happy to say) now found lenses that are really sharp and am using them. I sold my 18-200mm Nikkor long ago. As pointed out, this is a ‘convenience’ lens that trades compromises in lens quality for that convenience – perfectly understandable. However, one does not have to be a pro to want sharp focus.

Every lens is a compromise of some sort… the moral of the story is to understand what those compromises are, and what’s important to you in any given situation. I’ve used the 18-200 just once in the last year, on a trip to Disneyland where luggage was really limited. That was a situation where the “important to me” ended up selecting that lens, and I’m glad I had it at my disposal. The other 500 times I made a lens selection last year, it came up shorter than other lenses I have. —Jeffrey

— comment by Michael Erlewine on December 27th, 2009 at 11:00pm JST (7 years, 4 months ago) comment permalink
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