Nikon 18-70mm
© 2006 KenRockwell.com

Nikon 18-70mm f/3.5-4.5 AF-S DX. I'd get it at Adorama or Amazon. It helps me keep adding to this site when you use these links, thanks! Ken.

June 2008     More Nikon Reviews

This 18-70 was Nikon's first midrange zoom designed for the shorter focal lengths required by digital cameras. It was introduced along with the D70 in February 2004. It was my favorite midrange zoom for digital until the better and cheaper 18-55 came out in April 2005. Then the 18-200 VR came out in December 2005 which is two choices ahead of this 18-70mm, if you can justify it.

The 17-55mm f/2.8 weighs a ton and costs $1,500. I'd skip it.

I suggest the 18-55 or 18-200 VR first depending on your budget. This 18-70 would be my third choice and dead last would be the heavy 17-55 2.8. My biggest beef with this 18-70 is the weird camming of the zoom. The wide focal lengths are crunched together making it hard to set the composition precisely.

This 18-70mm goes for about $350 alone, and also comes as kits with camera bodies.

This is a serious lens, not a "kit lens" or a cheap replacement for a lens cap sold as part of a kit as with most other cameras. The fast f/3.5~4.5 speed should be your clue; the cheapies are all f/3.5~5.6. The 18-55 is a cheapie, but good.

This 18~70 is similar to a 27~105 mm on a 35 mm film camera.

It ONLY works on digital SLRs. Using it on a film camera will result in a semi-circular image with dark corners. If you need a wide angle zoom for a film camera you need the 18-35 instead. It is a DX Lens.

It's an easy to use, sharp, compact and all around nice lens. I've shot with it and even owned one. It's pretty much identical in size, feel and weight to the 24-85 AFS I use for my film cameras but with a much more useful focal range for digital cameras.

Specifications     back to top

Optics: 15 elements, 13 groups, one of which is an aspheric. This is not a cheapie "kit" lens (the 18-55mm is).

Diaphragm: Seven-bladed rounded diaphragm, f/22 - 36 minimum aperture.

Size: 2.9" (73 mm) long by 3" (74 mm) long.

Weight: 14 oz (390 g).

Close focus: 15" or 0.38m, very good.

Filter Thread: 67 mm. I suggest permanently attaching a 67 -> 77 mm step-up ring and treating this lens as if it's got a 77 mm thread just like the rest of Nikon's pro lenses. This way you only need one size of caps and filters and other accessories. Trust me, you'll go insane if you buy different filters for every lens! No, you can't use the lens hood this way; I never use lens hoods so no problem. I just use my hand to block the light of the sun if it's shining directly into the lens, which works a lot better than the hood when you need it.

Nikon Product Number: 2149, in catalog as of spring 2008.

Performance     back to top

It's sharp, focuses fast and silently and has instant manual focus override like all AF-s lenses. The distortion is fairly typical: barrel at wide, neutral in the middle and some pincushion at the tele end.

Some people worry too much about sharpness. On a digital camera you get up to a certain spatial frequency and the MTF drops to zero thanks to the antialiasing filter and the CCD layout, thus it's much easier to characterize lenses for digital cameras. Sharpness is easy to get on digital camera lenses and this is as sharp as it can be. Nikon posts the MTF curves at the bottom of this page.

Discount lens makers are trying to scare people into thinking that they just invented magical "digital" lenses in an attempt to make people think that the discount lenses somehow outdo the existing lenses you already own. Nope. Your 15 year old AF lenses are just great on a digital camera.

Film lenses are trickier since the MTF curve extends, albeit at a very low amplitude, to triple digit c/mm. Digital cameras stop at about 30 c/mm.

This lens is completely sharp. Go for it.

Distortion:

I have a page of explanation and examples with this lens, before and after correction, here. There is a lot of distortion at 18mm you can correct in PhotoShop CS2. It mostly goes away at other settings.

18 mm: barrel with somewhat complex signature, probably will require some cleverness to correct completely. It sort of bloats in the middle and straightens towards the far edges. If you need no distortion at this focal length use the 12-24 mm, or use the free Panorama Tools Photoshop to correct this distortion electronically. Like most wide range zooms this 18-70 will curve some straight lines parallel and close to the frame edges when set fully wide. I use CS2's lens distortion correction with a setting of +6.00 explained here.

25 mm: none

28 mm: none

35 mm: almost no pincushion

50 mm: very minor pincushion

70 mm: very minor pincushion

Flare and Ghosts

Shooting straight into bright lights I saw none, which is great.

Zooming

The zoom ring is nonlinear and squeezes together the wide angles. This means that you have to be careful moving the zoom ring at the wide end since small changes in rotation result in larger changes in focal length. At the tele end you can make very precise adjustments.

Note to techies: when I say linear I mean logarithmic, of course. An equal amount of rotation anyplace should give the same percentage change in focal length, as on the 18 - 200 and 80 - 400 VR lenses.

Is this the best lens?

I often get questions from new photo hobbyists like "I have priced the Sigma 24-70 f/2.8 and it is the same price as the Nikkor 18-70 f/3.5-4.5G that comes with the D70. Should I buy it instead of the Nikkor? I am not sure of the importance of the extra .7 f-stop vs. the extra 6 mm on the wide angle side."

Actually, the answer lies on both the surface and substance level.

At the surface level understood by the new photographer this answer is easy: the 2/3 of a stop means nothing today, since you can just increase the ISO of the D70 with little to no penalty in image quality if you run out of light. On the other hand, the 6 mm is a HUGE difference in how wide it goes on the D70: it's the difference between a 27 mm lens and a 36 mm lens on a 35 mm film camera. You will always be at the 24 mm stop and wishing you could get back out to 18 mm on the D70 for a lot of things, at least the way I use it. This is quite clear.

The substance level is something I never appreciated until I had a couple of decades of experience under my belt. A discount lens usually offers more features like faster speed or wider zoom range for less money than camera-brand lenses. Likewise, a cheap car like a Hyundai or Ford usually offers better specifications, like fuel economy, horsepower or number of radio presets, for a lower price than a Mercedes. You may realize that the Mercedes has a lot more fundamental quality for which there is no numeric specification, and so you probably understand why a Mercedes costs more even with worse specifications.

It's the same thing with lenses. Discount brands are usually pushed by camera stores because they make even more money selling them (more here on that). I avoid the discount brands and know of no professional photographer who uses them. Don't you think if even one pro photographer you'd heard of used them they'd push that in their ads? Anyway, the discount lenses cut corners in places that neophytes don't know about, like the internal construction quality. I find them to be a bad deal, but hey, get what you want.

Recommendations    back to top

Buy one if you want, I did in 2004!

Today (2008) I'd suggest saving for the 18-200mm VR instead, or using the 18-55mm DX I usually use because it's so small.

For the same price as this 18-70mm you can get the 18-55 and and the excellent 55-200mm VR. That's what I'd do with $350.

Your choice should be based on how you like how they feel and focus. Image quality is very similar.

More Information: See Nikon Japan for MTF predictions.