A lot of people assume that prime lenses are sharper than zooms so I wanted to see how this relatively inexpensive prime lens fared against this huge professional zoom. I chose to only show the corners since the center sharpness was pretty much even across the board.
One reason I did this test was because I use the 28-70mm / D700 combo for most of my concert shots. I noticed that I only shoot at the extreme ends of this lens. All of my shots are at either 28mm or 70mm and rarely anything in between. I was thinking about using the 28mm f/2.8D prime on the D700 and the 50mm f/1.4G on the D300 using two cameras with smaller lenses rather than one camera with a cumbersome zoom lens.
- Vignette. The first thing I noticed was that the 28mm f/2.8D had severe vignetting. At f/2.8 the vignetting was so bad that it was more like an overall underexposure than a vignette. The corners are about 1 1/3 stops darker than the center of the image. At f/2.8 the 28-70mm showed minor vignetting. At f/4 the prime lens was still vignetting pretty badly, the zoom lens however showed very slight darkening of the corners. At f/5.6 the vignetting was gone from the 28-70mm, but the prime still showed a little darkening. At the rest of the apertures the vignetting was completely gone.
- Sharpness. At f/2.8 I was surprised by the softness of the prime lens. It was very soft. At f/4 the prime wasn't much better and only started to improve when stopped down to f/5.6. At f/8 the prime was good and at f/11 and f/16 it was sharp, with f/16 being the sharpest. Which is odd considering that by f/16 you should see some softening due to diffraction. The zoom lens was as sharp at f/2.8 as the prime at f/8 and only continued to get sharper. The 28-70mm f/2.8D is an amazingly sharp lens at all apertures.
- Distortion. The prime lens showed a surprising amount of distortion in the corners. With an ultra-wide lens you expect to see this type of distortion, which looks like the corners are being stretched out, but with a moderate wide angle like the 28mm you shouldn't see it so much. With the zoom lens the distortion is controlled better and it looks exactly as it should. Both lenses show moderate barrel distortion, but unless you're shooting brick walls or a lot of straight lines, it's not really gonna show. You can fix it pretty easily in Photoshop using about a +2.5 - 3.0 correction on the lens distortion filter.
Click on the images to view large
This lens test was performed on a full-frame D700. On a DX camera such as the D90 or the D300 the corner performance will be much better and the distortion almost undetectable. Vignetting on the 28mm prime will be evident at f/2.8-4, but you won't notice any vignetting with the 28-70mm.
The 28-70mm f/2.8D is an extraordinary lens. It's almost as sharp wide open as it is stopped down. The 28mm f2.8D isn't very sharp wide open and has pretty bad vignetting, but it also costs less than 1/4 of the price and weighs almost nothing.
8 comments:
Interesting post. However the 28mm AF is not known to be the sharpest or distortion-free. THat honor goes to the Nikkor 28mm f/2.8 AI-s Manual focus. A gem of a lens -- one of Nikon's sharpest, ZERO distortion and focuses close -- 22cm from the film plane.
Mr. Thomas,
I've got your D-700 Guide on its way from Amazon, but I wanted to ask you a quick question. I have several of the MF built-like-tanks AI Nikon lenses. I know that these can be used on the D-700, but I have read several opinions that (out of sheer decency, I guess!)one ought to sell these and invest in new AF lenses instead. Is that your suggestion, too? If money was limitless, the answer would be obvious, but in lieu of winning the lottery, can I stick with my MF lenses without incurring too much shame?
Thanks for all your good work!
In all honesty, it's really up to personal preference. If the MF lenses are working for you and you like them, I don't see any reason why you should change.
On the other hand, I prefer AF lens. I have a few MF lenses and I rarely , if ever, use them. I have both the 50mm f/1.4G and the 50mm f/1.4 AI and the only time in recent memory that I used the 50mm AI was on the D90 for video (MF lenses are awesome for the video feature). I find AF works best for me (mostly because I'm lazy).
There's no shame in using MF focus lenses. It takes much more skill to focus manually than it does to let the camera do all of the work.
I say hold on to those MF lenses and add some AF lenses along the way as you can afford them.
Mr. Thomas,
Thanks for answering my question about MF lenses. I appreciate your characteristic thoroughness. I'll hang on to those MF lenses!
Dear Mr. Thomas,
Just purchased your D90 field guide which lead me to your blog. I'm just about to lay down a large amount of cash (for me) to purchase the Nikon 24-70mm f2.8 G AF-S ED Lens - so this review caught my eye. However, I can't find any reference to a current Nikon 28-70 f2.8 either from Nikon stockists or Nikon's web site. Is this a lens available only in the USA or is there a small typo in the blog (28 should be 24?). The 24-70 seems to be everything you are saying the 28-70 in your review is.
Many thanks for your blog with its frank and honest writing - we'll be visiting often in the future.
Best regards, Paul
Paul,
The 28-70mm f/2.8D is the pro lens that preceded the 24-70mm f/2.8G. Some people refer to it as "the Beast" due to its large size. It's only about 2 oz. more than the 24-70mm though
It was discontinued with the release of the 24-70mm. The 28-70mm was available in Europe and you should be able to find a used copy pretty easily on ebay or any other reputable online dealer at a fraction of the price of the 24-70. This lens is getting harder to find though because people are snatching it up because its a great bargain.
The 28-70 is an AF-S lens so it focuses quickly and silently and is just as sharp as the 24-70 for all practical purposes. Being a D lens the 28-70 also has an aperture ring which allows you to use it an all Nikon SLR camera previous to the F100 with full functionality.
Basically, all you gain with the 24-70 is a few more degrees of coverage and the Nano-crystal coating which is marginally better at handling flare.
If you can find a used 28-70mm f/2.8D, I recommend it whole-heartedly. If you can't find one in the UK I suggest checking at Adorama.com or B&H here in the States. They usually have at least one for sale at any given time.
Dear Mr Thomas
I am at University so am quite price sensitive. I have a D300 now having used a D40 for many years. The 28-70mm f/2.8D would seem the true race-horse of lenses at an accessible price point (also slightly shorter, I dislike 'intrusive' lenses). But will the data feedback from the lens to the D300 be adequate? From the information I can gather, Nikon doesn't list the 28-70mm f/2.8D as fully compatible with the D300 preferring to promote the 24-70mm. I'd be grateful for any comments you might have before I make the purchase.
Sincerely
DC
Hi Dan,
The Nikon 28-70 f/2.8D is 100% compatible with the D300. All data will information will be available. You will be able to use all of the the D300 metering and focus modes with no problems.
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