How to Use a Crop Sensor Lens on a Full-Frame DSLR
While reviewing the Nikon D600 recently, I had so many different lenses and cameras on my hands that I decided to conduct a little side experiment. I wanted to prove whether or not a decent crop sensor ultra-wide lens could compete with an exotic full-frame sensor ultra-wide lens, when used for landscape photography and/or the pursuit of optimal sharpness and image quality… I wanted to keep it simple, with as few variables as possible- Just a stopped-down, base ISO test to begin with. Depending on these results, I may pursue additional tests. So, let’s meet the contestants!
The bodies: A Nikon D600 and a Nikon D7000. Two cameras that appeal to pretty much the exact same type of photographer, with a “slight” ~$1000 difference. Both are capable of amazing image quality at their base ISO, which is where traditional landscape photographers spend ~90% of their time.
The lenses: A third-party, crop-sensor Tokina 11-16 f/2.8, …and the Ferrari of all ultra-wide zooms, the Nikon 14-24 f/2.8 AFS-G ED N. Two lenses with a similar ~$1000 difference, and yet for various reasons there is much more of a stigma separating them. But again, a landscape photographer will usually spend most of their time at f/11, …so can the Tokina hold it’s own against the Nikon?
Comparison #1: D7000 & 11-16 @ 11mm, VS D600 & 14-24 @ 16mm
How does a ~$1,500 setup compare to a ~$4,000 setup?
Nikon D7000, Tokina 11-16 @ 11mm, f/11
Nikon D600, Nikon 14-24 @ 16mm, f/16
The results are pretty dang similar. Central sharpness is the same in real-world situations, even off-center. I wish I had composed the shot better for gauging the extreme corners, but suffice it to say that both lenses are tack sharp at their stopped down apertures. Don’t believe me yet? Here comes round two:
Really, the biggest difference is just the overall “look” of the image. Two camera sensors just never look the same. I know they can measure these differences in a lab, and quantify and rank them, but I’m here to say that in the real world, most of the time, it’s just “different”… If anything, the full-frame shadows have a little bit more detail and a little less noise. As is expected of a next-gemeration, full-frame sensor.
Of course even if the above results are satisfactory for you as a crop-sensor shooter, in the given (easy) conditions, there are certainly some other reasons to upgrade to full-frame. The better image quality at higher ISO’s, the bokeh for portraiture… The question then becomes: if you go ahead and upgrade to full-frame, do you need to get rid of that ultra-wide zoom? Let’s find out…
Comparison #2: D600 & 11-16 @ 16mm, VS D600 & 14-24 @ 16mm
How does a $600 lens compare to a $2000 lens?
I went into the menu on the D600 and disabled the automatic DX crop mode. For each Nikon camera you can find this option in roughly the same place; in the Image Settings menu near the RAW and JPG options. On a Canon, there is no “crop mode” menu to worry about. (Either you have a Canon EF-S lens which will NOT mount on a full-frame body at all, or you have a third-party lens like the Tokina 11-16, and it will mount just fine.)
So, let’s see how the Tokina 11-16 looks at 16mm on full-frame!
Nikon D600, Nikon 14-24 @ 16mm
Nikon D600, Tokina 11-16 @ 16mm
Once again, the results are pretty impressive. The Tokina is equally sharp throughout almost the entire frame, and only in the most extreme corners does the image begin to stretch and blur slightly. In fact good sharpness goes so close to the corner that most slight horizon tilt corrections will negate the difference…
For a price difference of about $1400, I’d say it’s safe to conclude that the Tokina 11-16mm f/2.8 crop-sensor is very formidable as a 16mm full-frame “prime” lens! In fact, the Tokina 11-16mm f/2.8 is the ONLY way a Nikon user can get 16mm, f/2.8, and filter threads all in the same lens, on both full-frame and DX! All other lenses for Nikon are either f/4, or 17mm, or have permanent hoods.
If you’re an extreme sports photographer, or a rock climber, this is something I would strongly urge considering: Instead of risking a severe accident involving rocks or other impact with an un-protected $2,000 lens, why not get a $600 16mm f/2.8 “prime” lens that weighs a lot less and has much more protection?
The Tokina 11-16mm isn’t the only DX crop sensor lens that can be used effectively on full-frame, either. One other crop-sensor lens that works fantastically well on full-frame is the Nikon 12-24 f/4 DX. Again, with just a little horizon-fixing or cloning in photoshop, images are usable all the way to 16-17mm!
…Looking for more information on which crop-sensor ultra-wide lenses can be used effectively on full-frame bodies? Ken Rockwell has a very comprehensive chart HERE.
Again, I have never in my entire career (or hobby) been in a situation where a corner like this was un-acceptable. Worst-case scenario, if I were making a huge print for a gallery exhibition or something, I’d clone the corners to sharpness perfection.
Wait a minute, do you have time for one more test? …Let’s have a look at what happens when the 11-16 is shot throughout it’s entire focal range on full-frame:
As you can see, the big black circle creeps into the image pretty quickly, and by 12mm the entire sides of the image are black.
However 15 and 14mm don’t reveal any vignetting yet, if you leave your UV filter off, although their corners are starting to really get “stretchy-blur”. Again, something easily fixed when straightening a slightly crooked horizon, or with a few quick clone stamps in Photoshop.
At 13.5mm or so, I can still make a great 1:2 panoramic crop from the images. By 13mm or 12.5mm, I must crop to 1:3 in order to avoid severe vignetting. How sharp are the edges, though? We’re even past the territory of the 14-24mm now; we’re in the land of the legendary Nikon 13mm f/3.5..
…On a 36 megapixel Nikon D800, or a 24 megapixel D600, when cropped this is still an 8-18 megapixel image; plenty big enough for making a nice 12×36 or even 20×40″ panoramic print!
So, there you have it folks. Crop-sensor ultra-wide lenses can hold their own against even the best ultra-wides in the full-frame arena! Are you an adventure photographer who loves stopped-down sharpness almost as much as you love to save weight? You can be fully confident in a setup like the Nikon D7000 and Tokina 11-16, or Nikon 12-24 DX. Personally, I’m very excited about the idea of seeing Nikon’s new DX 24 megapixel sensor in a D7000 replacement, maybe a D8000?
Or, if you’re already on the path to a full-frame upgrade, you can certainly prioritize your investments for other lenses such as fast primes or other full-frame goodies like a 70-200, and continue to use your current crop-sensor ultra-wide quite effectively.
Until next time, take care and happy clicking!
PS: Why didn’t we test these lenses wide-open, in low light, etc. etc? Quite frankly, because this article is already long enough. ;-) One comparison at a time. I have plenty of test images that I will continue to go through, so keep an eye out for future articles!