camerapapi Loc: Miami, Fl.

The answer is YES but...an FX lens works better with an FX body. Because a digital factor is introduced due to the cropped sensor now your 18mm becomes almost 28mm, still very good as a wide angle and the 105mm side becomes almost 160mm. I like to use teles with my D7000 because the digital factor makes them appear longer and that is a godsend for action and wildlife photography.

burkphoto Loc: High Point, NC

I can't find any evidence that an 18-105mm *Sigma* lens exists. There's an 18-105mm Nikon lens, and an 18-200mm Sigma, and a 24-105mm Sigma ART lens that is very good indeed... but I can't find an 18-105mm Sigma on the Internet! (Is it an older film lens?)

If it is the Sigma 24-105mm f/4 DG OS HSM Art Lens, DPReview reviewed the Canon version of it, which should perform similarly to the Nikon version of it. You can find that review here:

https://www.dpreview.com/articles/6154129071/lens-reviews-update-test-data-for-the-sigma-24-105mm-f-4-dg-os-hsm

...and view the interactive test chart of it (tested on Canon full frame EOS 5SIII and APS-C EOS 7D) here: https://www.dpreview.com/reviews/lens-compare-fullscreen?compare=false&lensId=sigma_24-105_4&cameraId=canon_eos5dmkiii&version=0&fl=24&av=4&view=mtf-ca

That said... The short answer: YES. If someone gives you an FX lens, use it. You'll probably like the results. Many people use their FX lenses on DX cameras without issues, with the side benefit that they can use them on all their Nikons. In fact, some people consider that a lens collection strategy... They never buy DX lenses.

The long answer is a bit more complicated, and not widely understood.

The projected image "cone" from an FX lens is spread over a wider area. It has a diameter of about 40mm, so it can cover a 36x24mm sensor. The projected image "cone" from a DX lens only has to cover about a 24x16 area, so the light does not have to "bend" as much. So a DX lens of the same focal length projects about a 28mm diameter image.

What this means is that an FX lens' projected image is "cropped." The DX sensor records only the center 24x16mm area of the projected 40mm wide cone. Because lens performance suffers least from chromatic aberrations, coma, astigmatism, vignetting, etc. in the CENTER of its image, the recorded DX image is more consistent from edge to edge, corner to corner. But because of the magnification factor required to crop the center out of a larger image, absolute performance of an FX lens on a DX camera is potentially lower. Typical performance of lenses tested by DPReview/dxo.com on both camera formats is slightly lower on the smaller sensor, as shown in the link above. If you study the comparisons, you'll see how performance differs at different focal lengths, apertures, and positions across the frame.

Whether — and how — that is true in YOUR case depends on many factors, including sensor size, pixel pitch, lens design, manufacturing tolerances... and the cameras being compared.

mborn Loc: Massachusetts

rehess Loc: South Bend, Indiana, USA

Please do not say “becomes” - that confuses people. It doesn’t change - become something different. An 18mm lens on an DX camera acts as a 27mm lens does on an FX camera. A 105mm lens on an DX camera acts as a 157.5mm lens does on an FX camera.

burkphoto Loc: High Point, NC

SteveR Loc: Michigan

There are all kinds of things wrong with this statement. FX lenses work just fine on DX cameras. In fact, since the center portion of the lens is used, any problems at the edges that would be seen on an FX sensor are not seen by a DX sensor, so FX lenses would probably be BETTER than DX lenses on DX cameras. Having purchased FX lenses for my D7000 such as the 28-300mm and 50mm f1.8, I had lenses that I could use when I purchased my D800. Since then I've purchased a 24-70mm f2.8 and 70-200mm f2.8 as well.

burkphoto Loc: High Point, NC

FX lenses are MORE CONSISTENT across the frame, and corner to corner, on DX bodies. But they are not sharper performers on an absolute level.

When I first bought my GH4, a Micro 4/3 camera, I tried my old Nikkor primes on it, using an adapter. With a 2X crop factor, the 35mm f/2 has the field of view of a 70mm lens. But it is much softer than my 12-35mm Lumix Pro zoom. The same is true for my 55mm f/2.8 and 55mm f/3.5 Micro Nikkors, and my 24mm f/2.8 Nikkor. I stopped testing there... and bought Panasonic lenses. They are image stabilized, sharp, much lighter, and much smaller than their full frame equivalents. And automatic diaphragm and automatic focus both work.

SteveR Loc: Michigan

There might be an entirely different study as to why that is so.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

Remember that the edges of FX lenses on DX bodies are not seen. Only the middle part of the lens is used when you mount FX lenses on DX bodies, you are thus using the sharpest part of the lens and should be sharper in the corners than the FX lens on a FF camera.

burkphoto Loc: High Point, NC

That’s easily checked by referring to the interactive DPReview/dxomark tests of the same lens on both FX and DX or full frame and APS-C bodies...

The general trend and the common wisdom are usually at odds here, because multiple factors are in play.

I have found my old Nikkor lenses, adapted to my Micro 4/3 camera, are mediocre at best. Results at 8x10 look as soft as an 8x10 cut out of the center of a 16x20 made from 35mm film! Native lenses, by comparison, are tack sharp. But yes, the cropped center of the frame is more consistent. It is not as sharp.

chrisg-optical Loc: New York, NY

An FX lens on a DX body will capture the central "sweet spot" of the lens, so there will be less chance of distortion and possible vignetting which occurs more toward the outer parts of the lens circle.

Motorbones Loc: Fair Oaks, CA

Kinda makes me wonder what the depth of field comparisons would be between the two formats on a DX camera...

burkphoto Loc: High Point, NC

If you select a 35mm lens for APS-C/DX and a 50mm lens for full frame/FX, you will get nearly the same field of view from the same distance. The APS-C/DX camera will have roughly "one stop" more depth of field if you use the same aperture on both lenses..