mstuhr Loc: Oregon

Have used it for years on my D70. When I got beyond the kit lenses I decided to buy FX lenses thinking I might one day by an FX camera. I did. Last fall bought a D750.

Bazbo Loc: Lisboa, Portugal

I use fx lenses on dx cameras frequently. It is especially useful if you need the extra reach. Also, my dx camera has faster focussing and higher frame rates than my fx bodies, so there is that as well.

DavidJon Loc: Ada, Oklahoma

The Tony Northrup video was interesting. I didn't realize that the crop factor on a DX camera applied not only to the focal length but to the aperture also. Now that is disappointing.

lowkick Loc: Connecticut

The 70-200 on a crop sensor camera will act like a 112-320mm lens. That is neither good or bad, it just depends on what you are using it for. The good news is that the Canon 70-200mm f2.8 is a spectacular lens with great optics and is used by many professional photographers for portraiture as well as sports and other situations. You should decide whether you have more use for a full frame camera or the 70-200 lens now, especially if you are planning to eventually buy the other.

DavidPine Loc: Fredericksburg, TX

I use my 70-200 on a DX D500 frequently and I love the results. You don't need to purchase a FX Camera to get quality images.

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

So you'll have a 105-300 on a Nikon and a 112-320 on a Canon. And your point is?

RickL Loc: Vail, Az

I use fx 70-210 frequently to great success on my D7000. I have five FX lenses that I use, they have exceptional glass,

moonhawk Loc: Land of Enchantment

It only applies to aperture as that pertains to depth of field.

NOT as it pertains to the exposure triangle. F/2.8 is always f/2.8 when it comes to exposure.

Also, the aperture you choose with DX glass has the same effect on depth of field as the same aperture with an FX lens. f/4 on a DX lens will give you the same DOF on ANY given camera as an FX lens set to f/4. So, the DOF is determined by the camera format, not the lens format.

moonhawk Loc: Land of Enchantment

Another point to consider is that using FX glass on a DX body means you're using the center of the inage circle, which is generally the best part. Not as much with your best pro lenses, though.

chrisg-optical Loc: New York, NY

FX or DX doesn't matter with regards to focal length - that doesn't change. What is different is the circular area projected onto the sensor - which is larger on an FX full frame lens to cover the larger FX/FF/35mm sensor. However, FX lenses are generally of better quality and placing one on a DX will capture more of the central "sweet spot" of the lens projection - less vignetting and distortion possibly. Of course the cropped image will provide a 1.5 x "magnification" or crop factor (1.6 on Canons) However putting a DX lens on an FX body will result in in-camera cropping and loss of megapixels. Whenever possible only buy FX lenses or full frame film era lenses so they can be used on either - having both is a distinct advantage for many enthusiasts.

amfoto1 Loc: San Jose, Calif. USA

I use two different 70-200s on crop sensor cameras very frequently...

Lenses are more important than the camera body or sensor format and 70-200s are among the most fully developed and high performance, pro-quality zooms offered by most manufacturers.

I definitely wouldn't wait to buy a 70-200 after you buy a full frame camera. In fact, with quality lenses, such as most 70-200, you might never need a full frame camera!

Regarding depth of field and lens aperture... those actually don't change with sensor format either (same as focal length doesn't actually change).

Depth of field rendered by any given aperture actually only changes with change in focal length or distance to the subject. Sensor format alone makes no difference.

However, when we change sensor formats, in order to frame a subject the same way we have to also change other things.

For example, in order to frame a subject the same way with a full frame camera, you'd need to either use a longer focal length lens or move closer to the subject... or a little of both. And those changes do make for shallower depth of field with any given aperture.

At the other extreme, an optical effect called diffraction, which at exceptionally small apertures will rob fine detail from images, is a little less of a problem with full frame cameras than it is with croppers. But, once again it's not the difference in format that causes the difference. A full frame shot is less susceptible to diffraction only because it ultimately will be less magnified, for any eventual use. For example, to make an 8x12 print from a crop sensor camera shot requires approx. 13X magnification (assuming no cropping of the image). The same print size done from a full frame image will see roughly 8X magnification (again assuming no cropping). The greater magnification done to the crop sensor shot will make any diffraction more apparent.... so crop sensor cameras are about one stop more "diffraction limited".

So, it "seems" like full frame cameras give stronger blur effects with large apertures... as well as being able to "safely" use slightly smaller apertures. Conversely, crop sensor cameras "seem" to make wide angle lenses less wide and telephoto lenses more powerful, even though the lens focal length doesn't actually change.

sathca Loc: Narragansett Rhode Island

I used a 80-200 2.8 d on my Nikon D7100 and I loved it. It was a vast improvement from any dx lens I ever had. I wouldn't expect just any fx lens to be as good. I had a 70-300 vr and it didn't compare. Once I saw the difference with the fx lens I bought all fx lenses after that.

GENorkus Loc: Washington Twp, Michigan

If you're a perfectionist, then just don't use aperture values above 16. That's where you start getting a bit of defraction on most of the full frame lenses out there. If you're like most people, don't worry about it. I've used full frame lenses on my crops since I started using digital and just attempt to stay at f:16 or less. No real problems. (Truth be known, I rarely need high values with most of my photography.)

They are improving things all the time. Defraction may not be a problem at all in the future.

kb6kgx Loc: Simi Valley, CA

How can that be? It's not like you're using a TC. You're only changing the field of view.

bull drink water Loc: pontiac mi.

80% of my lenses for both aps-c or medium format are fx/dx combos. it's a no brainer for me.