jimkh

Again, thanks for all the responses. I don't intend to use APSC lenses as a general rule on my full frame camera - just maybe occasional use of the 16-50 "kit". I was also lucky to find a local Long Island camers store who had the Tamron lens that's so difficult to find and it is as great as the reviews claim.

joer Loc: Colorado/Illinois

Of course it will fit its not like Canon. You will have fewer pixels which really is not a problem unless you crop or enlarge to extreme. It wasn't that long ago when 10mp sensors were considered huge and just about every one was more than happy to have them.

Its too bad that DXO doesn't test crop lenses on full frame sensors...I suspect that many would be surprised.

Use it and enjoy.

jerryc41 Loc: Catskill Mts of NY

larryepage Loc: North Texas area

With most zoom lenses, the image circle varies in size. It is almost always quite a bit smaller at the shorter focal lengths. The result is that vignetting is worst at widest angle settings. My Nikkor 17-55mm f2.8 vignettes very little at 55mm. It covers probably a 20x32mm area of the sensor at that focal length. It does vignette quite a bit more at the wide end, but still less than in your example. It will cover a 24x24mm square image at all focal lengthe, which is quite a bit more real estate than the DX crop. I have found that you have to watch out for the lens hood at short FLs, because the view may be wider than the hood is designed to accommodate.

Please note that I am not trying to say that DX lenses on FX bodies should necesarily be anyone's primary mode of photography. But DX on FX can produce very useful and even interesting images, and using them will absolutely not damage or harm anything. It is true that a smaller number of "premium" (Gold Ring, in Nikon's case) dedicated DX lenses are available. When transitioning from DX to FX, any dedicated crop lenses can continue to be used with confidence while re-equipping, either in crop mode, square mode, or full frame mode. In fact, I have found that matrix metering even works fine when doing this. In some cases, printing an image even including the vignetted area can add to the image...providing a sense of peeking through a knothole, for instance.

larryepage Loc: North Texas area

Jerry--

I note in Nikon's article that they mention that FX bodies automatically switch to DX Crop when a DX lens is mounted. I can't remember if that was the default setting on the D810 and D850 or not. But image area is a menu selectable option on those bodies, and the automatic switch can be disabled, allowing images to be recorded in any of the available formats. Is that also true on the D750? I am wondering whether there are some models that do not offer options.

RolandDieter

The APS-sized Sony 10-18mm works very well on the full-frame cameras between about 12 and 16mm. At 11 and at 17mm the slight corner vignetting can usually be removed in Photoshop. I also find this is usually the case at 18mm. However, at 10 the vignetting is not correctable and requires cropping. I did not have these good results with the other APS Sony lenses on full frame. But the 10-18 can give you a great, cheaper, lightweight full-frame ultra-wide.

Allen K

It's my understanding that using an APS-C lens in a full frame (Canon) camera has potential to damage the sensor screen. Maybe that's not a problem with Sony and other cameras. But you will get terribly severe vignetting (especially with a wide angle lens), and the image you get will more than likely be much less than what you intended. Welcome to the world of full frame cameras; now get yourself a full frame lens that will deliver what you were aiming for.

larryepage Loc: North Texas area

I'd have to understand the expected damage mechanism to accept that is a risk. The crop lens, if anything, is going to leave dark areas on the sensor. A lot of images contain dark areas. Don't see how that would be expected to cause damage. If I'm missing something here, I'd be happy to learn. Otherwise, it sounds like marketing hype seeking to pressure folks to buy more stuff quicker than is absolutely necessary, rather than make a perhaps more rational equipment transition.

photogeneralist Loc: Lopez Island Washington State

Although I have no direct experience with a APSC lens on a FF body, I seem to recall reports that the amount of vignette varies according to the zoom setting and the f/stop. Some APSC lenses were reported to be usable on FF bodies under some conditions with only very minor vignetting. Your A 7III is a digital, so it costs nothing to take test photos at various zoom and f/stops, After viewing the test photos, you can answer your question for yourself then delete the test photos if you want.

chapjohn Loc: Tigard, Oregon

Use the "35mm equivalent" menu setting with crop lenses on Sony FF cameras. Set it to "auto" and the will detect what lens is being used to make the adjustments needed. This should avoid vignetting. I do not get vignetting when using DT A-mount lenses on the FF A7Rii.

GoofyNewfie Loc: Kansas City

It’s the mirror that can be damaged when using Canon, not the sensor.
Evidently some Canon EF-S lenses are deeper that the full frame lenses and can interfere with the mirror function.

Allen K

Regarding sensor damage, it could well be a "marketing hype" on Canon's part. But, as you yourself have noted, there is considerable vignetting and loss of image at the wide end of images taken with a crop lenses on a full frame camera, and since the original inquiry was about the ability to continue using his 17-50 crop lens on his full frame camera, he needs to understand that he's going to lose 25-30% or more of his image. That's what I experienced in my transition from a Canon7D (crop) to the Canon 5D (full frame). I loved my Canon EF-S 10-20mm lenses, but I lost so much image that I traded it in for a used Canon 16-35 full frame lens. But, again, that may be a problem peculiar to Canon.

Allen K

You're right. Thanks for the clarification.

larryepage Loc: North Texas area

This could be a possible concern. I remember when I was shooting film in Olympus equipment that certain fisheye lenses required the mirror tpo be locked up before mounting certain fisheye lenses, because the rear element extended into the body of the camera. I would also not ever counsel anyone to ignore cautions or warnings where damage to equipment might occur. So careful investigation in extreme cases is always appropriate.

That being said, flange to film distance is a key design parameter for any lens. If a crop body is able to successfully use full frame lenses and focus over the entire distance range, then there is no flange to film difference between the two systems, and interchanging the other direction should be safe to do. Adding to that the fact that the mirror in the crop body is smaller than the full frame mirror, it just seems very unlikely that there would be any mechanism for damage from interference.

If there is a strong desire by the OP and others to use crop lenses on FF bodies, I guess I'd suggest to check the documentation that came with the lens and the documentation that comes with the camera and verify one way or the other whether there is a caution or warning against their use together.

GoofyNewfie Loc: Kansas City

It’s not a problem on Nikon or Sony.
Canon on the other hand....