Canon mount dapter eos ef R vignettes

[clifff27]

Canon RP camera with adapter.  Sigma 18-200 vignettes terribly so that picture is an oval surrounded by black.  If shooting at 200 it is fine, but anything less vignettes.  Same with Tamron.  Is this to be expected?  If so the adapter is useless...Thanks

[kvbarkley]

Which Sigma 18-200? Is it the EF-S version?

Is it the Canon Adapter?

Note that all the adapter does is put the lens at the same physical location it would be on an EF/EF-S camera, so it should not vignette any more than the lens on an EF or EF-S camera.

[clifff27]

It is the standard Canon adapter...Lens is Sigma DC 18-200 with Canon mount. Not sure if EF or EF S... Used with D80 and no problem...Vignette problem is 18-150

Have a Tamron SP 10-24 same problem.  Vignette from about 10-16.

Tamron 200-500 seems fine.

Canon ef 28-80 is also fine.

[rs-eos]

A D80 is a crop-sensor camera.

No doubt, wide angle lenses as well as wide aperture lenses (e.g. EF 50mm f/1.2L) will vignette.  But as mentioned earlier, if you are using a lens on your full-frame camera that was desgined for a crop (smaller) sensor camera, that will really add to amount of vignetting.  And entire portions of the corner of the image may also now be completely black since not possible for any light to reach that area.

[clifff27]

Disappointing that this has happened...read numerous reviews of the adapter and do not remember this being mentioned as a problem...

[rs-eos]

It's not the adapter.  Please re-read the answers you got above.  Also, you'll want to find out if your lens is EF-S or not.  I suspect it is.  If so, that's the issue.

[Waddizzle]

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@clifff27 wrote:

Disappointing that this has happened...read numerous reviews of the adapter and do not remember this being mentioned as a problem...

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The problem is not the mount adapter.  It is the lenses.  Canon EF-S lenses cause the camera to automatically enter a crop mode.  Somehow the camera senses the EF-S lens through the adapter and it "adapts" itself into a crop mode.

Apparently, this is not automatically taking place with your third party lenses.  The cause must be due to the fact that even though lens circle is for a crop sensor body, many third party lens manufacturers use only one lens mount for both full frame and APS-C lenses.  

Of course the one lens mount they tend ot use is for full frame lenses.  It works on both types of bodies.  I would speculate that the camera thinks there is a full frame lenses mounted to it, so it is notautomatically  going into crop mode.

[rs-eos]

Sounds like your Sigma lens may be EF-S (designed to work with crop-sensor cameras).  But the RP is full frame so the lens' image circle isn't large enough to cover the entire sensor.

[clifff27]

thank you..all is well...just need to save for a full frame lens...

[ebiggs1]

I believe the DC name is Sigma’s note for crop sensor cameras. DN is for mirrorless.
I can’t remember mounting a DC on my FF body so I don’t know if it will.