shooting a efs lens on a full frame

Is there any mechanical interference a person would have to worry about if you were to mount a efs lens on a full frame or is it you will just get vignetting? Im wanting to try my 50-100 sigma on my 5D to see what results i get with that combo but I'm worried about damaging the shutter or something.

I have not tried it myself but I have heard varying responses.

First one is that a Canon EF-S lens will not mount to a full frame body due to mounting tabs or something.

Next, third-party(?) lens such as Sigma doesn't necessarily use different mounts between EF-S and full frame. The lens may be manufactured for EF-S but the mount may be generic to a Canon body without the EF-S restriction.

Last, if it does fit, you take the risk of the mirror hitting the lens as it flips up. Some people have said there is a way to take a bit off the mirror holder and it will work while others said it hasn't been a problem. The EF-S lenses by Canon mount deeper into the camera body than a non EF-S lens.

I may be wrong but this information is what I have heard about the question.

Gart

If the rear element moves, don't use the lens on FF.

I think most third party lenses will be fine.

EF-S 18-55 beside EF 70-200 2.8

The extra depth is what messes things up.

Im thinking its not worth the risk. Thanks for the input

jlstan wrote in post #18188354
Im thinking its not worth the risk. Thanks for the input

I've mounted third party S lenses on FF with no problem.

Only issue is the few mm of extra depth needed for the way canon designs their EFS lenses. No extra depth? go for it.

jlstan wrote in post #18188354
Im thinking its not worth the risk. Thanks for the input

Third party lenses are EF mounts...so there is zero risk

I know others have mounted the 18-35 f1.8, and it was pretty usable at 35mm... I wonder how usable the 50-100 would be

So all sigma specific to crop will also mount to full frame without mechanical damage?

jlstan wrote in post #18188494
So all sigma specific to crop will also mount to full frame without mechanical damage?

yeah...do you have an ef-s lens? or another EF lens...you can look at the mounts and see the difference...all third party mounts are EF...with most EF-s lenses it's just a plastic baffle that physically prevents you from mounting it to a FF camera...you can pull that out and mount it fine though...this is only with metal mount lenses though

when you line up the dot on the lens you line it up with the dot on the camera and not the square right?

so could a person shoot a crop specific lens with a extension tube to take care of the vignette issue? This was shot at 100mm f1.8 iso 6400 using the Sigma 50-100. If I could solve the vignette issue it could be a fun lens on a full frame too.

that was shot on your 5D? the vignette doesn't look too terrible to me...there are some instances where it is really black, like you can see the circle, yours isn't like that

the problem with an extension tube is that in makes it hard to focus on anything that is a couple feet away...it's really only good for macro uses

people do mount 1.4X TC on the end of crop specific lenses to mount them to FF without any vignetting...although typically i feel like this is mainly done with wider lenses for landscapes where you don't care about the loss of a stop...something like a sigma 10-20mm with a 1.4X becomes a cheap 14-28mm lens on a FF

your lens would be a 70-140mm f2.5...so even then you'd be a 1/3 of a stop faster than any 70-200mm which could be useful

just the fact you can get 100mm f1.8 on a FF camera is kinda cool though, i don't think there's any other way to achieve that...yeah maybe the corners aren't super sharp...but if you're shooting f1.8 who cares about corner sharpness

50mm F1.8 Ive been wanting 1.4x to use with my 150-600 so maybe this is all the more reason to get it so I can see how the 50-100 + 1,4x combo on the 5d would work