Canon 5D vs. Sigma DC Lenses

[DKing9]

Just received my new 5D body (started with a 20D) and when attempting to use my Sigma 50-150mm and the 17-55mm I get a black circle around the photo. I know that the 5D is full frame but are there settings that do not make my Sigma glass obsolete??

[Andy]

Just received my new 5D body (started with a 20D) and when attempting to use my Sigma 50-150mm and the 17-55mm I get a black circle around the photo. I know that the 5D is full frame but are there settings that do not make my Sigma glass obsolete??
Why the flame icon? Those lenses are designed for digital bodies, 1.6x crop factors.

[cmason]

Just received my new 5D body (started with a 20D) and when attempting to use my Sigma 50-150mm and the 17-55mm I get a black circle around the photo. I know that the 5D is full frame but are there settings that do not make my Sigma glass obsolete??

No settings, those are DC lenses. DC lenses are "Specially designed for digital SLR cameras with an APS-C size image sensor" as described by Sigma. This is one of the issues with buying lenses designed for crop sensor cameras, (and an issue with going with a 5D if you have these lenses).

[ziggy53]

Just received my new 5D body (started with a 20D) and when attempting to use my Sigma 50-150mm and the 17-55mm I get a black circle around the photo. I know that the 5D is full frame but are there settings that do not make my Sigma glass obsolete??

That would be; no, yes and maybe.

The "no" part is that your lenses are designed for a 1.6x "crop" camera, which has a reduced sized imaging chip. Those lenses, by themselves, will not fill a full-sized imager or full-frame 35mm film camera.

The "yes" part is that you will get an image that you can crop from the center portion to yield a decent 4 x 5 aspect ratio with around 6 MegaPixels resolution.

The "maybe" part is that you might be able to use a 1.4x teleconverter on the 50-150mm lens, in the 100-150mm range, that might get closer to a full-frame image circle. The edges of the image will suffer, probably pretty badly, but it might be a useful expedient, and you could use the teleconverter later.

I don't think you will be happy with any of the above, so my first recommendation is that you purchase a Canon 50mm, f1.8 II, which is about the cheapest quality lens you can buy. Ultimately, you will probably want to get some new lenses, more appropriate for the new camera.

[DKing9]

Thanks for the info. I do have a teleconverter so I will try my luck with that but ultimately I will be getting more lenses. Very helpful!!!

[pathfinder]

Lenses are designed to create an image over a specific circular area in the sensor plane.

For example, lenses for an 8x10 view camera have to create an image that covers a full 8x10 glass viewing plate, or an image circle about 10 inches in diameter.

35mm lenses for full frame 35mm cameras create an image circle that is ~ 36mm in diameter, since a 35mm frame is 24 x 36mm in size.

Lenses designed for an APS sensor need only cover about a 23mm circle, since APS sensors are 14.8 x 22.2mm in size, hence the vingetting you noticed.

[DoctorIt]

Anybody mind if I change the title of this thread to specify "DC" lenses? with the flamey face, this really comes off as bashing of what is otherwise good glass.

[ziggy53]

Anybody mind if I change the title of this thread to specify "DC" lenses? with the flamey face, this really comes off as bashing of what is otherwise good glass.

That seems reasonable to me.

[Manfr3d]

Why the flame icon? Those lenses are designed for digital bodies, 1.6x crop factors.

Not to forget 1.5x crop factor bodies (Nikon, Pentax). :wink

[Art Scott]

Those lenses are designed for digital bodies, 1.6x crop factors.

Not to forget 1.5x crop factor bodies (Nikon, Pentax). :wink

Let's not forget Konica/Minota/Sony 1.5 crop factor either...:D