Charles Measter

I have a new D800 with it I purchased two Sigma Lens a 17-50 mm F2.8 and a 70-200 F2.8 I have been learning the camera but I can not understand something. These are compatible lens but not CPU lenes, I guess? In the setting menu under non CPU lenes I put in 50mm and F2.8. When I have the camera set to metrix metering I keep hearing the lens trying to focus. What am I doing Wrong?

Non CPU lens are for fully manual lens that the camera cannot "read" the lens (because it is missing the cpu contacts), and hence does not know the minimum Fstop of the lens, so,, when the mechancal linkage of the old AI connector is engaged, without manually telling the camera the minimum aperature, the camera cannot display the right aperature.

The setting as nothing to do with the focusing..

Sounds like the camera is trying to focus with the lens, but is having issues, try spot meeting, and pick a like a tree, something with high contrast. If the camera tries, but can't lock, it might be something
with the lens. Does this do this with both lens?

Isn't the sigma 17-50 a DX lens?

Looks like Marcel is right. At least the first lens is for DX cameras. You should probably send this lenses back. You want FX lenses, and probably auto focus lenses. You have the most sophisticated prosumer camera ever built, at least for the first couple lenses I would do Nikon FX. And alway FX, unless you really know what you are doing and have a need. JD

the DX lens should at least focus correctly, it will be in DX mode, throwing away half the pixels, I turn off the DX mode, and will see the circle, but if you zoom out, often the lens can fill the whole area.

but yes, if you own a D800, then well own FX lens...sell the lens to a DX user.