Sigma User Manual for 105mm f2.8 Macro

I believe on some Sigma lenses there is a switch to lock it in a 'Macro' position, usually at the long end of the zoom range. If this applies to your lens, it may be worth checking that this has not been accidentally set. There may also be some information in the manual whichcame with the lens.

Not sure that the lenses come with an actual manual more of an instruction sheet. Google your camera make and model and select a site that reviews the lens. You may find the info you need.

The user manuals coming with lenses most of the time have little information about how to use them. The lens will have a MF and AF and perhaps a VR switch. If you want to learn more about macro photography, check this site from Ken Rockwell, where he is explaining how to do so with a Nikon camera.
Be aware the macro lenses are designed to focus close to the camera and will have the sharpest pictures close to the camera. I would not say you can't use a micro as a tele, but the results with a normal 105 could be better.
Still I think you have a great lens with your Sigma.
How to Shoot Macro

This is not a solution but the same kind of problem.

I just bought a Nikon D5100 and found that my Sigma 105mm macro has a problem. The camera will not power up, but if I turn it on, untwist the lens and then twist it back in, the camera powers up. If I leave it for a few seconds, it powers down again. Provided I keep taking photos, it works, but this is not acceptable because it can take several seconds to get a focus on a close-up, and by time I get the focus, the camera powers down again.

I never had any problems with this lens on my Nikon D80. I also use several lenses, all of which work well with both cameras. It's only the Sigma that has the problem. And I did clean the contacts with a proper contact cleaning solution and a swab, but still no joy. My lenses are made by Tamron, Pro Optic, Nikon and Sigma, and the only problem lens is the Sigma.

Turn the aperture ring to f/32 and leave it there. After that, forget the lens has an aperture ring at all. You can let the camera control the aperture in any mode except the M and A modes. In the M and A modes, you control the aperture by turning the command dial on the front of the camera, the same way you control the aperture on a lens without an aperture ring.

In all modes the aperture ring on the lens should be locked at the smallest aperture. In the M and A modes you control the aperture by turning the command dial on the front of the camera. In P and S modes you control the aperture indirectly by turning the command dial on the back of the camera.

Hi there,

Well you can please follow the below link to get your manual (you just make contact to sigma and ask them for the manuals they will send you the manual, there are no digital manual available on net) -

http://www.sigmaphoto.com/contact/contact.asp

(Just copy and past the above link in your web browser)

Good Luck!!

Thanks

Hi I had a similar problem with a 50mm prime and I fixed it by locking the aperture ring on the lens in place.

if the lens has a iris ring if so you need to turn it to the f16/22 also what camera you use

It will not focus on anything closer than 5 feet.

(From Sigma lens literature) Capable of macro photography, this lens has a 1:2 maximum close-up magnification at the 300 mm focal length. It's the ideal high performance lens for portraits, sports photography, nature photography, and other types of photography that frequently use the telephoto range. It also has a switch for changeover to macro photography at focal lengths between 200mm and 300mm with a maximum close-up magnification from 1:2.9 to 1:2. The minimum focusing distance is 1.5m / 59 in. at all zoom settings.