Is adding grip for nikon d5100 solve the problem of auto focus with sigma 170-500 lens

When you connect a lens from another firm, or an old one without a chip, The camera can't work in the automatic settings. So not one scene and also you can't use the A, S, P and Auto. Really only manual is possible. And you have to dial in everything. like shutter time and you have to set focus and Aperture on the lens.

Chuck, sorry for the late response. Last days I had to work through several hundred anonymous questions. Most irrelevant and not complete, so I could not answer most of them, but I had to read them all.
Sigma, does not have a service, where you can download a manual. But the manuals from Nikon, most of the time don't tell anything about how to use the lens.
I found a page with all specs. The link is down here.

I have to guess why you did put the question here in the first place. I think because you have a Nikon camera without a focus motor. Like a D3x00 or the D5x00 or a D40 or D60. (for the x you can add 0 1 2 or 3)
If you have one of these camera's the lens can't be used with auto focus You only can use the lens in manual focus. Most other camera's from Nikon, like D80 D90 D7000 D300 and more expensive, all do have a focus motor and can work with this lens in full automatic focus mode.

50mm F2 8 EX DG Macro

do you have it set on automatic focus and if so you may have a bad lens
push shutter buton half way down when select in auto it will focus it for you if that don't work send lens in

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.

Quantaray makes lenses with a variety of mounts for a variety of cameras. A lens with a Sony mount, for example, will not fit onto a Nikon camera. Assuming the lens has a Nikon mount, it will fit on the D5100. However, the D5100 requires the lens to have an autofocus motor. If the lens does not have such a motor then it will not autofocus. It will still work fine as a manual focus lens.

The Nikon D40 does not have an autofocus motor, relying on the lens having one. This Sigma lens does not have such a motor, relying on the camera having one. Nikon designates lenses with an autofocus motor AF-S, Sigma calls theirs HSM.

Yes. The D300 has a focus motor built into the body and thus does not need one in the lens. The lens will also meter properly with the D300.

Yes its a HMS lens it will work on most Nikons

hi ! iam too a D40 holder,u can opt for AF-s versions or HSM sigma,both of them autofocus on d40,can go for 18-200 AFs VR or if u need still longer end go for 70-300 but it is costly than the sigms 70-300APO DG HSM MACRO..,its a much better reviewed lens and dont forget the cost..anyway do some research before considering..good luck

Your 28-90 AF-D lens can't autofocus with the D40, which requires AF-S lenses with a focus motor in the lens. Sigma lenses with "HSM" (HyperSonic Motor) in the name also have the focus motor.