CAN I USE IT ALONG WITH MY NIKON D5100 - Nikon Cameras

To use Metz 45CL-1 with Nikon D5100, you need use in apperture priority mode (A), adjust same ISO and apperture in Flash and Camera (Ex: ISO400 and F: 5.6) . The flash adjust light intensity to mantain correct exposition. You need use an adapter to conect Sync cable in your camera.

Open your appuatue set your ISO to 200 or 1600 what ever it needs

You can't pop up the flash in the Auto mode. In this mode the camera decides whether to use the flash or not.

Try switching to one of the PSAM modes. Does the flash then pop up when you push the flash button?

If you do not have a D5100 manual, download it from Nikon by following this link and then look on pages 58, 152 and 157 for instructions: http://cdn-10.nikon-cdn.com/pdf/manuals/dslr/D5100RM_EN.pdf

No Nikon lens ever zooms automatically, so I assume you mean focus.
The D5100 lacks an autofocus motor, requiring the lens to have one. The older 70-300mm lenses lack this motor, expecting the camera body to have one.
The D5100 will only autofocus with lenses designated AF-S or AF-I. It will not autofocus with older AF-D and AF-G lenses.

Replace
CCD

No. This lens lacks an autofocus motor, relying on the camera to have one. The D5100 lacks an autofocus motor, relying on the lens to have one. Adding a battery grip does not change this situation.

The D5100 only autofocuses with lenses having an internal autofocus motor. Nikon designates such lenses AF-S, Sigma calls it HSM. Lenses without the motor will only autofocus with the larger and heavier Nikon cameras such as the D7000.

Hi I'm having the same problem!!!
My Nikon D5100 camera giving a sin of Autoexposure error after it's drooped from my tripod on the deck floor (Wooden Floor). How can I fix that? I tried few does not work, please help me, it's an emergency. Thanks!

If your lens has a Nikon mount then yes, you can use it on the D5100. You'll have to switch to the Manual exposure mode and you won't get any exposure help from the camera's light meter.

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.