6.5mm Opteka fisheye not locking onto my d3100 plz help :( "lens not attached"

[theGrandWizz]

Hi Guys,

I am a little new to DSLR photo/video, I am a videographer and trying to get into both but I am a little unexperienced so I am having a little trouble with something at the moment.

I recently purchased an Opteka 6.5mm (Nikon threads don't worry not THAT noob) off ebay and it came in the mail, but when I went to go set the lens up it would not screw on fully. I lined the white dots on the lens up like I do with my other lenses except it doesn't rotate the full 90 degrees or so to lock into place like my other ones do :s and just reads lens not attached. So I got a little panicked and did some extra research and this lens should indeed fit on my camera.

My question is am I just a noob and not screwing it on properly (special setting or something I am missing) or is there an adapter ring I need to get for it to fit on properly because it is a manual focus lens and if so where can I purchase said adapter?

Any help would be much appreciated I am so sad right now

 

[Derrel]

Lens Not Attached...hmmm...I think that might be a warning message from the camera that the lens attached does NOT HAVE A CPU nor does it have contacts in the lens, and that in order to use the lens, the camera MUST BE set to M- metering mode, and the exposure determined by YOU. My guess is that the Opteka fisheye has no CPU and thus no "little gold contact pins" on the back of the lens...

If you put the D3100 into M- metering mode, and go outside on a sunny day, and set the ISO to 200, the shutter to 1/500 second, and the f/stop to about f/8, that's a starting point for a good, generous sunny day exposure that will give plenty of shadow exposure, and the D3100 oughtta be able to hold the highlights in RAW mode, and you oughtta get some good exposures.

 

[KmH]

It sounds like it does not have a Nikon lens F-mount.
The mount, except the electronics contacts has to look exactly like any other lens you have that goes on your camera correctly.

Opteka makes that lens with Nikon, Canon, Sony, Olympus, or Pentax mounts. - Opteka 6.5mm f/3.5 Manual Focus Aspherical Circular Fisheye Lens for Digital SLR Cameras (New Version)

 

[theGrandWizz]

It sounds like it does not have a Nikon lens F-mount.
The mount, except the electronics contacts has to look exactly like any other lens you have that goes on your camera correctly.

Opteka makes that lens with Nikon, Canon, Sony, Olympus, or Pentax mounts. - Opteka 6.5mm f/3.5 Manual Focus Aspherical Circular Fisheye Lens for Digital SLR Cameras (New Version)

any way of mounting the version I have, it has no electrical contacts

I actually looked it up and that is the exact lens I have