Sigma/Nikon Lens Adapter

[BellaFoto34]

I have a Nikon D60 SLR camera and have some older AF - Aspherical Sigma lenses that went to my old Pentax ZX-7 film SLR. I am trying to find an adapter that will allow me to use the Sigma lenses on my Nikon DSLR. Could someone tell me where I can find an adapter? Any help would be appreciated. Thanks.

[Abel]

moving thread to the Equipment Section now...

[shnitz]

Cristina, it's not realistic to do that, the Pentax K mount is smaller than the Nikon mount register, so there aren't any good ways to go about adapting. Plus, for adapted lenses, you have to use stopdown metering, lose autofocus, etc.

You're better off selling the Pentax lenses and just buying the Nikon-mount versions, or the newer equivalents. If you don't mind posting all of your lenses up, we can advise you on which are worth keeping, and which are considered "dogs" in the lineup and have a better equivalent. Make sure to post the focal length range AND aperture range, so that we know which specific lenses you're talking about. Sigma overall is a lower-end thirdparty brand, until recently, so there's a good chance that your current Nikon lenses perform better anyway. If you are dead-set on using those lenses, you may want to consider selling your D60 and getting yourself a Pentax K-r or the lower-end K-x. Pentax still makes great cameras; I was handling a friend's K-5 with 21mm and 77mm lenses just this past weekend.

[auddii]

Just using google I found this one:

Amazon.com: Kipon Pentax K Lens to Nikon Body Mount Adapter: Camera & Photo

Amazon.com: Kipon Pentax K Lens to Nikon Body Mount Adapter: Camera & Photo

Personally I have a nikon to canon mount adapter, and it's much, much smaller than this one. I agree with what Ariel said above about losing a fair amount of light. It also says that it can still focus to infinity, but that surprises me. This adapter almost looks like an extension tube, and on those you do lose the ability to focus to infinity. I'm not really sure, but it may not be worth it. (This adapter is also 8x the cost of mine.)

However, several forums says that it's just not possible because the "register is shorter" (no idea what it means, but I'm sure those people know a lot more than me). Makes me wonder what this adapter actually does and if it works or not.

[shnitz]

The register being shorter means that the Nikon flange on a camera body, the metal ring that you mount the lens to, is 46.5mm away from the film/sensor plane. Pentax K-mount has a register distance (flange to sensor) that is shorter, so the lens when mounted is only 45.5mm away on a Pentax. Factor in that an adapter must be at least a few mm thick, and you are correct, in that the adapter is like using an extension tube. Moving the lens further away from the sensor than it is supposed to be effectively turns the lens into a macro lens. It will only be able to focus a short distance in front of you; the further you move the lens away, the more focus distance it will lose. Many adapters can put a glass element in the lens, that makes the adapter act like a short teleconverter, but you foremost lose serious image quality, since you're putting a cheap piece of glass between your lens and sensor. Also, it extends the focal length, so your wide angle is no longer as wide, which is a problem on DSLRs, since most of them have an inherent crop factor anyway. I don't understand how they can claim that the Nikon-Pentax adapter that you linked to has no correcting glass yet doesn't change the focus properties.