Pentax lens to Nikon D3000

[mrslyn]

I have a Nikon D3000 SLR and a friend recently gave me on loan an old Pentax film camera and it came with a 200mm zoom lens.
Is there any way I can attach the Pentax lens to the Nikon body?
Any help would be gratefully received

[Fit]

Depends on the type of lens - whether an adapter will work.

Various thoughts: https://www.google.com/search?q=Pent...ient=firefox-a

[mrslyn]

please bare with me, im very new to this... the lens has on it. SMC Pentax-M Zoom 1:4.5 80-200mm Ashati Opt. Co..Japan.

[FrankMi]

Hi Lyn, I did a web search for this lens and based on what I see in the following link, a Pentax K-mount lens will match several other manufactures of cameras, but not the Nikon F-mount. http://en.wikipedia.org/wiki/Pentax_K_mount

Chris has pointed out a lens adapter that 'might' work but may have limited capability. I would tread carefully when mismatched components are fitted together as often the cost doesn't provide a viable solution, there is increased risk of damage, and in some cases, warrantees may be voided.

[Glenn NK]

There is another nasty little problem with making a lens fit another camera - the register distance (RD).

The RD is the distance from the mounting flange on the camera (and the rear of the lens) to the film or sensor plane. This value is different for different camera systems.

This distance influences whether a lens from one system can be mounted with an adaptor to a camera body of another system. In order to achieve focus to infinity without corrective optics, the RD of the lens must be greater than that of the camera body it is to be adapted to, giving room for the adaptor.

The following are the RDs for a few manufacturers:

Nikon and Fuji = 46.50 mm
Pentax/Samsung/Contax = 45.50 mm
Konica/Minolta/Sony/Alpha = 44.50 mm
Canon EOS = 44.00 mm
Olympus 4/3 = 38.67 mm

As one can see, fitting any other manufacturer's lens on a Nikon body will inevitably require an adaptor with optics, and even if one is available, it can cost as much or more than the lens is worth.

Even with two common makes such as Nikon and Canon, the Canon body has only (46.50 - 44.00 = 2.50mm) to work with for an adaptor, and this doesn't take into account the electronics to render the Nikon lens compatible with the Canon body. Going in the opposite direction (Canon lens to Nikon body) requires an adaptor with optics plus the electronics problems.

Glenn

[inkista]

As Glenn says, the problem is the registration distance. You probably can find an M42 or Pentax-K (you didn't mention which mount the lens was) lens to your Nikon body, but the adapter you're going to find is going to have to have an optical element in it if you want to be able to focus to infinity. And if it's a good optical element, will cost a bomb, and if it costs a reasonable price (like, say a Fotodiox ring), the glass will probably add softness.

If you want to use the lens solely for portrait or macro work, and you always plan on using it for closer focusing, you might be able to get away with a ring that doesn't have a glass element in it and only does mechanical linkage.

If your expectations aren't too high, and you're budget-strapped it might still be a way to go. But you won't have autorfocus, you can only control the aperture from the ring on the lens, and with a D3000, you're also going to lose accurate metering, since the D3000 does not do stop-down metering. You'll also have empty EXIF fields where the lens information goes.

[Glenn NK]

Kathy Li makes some good additional points.

If one is considering using lenses from other brands, then one should consider a body that has the shortest register distance. This makes it much easier to find glass that will "fit" without huge cost and/or poor quality images because of additional optics.

There are photogs that really get into this:

http://forum.manualfocus.org/

http://forum.mflenses.com/

I'm registered in both forums, but haven't taken part - it's like an obsession within an obsession.

I've delved into it a bit, but searching the world for lens jewels (the good ones are well known and demand a high price) only to end up with manual focus (and sometimes manual aperture) will simply take me back to where I started - with a Asahi Pentax S with manual focus and manual aperture - what fun that was.

And to think people are constantly belly-aching about poor AF.

Glenn

[mrslyn]

Wow, thanks for all your help.. lost internet last night so couldnt respond.

Maybe I will just save up for the zoom lens instead of messing about with something Im not sure on.

[FrankMi]

Wow, thanks for all your help.. lost internet last night so couldnt respond.

Maybe I will just save up for the zoom lens instead of messing about with something Im not sure on.

I suspect that you'll be much happier with that. The pain of a poor decision endures long after the sweet savor of a great price has faded away.

[Dave Humphries]

Hi Lyn,

Welcome to the CiC forums from me.

I'd suggest saving up your pennies/cents for a Nikon AF-S lens for your D3000.
I say "AF-S" because other types will not Auto-Focus (and may not meter) on that body.

In fact I wouldn't recommend a manual focus only on any telephoto lens, with wide angle, increased Depth of Field (DoF) allows you to get away with not being so accurate with focusing, but with a telephoto, like 200mm it won't. So the Pentax, or any Nikon "AF-D" or "AF" lens, would be an unwise choice in my view, as Frank says.

If you go third party (Tamron, Sigma, etc.), to save on cost, do ensure you buy one with a focus motor in the lens, these may come with an acronym like "USM" or "HSM".

Before you buy anything, work out what you want to photograph though and if need be, ask for advice here, we're all here for you.

Hope that helps,