I'm thinking about buying my first DSLR (I have no experience) and was thinking about the lens brand issue. I'm thinking I should buy a Pentax Kx because of it's cost-effective value, but I'm wondering if some time from now I'll end up spending more because I decided to change platforms, know what I mean?
So the question is: is there any way I could adapt lenses from Nikon or Canon into a Pentax body and what are the implications of doing this?


Theoretically yes. It depends on the flange focal distance for this given bayonet mount. You can mount, say, Nikkor F lens to Canon body. Nikon F lens have longer flange focal distance and even mounted on top of a Canon mount (farther away from the film than the original canon lens) will still be close enough to the film (sensor) to focus to the infinity. But not vice versa, because Canon EF bayonet has a shorter flange focal distance and Canon lens will not be able to focus to the infinity on Nikon bodies.

Practically no. You loose all coupling - aperture, focusing and often metering. Precise manual focusing on modern non-pro SLR is barely possible; metering will be just a guess and manual aperture will make things unbearable.

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    You can buy a Nikkor -> Canon lens mount adapter for cheap on eBay. I've tried this with a Nikkor 500 mm mirror telephoto lens and it worked great. – pixel Jul 22 '10 at 22:07
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    I think this is broadly correct, but is perhaps making it a bit more black/white than is really the case. Two quick examples: Nikon -> Canon is actually fairly popular (at least insofar as any adapter is popular), and focus confirmation adapters do exist. Until Nikon brought out its FX range, this was the only way to use some of the higher-end Nikon lenses on a full-frame digital. Anything -> µ4/3 (or similar). At least to me, it's the killer app for these cameras; adapters are made by a few major manufacturers, and they seem to sell well. – ex-ms Jul 24 '10 at 6:45
  • Oh that hugely depends on what are you shooting. Street? Forget the adapters. Macro flowers in the studio? Perfect. – egorFiNE Jul 25 '10 at 21:13

Short answer: Yes.

Long answer: But you probably don't want to. You can often make stuff like this work, but you almost always lose autofocus, aperture stop-down, and perhaps metering. If you're going to shoot a manual lens, you should buy one of the cheap classics for your system (of which Pentax has many - look into Super Takumar and SMC Takumar).


It depends on the distance between the mount and the film plane for your particular mount, you are only able to adapt lenses made for cameras with longer distances (the adapter makes up for the difference). Canon cameras can mount Pentax and Nikon lenses, Nikon cameras can mount Pentax lenses, but Pentax cameras cannot mount either Nikon or Canon. Any adapter will also make you lose autofocus, and you probably lose metering and auto-closing of the diaphragm, too, meaning you have to stop down the lens before each shot (or try to frame and focus with a darker image).

TL;DR: You usually can adapt, but you lose quite a lot of functionality if you are used to auto-focus, auto-metering, auto-everything SLRs.


There are converters available but they are not ideal, not all that common and probably not worth it. You would lose some of the functionality in the lens such as auto-focus.

Not sure what you mean by the "lens brand issue"? When you choose a DSLR manufacturer you are investing in a system. Any of the big manufacturers will have all the lenses you will need, plus there are third party manufacturers such as Sigma and Tokina.


Some older Nikkor lenses can be mounted on a Pentax body (I know somebody who does just that with a K-x), but in general there is little reason to do so. However, as Pentax shooter myself (K20), I have to ask why you think you will switch platforms? If you seriously feel that this will happen, then you probably should look at Canon or Nikon, but I think you'd be selling Pentax short. Sure, it's not as big as those two, but it's actually older and you can mount their entire lens history (which is highly regarded) to their cameras, though M42 will require an adapter that's easily purchased.

Anyways, the K-x is a very good camera, great at high ISO (up there with full frame options) that will serve you well for years and the price is fantastic.

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