[Fenwoodian]

I currently shoot Pentax, Fuji X, and Nikon camera systems.

I regularly use some of my Pentax K mount lenses on my Fuji X body (with an adapter). Frankly, some of my Pentax glass looks really terrific on my Fuji X-E2 camera!

I have read that Nikon F mount lenses (aka Nikkor lenses) will "sort of" fit onto a Pentax K mount body. Today was a sunny warm spring day here in northern Wisconsin USA - so I thought I'd put some of my Nikon F mount lenses on my Pentax K3ii body to see for myself how this combo really works.

I tried out the following two classic old manual focus Nikkor lenses: 75 - 150mm f/3.5 AIS ; and 105mm f/2.5 AI. Please note that both of these lenses have aperture rings (the newer "G" type Nikkors without aperture rings would not work). I shot in the "A" mode, and did not have to use the "green button" technique. Also, all shots were handheld.

Some things that I learned in this short test were that:

1. The Nikon lens must be put onto the Pentax body with extra care. The alignment holes are a little bit off, but once you do it a couple times it's really easy to do
2. The Nikkor lens does not "lock in place". I turned the Nikkor lens only enough until it was "snug" on the K mount.
3. The Nikkor lenses were extremely tight on the mount, no wobble or play at all. In fact, the Nikkor lenses were on the mount tighter and had less play in them then any of my Pentax K mount lenses have!
4. Auto focus does not work. Also the image file does not record what the aperture and shutter speeds were
5. Upon removing the Nikkor lens from the K3ii, I saw no damage what-so-ever to either the lens or the body
6. Both lenses focused perfectly at infinity
7. The keeper rate was about the same as the keeper rate I have when using manual focus Pentax lenses
8. The sharpness of the images taken with the Nikkors was just as good as the sharpness I achieve using my best Pentax K mount lenses
9. I will not be mounting any of my "larger/heavier telephoto" Nikkor lenses onto my K3ii body because the mount is not as secure as when mounting Pentax K mount lenses onto this body
10. While the Nikkor lenses fit extremely snuggly onto the K3ii, they do not "lock in place". So when using Nikkors on Pentax bodies the photographer needs to be "gentle" when handling the rig. In the past, I'd often mount a lens on a camera body and then mount the camera onto a tripod and hike and climb with this rig over my shoulder - I would never subject an unlocked Nikkor lens on a Pentax body to such extreme shaking/vibration/rough-handling.
11. I have no idea how well Nikkor lenses will fit onto other models of Pentax bodies. However, I would guess that the experience would probably be pretty similar to my experience with my K3ii body

Below are a few of the photos that I took today with my two Nikkor lenses on my K3ii body. All I did in post to them was to resize them and give them each a little sharpening.

Based upon today's test, I would not hesitate to use my lighter weight Nikon F mount lenses (with aperture rings) on my Pentax K3ii in the future. Doing so might not be for everyone, but if you are a slow and deliberate photographer (like I am) and enjoy using manual focus lenses you just might want to give it a try too.
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Last edited by Fenwoodian; 11-14-2016 at 08:49 PM.

[Adam]

This might also be of interest to those who want to adapt older Nikon lenses:

Pentax K+ Multi-Mount - Influential Photo Gear | PentaxForums.com

[Fenwoodian]

This might also be of interest to those who want to adapt older Nikon lenses:

Pentax K+ Multi-Mount - Influential Photo Gear | PentaxForums.com

Interesting link Adam. But this technique appears to involve removing and grinding down your own cameras' mounting ring. I don't think that I'll be doing that to my newish K3ii. Would making this type of home-made modification void the warrantee? How it might adversely affect the ability to properly mount my Pentax K lenses onto this modified mount.

This technique is not at all precise. The article says that "trial and error is definitely required". If I had an inexpensive Pentax body like the developer of this modification had, I too might be more prone to doing experimental self-modifications to it - but not to a newer/expensive Pentax body.

For occasional use of Nikkors on a Pentax body, directly mounting the Nikkor onto an unmodified Pentax body (as I described above) would probably be preferred by most photographers to a "do-it-yourself hack job" to a beautiful and expensive camera.

[boriscleto]

Interesting link Adam. But this technique appears to involve removing and grinding down your cameras' mounting ring. Sorry, but I don't believe that I'll be doing that to my newish K3ii. It might voids the warrantee; and who knows what it might due to the precise alignment needed for a good mount with a lens.

For occasional use of Nikkors on a Pentax body directly mounting the Nikkor onto an unmodified Pentax body I would think would be preferred to a do it yourself hack job to a beautiful and expensive camera.

The guy who wrote that article started a company to make them.

Adaptist - Home

There is a version for WR cameras, but it makes the camera less than WR. You have to break the seal on the lens mount and there is no room for a replacement with the multi-mount. He used to have a version for non-WR cameras, but he has discontinued it.

I'm disappointed that he discontinued the non-WR version, I had been thinking about buying one for a film camera or a K-x. I was even considering a *ist DS.

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Last edited by boriscleto; 03-29-2016 at 08:35 PM.

[Adam]

Interesting link Adam. But this technique appears to involve removing and grinding down your own cameras' mounting ring. I don't think that I'll be doing that to my newish K3ii. Would making this type of home-made modification void the warrantee? How it might adversely affect the ability to properly mount my Pentax K lenses onto this modified mount.

This technique is not at all precise. The article says that "trial and error is definitely required".

For occasional use of Nikkors on a Pentax body, directly mounting the Nikkor onto an unmodified Pentax body (as I described above) would probably be preferred by most photographers to a "do-it-yourself hack job" to a beautiful and expensive camera.

Yes it would- I wouldn't recommend converting current bodies But it's nice to do with a K-50 or something like that, to experiment with other lenses.

[Fenwoodian]

Yes it would- I wouldn't recommend converting current bodies But it's nice to do with a K-50 or something like that, to experiment with other lenses.

I totally agree!

Maybe I'll buy an old, inexpensive body and try this modification to it.

If it works perfectly on the cheap body, I may try it on my K3ii....