[Pan Kleks]

I own the legendary Nikkor Ai 105mm f/2.5 that I've been using on my D700. I was researching mounting brackets that can be used to convert the Nikkor to be used on Pentax cameras but I came across a post on here about a member who said he already did that and the results were just OK and that Pentax already had lenses that were even better than the Nikkor 105mm.

I would like to know if you could talk to me about some of these lenses, thanks!

[Madaboutpix]

As a start, you may want to check out the smc PENTAX-A 100mm F2.8, which seems to be the closest Pentax relative to the Nikkor, if perhaps not as legendary. But the user reviews suggest that it's a solid performer. (In fact, the lens finder tool should lead you to quite a few more options):

SMC Pentax-A 100mm F2.8 Reviews - A Prime Lenses - Pentax Lens Reviews & Lens Database

[FozzFoster]

My Pentax D FA 100mm f/2.8 Macro WR is one of my sharpest lenses I own.

I've owned the Pentax Super-Multi-Coated Takumar 105mm f/2.8 and it was a joy to use, but in M42 screw mount!
Super-Multi-Coated Takumar/Super-Takumar/Takumar 105mm F2.8 Reviews - M42 Screwmount Telephoto Primes - Pentax Lens Reviews & Lens Database

[Swift1]

The various versions of the Takumar 105/2.8 and the original K mount 105/2.8 will be similar to the AI Nikkor 105/2.5, and then the M series and A series versions of the 100/2.8 will also be similar to the Nikkor.
I've recently used both the Nikkor and the Pentax M 100/2.8 and they seemed very comparable to me.

[swanlefitte]

The 77 limited and the 6 element 135 2.5 complement my converted nikkor 105 2.5. The Pentax dfa 100 2.8 seems better than the nikkor except maybe portrait or flowers and is small with quick shift.

[Pan Kleks]

Thanks everyone for the advice. I used to own a 70-300mm on Nikon so I think I might need something longer.

What do you guys think about the SMC Pentax 200mm f4? The non M or A version that's from the 70s?

[Ray Pulley]

I own the legendary Nikkor Ai 105mm f/2.5 that I've been using on my D700. I was researching mounting brackets that can be used to convert the Nikkor to be used on Pentax cameras but I came across a post on here about a member who said he already did that and the results were just OK and that Pentax already had lenses that were even better than the Nikkor 105mm.

I would like to know if you could talk to me about some of these lenses, thanks!

This lens is not Pentax, but can be found under various brands in the K mount and seems to be well-thought of:

Vivitar Series 1 (Kiron - 22xxxxx) 105mm f2.5 (100mm f2.8) Macro Lens Reviews - Vivitar Lenses - Pentax Lens Review Database

Then there is the legendary "Bokina" by Tokina:

Tokina AT-X Macro 90mm 1:2.5 Review

I do not own either of these lenses and don't recall ever owning any of them, but they are pretty universally acclaimed, so there must be something to the reputations they have earned.

[Mans Hagberg]

As a start, you may want to check out the smc PENTAX-A 100mm F2.8, which seems to be the closest Pentax relative to the Nikkor, if perhaps not as legendary. But the user reviews suggest that it's a solid performer. (In fact, the lens finder tool should lead you to quite a few more options):

SMC Pentax-A 100mm F2.8 Reviews - A Prime Lenses - Pentax Lens Reviews & Lens Database

I used Nikon and Nikkors for quite a few years and the 105 mm f 2,5 Nikkor was super! (There are 2 versions, I had the one with a larger rear lens.) Very sharp and good bokeh. Mine had a large hood, bulky but effective. I used it on a Nikon F-3 usually with Fuji Superia negative film.


Before and after the Nikon period I used and use Pentax. I still have a Pentax SMC 105mm 2,8 m42. It is beautifully made and a joy to use. There is a K-mount version. Mine is a good lens but, I feel, not on par with the Nikkor. Perhaps better on a FF, I haven´t checked on my K-1. Some users love it, just check the review section here.