Using Pentax FA Lenses on the Sony NEX-5n by Tord Eriksson

Using Pentax FA Lenses on the Sony NEX-5n by Tord Eriksson  – Tord’s Flickr

Hi Steve,

My name is Tord S Eriksson, I am 59 years old, married, and I drive buses in Gothenburg, Sweden, but I have been around cameras much of my life, but not taken more than a few shots in my previous life as a journalist, and editor (as illustrations to articles, or photos of my interviewees).

The NEX-5n

In my twenties I had some training as a photographer, and in studio work. We students used the school’s cameras: Nikon F-1, Canon Pellix, Leica M3, and Hasselblads of various versions, including my favorite, the SWC.

We even got a chance to try the real heavy stuff, like Sinar – lovely cameras, but certainly not your point & shoot. Soon 40 years ago, but I remember those years fondly!

I got my first SLR system as a young teenager: an old Edixa Reflex (1957 version) – one of many screw-mount cameras coming out of Germany after the war, with three primes, and a Japanese zoom – very rare in those days). I bought the whole kit very cheaply from my sister’s boyfriend, who then moved up to a Hasselblad 500C). Gave the well worn kit away ages ago, after it had sat in a box for decades, together with a lot of other camera stuff.

Began my second SLR system about 40 years later: It is by now fairly complete, with zooms from 10mm to 500mm, and a respectable range of primes from 15 to 400mm (800mm using a converter).

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Various reasons, including size, weight, and price, led me to Pentax DSLRs (my first was a K-x, with the DA 18-55 kit lens). Pretty soon I learned about the famed lenses that carry the unusual designation ‘Limited’, so I started to collect a few (not that many in production).

These Limited lenses are not the fastest there are, but all really sharp, and most with a nice bokeh. There are two groups, the DA series, optimized for Pentax APS-C cameras (thus have no aperture ring), and the FA group, which is a relic from the days Pentax made full frame cameras. The FA all have aperture rings, thus can be used in manual mode, essential if you’re going to use them on another camera system.

After having read various reviews of the Sony NEX-5N, including yours, Steve, I realized that this little marvel could be a great backup, if I could find a K Mount adapter. Amazon had both very cheap, and very expensive ones, so I went the middle of the road: a Chinese adapter for about $40.

Over the last two years I’ve have got myself a nice selection of FA Limited prime lenses, actually almost all of the FA lenses still in production: the Pentax-FA 31mm F1.8 AL Limited, the Pentax-FA 43mm F1.9 Limited, and access to my wife’s Pentax-FA 77mm F1.8 Limited. There are two more: the FA 35/2.0, which is still in production, but that’s not a Limited, and neither is the Pentax-FA 50mm F1.4, which my wife owns a copy of.

NEX-5n with Pentax 31 Limited

The Limited designation is not restricted to FA lenses: A few really outstanding DA lenses also have it, like the tiny DA40, equally small DA21, and the superb DA 50-135/2.8 zoom. The FA43 is much bigger than the ‘pancake’ DA40, but also quite a lot sharper, faster, and more expensive. Like the others, the FA31 is superbly sharp, with a really nice bokeh, but doesn’t handle flare as well as most modern lenses, so not ideal for all situations!

In addition to these lenses I have two other K Mounts suitable for my NEX-5N: The Tamron SP 90 Macro, a truly classic design, and a very old Pentax-M 400/5.6, both equipped with the needed aperture rings. The 400 suffer from CA at times, but overall works superbly with the NEX!

After a lot of ‘studio’ test shots with my, and my wife’s, Limiteds (and the Tamron), using Theodore the Bear as model (he never tires), I noted a few things …


Pentax K5

Using both my beloved Pentax K-5 (my second!), and the new friend, the NEX-5N, with exactly the same lenses, at various apertures, it is evident that to get similar results you have to set the K-5 slightly lower, say -1.0 EV, or thereabout. But the K-5 can be pushed up to ISO 51200, leaving the NEX-5N far, far behind, but I did my tests from 100 up to 1600, more normal settings. All test photos are totally unedited, and you note that the AWB of the two cameras handled the light quite differently – the 5N has a yellowish tone, while the K-5 is more like my eyes saw it.

You have to have a steady hand, as neither the lenses, nor the NEX body, have any kind of stabilisation.

Or even better, use a good tripod, and a serious ball/panorama head. I used my Berlebach Reporter 3032, which has a big ball head integrated into its design, so setting it level is very easy, even on a sloping surface. You extend the legs to the approximate setting and use the spirit level to set the top perfectly level, and then tighten the clamp – as easy as it could be! I maybe overdid it slightly as I used my Wimberley WH-200 on top of that (made changing cameras so much easier).

What more to say about the NEX-5N? A little jewel of a camera, that is on par with the K-5 in most situations, and when used as a video camera, surpassing the K-5 easily! The NEX-5N is very nice to use, especially if you have the hard-to-find electronic viewfinder. The menu system is simpler on the Pentax, and I do like to have buttons to access things, like the K-5, and the NEX-7, have, but as the latter is currently unavailable.

The 5n and 18-200

The Sony E 18-200 that my wife bought for her NEX-5N is an excellent lens, even when not making videos. This lens was designed with the pro NEX video cameras in mind, so it is kind of oversize on NEX-5N. But help was at hand: For a small fee SRB-Griturn in the UK made a tripod attachment for that lens and since then attaching it on a tripod head is a simple task – the 5N isn’t quite up to being the sole support for this amazing lens.

I love the NEX-5N, and it has indeed become a perfect compliment to the K-5!


Tord S Eriksson


  1. Is there any PKA to NEX adapter made by anyone? Pentax were so far ahead of everyone else in adding data capable lens mounts that it would be such a shame to be limited to PK mount like Canon, Nikon, Olympus, Minolta (Sony) equivalents.
    I’m not thrilled with the Pentax K-01 and would love to be able to utilise my extensive PKA lens collection on a NEX camera.

  2. Nice to see the Pentax lenses getting used on other cameras. I have the K5, the FA77, DA35 Macro and the DA15. All three are excellent lenses, and make a great travel kit. I am thinking about getting the DA300 for wildlife and astrophotography with my K5.

  3. I also have a K-5 and a couple of the FA Limited. Just ordered a 5n because I am curious how well the peaking feature works. I really wish my EPM1 and GH2 had that feature (then I wouldn’t have had to buy the 5n).

  4. This was a great read. thanks for sharing your experience wit the Pentax glass. There isn’t many sites detailing the NEX 5N and Pentax glass pairing.

  5. Nice review Tord! I also own a K-5 and a Nex-3 and i am very happy with them.
    My favourite lens setup for the K-5 is with a Tamron 17-50 and various filters, and 18-55WR for rainy days. However, I am also thinking about the Pentax 55-300 and the Pentax 70, 2.4.
    Do you have any experience with these lenses?

    Ferdinand (from Hungary)

  6. I just traded my nex 5n that I praised so much for an Oly EP2 plus couple of really nice primes to go with it ;)! And I love the Oly so much more. Jpegs are beautiful and it has buttons I am so used to on a camera. ISO performance is obviously not on par but grain looks almost film like in situations. Oly files don’t look digital at all.

  7. There is a Pentax K/DA-Nex adapter on eBay which works good with DA lenses. There is a tiny screw inside the adapter which move the lever of the aperture all the way of the DA lens. So, it is possible to use the DA lenses on NEX. Search for Pentax DA-Nex adapter. I bought one from a Sweden seller.

      • You are welcome Thor. By the way, I also own a K5 and love it, I owned Canon and even a M9, sold both/all and now have besides the K5 a Sony Nex7. Hold my Leica glass, bought the Zeiss 1.8-24mm and have three Contax G2 lenses (28-45-90mm) with adapter. I can only say the Nex7 with Leica and Zeiss G2 glass is superb. The Zeiss 1.8-24mm is awesome. For the K5 I have the 4.0-300mm DA IF ED SDM and the WR 2.8-100mm macro which are both fantastic lenses. Also I use some older SMC Pentax lenses 1.7-50, 1.4-50 and 2.8-28mm, these old lenses are great on the K5. Now I ‘m in for a few limited lenses but haven’t decide which. At the Pentax forum they have a lot of serious reviews so I take my time.

  8. Interesting article, Tord. As a k5 owner it’s great to hear someone praising pentax, and the k5 inparticular. (just wish i had some of them limiteds to go with mine) !!!.

  9. The NEX-5n and the K-5 use the same Sony sensor. According to DXOmark, Pentax is able to squeeze a bit more performance out of it, especially with regards to dynamic range. Any small variations in exposure and color are simply personal preference and can be adjusting by tweaking the white balance and exposure compensation. The “F” in the Pentax “FA” line denotes autoFocus. So, unless there is some pressing issue that precludes one from carrying the K-5, you lose auto stopdown, autofocus, the viewfinder, and the on-body controls for no real gain, especially in that photo above, in which the photographer already dragged a large lens and 7-lb tripod out to a field. I guess if you want very small size, it works for you, but I don’t see the point. Thanks for the review regardless.

    • Not according to Sony sources – the 5N uses a later version, while the D7000 uses the same!

    • With the Novoflex adpater you are supposedly able to use the slider to affect the aperature – at least it works well on my wife’s E-PL1!

      • There are adapters on Ebay that do the same thing, a rotating collar to adjust aperture on the new lenses that don’t have a aperture ring. The Ebay adapters (look for Kiwi brand) are considerably less than what Novoflex offers, hundreds vs $25.

    • While I lose much control the results with the 5N, at least with the 400, the end result is better with the very much manual lens than using the K-5 in manual mode!

    • Simple. As a Pentax owner as well as a 5N owner, I can now utilize my Pentax lenses whenever I want with my 5N and also use my Sony lenses whenever I want…not able to do the same thing with my Pentax body. Secondly, the 5N with the kit lens is by far smaller and lighter than the K-5 with practically any lens in the Pentax lineup. The only downside I have experienced when using my Pentax lenses with the 5N is no shake reduction, but that is easily solved when using my Sony lenses. Other than that, bit great bodies and there are Pros for owning both or each.

  10. The K-5 with my limited (77 and 43) + a FA 24mm F2 is a fabulous setup, I’m now avidly awaiting for my next purchase the DA 50-135 to complement my setup.

    But as you do, I have old fast C/Y lenses that I’d like to use along with my K limited, and I was thinking about a NEX-5N, and your writing might just have convinced me…

    • Hope I have convinced you! I am waiting for the new mirrorless Pentax, before joining the NEX-7 waiting list!

    • The 50-135 is an awesome lens, very much prime quality! The only zoom I’ve come across that equals any Limited prime, so far!

  11. Thanks for the write up Tord. I love my K5 as well, and recently got the DA70 Limited for it. Excellent lens!! Also had a NEX5n (and 3) for about a week, but decided to wait on the 7 to become available. I suppose we can’t really use the DA lenses on the NEX given that we’d lose aperture control. I’d imagine that the DA40 would have been a nice compliment to any NEX due to its tiny size.

    • They sell adapters on eBay that allow you to change the aperture on the adapter for the DA lenses. They obviously also work for the FA lenses as well. Tried it for my DA 15 but wasn’t thrilled with the very soft corners so opted out of the 5N and Ltd lens idea. My 43 and 77 were good on it though.

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