[John Hales]

So if you can't afford the prices of the full frame lens for the K1, what other third party or older film lenses have you used with good results?

[BullsOnParade81]

Look used in marketplace perhaps.

[LennyBloke]

A great little pairing would be an FA 24-90 f3.5-4.5 and an F or FA 80-200 f4.7-f.6 - both very capable lenses, won't break your back or your bank.

[Dericali]

What are you intending to use these for? There is the tamron 70-200 which is okay and a quarter of the price /weight of the pentax.

If it's portraits you could look at some of the prime lenses, 50mm or 85.

The temptation might be to go for the 28-105mm because it's a DFA lens and it's pretty decent. But it's not really a 'pro' lens because of the variable f-stop and the bokeh at 105mm /f5.6 is not very dreamy. It's worth getting this lens if you can get a deal on it with a body, or second hand, or you would use this lens for at least a year before upgrading. (not worth getting if you'll use it for 3 months, realise its limitations and then buy the 24-70).

Have you bought the body already?

[LensBeginner]

Plenty of nice 70-200/2.8 from Sigma and Tamron, and they won't break the bank.
Make sure the sigmas are compatible though... both the AF (some need a firmware upgrade) and physical clearance (there were reports of some scratching the camera body when mounted).

[steve_k]

Considering the K-1's high iso performance I don't see why I need to buy f2.8 zoom lenses. I would probably purchase the D FA 28-105 for when I need a WR walk around. The Tamron 24-135 I already own would probably be my regular walk around lens because of its range. I might get the 3 princesses and the Irix 15mm for Astro and for when I need a larger aperture or want to shoot portraits. Don't think I would need anything longer than 135mm as I primarily shoot landscape and own a K-3 II and longer lenses for when I want to shoot wildlife.

[normhead]

Having been in that exact position, I have to say, the DFA 28-105 is a great lens. and really your only option if you want to max out the K-1 sensor. I waffled for a long time before I ordered it. The day it came, I opened the box and put it on the camera in the post office and took a few images on the way home. The very first images I took with it were impressive, and it's continued to impress ever since. To the point I almost caught myself recommending it to an APS-c user today. To me, it's the answer to "what's the best general purpose zoom in Pentax's line up?" It wins that one by a huge margin. I love it on my K-1, my wife loves it on her K-5. It's a no brainer.

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Last edited by normhead; 06-28-2018 at 02:31 PM.

[UncleVanya]

I see a lot of 28-75 f/2.8 lenses being used by some budget full frame photographers.

[victormeldrew]

Tamron 28-75 and 70-200. Sorted.

[hadi]

Tamron 70-200 2.8. Used they go for about 500 bucks.
Sigma 24-70 2.8. Used they go for cheap.

Even new those lenses are cheap

[D1N0]

Get primes. The DA 50 1.8 35 2.4 Or an older 50 1.7 D FA 28-105 is meant for lower budgets but is easily as sharp as the 24-70. Wait for the cheaper 70-200 F4 or (55-70)-300 F4-5.6 zooms. If you really want a longer zoom then You could also a Sigma or Tamron 70-300 zoom. They are very cheap..

[LensBeginner]

Considering the K-1's high iso performance I don't see why I need to buy f2.8 zoom lenses. I would probably purchase the D FA 28-105 for when I need a WR walk around. The Tamron 24-135 I already own would probably be my regular walk around lens because of its range. I might get the 3 princesses and the Irix 15mm for Astro and for when I need a larger aperture or want to shoot portraits. Don't think I would need anything longer than 135mm as I primarily shoot landscape and own a K-3 II and longer lenses for when I want to shoot wildlife.

Because some of them are quite cheap and optically very good.
Being 2.8 across the whole range can be considered a side effect.

[ChristianRock]

Sigma and Tamron both have 70-200 2.8 lenses, both aren't terribly hard to find I think. Neither is their latest design, but they should still perform pretty well especially a click down from wide open and smaller. If you want something really affordable in that range, albeit quite slower, Pentax made a lens called the F 70-210 f/4-5.6 that punches well above its weight with a very good performance, despite costing very little in the used market.

Tamron has the 28-75 2.8 that was already mentioned, and that is also usually fairly easy to find.

Sigma has a 24-70 2.8 lens that is a bit more rare, and an even more rare 24-60 2.8 (and from what I have seen, really nice and slightly superior to the later 24-70 design).

The Pentax 28-105 3.5-5.6 is also a great design that can be paired with an FA 35 f2 and F 50 1.7 or FA 50 1.4 for indoor use. Or just use a flash...

Finally, there were a few good affordable third party 17-35, 19-35 and 20-35 designs, along with the now-not-so-affordable Pentax 20-35mm f4 lens. Sigma and Tamron both released nice 17-35 2.8-4 designs that are very nice stopped down. The Tamron is better wide open than the Sigma.
Tokina had a 19-35/20-35 f/3.5-4.5 design and also a 20-35 2.8 design. The 3.5-4.5 aperture design always tested sharper stopped down than their 2.8 design, and in fact was sharper in the corners than the 17-35 designs by Sigma and Tamron, according to lenstip.com.
Pentax had an older FA J 18-35 f/4-5.6 design that produces pleasing colors and center sharpness but from what I've seen, is very weak in the edges and corners at 18mm. It does not compare favorably with the Tamron, Sigma and Tokina designs, but it's there and it costs very little (about the same as the Tokina versions).

[jatrax]

The DFA 28-105 is very good. By some reports as good as the DFA 24-70. The film era FA 24-90 is also well regarded.

[BigDave]

I have the Sigma 24-70 f2.8, macro version, a bit big (I don't mind this) but definitely a nice well built lens that gives great image quality. It is my general walkaround lens most of the time!