[Sylwester]

I want a wery wide angle lens for my fresh new K-1, and i just need to confirm:
- Sigma 10-20 f3,5 covers FF from 14mm
- Pentax 12-24mm covers FF from 16 mm
- Samyang 14 mm is very "fishy"
- Pentax D FA 15-30 is expensive
Am I correct?

[clackers]

The Samyang is rectilinear.

[bm75]

Sigma 12-24 (it's not in your list) is FF. But I don't have any personal experience with that lens.

[rawr]

The Samyang is rectilinear.

Absolutely. A great FF lens, and not at all 'fishy'.

[Na Horuk]

Samyang 14mm is rectilinear and it is FF compatible. It is great in that respect, and very sharp. But it has its downsides. There is some distortion on APSC, so I assume it becomes more apparent on FF. You can use a lens profile to correct this in PP. But it also depends what kind of shots you are taking - sometimes the distortion will be more apparent than others, depending on the subject.
Other downsides are QC (miscalibrated distance scales, decentering) and lack of filter threads (and the lens cap, I guess. Its a bit awkward, but that is not so unusual at this lens size).

I don't have experience with the other lenses, but yes, those are the main FF UWA candidates. You can also look for Zenitar 16mm fisheye, or some of the legacy UWA lenses. There are a few in the range from 15mm to 25mm, from Sigma to Zeiss to Voigtlander and of course Pentax.
Note that FF will give you a wider FoV already, so even 35mm will be wide angle. 28mm even moreseo, and 24mm begins UWA range. So even something like Samyang 24mm f1.4 or Sigma mini wide or Pentax FA 24mm can give you really wide FoV. Sometimes people get obsessed with ultra ultra wide, but then once they get it, they notice how many limitations it has. I don't know how much experience OP has with UWA, but I would recommend starting with 28mm, 24mm. On FF, that is plenty wide.

Edit: And isn't there a Tamron 10-24mm? Not sure at what focal length it covers FF, if ever. Here is a comparative review of APSC UWA zooms: https://www.pentaxforums.com/reviews/pentax-12-24mm-lens-comparison/introduction.html?src=lrdb
Some people buy Samyang 8mm, which is an APSC fisheye, then remove the hood so the image circle is as big as possible. This modification is especially popular with Canon users, I think. Feel free to search for it

Irix and Laowa are going to release some ultra wide Pentax lenses soon. 15mm macro, 12mm with zero distortion. Definitely interesting lenses, not sure if they are available yet, but feel free to preorder. Irix comes in two versions, but with same optics.

Of course, you can also look at Ricoh Theta 360 for.. not only ultra wide, but ultra widest! As it captures 360 degrees, everything. But yes, get that Samyang 14mm. It is very sharp and quite great overall, just make sure you get one with warranty and double check for decentering. Samyang lens club here: https://www.pentaxforums.com/forums/122-lens-clubs/137335-samyang-lens-club-38.html
Many samples of various Samyang primes, but most of them from APSC cameras

[interested_observer]

With the Samyang lenses you have a couple of additional options

• Samyang 14mm Ultra Wide-Angle f/2.8 IF ED
• Samyang 16mm f/2.0 ED AS UMC CS
• Samyang 10mm f/2.8 ED AS NCS CS
• Samyang 8mm Ultra Wide Angle f/3.5 Fisheye
• Samyang 12mm T3.1 VDSLR Cine Fisheye

Irix indicates that they are going to have a new lens for Pentax coming out soon.

• Irix. Prepare for more

There are also the Pentax K, M, A, F and FA lenses.

• 15, 17, 18, 20, 21, 24, 28 mm across the various lens lines

• Pentax Lenses - Pentax Lens Reviews & Lens Database

There are the Zeiss ZK lenses - also the ZS (M43 lenses)

• ZK Lenses | ZEISS United States
• ZK 21mm/f4
• ZK 25mm/f2.8
• ZK 28mm/f2.8

You also have the older Contax Zeiss lenses that can be remounted to the K mount using the Leitax.com remount kit (need the mm version of the C/Y mount)

• Contax Zeiss 18mm/f4
• Contax Zeiss 21mm/f2.8
• Contax Zeiss 25mm/f2.8
• Contax Zeiss 28mm/f2.8

Also, Leitax.com is coming out with a mount kit allowing Nikon lenses to be natively mounted to Pentax bodies. They say it will be available in a couple of weeks....

[Na Horuk]

With the Samyang lenses you have a couple of additional options

Note that 10mm and 16mm are APSC. 8mm fisheye is APSC, but some still use it on FF once they remove the hood. The 12mm is not even available in Kmount if I remember right. Edit: Double check before purchasing, as I found some conflicting info online about this. Looks like there are two 12mm, one for mirrorless (rated f2), and one for APSC DSLRs (rated f2.8)

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Last edited by Na Horuk; 06-18-2016 at 06:00 PM.

[interested_observer]

Note that 10mm and 16mm are APSC. 8mm fisheye is APSC, but some still use it on FF once they remove the hood. The 12mm is not even available in Kmount if I remember right. Edit: Double check before purchasing, as I found some conflicting info online about this. Looks like there are two 12mm, one for mirrorless (rated f2), and one for APSC DSLRs (rated f2.8)

Thanks!! I was going to go back and correct it, but my wife asked me to go run an errand.

[dave2k]

I'm in a similar situation as I am also looking for a very wide angle lens for my K-1 without breaking the bank on the Pentax 15-30. I thought the Sigma 10-20 would be more useful than my Sigma 8-16, which hasn't been mentioned as a candidate, because the Sigma is not as wide and it has a removable hood. I just took a few test shots and it seems the 8-16 may be better suited to FF. Both 14 mm shots below are straight out of the camera except for resizing.

Sigma 10-20 4-5.6 at 14 mm


Sigma 8-16 4.5-5.6 at 14 mm


I'm not sure what to make of this discovery, but I will be conducting more testing.

[Sylwester]

I had K-5 and Sammy 10mm 2.8 ED etc.. I was very satisfied.
Any similar lens? 14mm Sammy?

[Adam]

If you're on a budget, the F 17-28mm fisheye might be a good choice. It can easily be de-fished toward the wide end, and the image quality is pretty good. That said, if you do a lot of wide-angle shooting it might be worthwhile to save up for the 15-30mm.

[kooks]

Pentax 10-17mm fisheye works very well with FF from 14mm to 17mm .. Wide enough.. and its only around $350

[elho_cid]

I'm currently using a FAJ 18-35, which is small, light and cheap, but has its limits regarding corner image quality. I don't want the 15-30, it is too big and expensive. What I want is a decent f4 ultra wide angle zoom. FF alternative to the excellent DA12-24. Just that.

[VoiceOfReason]

The Sigma 12-24 works great on it.

[Na Horuk]

I'm telling you guys, Peleng 8mm fisheye, Zenitar 16mm fisheye, Samyang 14mm Or wait for Irix 12mm and Laowa 15mm and Laowa 12mm.
VoR mentioned Sigma 12-24mm: Sigma 12-24mm F4.5-5.6 EX DG Aspherical HSM Lens Reviews - Sigma Lenses - Pentax Lens Review Database