[sheld]

I was thinking of getting an ultrawide rectilinear lens.
What are folks opinions of the Pentax 12-24mm F/4? Are 2nd hand copies usually pretty good?
The other lens I was looking at was the Rokinon/Samyang 10mm F/2.8, but it is harder to find used.
Then there is the Sigma 10-20mm; Sigma 8-16mm; Tamron 10-24mm; I've heard the Tamron 10-24mm doesn't have great image quality and the Sigma 8-16mm is pricey.

The widest rectilinear lens I have is the Pentax DA15mm. I own the Pentax 10-17mm fisheye, which I use a lot.
- Sheldon

[roberrl]

I had the Sigma 10-20 older version with variable aperture and was very happy with it. I traded up to the 8-16 to get a bit more space and am equally happy.
Recently acquired a 10-17 (Samsung variant) which I'm still getting used to.
The older 10-20 is often available for not a lot of money and will probably give as good an image as the 10-17.
Can't comment about the Pentax.

[house]

I've had the 12-24mm Pentax for a couple of months. It's quite good optically, much better sharpness than the 15mm towards the corners. You can find mtf charts of the Tokina version. The downsides are a somewhat flatter rendering, it doesn't pick up all the subtle colour changes the da15 does, and *epic* purple fringing.

For me another downside is that it's a zoom, it affects the handling in a negative way imho. I got mine, really cheap second hand, to see if I could work with zooms again. I was actually looking at the da 11-18 but couldn't spend that amount of money knowing I don't really like zooms. It has diminished my lust for the 11-18.

[blackcloudbrew]

I don't have the Rokinon 10mm. (I have quite a number of UWA lenses but not that one.) I do have the DA 12-24 (actually I have the Pentax rebranded Samsung 12-24). Until I got my K-1, it was always my favorite UWA zoom for landscapes. An old article here DA 12-24mm vs Sigma and Tamron 10-24mm Comparison Review - Introduction | PentaxForums.com Reviews did what I felt then and now as a very good review of the Sigma, Tamron, and Pentax UWA zooms in 2012. You may find some answers in that review.

I also have the Sigma 8-16. It's really quite a different lens than the three lenses described in the review. Great lens, but really, really wide.

You might also check out the Laowa Venus 12mm f2.8 as an alternate to the Rokinon. It's an awesome lens for both APS-c and full frame.

Happy deciding.

[nicolpa47]

After reading the comparative review referred to above, I bought the Tamron 10-24 as I didn't want to spend too much on a wide angle lens such as I had little used in film days. I have found that I have used it a great deal, and when stopped down I find the image quality acceptable for me. The review did mention that there was an issue with flare, and I do find this an occasional restriction on its use. I often find the Pentax 18-135 will handle similar lighting much better.

I had thought of buying the Pentax 12-24, but I would miss the extra coverage and the 11-18 is too pricey for me.

[disasterfilm]

I've got the Rokinon 10mm, and I've had both versions of the Sigma 10-20. Never shot the Pentax DA 12-24 though.

If you want to have the flexibility of filters, I recommend either version of the Sigma's. I like the 10-20 f/3.5 HSM version a bit more, but that's probably because that's what I'm carrying around now - and the photos look better because I'm better than when I shot the variable-aperture older model.

If filters aren't a concern, and you want to shoot corner-to-corner sharpness at more open apertures (say f/4), the Rokinon is a great pickup. Someone sold one in the marketplace for relative peanuts recently, and there are other copies out there for $200ish.

[Biff]

I like the 12-24: sharp and has great colors. Don't know about the others.

[beachgardener]

One thing for sure the 12-24 is not a portrait lens.

[tokyoscape]

The widest rectilinear lens I have is the Pentax DA15mm. I own the Pentax 10-17mm fisheye, which I use a lot.

I was in the same boat late last year. I used to have the DA15 and now use a lot of 10-17. I was looking at 12-24, Samyang 10, Irix 11 (FF lens).
the 12-24 was my first choice and I jump on the first one I saw on this site but the guy doesn't want to ship outside of his country and it turns out to be very good for me because after I research more on another alternative, I actually like Samyang 10 f2.8 more than the 12-24 and I think the new one is not too expensive. it is about the same or a bit cheaper than DA 12-24 used, But both of them are not a Weather-Sealed lens.
Then the Irix 11 Firefly is not Weather-Sealed at the Front Lens Element only. I can live with that and the price point is very very attractive. But it is f4 so it is slower than Samyang 10 f2.8 and both are manual lenses. Not a big problem for ultra-wide, IMHO.
So I go back to I ask myself why do I want a new ultra-wide?
I want a non fisheye 10-17 + WR, that is what I want. But then look at the 10-17, I can defish it at 10mm if I want to. With the right post-processing technic, it is still good enough for me. And all the other option comes with no WR but only DA11-18. I am not going to carry something that heavy.

So what is my conclusion? I am still stuck with 10-17!
Not sure if that helps?

I think Irix 11 Firefly is what I will go with if I had to buy one.
I just feel like, well, I could be wrong and I demanding too much but it size+weight and it is f4 make me feel like it is not enough to call an upgrade from my 10-17.

[ramseybuckeye]

I had the Tamron 10-24 and used it quite a lot until I got the DA 15. The Tamron does flare quite easily if a light source is in view. There is quite a lot of distortion at the wider focal lengths. It's not a bad lens though and you can get some good results. The example below at 10mm shows the strengths and weaknesses.

[northcoastgreg]

I own both the DA 12-24 and the Rokinon 10mm. Optically, the lens are pretty close: about the same in terms of sharpness, with the 12-24 enjoying a slight advantage in contrast and color rendering. I originally had planned to take care of my UWA needs with the DA 15 and the Rokinon 10, but in use in the field, I found that I was swapping the lenses too much and so decided to get the DA 12-24. And that's why I would recommend the DA 12-24 over the Rokinon 10mm. The 12-24 is just so much more versatile. And it's smaller and doesn't weigh as much and is AF.

Reflection Lake with the Rokinon 10mm:



Sunrise on Humboldt Bay with the DA 12-24:

[dms]

The above example (by Ramseybuckeye) shows the "distortion" at the periphery (lights and drum strongly oval rather than round) but in reality that is not a distortion, but a result of the geometry, at the extreme angles the curvature is affecting the image which is mapped onto a flat surface. It is this effect that (for me) makes the image from a fisheye lens, after pp with fisheye-hemi software, so useful--namely that it is "visually" fixed to what we would "like" to see. (That and the wider coverage of FE for the same FL lens.)

[sheld]

I own both the DA 12-24 and the Rokinon 10mm. Optically, the lens are pretty close: about the same in terms of sharpness, with the 12-24 enjoying a slight advantage in contrast and color rendering. I originally had planned to take care of my UWA needs with the DA 15 and the Rokinon 10, but in use in the field, I found that I was swapping the lenses too much and so decided to get the DA 12-24. And that's why I would recommend the DA 12-24 over the Rokinon 10mm. The 12-24 is just so much more versatile. And it's smaller and doesn't weigh as much and is AF.

Great pictures! Do you think 10mm rectilinear APS-C is so wide that it is rarely useful? I didn't realize the Rokinon 10mm was also heavier than the Pentax 12-24mm. I do like the compact DA15, but you have to be aware of its curved focus field which makes it harder to get the corners in focus. And I already have the 10-17mm fisheye. I wish I could rent/borrow an ultrawide rectalinear and get it out of my system.

[northcoastgreg]

Do you think 10mm rectilinear APS-C is so wide that it is rarely useful?

Yes, I do tend to think that. It can be pretty challenging to find compelling images at 10mm. That's why in these more extreme focal lengths it's often better to have a zoom. That's true even with a lens like the DA 10-17. It's just a lot easier to shoot that lens than a fisheye prime, because zoom flexibility allows for so much greater flexibility. And with ultra-ultra rectilinear primes, while it's true that they keep your straight lines straight (or close enough), it doesn't always lead to images that look natural to human perception. Depending on whether you point the lens up or down, you can get all kinds of weird and unnatural looking keystoning effects.


A couple of other images from these lens, first from the DA 12-24 @18mm:





And the Rokinon 10mm:

[kh1234567890]

What are folks opinions of the Pentax 12-24mm F/4? Are 2nd hand copies usually pretty good?

Mine was second hand ...

Flickriver: Photoset 'SMC Pentax DA 12-24mm f4 ED AL (IF) Set' by kh1234567890