[TomB_tx]

The definition of Ultra wide has changed a lot over the years. The first 28mm lenses for 24x36 were called ultra wide, since the wide option before that was 35mm. In the 1960s 20 or 21 was as ultra wide as anyone wanted. My Pentax-M 20 f4 is still wide enough for me on FF, but it was lacking on the K-5. I use the 20 a lot on my A7.
Voigtlander now has a 10 mm too ultra wide for the A7 series and for Leica mount. Their 15 mm for these cameras was too wide for me to use, but tastes vary.
Waiting for a Pentax FF I gave up and got the A7. It does all I want.

[dakotapix]

Yes, that's true for the center of the image. But that's not necessarily true for the edges. I've been looking at some FF images taken with the FA 20-35, and while the center of the image is definitely sharper than what I could get with the DA-12-24 on APS-C, the edges are not as sharp. Outside the APS-C crop, the resolution of the FA 20-35 seems to fall off a cliff. If you're a landscape photographer, the primary reason you would migrate to FF would be for the added resolution. But if you can't improve resolution across the entire frame, what's the point?

I wouldn't argue that options for full frame are better than APS-C; I'd certainly welcome more choices, and it sounds as if this may improve a little bit over the next year or two. My very limited point was that there's more to parity than FOV, and you seem to agree with me. Although the currently available selection of lenses at a palatable price/performance/feature point may be less than desirable, there is a path to excellent performance for those who can afford it.

FWIW, at f/5.6, my A 24mm f/2.8 is still noticeably better on the edges than my DA 15mm f/4 or my DA 16-45mm f/4. That's at the K-5/K-1 pixel pitch. I'd still be interested in seeing comparisons from a K-3 (although more pixels won't help the limited on the edge, lol).

[Timd]

I suspect the OP asserted a bit more than that. For a long time we've been hearing about the advantages of FF in terms of wide angle photography. Wide-angle lenses for FF tend to be cheaper (especially legacy WA's) and they will of course perform better (at least in terms of center sharpness). For example, you can purchase an old M 28 f3.5 for around $60. The closest you can come to that FOV on APS-C is the DA 21, which is considerably more expensive (used prices approach $300). Is the DA 21 a better lens? Yes. But on FF the M 28 will outresolve the DA 21 on APS-C.

Yet despite this seeming huge advantage for FF, right now (and at least for the immediate future) K-1 landscape photographers are really struggling to find viable wide angle solutions, especially once they wish to go wider than 28mm.

Thanks, Northcoastgreg, you're correctly encapsulated what I was trying to express. My apologies for being a bit vague.

It has been an interesting thread. I now realise the expectation of wide angle has moved.

While UWA (8-15mm on APC) is a niche, it is one I enjoy. While I have a FA*24f2 and my Sigma 10-20 (which I can use in crop mode) I would love a FF 14mm. For UWA, manual focus is probably best..

(LBA, you cruel mistress...)

[ScooterMaxi Jim]

Some of the old UWA primes were pretty good, at least in the center. Very few of the UWA zooms from the film era were good - center or corner, even stopped down. I say this as someone who likes many old lenses that perform nicely on digital. Wider than 24mm on FF was a real design challenge back in the previous century.

I realize that several DA lenses perform quite well on FF, but none of the UWA lenses designed for crop are good on FF (unless you are using crop mode setting - which kind of defeats the purpose of what Timd in asking).

A fantastic amount the R&D went into the crop UWA zooms that came out as the dSLR era emerged. Not so much has happened on the FF front more recently. It is clear that the Tamron/Pentax 15-30 will be very good, but that's a far cry from 12mm and it will be costly and heavy. For the K-mount system, you could go with one of the various third-party manual focus prime UWA lenses (typically sourced from Samyang).

As for something similar to the very fine crop Sigma 8-16 in FF K-mount the Sigma 12-24 is your only really comparable option. The lens can be quite good, or very bad depending on the sample (I've had both - obviously returning the bad one which I hope got fixed before going out in that final refurb liquidation sale). So, the 12-24 is a good option, as long as you have it set up with the ability to return a bad sample.

[Kerrowdown]

I must admit I find my "Mistress" is plenty wide enough.

[gaweidert]

My DA 12-24 works good form 18-24mm.

Below is a shot I made while fooling around with a Polar (Samyang) 18-28mm zoom I purchased in the duty free shop at Kimpo Airport in Korea in 1994 or so. It was all of $120 US new. When I tried it on my Ricoh XRM at the time I was surprised at the results. Pretty good. This is at the 18mm setting on my K1. Maybe because I had such low expectations of it I was surprised at how good it actually was. Pretty sharp in the center with expected image distortion, CA, PF etc as you neared the edges. But it is usable in certain situations.

[UncleVanya]

I must admit I find my "Mistress" is plenty wide enough.

Most of us lose track of which lens is called what in your harem. Which is that?

[jlstrawman]

Most of us lose track of which lens is called what in your harem. Which is that?

Listed in his signature.

[UncleVanya]

Listed in his signature.

Had those off - thanks for the reminder that resolved my confusion.

[Kerrowdown]

Most of us lose track of which lens is called what in your harem. Which is that?

It's wot he said... jlstrawman.

[Kerrowdown]

Had those off - thanks for the reminder that resolved my confusion.

Now I can understand why... the harem does take some remembering at times and requires control all the time.

[RobA_Oz]

If I'd never had the Sigma 8-16 for APS-C, I'd probably not have thought much about needing anything wider than my FA20 on 35FF, in spite of also once having had the 10-20 Sigma. However, for the number of times I'd need something that wide, I would probably just revert to crop mode on the K-1, and put up with the lower pixel count, in comparison with using it on the K-3.

The sheer price of the D-FA15-30 is daunting, especially given that the equivalent in APS-C is the Sigma 10-20, which is about a third of the price, and the 15-30's widest FoV on 35FF is still not in the same street as that of the 8-16 on APS-C. All this deliberately ignores any low-light potential and DoF (barely arguable at this end, anyway) factors.

Then again, I really bought the K-1 to allow my old film glass to realise its original FoV on digital. I'm enjoying the FA31 anew, and even the humble FA20 is no optical slouch, so I should be content. And I am, except for that little itch that a MF 12 or 14 might just scratch...

[infoomatic]

I would love to see some comparisons, especially edge sharpness, are there any owners of both M20 f/4 and the new dfa 15-30? ... If the latter was an f/4 or even an f/5.6 lens I would buy it in a hearbeat, I just don't need the weight of an UW-f/2.8 zoom and I am still not convinced that the dfa is worth the money compared to my M20 I already own.

[Sandy Hancock]

My DA 12-24 works good form 18-24mm.

Those corners are *very* dark. Usable, but not fully full frame compatible....

[gaweidert]

Those corners are *very* dark. Usable, but not fully full frame compatible....

That shot of my sun room was made with my old Polar 18-28mm lens.