[Mtathos]

I have a Pentax K-70 however i am waiting for the Pentax K-1 mark 3 at which point I’ll jump to full frame. In the meantime, I'm hesitant on buying Apsc specific lenses because I’ll eventually need to sell them at a loss and buy the full frame equivalent. Right now I’m looking at the DA*11-18 F2.8 ED DC AW however I was wondering, if in fact, I should be looking at the D FA 15-30mm F2.8 ED SDM WR considering my desire to move to full frame once the K-1 mark 3 is released (hopefully it will be). Is anyone shooting with the 15-30mm on an APSC camera that can give me with the pros and cons? Does this even make sense? Thanks in advance for your valuable inputs. Merry Christmas and happy holidays to all.

[Wasp]

I do not own any of the above, but it seems to be that you will be losing out on a lot of ultra wide goodness by going with the D FA 15-30. The DA* 11-18 for crop frame goes a lot wider (and I mean a lot) for about the same money. As a bonus it is 30% lighter.

As an aside, that K1 III is (probably) a long way off, but it is a topic already covered elsewhere.

[biz-engineer]

11-18 and 15-30 is not the same on apsc. 11mm is ultra-wide, 15mm is almost the same at shooting with a da*16-50 at the wide end.
About the K1 III, even having a K1 and K1 II currently, I've put all my lens purchase decisions on hold until we get the specifications and price of a Pentax K1 III if there will be one.
I'm saving money and keeping a close look on Nikon Z8 rumors, if the Z8 come with the right specs for me, and at the time of Nikon Z8 release we still know nothing about K1 III, I'll switch to Nikon.

[zapp]

The DA* 11-18 works fine on FF from 15-18 mm. It was not designed for that, but it works and it is much smaller than the 15-30. The 15-30 requires extra large filters and is not handy. Still it is fun to use on FF, quite a large lens for an apsc body.
The 21ltd works on both systems. Pentax is updating the zooms on apsc and the fixed focal length lenses on FF if we look at * glass or even Ltd glass.
A used K1 could be the better option here. You will get the lenses you want much sooner and still not lose that much money.

[JensE]

I am using the 15-30mm sometimes on APS-C (KP with battery grip), but only because I don't own a 'standard' f/2.8 zoom lens for it and occasionally need one indoors. It reaches from very wide to 'perfect normal' perspective, but is of course extremely bulky compared to even the new DA* 16-50mm PLM, making it fairly intimidating. It's no substitute for an ultra-wide lens. For the K-1, if I had not already purchased it, even though the DFA 15-30mm is optically very good and versatile, I would reconsider, because a set of primes seems to be more fitting for my needs and there is a good selection covering the range by now, including the wonderful DFA 21 Ltd.

So if you intend to stay on APS-C for a while or you are considering to keep your camera in parallel, go for the 11-18mm. The 11mm - 15mm range is where the ultrawide magic happens, 15mm - 18mm is merely very wide.

[acoufap]

I am using the 15-30mm sometimes on APS-C (KP with battery grip), but only because I don't own a 'standard' f/2.8 zoom lens for it and occasionally need one indoors. It reaches from very wide to 'perfect normal' perspective, but is of course extremely bulky compared to even the new DA* 16-50mm PLM, making it fairly intimidating. It's no substitute for an ultra-wide lens. For the K-1, if I had not already purchased it, even though the DFA 15-30mm is optically very good and versatile, I would reconsider, because a set of primes seems to be more fitting for my needs and there is a good selection covering the range by now, including the wonderful DFA 21 Ltd.

So if you intend to stay on APS-C for a while or you are considering to keep your camera in parallel, go for the 11-18mm. The 11mm - 15mm range is where the ultrawide magic happens, 15mm - 18mm is merely very wide.

+ with the DA*11-18 at FF you can go below 15mm if you decide to use Square Mode or Crop to by example 4:3 aspect ratio. The DA*11-18 offers more flexibility than the DFA15-30 on ultrawide territory whereas you get more versatility with the 15-30 above 18mm.

[Oldbayrunner]

When I still had my Apsc cameras I considered the Sigma 10-20mm an awesome wide angle for that system. Now that I am strictly FF I have the 15-30mm, yes it's big, yes it can be slightly cumbersome, yes it takes an entirely different filter holder and filters, would I use it on an apsc......no........ but it has become my most favorite lens for my shooting needs along with a couple others I own on my FF.

[UncleVanya]

@Sandy Hancock has carried his 11-18 with his k-1 before due to the size and weight of the 15-30. The 11-18 can be used at the long end with excellent coverage on ff. This gives you a very wide option even on ff - although more like an 18mm prime than a zoom when used this way (it might cover a little wider I don’t recall). On apsc it’s very very good. The 11-18 also has a filter thread which the 15-30 does not.

Other options: Pentax SMC DA 12-24/4. This lens covers apsc but does also cover ff from around 20-24mm. It’s not as sexy, but it does a pretty good job. The da 10-17 fisheye also covers ff at the long end. The lens doesn’t have as much fishy perspective at the long end and can be defished using software. There’s also a few older wide angle options that cover ff starting around 12mm.

My advice… if f4 is doable, buy a used Pentax 12-24 for now, then see what the future brings in terms of ff.

[AfterPentax Mark II]

In the meantime, I'm hesitant on buying Apsc specific lenses because I’ll eventually need to sell them at a loss and buy the full frame equivalent.

That is a good reason to limit your hobby to working with APS-C. If you were to start from scratch you might consider buying FF, but seeing you already invested in APS-C it is a ridiculous thing to do. And by the way: the 11-18 is a fabulous lens!

[btnapa]

Does this even make sense?

K1 and K1 II are fantastic cameras and available now. Why not get a used K1 with the 15-30 and later on add the K1 III if and when it shows up. I had the K1 and it is a beast of a camera. I never bought the 15-30 but used an old Tokina 20-35 with great success. I chose the Tokina because it takes filters easily. Not so easy to use filters with the 15-30. If you are not a filter user, go for the 15-30.

[biz-engineer]

K1 and K1 II are fantastic cameras and available now. Why not get a used K1 with the 15-30 and later on add the K1 III if and when it shows up.

The advantage with APSC is that there is the K3 mk III , already available in case the OP want a camera performance upgrade. And that kind of performance upgrade doesn't exist for the Pentax K1/K1 II. Problem is we have neither evidence, nor hint that Ricoh will produce and sell a K1 III. Recent announcement was about starting a project for a film camera, not about Pentax digital FF successor.

[btnapa]

Problem is we have neither evidence, nor hint that Ricoh will produce and sell a K1 III

You are correct on that count. I say if and when because if I say only if, I would be labeled a Pentax hater and threatened to be banned from the forum. I love Pentax but the reality does not match the fantasy. I hope they release a K1III. I will be the first to get one. I was one of the first people who had a chance to see the K1 and shot with it almost a month before it was even announced to the public. I loved what I saw and placed my order immediately. I kept my Three Amigos and a few other Pentax lenses with the hope of a hi-res K1 III. Otherwise, my move to Sony/Tamron has been positive so far.

[Paul the Sunman]

The 15-30 is a very good lens, but a pain to carry, more for its width than its weight. I never use it on APS-C, preferring the very compact DA 15 Ltd. I don't have the 11-18, so can't comment there.

Actually, I don't think I ever shot with the 15-30 on APS-C. So I just popped into the next room with it on the K3iii to try it out. It's pretty front-heavy, but the images look good at 15mm f/2.8.

[biz-engineer]

The 15-30 is a very good lens

My 15-30 is soft, softer than my D-FA28-105 @ 28mm. The 15-30 is the worst lens in my lineup, really a problem for printing at A1 size because the lens isn't good enough so such enlargement, other lenses can do it. The Pentax DA* 11-18 is way better lens.

[Paul the Sunman]

My 15-30 is soft, softer than my D-FA28-105 @ 28mm. The 15-30 is the worst lens in my lineup, really a problem for printing at A1 size because the lens isn't good enough so such enlargement, other lenses can do it. The Pentax DA* 11-18 is way better lens.

Not my experience at all.