[bobbotron]

I have a huge appreciation for the 28mm FOV in the 35mm format. It lets you get a ton in the shot without succumbing to as much field distortion as a wider FOV. You don't need to get perilously close to things when it's your only prime with you. It's odd that 28mm was a common format in 35mm, and yet there are no 18mm primes K mount APS-C lenses. I think it would be fantastic if Pentax/Ricoh made a 18mm plastic fantastic... Anyone else feel the same way?

[lytrytyr]

There are K-mount 18mm f/3.5 primes from Pentax and Zeiss,
both made the old-fashioned way.

If you want something newer, the Ricoh GR has an f/2.8.

But I guess the DA 21 is closest to what you're asking for,
even if it isn't a plastic-fantastic.

[THoog]

While I agree that there is a gap there and a third plastic fantastic would be welcome, I think their attention for the next couple years is going to be on higher-end lenses for the FF system, not budget-friendly APS-C lenses. With the current low prices on the DA 35/2.4 and 50/1.8, I hope it is a sign that they are going to get the HD treatment and will remain as a budget option, and not be replaced in the lineup by (larger, heavier) premium FF+WR+DC equivalents.

[Sandy Hancock]

The DA21 does all that quite nicely for me, but we're all different.

[Alex645]

You have an excellent point in that 28mm was probably the default wide angle prime on 35mm. Why there isn't an 18mm for APS-C prime is probably just a perceived lack of need from marketing. On some lens tests, I've noticed that some brands have designed their zooms to be sharp at the extremes (18mm and 55mm) instead of in the center around 35mm. 18-55mm kit zooms are already small, and have a larger aperture for a wide is not a priority.

Most everyone has an 18-55mm kit, so maybe they'll go for wider than a wider to longer zoom like the 16-85mm or they'll settle with the more extreme or more normal primes. And then the wide angle enthusiasts usually go for the 10-18mm or 10-20mm zooms.

My first wide angle lens was a 28mm prime for 35mm film, but as soon as tried a 24mm and then a 21mm, I never went back to 28mm. So that's my best guess to answer your question...it's just doesn't have the attraction of 16mm or less, nor the normalcy of a normal. Of course a true purist can get their 18mm prime from a Zeiss Distagon f/3.5, but it is surprising that Sigma hasn't created an Art lens in this focal length.

[normhead]

The Sigma 8-16 has no field distortion until 12mm. That's what you're looking for.

[fuent104]

I have a huge appreciation for the 28mm FOV in the 35mm format. It lets you get a ton in the shot without succumbing to as much field distortion as a wider FOV. You don't need to get perilously close to things when it's your only prime with you. It's odd that 28mm was a common format in 35mm, and yet there are no 18mm primes K mount APS-C lenses. I think it would be fantastic if Pentax/Ricoh made a 18mm plastic fantastic... Anyone else feel the same way?

I agree. The lack of a 28mm equivalent prime is no good.

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Last edited by fuent104; 02-02-2016 at 10:36 PM.

[bobbotron]

The Sigma 8-16 has no field distortion until 12mm. That's what you're looking for.

Not really. I'd like that lens... but there's something kind of awesome about going out with one or two primes. I have the 15 now, it's nice if you have a specific wiiide goal in mind. I bet the 21 would be great, but an 18 would be really great!

---------- Post added 02-02-16 at 10:41 PM ----------

The DA21 does all that quite nicely for me, but we're all different.

Yeah, I've often thought it's the closest I'd get to what I'm looking for. I have a 35mm equiv lenses in other formats, it is a nice FOV. I think that a 18mm plastic fantastic would be a great counterpoint to the 21 for budget minded pentaxians, like the limited lenses compared to the 35 and 50.

[JPT]

Back in September Ricoh Japan sent out a lens survey to customers of its online store to ask what lenses they'd be interesting. The wide angle options for DA (APS-C) that respondents could select were these.

- Large aperture (F1.4 class）Ultrawide（16ｍｍ）Prime Lens
- Large aperture (F1.4 class）Wide（18ｍｍ）Prime Lens
- Large aperture (F1.4 class）Wide（23ｍｍ）Prime Lens
- (F1.8 class）Ultrawide（13ｍｍ）Prime Lens
- (F1.8 class）Ultrawide（16ｍｍ）Prime Lens
- (F1.8 class）Wide（18ｍｍ）Prime Lens
- (F1.8 class）Wide（23ｍｍ）Prime Lens

So looking at focal lengths they were asking about, it seems like an 18mm is at least in consideration. The only problem is that that list had so many items, they would only ever be able to make a small fraction of them.

Personally, I'd like to see something between 21 and 31 first, but an 18mm would be nice.

[ScooterMaxi Jim]

Valid concern, Bobbo.

When a nice smc 21mm came available used for a good price, I decided to give it a try. Not that I think this lens should fetch more than about $300 in excellent condition, but the small size and overall consistency throughout the frame sold me. It is better than the old 28mm lenses in some ways, including size, wide open sharpness and great sharpness into the corners. If anything, the slightly narrower view yields a more "normal" look than 28mm on film. I rarely want to "correct" distortion because rectilinear shows an odd look (but is needed and easily attained for that rare architectural shot).

While it qualifies as a 28mm substitute, I was pleasantly surprised to find that it was better in several ways, as well.

[clackers]

DA15 and DA21 are the modern lenses around that.

The Ricoh GR is 18mm AFAIK.

[calsan]

I remember thinking a 28mm was a mindbogglingly wide angle and always wanted one. 35 was the widest I actually had prior to digital.

[Simen1]

Is 18mm really that missing when we have the 15/4 and 21/3,2? I think the span is tight enough, but I would prefer a wide angle with larger aperture. Personally I'm not a fan of the 28mm ff-equivalent, but I want the Sigma 20mm f/1,4 on the new FF. My closest prime up from 20mm will probably be a 50mm. I'm not a fan of 85mm equivalent ether. Next up from 50 will be in the range 100-135 mm. Those three primes would be enough for me.

[Na Horuk]

I think the span is tight enough

I don't think so. Wide angle there is a big difference between a couple mm. Pentax has two big gaps in wide angle primes. Like between 15mm to 21mm, and from 21mm to 31mm.

We have options from third party and legacy glass. Samyang makes a nice 16mm. Oh, and there are zooms like Sigma 8-16mm, Sigma 10-20mm, Tamron 10-24mm, Pentax 12-24mm

[normhead]

OK, so how many primes do you think the average user is willing to carry, one every 3mm, one every 4?

Can Pentax sell 15, 18,21,24, 28, 31? That's six lenses between 15 and 31. With all due respect, that's absolutely insane.

But just to hyperbolize the point lets go on.

31, 35, 40,50, 70, 85, 100, 7 more lenses to get to 100mm. This is a really good example because all these lenses are available, so who actually would carry those all?

The over 100, you probably want 135, 150, 180, 200, 250, 300 and 400. 7 more.

You now have fantastic coverage in primes based on the "a couple of mm makes a difference" theory.
20 lenses to cover 15-400.

Now the reality Sigma 8-16, Pentax 18-135, DA*60-250 +TC, 21 ltd, 40XS and FA 50 1.7, Sigma 70 macro (or could be a Pentax 100 macro.)
7 lenses, I cover more in terms of wide angle 8-350mm, and I can carry that kit.

I'm not buying it. No one "needs" 20 lenses to cover every useful focal length. There is absolutely no pay off in filing every imagined gap in your prime lineup. That is absolute nonsense. If Pentax were a big company and could run more product lines based on their sales numbers perhaps you fill the so called "gaps". This is just a little grandstanding. "I can't get by on what Pentax makes." You call yourself a photographer?