[Na Horuk]

Plan was to fit the K70 in the order below: 1st- DA 35mm f/2.4 2nd- 100mm f/2.8 WR D FA smc Macro Lens 3rd- either the HD DA 15mm f/4 or DA 21mm f/3.2 (thus the original questions).

That sounds like a great kit, very close to what I have. My first Pentax prime was DA 35mm f2.4, and the DFA 100mm is an amazing telephoto, very versatile (can be used for portraits, product photography, macro,..). But instead of DA 15mm I have Samyang 14mm (was much, much more affordable than the 15mm at that time). Not very long ago I got a used SMC DA 21mm and it is starting to replace my DA 35mm (now often choose to carry DA 40mm XS instead of 35mm, as its lighter and further from 21mm)
The great thing about Pentax is you can use lenses from the 80s and 90s and they still work on your new camera. Many of those old lenses have great character and good sharpness. Some of my lenses are even older, like Helios 44-2.

[pres589]

Na Horuk

Actually moving from Canon to Pentax and do not yet have lenses for intended K70 purchase in December.

Plan was to fit the K70 in the order below:
1st- DA 35mm f/2.4

2nd- 100mm f/2.8 WR D FA smc Macro Lens

3rd- either the HD DA 15mm f/4 or DA 21mm f/3.2 (thus the original questions).

I thought the above may be a fair distribution of focal lengths.

I am clearly getting ahead of myself researching my 3rd purchase as that will be a bit down-the-road.

Okay, firstly, welcome to the fold. Here's what I would do instead;

The DA 35 f2.4 is very sharp wide open but doesn't produce very interesting images. It's okay but kind of polarizing around this forum lately. I'd personally rather have a 28mm on a crop body, like the old Pentax F or FA 28's, the Sigma 28 f1.8 EX (bought one recently, reconditioned, may still be available from Adorama) or one of the many manual focus 28's that are available used. OR got a bit tighter and get one of the Pentax 40mm pancakes. The 40XS doesn't cost much more than DA 35 2.4's although it's got that stupid lens cap that I'd probably end up converting to 49mm with a step up ring.

Your second lens, the D-FA 100 Macro WR, is apparently an excellent lens and seems to have a lot of fans here. No debate with you there.

The third lens... the DA 15 is maybe my favorite Pentax lens. Not that there aren't other excellent lenses, but that this seems to be a really rare kind of lens. Who else sells anything like this? The DA 21 is pretty cool and I'm considering purchasing one at some point, but it's not quite as special. The old FA 20 is faster and may actually perform better (it's also not quite as small, but it's not big either) and then various out of production manual 20's are out there as well. There's also the Sigma 24mm f2.8, the Super-Wide, which came in an AF version and is available used. It's not made as well, and it doesn't offer quite the same color rendering as the Pentax 21's (with a real preference for the 21) but it seems to be quite sharp with good contrast.

So basically I'd get an F or FA 28, the 100 Macro, and the DA 15.

[Sandy Hancock]

The old FA 20 is faster and may actually perform better (it's also not quite as small, but it's not big either)

Sorry, but you have obviously not owned either of these lenses.

67mm filter diameter with a HUGE screw-on hood, vs 49mm and a tiny minimalist hood which is integrated with the front cap.
Big six point stars vs the signature slender 14 pointers of the (SMC) DA15 and DA21
Fair flare resistance vs second only to the unrivalled DA15.
f/2.8 vs f/3.2 is not much of a difference, especially with the high-ISO capabilities of modern crop cameras.
The FA20 is also considerably more expensive used than the DA21 is new. And it's hard to find.

If you're planning to stick with a crop system, the FA20/2.8 makes no sense. I regret selling mine, but that's mainly because of the size of the DFA15-30 as its alternative on full frame.

But I agree that the DA15 is a uniquely wonderful ultra-wide lens, despite its pretty mediocre edge sharpness. It (along with the DA21 and DA35 macro) is one of the reasons I remain invested in the crop ecosystem.

[rptdc]

Your photo is demonstrating keystoning, due to your shooting upwards.

Love this forum. Nearly equal, at times, of a photography class.

Thanks.

[bdery]

1. Never purchasing a prime wide angle before, should I expect some image distortion with the 15mm?

Both the 21 and 15 show some distortion, easy to correct (and in fact, automatically corrected by recent bodies).

2. Also, any general opinion on the above 15mm vs 21mm?

Both are amazing. I find the 21 "easier" to learn, the 15 has a steeper learning curve I find (but I haven't used it long).

for me, the main quality of these lenses is that the SMC version is able to create astounding starbursts, something not often seen.

[pres589]

Sandy: You are correct, I have not owned either the FA 20 or the DA 21. I thought the 20 was smaller. I don't care about 3.2 vs 2.8 from a light standpoint, I want great DoF control. The starburst factory SMC DA 15 does me just fine with that effect.

It's too bad that the Canon 24 STM isn't available in k-mount...

[RGlasel]

this is perspective, not distortion. Ultra-wide lenses exaggerate it, but the only way to avoid it for this sort of shot is to climb a very tall ladder

Please pardon my penchant for being pedantic. Pointing the camera upwards is not the only reason why distant objects on the sides tilt towards the centre of the image. In the first picture below, the camera is level, yet the flag pole on the far right is still tilted. Some kind of distortion is inevitable when transferring a 77 degree horizontal field of view (horizontal field of view of the DA 35 is 38 degrees in comparison) onto a flat surface instead of the curved rear surface of our eyeballs. In the second picture, the fisheye lens doesn't worry about being rectilinear and even though the distance to the wind turbine in front is only one-third of the distance in the picture taken with the DA 15 (so it was pointed upwards at a much greater angle), the other wind turbines and the 30 foot high power poles more than half a mile away are nearly perpendicular to the ground. Our brains are trained to correct the inherent distortion of a "normal" field of view projected onto a flat surface, but not a 180 degree field of view.

In case the Centre Block of Canada's Parliament Building looks tilted to anyone besides me, I carefully aligned the image to the main roof line in post processing. Our minds can play tricks on us.

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[Glen]

Buy your lenses used here on the forums, save enough to also get bot the 15 and 21. For both the 21 and 15, get the green ring SMC versions and not the red ring HD version. The older SMC has nicer sunbursts.

IMO, get the 15. Exceptionally unique. Here is a 700 page thread on the joys of the 15mm: The 15mm Limited controls my mind - club - Page 712 - PentaxForums.com

I second the above. I had an older DA15 that was a wonderful lens with grand starbursts and minimal flare. My copy had an unusual situation of not being able to open the little lens hood when a B&W ND filter was attached. I don't know if that was the lens or the filter's fault but the hood is of minimal value or need on this lens.

When my wonderful DA15 followed my K5 down a deep canyon, I replaced it with a K3-II and an HD DA-15. No more starbursts. Flare is the same level as before. The hood opens easily over a non B&W ND filter. I still like the lens and use it often but with the benefit of hindsight I would not buy the HD DA15 if there was any possibility of getting a used DA-15 (made without the HD coating). You can even see in one of the Pentax Forum's reviews that they say the HD coating doesn't appear to have added anything to the DA 15 (unlike in other lenses where it has some tangible benefits) my experience confirms that review's findings. It's a wonderful lens but it's even better without the HD coating.

As for the DA14mm lens, I have never used it but it's large (expensive filters) and in my opinion overpriced. I have never met anyone using the 14. I don't know the actual sales numbers but it would be my guess that Pentax sells a thousand DA15s for every one DA14.

[pres589]

I second the above. I had an older DA15 that was a wonderful lens with grand starbursts and minimal flare. My copy had an unusual situation of not being able to open the little lens hood when a B&W ND filter was attached. I don't know if that was the lens or the filter's fault but the hood is of minimal value or need on this lens.

When my wonderful DA15 followed my K5 down a deep canyon, I replaced it with a K3-II and an HD DA-15. No more starbursts. Flare is the same level as before. The hood opens easily over a non B&W ND filter. I still like the lens and use it often but with the benefit of hindsight I would not buy the HD DA15 if there was any possibility of getting a used DA-15 (made without the HD coating). You can even see in one of the Pentax Forum's reviews that they say the HD coating doesn't appear to have added anything to the DA 15 (unlike in other lenses where it has some tangible benefits) my experience confirms that review's findings. It's a wonderful lens but it's even better without the HD coating.

As for the DA14mm lens, I have never used it but it's large (expensive filters) and in my opinion overpriced. I have never met anyone using the 14. I don't know the actual sales numbers but it would be my guess that Pentax sells a thousand DA15s for every one DA14.

pepperberry farm here on this forum has a DA 14 that he seems to like using a lot. But I agree that it seems rare and wasn't really priced right.

I don't think the HD coatings hurt startburst production with the DA 15. It seems squarely on the shoulders of the rounded aperture blades of the HD version vs. the straight blades on the SMC version. This is why I went hunting specifically for the SMC version on the used market when I got my DA 15.

[Glen]

pepperberry farm here on this forum has a DA 14 that he seems to like using a lot. But I agree that it seems rare and wasn't really priced right.

I don't think the HD coatings hurt startburst production with the DA 15. It seems squarely on the shoulders of the rounded aperture blades of the HD version vs. the straight blades on the SMC version. This is why I went hunting specifically for the SMC version on the used market when I got my DA 15.

Yes you are correct. I forgot about the change to the blades. I thought they were changed at the same time as the HD coating added though. That would make for just two versions of the the popular lens. Please correct me if I am wrong.

As for the DA 14, one place where it would shine is in a pet store. The extra speed and 1mm might be an advantage.

[pres589]

You're right, two versions; SMC coatings with the green ring and the straight blades, and then the HD red ring version with the curved blades.

[BigMackCam]

Please pardon my penchant for being pedantic. Pointing the camera upwards is not the only reason why distant objects on the sides tilt towards the centre of the image. In the first picture below, the camera is level, yet the flag pole on the far right is still tilted. Some kind of distortion is inevitable when transferring a 77 degree horizontal field of view (horizontal field of view of the DA 35 is 38 degrees in comparison) onto a flat surface instead of the curved rear surface of our eyeballs.

Just an observation... What I see here suggests that the camera was (1) tilted slightly to your right, (2) pointing slightly upwards, and (3) not horizontally perpendicular to the building - i.e. the part of the building at the left hand side of the photo was closer to the camera than the part at the right hand side. It's easily-enough corrected in Lightroom using the Transform section of the Develop module - I used Vertical -6 (because the camera was pointing upwards), Horizontal +6 (because the camera wasn't perpendicular to the building) and Rotate +0.5 (because the camera wasn't level). It's not perfect, but certainly a lot better. Unfortunately, the resulting image crops out the wind turbine on the right, but if it didn't, you would see that it's now much better aligned vertically.

EDIT: I will say, it's challenging to take photos like this, where you're trying to get the camera absolutely perpendicular to a subject both horizontally and vertically (in fact, often it's just not possible to be spot on - especially in the vertical axis, where camera height is a limiting factor), and wide angle lenses really exaggerate the resulting perspective distortion. If it weren't for all the people in the scene, I'd have found it much easier to take two or three shots from further back, with a longer focal length lens, and stitch the result into a panorama. Personally, I find very wide angle lenses tough for this kind of thing (though I'm sure there are others here who've mastered them!)...

[Madaboutpix]

Pointing the camera upwards is not the only reason why distant objects on the sides tilt towards the centre of the image. In the first picture below, the camera is level, yet the flag pole on the far right is still tilted. Some kind of distortion is inevitable when transferring a 77 degree horizontal field of view (horizontal field of view of the DA 35 is 38 degrees in comparison) onto a flat surface instead of the curved rear surface of our eyeballs.

FWIK, what we are seeing in the flag pole on the right is a mild case of keystoning, or perspective distortion. It is caused by the imaginary horizon, with the vanishing point in its middle, placed ever so slightly below the image centre. Insofar the camera was not strictly level on the vertical axis.

With ultra-wideangle lenses, the effect can be quite noticeable even with slight tilts, so that we may be a little surprised by it.

But obviously Mike beat me to it and even provided detailed empirical corroboration from Lightroom.

[Sandy Hancock]

What I see here suggests that the camera was (1) tilted slightly to your right, (2) pointing slightly upwards, and (3) not horizontally perpendicular to the building - i.e. the part of the building at the left hand side of the photo was closer to the camera than the part at the right hand side.

Absolutely correct on all three points. The "distortion" you are seeing is due to perspective.

The second image does indeed show extreme barrel distortion, but that is the point of fisheye lenses.

[mikesbike]

Absolutely correct on all three points. The "distortion" you are seeing is due to perspective.

The second image does indeed show extreme barrel distortion, but that is the point of fisheye lenses.

Amen to these very good comments and examples to differentiate between linear and perspective distortion. People often do get the two confused or think they are the same. Getting more into the frame via wide angle lenses does come with a price, and we normally just accept this fact.

A fisheye is a funhouse fun lens having both types of distortion to a very high degree but it also achieves a super-wide angle view. The barrel distortion can be corrected pretty easily post process with the right software, but perspective distortion being a built-in phenomenon for a wide angle view is harder to compensate for. Even if we could position the camera at the right hight and leveling or correct the leaning of vertical subject matter, there remains the front-to-back aspect of perspective distortion. Depth is exaggerated so background objects appear smaller and farther away compared to foreground subjects. The depth of objects like buildings, busses etc. appear elongated.

The only way I've seen to get all of it accurate for a wide angle view is like BigMack suggested- use a "normal" perspective lens, the 43mm Limited on FF or a 28mm lens on APS-C, on a tripod, carefully pan 2 or more shots, and stitch them into a pano.

The DA 15mm and DA 21mm Limited are both excellent and useful lenses, and both remarkably compact and well-made. But they invite a different set of uses. For all-around, the 21mm is far more versatile, with its perspective situation not being so extreme. The 15mm is an amazingly compact and effective ultra-wide, and a wonderful accessory combination lens for other fine lenses, including the 21mm, the DA 20-40mm Limited, or any fine wide-to-tele zoom lens.

The excellent DA 12-24mm f/4 can produce images with even less linear distortion, and better edge performance than the DA 15mm Limited, and when those factors are important, it is a better one to take along. But in terms of a fine accessory wide angle carry-along to expand the wide angle capability of your kit, I pack my amazingly small, beautiful 15mm LTD into the front accessory pouch of my camera belt holster case, with the main lens on-camera in the case! Can't do that with any other ultra wide angle lens!