[Engineworks]

Hi Pentax people! Looking for some advice on the best quality 35mm equivalent lens (would be equal to a 35mm on a full frame) for my APS-C K-70. Requirements: fixed focal length, auto-focus and fast. Does not need to be a Pentax branded lens. As always, a huge thank you to all repliers in advance!

[tokyoscape]

DA21 is 31mm on FF.
I highly recommend it. This is a perfect focal length for urban street photography. I like night photography and I prefer SMC version mainly because of its starburst effect. HD version is the current version, Not bad in all account. Too bad both version are not weather sealed. Sample

[rogerstg]

I think that the closest would be the HD DA 21mm F3.2 limited
Edited - I see tokyoscape replied first. I concur with his thoughts on the SMC version.

[aslyfox]

perhaps this will help as well

The Crop Factor Unmasked
Field of View vs Focal Length on various formats
By PF Staff in Articles and Tips on Jul 23, 2014

Read more at: The Crop Factor Unmasked - Articles and Tips | PentaxForums.com

as far as choosing between a SMC and HD version of the 21mm F3.2 Limited :

HD vs. SMC Pentax Limited Primes
Introduction
At Photokina 2012, Pentax announced a brand new lens coating which they named the "HD Coating". This coating is slowly starting to replace the conventional "Super Multi Coating" (SMC) on high-end Pentax glass. According to Pentax, the new HD coating greatly reduces reflectance without making any sacrifices in terms of durability. This kind of coating isn't new to the industry, however: Pentax digital medium format lenses have been treated with a slightly less durable variant called Aero Bright coating ever since their debut, and other manufacturers have been using "nano" coatings on their premium lenses for several years.

The modern SMC coating that DA lenses have been using for about a decade now isn't the same as the SMC coating that Pentax originally launched in the 1970's. In fact, most DA lenses have been said to have a "ghostless" coating, so while we don't expect the difference between SMC and HD coating to be be a game-changer, it should certainly still be easy to observe. . . .

Read more at: https://www.pentaxforums.com/reviews/hd-pentax-limited-primes/introduction.h...#ixzz6BtqF3YVe

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Last edited by aslyfox; 01-23-2020 at 04:42 PM.

[krazny]

A 24 mm lens would be 36 mm

I suppose there are various 24 mm prime lenses with autofocus available for Pentax. No ?

Edited: Sigma 24mm f1.8 AF

https://www.pentaxforums.com/userreviews/sigma-24mm-f1-8-ex-aspherical-dg-df-macro.html

[pepperberry farm]

SMC A 20mm f2.8
Voigtlander Color Skopar 20mm f3.5
Carl Zeiss Jena MC Flektogon 20mm f2.8 (or f4)

or if you want to go 24mm

Sigma Super Wide II 24mm f2.8
Sigma 24mm f1.8 EX DG

[aslyfox]

A 24 mm lens would be 36 mm

I suppose there are various 24 mm prime lenses with autofocus available for Pentax. No ?

24mm Prime Lenses | PentaxForums.com

it appears only one - FA * 24mm F2.0

Description:
This is the fastest 24mm prime lens made by Pentax.

Like for all other FA* lenses you switch between autofocus and manual focus by pushing the focusing forwards (autofocus) or pulling it towards the camera (manual focus).

SMC Pentax-FA* 24mm F2 AL [IF] Reviews - FA Prime Lenses - Pentax Lens Reviews & Lens Database

[luftfluss]

Count me as another fan of the DA21 Ltd. However, I prefer the HD version, as I'm not as fond of the spiky sunstars as others are and I prefer the better flare resistance of the HD version.

[ChristianRock]

I enjoy that focal length and recently had up to 3 24mm lenses... all f/2.8 to keep them small and light. All full-frame though I don't shoot full frame anymore (haven't shot film in a few years).

The ones I have had were:

SMC-K 24 2.8 (great lens)
Rokinon 24 2.8 (made by Tokina, it's a rebadged Tokina RMC)
Vivitar MC 24 2.8 (made by Cosina, excellent lens, sold it because my Tokina is basically identical, has A contacts)

The ones I still have:
SMC-A 24 2.8 (excellent, but mine has non-working A contacts so it's basically a K or M series functional lens with A coatings. It's also up for sale very cheap in the Marketplace )
Tokina 24 2.8 - Identical to the Vivitar I sold, including the colors and fonts, as well as the coating reflections. - which tells me this lens was probably a joint collaboration between Cosina and Tokina, or maybe Tokina has been rebadging lenses longer than we thought! I kept this one because it had a Ricoh pin and when I removed it I made the aperture stepless - not on purpose. So it wouldn't be worth much selling and since it's a fantastic performer I'm happy with it! Focuses VERY close and renders beautifully, but the colors of course aren't as nice as a real Pentax lens.

All the aforementioned lenses are manual focus. If you want an autofocus 24, you basically have 3 options:

1. The Sigma 24 2.8 Super Wide II AF - very good by all accounts except the build quality which is a bit sub-par. But they have lasted well from what we can tell. They can cost about 150-200 dollars in the used market, but are getting pretty rare.
2. The Pentax FA* 24mm f2 - this will cost you 400-600 dollars depending on condition. Very nice lens, I wish I had one. On the downside, it's a bit large, and a bit soft wide open, but it still works well because the colors are beautiful and contrasty even wide open.
3. The Sigma 24 1.8 - it could cost you around 200 dollars, maybe a bit more, maybe a bit less. It's a very big lens though, so I'm not sure if it's worth having over the smaller older Sigma.

That's about all I know about 24mm lenses for Pentax K... there's more older models by Rikenon (I think it's a rebadged Tokina as well), Cimko, Miranda (also made by Cosina like my Vivitar was), and several different Vivitar-branded lenses (they changed every year it seems...) but I don't have experience with those. M24 lenses are also out there but I personally don't like those especially for lenses that you would use at f5.6 and smaller.

[bertwert]

Another vote for the 21 Ltd, definitely my favourite and most used lens.

[mikesbike]

Well, good luck in finding a 24mm lens with good edge performance at larger apertures. However, I do have the Sigma 24mm f/1.8 EX DG, which was rated poorly at edges of the frame until up into mid apertures, but that was tested on FF bodies, not APS-C. Since the frame edges are cropped off with APS-C, the situation should thereby be improved to a significant degree.

Now having the KP, I will get around to see how well it does when faced with a higher performance sensor, when next we have decent shooting weather. My experience with my K-5 IIs has been fairly decent, and then yet better edges when stopped down even a little bit. The DA 21mm does not yield edge performance all that great wide open either, which at f/3.2 is nowhere close to being a fast prime lens. Yes, the Sigma is a chunky lens, but expected with its wide aperture and FF design. Performance was tested at least as good as the Pentax FA* 24mm which was tested with APS-C crop factor, and would maybe be even better on APS-C, since this Sigma lens was tested on a FF body.

[Alex645]

Looking for some advice on the best quality 35mm equivalent lens (would be equal to a 35mm on a full frame) for my APS-C K-70. Requirements: fixed focal length, auto-focus and fast. Does not need to be a Pentax branded lens.

The closest in focal length for that field of view would be 24mm. Unfortunately, both Samyang and Rokinon f/1.4 24mm which are fixed and fast are manual focus. The Pentax DA 20-40mm f/2.8-4 ED Limited DC WR is auto focus but neither fast nor fixed, but given the low light capability of your camera, is a great walkabout lens (with WR).

IF it doesn't have to be exactly the 35mm equivalent, then I agree with others on the DA 21mm (which is more like a 31 or 32mm wide angle equivalent).

[stevebrot]

As noted above, the FA* 24/2.0 would be a good bet, though not cheap...$$$.


Steve

[Sandy Hancock]

Here's an album of shots with the FA* 24/2.0 - all shot on a crop camera. I'm a fan.

[cport]

Although I am a big fan of Pentax (sorry, Ricoh). I think that this is the biggest mistake they did. Their concentration was on APS-C line, so they needed not only a small 21mm (which I already have) but also a perfect 23/1,4 WR APS-C lens!