[UncleVanya]

OK - odd question and mostly just a fun way to talk about lenses. Recently I used the FA 31 on a loaner K-1. I really liked the perspective and of course the 31 is a special lens in many ways particularly on FF. So which of the choices out there for Crop gives the most FA 31 on FF like experience on crop? The lens need not be a crop lens - but what combination works best to emulate the perspective and some of the special mojo of the FA 31?

These came to my mind immediately:
DA 20-40
DA 21

I'm curious what others think. I have never shot the DA 21 so I have only the DA 20-40 to compare and I'm not sure I find any fault with it but it didn't seem as "right" as the FA 31.

(It is possible this is a fools errand..)

[enoeske]

OK - odd question and mostly just a fun way to talk about lenses. Recently I used the FA 31 on a loaner K-1. I really liked the perspective and of course the 31 is a special lens in many ways particularly on FF. So which of the choices out there for Crop gives the most FA 31 on FF like experience on crop? The lens need not be a crop lens - but what combination works best to emulate the perspective and some of the special mojo of the FA 31?

These came to my mind immediately:
DA 20-40
DA 21

I'm curious what others think. I have never shot the DA 21 so I have only the DA 20-40 to compare and I'm not sure I find any fault with it but it didn't seem as "right" as the FA 31.

(It is possible this is a fools errand..)

Well, the field of view of the 31mm on FF will be the same as using a 20.66mm on APS-C, so you're correct that the 20-40mm and DA 21mm come pretty close. However, the depth of field won't be the same unless you were using a 21mm f/1.2 or something. There aren't really FF - APS-C equivalences without some drawbacks. You can have the equivalent FoV, perspective or DoF, but not all of them typically.

There is a Rokinon 20mm f/1.8 which would give you a lot of what you want, but it is manual focus

Rokinon 20mm f/1.8 ED AS UMC Lens for Pentax K RK20M-P B&H Photo

[UncleVanya]

Well, the field of view of the 31mm on FF will be the same as using a 20.66mm on APS-C, so you're correct that the 20-40mm and DA 21mm come pretty close. However, the depth of field won't be the same unless you were using a 21mm f/1.2 or something. There aren't really FF - APS-C equivalences without some drawbacks. You can have the equivalent FoV, perspective or DoF, but not all of them typically.

There is a Rokinon 20mm f/1.8 which would give you a lot of what you want, but it is manual focus

Rokinon 20mm f/1.8 ED AS UMC Lens for Pentax K RK20M-P B&H Photo

While that's true - the DOF wide open wasn't what was amazing. I was looking at the landscape side and f/5.6 or f/8 or even f/11 on FF.

[aaacb]

I don't have the 20-40, or the fa 31 or a k1, but I really like my da 21 (hd version). I had the smc version, sold it, then got the HD version for better flare resistance. I thought I could just use a zoom for that focal range/aperture (da 16-85) but it didn't look or handle quite the same... it's the only lens I bought twice.

The da 21 and 55-300 is now my default mountain landscape kit, when I need to save weight for hiking.

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Last edited by aaacb; 01-29-2019 at 04:21 PM.

[volley]

I've never used the FA 31 but I have been quite impressed with the DA21 on APSC .
You might want to check out the examples in the lens sample archive.

[Ash]

FA 31 has a useable f/2
Given the talk of equivalence on the forum, this may open up a can of worms, but what's available in the DA 21 or 20-40 doesn't compare in max aperture.
Perhaps the Sigma 20mm F1.8 EX Aspherical DG DF RF Lens Reviews - Sigma Lenses - Pentax Lens Review Database or the Samyang 20mm F1.8 ED AS UMC Lens Reviews - Samyang Lenses - Pentax Lens Review Database would give similar perspectives but certainly not similar results at the wider aperture. A good example of the difference in rendition would be this: Wide Open: Pentax 31 Limited & Leica 35 Summilux ASPH – Steve Huff Photo

[gaweidert]

The Pentax DA 12-24mm is pretty good. Too I like mine.

[clackers]

The FA31 is a fast lens, Brad.

The one I have that's closest is the film era Sigma 24mm f1.8 Macro. Nine aperture blades, etc. Not small like a Limited, though.

One I don't have, and it's not as quick, is the FA28 f2.8 - aka 'The Poor Man's FA31 Ltd'.

[monochrome]

The FA31 is a fast lens, Brad.

The one I have that's closest is the film era Sigma 24mm f1.8 Macro. Nine aperture blades, etc. Not small like a Limited, though.

One I don't have, and it's not as quick, is the FA28 f2.8 - aka 'The Poor Man's FA31 Ltd'.

I always thought that was the FA35/2. Silly me.

[Ash]

Or another alternative discussed here: Another Sigma 35/1.4 Art Vs FA 31/1.8 Ltd. - PentaxForums.com

[clackers]

I always thought that was the FA35/2. Silly me.

That's certainly true on FF, but on APS-C it's not wide enough.

[clackers]

Or another alternative discussed here: Another Sigma 35/1.4 Art Vs FA 31/1.8 Ltd. - PentaxForums.com

But he wants to emulate the FA31 field of view on APS-C, Ash, a wide angle rather than normal. He hired a K-1, remember.

[UncleVanya]

That's certainly true on FF, but on APS-C it's not wide enough.

Yes I have that lens also. But while I like it and the 31 on crop I just was curious

[pepperberry farm]

and don't forget the Sigma 20mm f1.8 EX DG...

[Sandy Hancock]

Just get the DA21 Brad