[BoogieEngineer]

Hi everyone. First time posting here. I was looking to get my first FF DSLR (used to do film with Leica and Hasselblad MF, was cool but I'm getting too lazy these days) and decided to get the K-1 which is on its way with the 28-105 kit lens.

Now I'm looking for a nice prime and came across the FA31 Limited. What isn't clear to me is if this lens is a APS-C lens, what will be its focal length on the FF K-1? Let's assume a crop factor of 1.5, I'm thinking it will be 31/1.5 = 20.7mm on the K-1. Is that correct?

Thanks for your reply!

[jpzk]

The 31 Ltd is indeed FF-"ready" !
I use mine on my APS-C cameras but I'm sure it is an FF lens.
Correct me (other members) if I'm wrong but you will have 31mm on your K-1.

[AquaDome]

The FA31 is an auto-focus film camera lens. There should be absolutely no issues using it on the K-1.

[jatrax]

What isn't clear to me is if this lens is a APS-C lens, what will be its focal length on the FF K-1?

Focal length does not change regardless of the camera. 31mm is still going be 31mm. If the lens was designed for APS-C only then on FF it will vignette most likely, but the focal length does not change. Crop factor was (IMHO) something invented by camera magazine journalists to confuse everyone.

However, the 31mm Limited is a designed for film, full frame lens. On the K-1 it is 31mm, just like it is on APS-C or a Q7 for that matter. Focal length is a physical property of the lens itself.

[BoogieEngineer]

Oh okay I understand. Thanks for the explanation guys!

I asked because I was using a Sony Zeiss 50mm on my mom's A6000 and it looked like a telephoto already.

[BoogieEngineer]

Or maybe I was confused with field of view.

[pakinjapan]

Now I'm looking for a nice prime and came across the FA31 Limited. What isn't clear to me is if this lens is a APS-C lens, what will be its focal length on the FF K-1?

A few more information might be useful for your future Pentax's lens purchase, check out this page Pentax K-1 Lens Compatibility Guide - Articles and Tips | PentaxForums.com
and this one https://www.pentaxforums.com/lenssearch/?type=Prime&inproduction=0&format=ff...%5B%5D=Non-SMC

K1 + FA31 is a fantastic setting, hope you have fun using them.

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Last edited by pakinjapan; 04-26-2017 at 04:50 PM.

[ChatMechant]

The 31ltd + K-1 is a very nice combo.




Along with the 77 in a pocket is a nice way to go.

[monochrome]

As I read this thread my FA31 is mounted on my K-1. Yesterday it was on my MZ-S (FF professional 35mm film camera). It most definitely completely covers the FF sensor.

[clackers]

Or maybe I was confused with field of view.

Yes, you're onto something there.

Welcome aboard.

The FA31 is a beautiful lens - you could travel abroad with nothing else, if you wished.

[MadMathMind]

It's very compatible and the only in-production option in that focal length range. But I've found it to be very middling on the K-1, definitely not up to snuff with lenses like the DA*55 and FA77, despite the much higher price tag. It's spectacular on APS-C but the edges display a number of issues; I've had two copies of the lens and waiting for my third as an exchange. Maybe I'm unlucky but I've just not found it worthy of a $1k lens on FF. On APS-C, it definitely is. I think if it were half the price, I'd like it more, but as the most expensive Pentax prime in production, the bar is high.

[BoogieEngineer]

Thanks guys! This forum is great and you are incredibly responsive and helpful!

My first lens is the kit lens 28-105 which I've heard good things about. The FA31 Limited will be next. One more question though. Does the date of manufacturing matter or do they all auto-focus just fine?

[Adam]

Thanks guys! This forum is great and you are incredibly responsive and helpful!

My first lens is the kit lens 28-105 which I've heard good things about. The FA31 Limited will be next. One more question though. Does the date of manufacturing matter or do they all auto-focus just fine?

Feature wise there is no difference. However, early 31mm's are made in Japan and generally command higher prices.

[Sandy Hancock]

Does the date of manufacturing matter or do they all auto-focus just fine?

They all auto-focus just fine. There is no objective difference between the older (Made in Japan) and newer (Assembled in Vietnam) versions.

To whet your appetite:





It's one of my favourite lenses for panoramas too.

[jatrax]

Or maybe I was confused with field of view.

Yep, angle of view will change with the sensor size but the focal length does not.

My first lens is the kit lens 28-105 which I've heard good things about. The FA31 Limited will be next. One more question though. Does the date of manufacturing matter or do they all auto-focus just fine?

You will really like the DFA 28-105, very nice lens. On the 31mm, there is usually a premium associated with the earlier ones made in Japan. However, they all are identical except for location of manufacture. Whether there is any benefit to "made in Japan" over "assembled in Vietnam" I have no idea, I suspect it is marketing hype by internet sellers, but that is just my humble opinion. Others might disagree. Regardless the 31mm is one of the prize gems in the Pentax catalog, one of those lenses you buy a camera to fit on.