Pentax heavy weights shootout - part I 31ltd vs 50mm/1.2

axl · 01-27-2011, 08:10 AM - **6 Likes**

In a recent thread started by dgaies, there was a point risen that 31ltd might as well be the 50/1.2 of digital era, considering it's IQ, and subject separation and OOF rendering. Since shots in previous thread were all shot wide open, some members wanted to see shots stopped down. So I decided that I will take my lenses and start comparing them against each other, and of course first two to shoot it out would be the "silver queen" SMC P-FA 1:1.8 31mm Limited and the "old laughing lady" SMC P 1:1.2/50.
The test was simple, I put on table just about anything I found in a living room, set up a tripod, put my K10D on it. Set manual WB using impartial FA43. Then run shots with 31ltd. First up @1.8 in Av fiddling with EV until I wasn't happy with histogram. Then to M mode and selecting shutter speeds to keep the histogram where I wanted it. All with 2sec timer and remote cord.
Then I slapped K50 on, and took shots at f 2.8 and f2 with the same shutter speeds as for 31ltd, and set new speeds for other two shots. Firs series was done from the same spot to keep the perspective the same, and for the second series I moved the tripod to keep the target magnification the same (as much as possible).
All shots were then imported to LR3 and converted on my basic settings, no adjustments at all. Opened in CS3 and resized and cropped for display purposes.
I will not pass my judgment and let you draw your own conclusions. Thanks for reading and viewing. And tips and comments for future shootouts welcome...

Regards
P

EXIF:
K10D GP fv1.3
Manual balance (LR: temp: 9100, ting +109)
ISO100
Shutter speeds for 31ltd
1.8 = 1/13
2 = 1/13
2.8 = 1/10
Shutter speeds for K50
1.2 = 1/25
1.4 = 1/20
2 = 1/13
2.8 = 1/10

note: K50 doesn't support Av in other than wide open and f stops are selectable via aperture ring only! The f stops on the ring are as follow: 1.2 (marked) 1.4 (first mid click) 2(marked) 2.4 (second mid click) 2.8 (marked) and so on... that's why I couldn't and didn't do comparison on f1.8 and f2 is the first f stop these two lenses have in common.

now to the pictures:

IMGP5954

IMGP5957

IMGP5959

IMGP5963

IMGP5962

IMGP5961

IMGP5960

IMGP5969

IMGP5970

IMGP5971

IMGP5972

100% crops of focus target when keeping it the same mginfication:

IMGP5954c

IMGP5957c

IMGP5959c

IMGP5969c

IMGP5970c

IMGP5971c

IMGP5972c

and 3 composites to compare the sharpness:

Untitled-1

Untitled-2

Untitled-3

Pentaxor · 01-27-2011, 02:16 PM

great job Peter and thanks. this test would had taken a lot of work to do and time to spare. anyway, if it's not much of a bother, can you include the crop images of the first K50/1.2 set alongside the compared 2nd set of images between the FA31 and K50/1.2 ? like a 3 image side by side comparison? just to see the DOF difference at the same distance and FOV. thanks.

SteveM · 01-27-2011, 02:29 PM

These are great.

I would be interested in seeing the comparison when shot at F11 or so as the 50 is listed as being one of Pentax's sharpest lenses at that F stop....

timh · 01-27-2011, 02:43 PM

Based on this, in pure quality terms, I think the 50 looks better.

axl · 01-27-2011, 03:03 PM

Originally posted by Pentaxor

great job Peter and thanks. this test would had taken a lot of work to do and time to spare. anyway, if it's not much of a bother, can you include the crop images of the first K50/1.2 set alongside the compared 2nd set of images between the FA31 and K50/1.2 ? like a 3 image side by side comparison? just to see the DOF difference at the same distance and FOV. thanks.

No problem, will try to post that later, probably Saturday, depending on time...

Originally posted by smc

These are great.

I would be interested in seeing the comparison when shot at F11 or so as the 50 is listed as being one of Pentax's sharpest lenses at that F stop....

Sorry but this won't be straight away... I only did wide to f2.8... nothing behind..

But I'll reshoot it one day

SteveM · 01-27-2011, 03:07 PM

Originally posted by axl

Sorry but this won't be straight away... I only did wide to f2.8... nothing behind..

But I'll reshoot it one day

Thanks axl. It is really nice to see the comparison at the wide end. I think that is what most people think of when they buy a 50/1.2.

farfisa · 01-27-2011, 03:22 PM - **2 Likes**

Wow, your K50/1.2 does extremely well wide open!

The 31 shows smurf in the smurf, but it's gone once you smurf down to f/2.8 (or possibly sooner), while the K50 shot is very well smurfed even wide open (maybe a hint of red smurf there in the high smurf areas, but nothing you'd notice unless you really smurfed).

deadwolfbones · 01-27-2011, 03:57 PM

Originally posted by farfisa

Wow, your K50/1.2 does extremely well wide open!

The 31 shows smurf in the smurf, but it's gone once you smurf down to f/2.8 (or possibly sooner), while the K50 shot is very well smurfed even wide open (maybe a hint of red smurf there in the high smurf areas, but nothing you'd notice unless you really smurfed).

I love this post.

ewig · 01-27-2011, 03:58 PM

me too

**Deimos** · 01-27-2011, 04:06 PM

Originally posted by timh

Based on this, in pure quality terms, I think the 50 looks better.

+1

Nice test!

The next interesting comparison is the cost of these two lenses

Pentaxor · 01-27-2011, 05:00 PM

thanks Peter. looking forward for the updates.

anyway, from what I'm seeing, the K50/1.2 looks impressive (resolution) at equal openings.

yeatzee · 01-27-2011, 05:32 PM

Not that I didn't already know this.... but DAMN that K 50mm F/1.2 is a nice lens

Nice and sharp, VERY usable @ F/1.2.

**Ash** · 01-27-2011, 06:34 PM

Good job Peter, you've really put in some work presenting these findings.
There are some clear differences (what to expect with the different max. apertures?) but they are both so good - wide open's usual haloing and softness isn't objectionable either.
The 50/1.2 really comes into its own, with no doubt a great advantage in FF.
Thanks again Peter.

8540tomg · 01-27-2011, 06:47 PM

A lot of effort in this Axl. well done.

I don't own either of these lenses (sadly) but I prefer the overall look of the 31 to the 50. That said the 50 is the hands down winner as far as bokeh is concerned. It just obliterates the background at 1.2 yet stays surprisingly sharp in its very narrow range. Focusing must be difficult at 1.2. Thanks for sharing.

Tom G

Nick Siebers · 01-27-2011, 06:52 PM

Yeah, focusing at f/1.2 is tricky. Live View helps some, and practice as well. Understanding that the VF will show a lot more in focus that the final picture, I try to find the "middle" of the in focus range. I'd love an AF version, although I suspect it would miss a fair amount as well.

01-27-2011, 08:10 AM - 6 Likes	#1
axl Veteran Member Join Date: Mar 2007 Location: Nove Zamky, Slovakia Photos: Gallery \| Albums Posts: 7,183	Pentax heavy weights shootout - part I 31ltd vs 50mm/1.2 In a recent thread started by dgaies, there was a point risen that 31ltd might as well be the 50/1.2 of digital era, considering it's IQ, and subject separation and OOF rendering. Since shots in previous thread were all shot wide open, some members wanted to see shots stopped down. So I decided that I will take my lenses and start comparing them against each other, and of course first two to shoot it out would be the "silver queen" SMC P-FA 1:1.8 31mm Limited and the "old laughing lady" SMC P 1:1.2/50. The test was simple, I put on table just about anything I found in a living room, set up a tripod, put my K10D on it. Set manual WB using impartial FA43. Then run shots with 31ltd. First up @1.8 in Av fiddling with EV until I wasn't happy with histogram. Then to M mode and selecting shutter speeds to keep the histogram where I wanted it. All with 2sec timer and remote cord. Then I slapped K50 on, and took shots at f 2.8 and f2 with the same shutter speeds as for 31ltd, and set new speeds for other two shots. Firs series was done from the same spot to keep the perspective the same, and for the second series I moved the tripod to keep the target magnification the same (as much as possible). All shots were then imported to LR3 and converted on my basic settings, no adjustments at all. Opened in CS3 and resized and cropped for display purposes. I will not pass my judgment and let you draw your own conclusions. Thanks for reading and viewing. And tips and comments for future shootouts welcome... Regards P EXIF: K10D GP fv1.3 Manual balance (LR: temp: 9100, ting +109) ISO100 Shutter speeds for 31ltd 1.8 = 1/13 2 = 1/13 2.8 = 1/10 Shutter speeds for K50 1.2 = 1/25 1.4 = 1/20 2 = 1/13 2.8 = 1/10 note: K50 doesn't support Av in other than wide open and f stops are selectable via aperture ring only! The f stops on the ring are as follow: 1.2 (marked) 1.4 (first mid click) 2(marked) 2.4 (second mid click) 2.8 (marked) and so on... that's why I couldn't and didn't do comparison on f1.8 and f2 is the first f stop these two lenses have in common. now to the pictures: IMGP5954 IMGP5957 IMGP5959 IMGP5963 IMGP5962 IMGP5961 IMGP5960 IMGP5969 IMGP5970 IMGP5971 IMGP5972 100% crops of focus target when keeping it the same mginfication: IMGP5954c IMGP5957c IMGP5959c IMGP5969c IMGP5970c IMGP5971c IMGP5972c and 3 composites to compare the sharpness: Untitled-1 Untitled-2 Untitled-3

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01-27-2011, 02:16 PM	#2
Pentaxor Veteran Member Join Date: May 2009 Location: Vancouver, B.C. Photos: Gallery Posts: 6,513	great job Peter and thanks. this test would had taken a lot of work to do and time to spare. anyway, if it's not much of a bother, can you include the crop images of the first K50/1.2 set alongside the compared 2nd set of images between the FA31 and K50/1.2 ? like a 3 image side by side comparison? just to see the DOF difference at the same distance and FOV. thanks.

01-27-2011, 02:29 PM	#3
SteveM Veteran Member Join Date: Jan 2009 Location: Vancouver Island, BC, Canada Photos: Gallery Posts: 3,294	These are great. I would be interested in seeing the comparison when shot at F11 or so as the 50 is listed as being one of Pentax's sharpest lenses at that F stop....

01-27-2011, 02:43 PM	#4
timh Veteran Member Join Date: May 2010 Location: Wales Photos: Gallery \| Albums Posts: 445	Based on this, in pure quality terms, I think the 50 looks better.

01-27-2011, 03:03 PM	#5
axl Veteran Member Join Date: Mar 2007 Location: Nove Zamky, Slovakia Photos: Gallery \| Albums Posts: 7,183 Original Poster	Originally posted by Pentaxor great job Peter and thanks. this test would had taken a lot of work to do and time to spare. anyway, if it's not much of a bother, can you include the crop images of the first K50/1.2 set alongside the compared 2nd set of images between the FA31 and K50/1.2 ? like a 3 image side by side comparison? just to see the DOF difference at the same distance and FOV. thanks. No problem, will try to post that later, probably Saturday, depending on time... Originally posted by smc These are great. I would be interested in seeing the comparison when shot at F11 or so as the 50 is listed as being one of Pentax's sharpest lenses at that F stop.... Sorry but this won't be straight away... I only did wide to f2.8... nothing behind.. But I'll reshoot it one day

01-27-2011, 03:07 PM	#6
SteveM Veteran Member Join Date: Jan 2009 Location: Vancouver Island, BC, Canada Photos: Gallery Posts: 3,294	Originally posted by axl Sorry but this won't be straight away... I only did wide to f2.8... nothing behind.. But I'll reshoot it one day Thanks axl. It is really nice to see the comparison at the wide end. I think that is what most people think of when they buy a 50/1.2.

01-27-2011, 03:22 PM - 2 Likes	#7
farfisa Veteran Member Join Date: Nov 2008 Location: Toronto, Canada Photos: Gallery Posts: 1,274	Wow, your K50/1.2 does extremely well wide open! The 31 shows smurf in the smurf, but it's gone once you smurf down to f/2.8 (or possibly sooner), while the K50 shot is very well smurfed even wide open (maybe a hint of red smurf there in the high smurf areas, but nothing you'd notice unless you really smurfed).

01-27-2011, 03:57 PM	#8
deadwolfbones Veteran Member Join Date: Sep 2007 Location: La Crescenta, CA Posts: 7,450	Originally posted by farfisa Wow, your K50/1.2 does extremely well wide open! The 31 shows smurf in the smurf, but it's gone once you smurf down to f/2.8 (or possibly sooner), while the K50 shot is very well smurfed even wide open (maybe a hint of red smurf there in the high smurf areas, but nothing you'd notice unless you really smurfed). I love this post.

01-27-2011, 03:58 PM	#9
ewig Veteran Member Join Date: Jan 2010 Photos: Albums Posts: 312	me too

01-27-2011, 04:06 PM	#10
Deimos Site Supporter Join Date: Oct 2010 Location: Kingdom of Wonder Posts: 1,777	Originally posted by timh Based on this, in pure quality terms, I think the 50 looks better. +1 Nice test! The next interesting comparison is the cost of these two lenses

01-27-2011, 05:00 PM	#11
Pentaxor Veteran Member Join Date: May 2009 Location: Vancouver, B.C. Photos: Gallery Posts: 6,513	thanks Peter. looking forward for the updates. anyway, from what I'm seeing, the K50/1.2 looks impressive (resolution) at equal openings.

01-27-2011, 05:32 PM	#12
yeatzee Veteran Member Join Date: Feb 2009 Location: Temecula Photos: Gallery \| Albums Posts: 3,675	Not that I didn't already know this.... but DAMN that K 50mm F/1.2 is a nice lens Nice and sharp, VERY usable @ F/1.2.

01-27-2011, 06:34 PM	#13
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Good job Peter, you've really put in some work presenting these findings. There are some clear differences (what to expect with the different max. apertures?) but they are both so good - wide open's usual haloing and softness isn't objectionable either. The 50/1.2 really comes into its own, with no doubt a great advantage in FF. Thanks again Peter.

01-27-2011, 06:47 PM	#14
8540tomg Veteran Member Join Date: Feb 2008 Location: Waterloo, Ontario Photos: Gallery Posts: 4,461	A lot of effort in this Axl. well done. I don't own either of these lenses (sadly) but I prefer the overall look of the 31 to the 50. That said the 50 is the hands down winner as far as bokeh is concerned. It just obliterates the background at 1.2 yet stays surprisingly sharp in its very narrow range. Focusing must be difficult at 1.2. Thanks for sharing. Tom G

01-27-2011, 06:52 PM	#15
Nick Siebers Veteran Member Join Date: Jun 2008 Location: Madison, WI Photos: Gallery \| Albums Posts: 2,165	Yeah, focusing at f/1.2 is tricky. Live View helps some, and practice as well. Understanding that the VF will show a lot more in focus that the final picture, I try to find the "middle" of the in focus range. I'd love an AF version, although I suspect it would miss a fair amount as well.