smc P-FA 31mm F1.8 Wide Angle Lens

pingflood · 10-26-2008, 02:33 PM

Hi Josh,

I have experience with the Sigma only, but a few comments:

The Sigma is not a great lens for landscapes where you want as much detail as possible across the board. It is BRUTALLY sharp in the center (the 31 is no slouch, but the Sigma does outperform it there according to tests), but the edges are pretty much crap compared to the Pentax... (edit: I should have stated that differently, the edges aren't horrible but noticeably weaker than some other lenses -- depends on the image/scene and print size. For most regular day to day shots you probably won't be bothered by it at all.)

That said, the Sigma is cheaper (much), is nearly a stop faster, and for pictures where you don't fret over uniform sharpness edge-to-edge it's superb.

If I had the same requirements you do I'd probably get the Sigma for low light and portraits, and another wider lens for landscape work. For me the 31 would be too tight for doing landscape, but you might have a different take on it.

I have a couple of shots and some commentary here with the Sigma... (also posted in a thread here)
storpotaten: A tonion of onions (Sigma 30/1.4)

Last edited by pingflood; 10-27-2008 at 06:54 AM.

felix68 · 10-26-2008, 03:29 PM

Originally posted by joshmas

I'm looking to fill out my primes and pick up one of these 2 lenses next for my k10d.

I was wondering if anyone had experience with both the lenses and could guide me. I'd be looking to use this for about 50% portrait, and 50% landscape.

All help appreciated.

Best regards,

Josh

I don't have the Sigma but have shot with it on a friends Oly. To me, even on 4/3 it was not good in the corners and soft wide open. The 31 is very good wide open. Here is a shot at f2:

pingflood · 10-26-2008, 04:12 PM

If the Sigma was soft wide open it was probably a poor sample. It may have many flaws, but being soft isn't one of them! Then again, Sigma quality control appears to leave a lot to be desires, which is unfortunate as the good Sigma samples are really, really good.

morfic · 10-26-2008, 09:04 PM

Originally posted by pingflood

If the Sigma was soft wide open it was probably a poor sample. It may have many flaws, but being soft isn't one of them! Then again, Sigma quality control appears to leave a lot to be desires, which is unfortunate as the good Sigma samples are really, really good.

I bought the 30/1.4 well knowing the borders and extreme corners never quite catch up to the center performance (in lab tests), but i have yet to try a Sigma lens and return it because the lens dissappointed.

Those who complain about Sigma QC should all consider the 16-50 thread, as great as Pentax gear is, they have a bad apple it seems, i think Sigma got their reputation from whatever Sigma's bad apple was, sponsored by brand fan boy touting "This is why i only buy L glass, then i know what i get." And even L lenses have their occasional bad seed. Let's just be glad the internet exists and one can find about those bad apples, too bad some people have to be the first to bite said bad apple.

All that said, i don't think the 31/1.8 is worth the extra money unless you plan on shooting it on film, it does perform better tested on a APS-C cam as far as border performance, considering you test the sweet spot. Just not twice as good and never reaches the Sigma in center resolution.
I find the 30/1.4 to be a stellar performer, considering i will want the center in focus at a wide aperture with the background blurring into oblivion. And if there was a 31/1.8 show off thread, it would be full of such shots, so why not choose the faster less expensive one?

EDIT: But let me add, if Pentax were to make a DA 30/1.4 that is anything like the 70/2.4 and cost less than a 31/1.8 or better under $500 (street), i would have to give it a try.

egordon99 · 10-27-2008, 06:20 AM

I LOVE the Sigma 30mm on my 40D/Xsi. Corners are fine, maybe not quite as sharp as the center, but still excellent. Fairly sharp wide open (remember the DOF at f/1.4 is really thin), and gets brutally sharp from f/2 up. Bokeh is excellent was well. Only wish it focused a little closer (not sure how it compares to the 31 in this respect....)

pingflood · 10-27-2008, 06:29 AM

Originally posted by egordon99

I LOVE the Sigma 30mm on my 40D/Xsi. Corners are fine, maybe not quite as sharp as the center, but still excellent. Fairly sharp wide open (remember the DOF at f/1.4 is really thin), and gets brutally sharp from f/2 up. Bokeh is excellent was well. Only wish it focused a little closer (not sure how it compares to the 31 in this respect....)

Yeah, I agree on the close focusing. Since 30mm is pretty wide it can be a bit limiting at times. But we can't have it all.

joshmas · 10-27-2008, 07:18 AM

Thanks for all the input.
I have the Sigma 10-20mm and have no issues with the build or quality of that piece of glass. That being said I can't find anyone near Austin with the Sigma 30mm with the Pentax mount.

Don't know if this would influence anybody's opinion of how I should leap, but I currently have:
Hogamods Lens
Pentax 18-55mm kit
Pentax 50-200mm
Pentax 50mm f1.4
Sigma 10-20mm

Best,

Josh

Miserere · 10-27-2008, 11:41 AM

Josh, another thing to consider is that the 31 Ltd is a full-frame lens, while the Sigma is for APS-C. This is only important if you want to use it with both film and digital.

As for price, the 31 Ltd is certainly expensive, which kept me from buying it for the longest time. When Microsoft brought back the Live.com cashback discounts a couple of weeks ago I saw it as a sign and bought the 31 Ltd with a $200 cashback.

Here's a tutorial on how it works.

In 2002 Popular Photography declared the 31 Ltd was one of "The 3 greatest prime lenses we've ever tested!!!". Read here. That's no small praise!

joshmas · 10-27-2008, 01:47 PM

The only film camera that I still have is a Nikon 6006, and it hasn't been powered since I got my k10d, so that is much less of an issue.

I plan on spending some time looking through flickr tonight and pulling the trigger on one of the 2 tomorrow so I'll have it in time for the TV on the Radio show later this week.

soccerjoe5 · 10-27-2008, 02:05 PM

If I had the money to spend, I'd easily get the 31 over the sig 30. As Miserere mentioned, the FA limiteds are known to be the "best" AF lenses money can buy.

But I couldn't afford the 31, I'm pretty sure I'd be happy with the sigma 30.

roentarre · 10-27-2008, 02:06 PM

The only one thing you could be re-assured about is the fact that many people bought Fa 31 ltd and sold it within a few months.

This is because many buyers do not know what they want from that particular lens, buying Fa 31 ltd because everyone says so. If you do not know why you want such a premium lens and cannot discern the subtleness of the optic rendering from a particular lens.

Sigma 30mm f1.4 is more than enough for any pro shooters but probably not good enough for so-called enthusiasts. Again, if you are more of a photographer getting the lens for real life applications not shooting f1.4 with subject off centre most of the time, sigma 30mm f1.4 is definitely more than enough.

The recent comparison I had seen between sigma 30mm f1.4 versus Leicasonic 25mm f1.4 on olympus forum reveals leica inferior to all rendering parameters except corner sharpness. This is in the setting where Leicasonic is 5 times more expensive than sigma. Well, funny thing about brand names.

joshmas · 10-27-2008, 02:36 PM

James,
Thanks for that. Exactly the kind of advice and perspective that I was looking for. BTW, I love the cottage photo on your blog!

It's as much a question of value as cost if that makes sense. I think that I'll grab the Sigma for now. I'm happier with the shots that I get with my Pentax 50mm f.4, than just about anything.

I just find myself backing up into people with it, and want to get something that will save peoples toes and still give me the results I crave.

Josh

joshmas · 10-29-2008, 03:00 PM

The Sigma just arrived via UPS, and I'll be putting it through the paces tonight!

Thanks to all for their input.

Josh

pingflood · 10-29-2008, 04:30 PM

Let's see some pics!

Here's one pretty fresh from mine:

Eigengrau · 10-30-2008, 08:39 AM

Quote:

It's as much a question of value as cost if that makes sense. I think that I'll grab the Sigma for now. I'm happier with the shots that I get with my Pentax 50mm f.4, than just about anything.

I just find myself backing up into people with it, and want to get something that will save peoples toes and still give me the results I crave.

Let us know how it turns out! I've thought about this same thing many times, but I have a habit of shooting with my subjects at the edge or off center in the frame, so I'm concerned that all that center sharpness won't count for much for my purposes. However, it sure would be nice to have that extra half stop and keep $400 in my wallet.

10-26-2008, 03:29 PM	#227
felix68 Senior Member Join Date: Aug 2007 Location: San Jose, CA Posts: 281	Get the 31! Originally posted by joshmas I'm looking to fill out my primes and pick up one of these 2 lenses next for my k10d. I was wondering if anyone had experience with both the lenses and could guide me. I'd be looking to use this for about 50% portrait, and 50% landscape. All help appreciated. Best regards, Josh I don't have the Sigma but have shot with it on a friends Oly. To me, even on 4/3 it was not good in the corners and soft wide open. The 31 is very good wide open. Here is a shot at f2:

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10-26-2008, 02:33 PM	#226
pingflood Veteran Member Join Date: Jun 2008 Location: Borås, Sweden Photos: Gallery Posts: 3,169	Hi Josh, I have experience with the Sigma only, but a few comments: The Sigma is not a great lens for landscapes where you want as much detail as possible across the board. It is BRUTALLY sharp in the center (the 31 is no slouch, but the Sigma does outperform it there according to tests), but the edges are pretty much crap compared to the Pentax... (edit: I should have stated that differently, the edges aren't horrible but noticeably weaker than some other lenses -- depends on the image/scene and print size. For most regular day to day shots you probably won't be bothered by it at all.) That said, the Sigma is cheaper (much), is nearly a stop faster, and for pictures where you don't fret over uniform sharpness edge-to-edge it's superb. If I had the same requirements you do I'd probably get the Sigma for low light and portraits, and another wider lens for landscape work. For me the 31 would be too tight for doing landscape, but you might have a different take on it. I have a couple of shots and some commentary here with the Sigma... (also posted in a thread here) storpotaten: A tonion of onions (Sigma 30/1.4) Last edited by pingflood; 10-27-2008 at 06:54 AM.

10-26-2008, 04:12 PM	#228
pingflood Veteran Member Join Date: Jun 2008 Location: Borås, Sweden Photos: Gallery Posts: 3,169	If the Sigma was soft wide open it was probably a poor sample. It may have many flaws, but being soft isn't one of them! Then again, Sigma quality control appears to leave a lot to be desires, which is unfortunate as the good Sigma samples are really, really good.

10-26-2008, 09:04 PM	#229
morfic Veteran Member Join Date: Feb 2008 Location: San Antonio, TX Photos: Gallery Posts: 428	Originally posted by pingflood If the Sigma was soft wide open it was probably a poor sample. It may have many flaws, but being soft isn't one of them! Then again, Sigma quality control appears to leave a lot to be desires, which is unfortunate as the good Sigma samples are really, really good. I bought the 30/1.4 well knowing the borders and extreme corners never quite catch up to the center performance (in lab tests), but i have yet to try a Sigma lens and return it because the lens dissappointed. Those who complain about Sigma QC should all consider the 16-50 thread, as great as Pentax gear is, they have a bad apple it seems, i think Sigma got their reputation from whatever Sigma's bad apple was, sponsored by brand fan boy touting "This is why i only buy L glass, then i know what i get." And even L lenses have their occasional bad seed. Let's just be glad the internet exists and one can find about those bad apples, too bad some people have to be the first to bite said bad apple. All that said, i don't think the 31/1.8 is worth the extra money unless you plan on shooting it on film, it does perform better tested on a APS-C cam as far as border performance, considering you test the sweet spot. Just not twice as good and never reaches the Sigma in center resolution. I find the 30/1.4 to be a stellar performer, considering i will want the center in focus at a wide aperture with the background blurring into oblivion. And if there was a 31/1.8 show off thread, it would be full of such shots, so why not choose the faster less expensive one? EDIT: But let me add, if Pentax were to make a DA 30/1.4 that is anything like the 70/2.4 and cost less than a 31/1.8 or better under $500 (street), i would have to give it a try.

10-27-2008, 06:20 AM	#230
egordon99 Inactive Account Join Date: Dec 2006 Location: Outside of Philly Posts: 1,561	I LOVE the Sigma 30mm on my 40D/Xsi. Corners are fine, maybe not quite as sharp as the center, but still excellent. Fairly sharp wide open (remember the DOF at f/1.4 is really thin), and gets brutally sharp from f/2 up. Bokeh is excellent was well. Only wish it focused a little closer (not sure how it compares to the 31 in this respect....)

10-27-2008, 06:29 AM	#231
pingflood Veteran Member Join Date: Jun 2008 Location: Borås, Sweden Photos: Gallery Posts: 3,169	Originally posted by egordon99 I LOVE the Sigma 30mm on my 40D/Xsi. Corners are fine, maybe not quite as sharp as the center, but still excellent. Fairly sharp wide open (remember the DOF at f/1.4 is really thin), and gets brutally sharp from f/2 up. Bokeh is excellent was well. Only wish it focused a little closer (not sure how it compares to the 31 in this respect....) Yeah, I agree on the close focusing. Since 30mm is pretty wide it can be a bit limiting at times. But we can't have it all.

10-27-2008, 07:18 AM	#232
joshmas New Member Join Date: Jul 2008 Location: Wimberley TX Posts: 21	Thanks for all the input. I have the Sigma 10-20mm and have no issues with the build or quality of that piece of glass. That being said I can't find anyone near Austin with the Sigma 30mm with the Pentax mount. Don't know if this would influence anybody's opinion of how I should leap, but I currently have: Hogamods Lens Pentax 18-55mm kit Pentax 50-200mm Pentax 50mm f1.4 Sigma 10-20mm Best, Josh

10-27-2008, 11:41 AM	#233
Miserere Veteran Member Join Date: Sep 2007 Location: Boston Photos: Gallery Posts: 1,993	Josh, another thing to consider is that the 31 Ltd is a full-frame lens, while the Sigma is for APS-C. This is only important if you want to use it with both film and digital. As for price, the 31 Ltd is certainly expensive, which kept me from buying it for the longest time. When Microsoft brought back the Live.com cashback discounts a couple of weeks ago I saw it as a sign and bought the 31 Ltd with a $200 cashback. Here's a tutorial on how it works. In 2002 Popular Photography declared the 31 Ltd was one of "The 3 greatest prime lenses we've ever tested!!!". Read here. That's no small praise!

10-27-2008, 01:47 PM	#234
joshmas New Member Join Date: Jul 2008 Location: Wimberley TX Posts: 21	The only film camera that I still have is a Nikon 6006, and it hasn't been powered since I got my k10d, so that is much less of an issue. I plan on spending some time looking through flickr tonight and pulling the trigger on one of the 2 tomorrow so I'll have it in time for the TV on the Radio show later this week.

10-27-2008, 02:05 PM	#235
soccerjoe5 Veteran Member Join Date: May 2008 Location: Philippines Photos: Gallery Posts: 1,343	If I had the money to spend, I'd easily get the 31 over the sig 30. As Miserere mentioned, the FA limiteds are known to be the "best" AF lenses money can buy. But I couldn't afford the 31, I'm pretty sure I'd be happy with the sigma 30.

10-27-2008, 02:06 PM	#236
roentarre Veteran Member Join Date: Oct 2006 Location: Melbourne, Australia Posts: 11,783	The only one thing you could be re-assured about is the fact that many people bought Fa 31 ltd and sold it within a few months. This is because many buyers do not know what they want from that particular lens, buying Fa 31 ltd because everyone says so. If you do not know why you want such a premium lens and cannot discern the subtleness of the optic rendering from a particular lens. Sigma 30mm f1.4 is more than enough for any pro shooters but probably not good enough for so-called enthusiasts. Again, if you are more of a photographer getting the lens for real life applications not shooting f1.4 with subject off centre most of the time, sigma 30mm f1.4 is definitely more than enough. The recent comparison I had seen between sigma 30mm f1.4 versus Leicasonic 25mm f1.4 on olympus forum reveals leica inferior to all rendering parameters except corner sharpness. This is in the setting where Leicasonic is 5 times more expensive than sigma. Well, funny thing about brand names.

10-27-2008, 02:36 PM	#237
joshmas New Member Join Date: Jul 2008 Location: Wimberley TX Posts: 21	James, Thanks for that. Exactly the kind of advice and perspective that I was looking for. BTW, I love the cottage photo on your blog! It's as much a question of value as cost if that makes sense. I think that I'll grab the Sigma for now. I'm happier with the shots that I get with my Pentax 50mm f.4, than just about anything. I just find myself backing up into people with it, and want to get something that will save peoples toes and still give me the results I crave. Josh

10-29-2008, 03:00 PM	#238
joshmas New Member Join Date: Jul 2008 Location: Wimberley TX Posts: 21	The Sigma just arrived via UPS, and I'll be putting it through the paces tonight! Thanks to all for their input. Josh

10-29-2008, 04:30 PM	#239
pingflood Veteran Member Join Date: Jun 2008 Location: Borås, Sweden Photos: Gallery Posts: 3,169	Let's see some pics! Here's one pretty fresh from mine:

10-30-2008, 08:39 AM	#240
Eigengrau Senior Member Join Date: Aug 2008 Location: Colorado Photos: Albums Posts: 250	Quote: It's as much a question of value as cost if that makes sense. I think that I'll grab the Sigma for now. I'm happier with the shots that I get with my Pentax 50mm f.4, than just about anything. I just find myself backing up into people with it, and want to get something that will save peoples toes and still give me the results I crave. Let us know how it turns out! I've thought about this same thing many times, but I have a habit of shooting with my subjects at the edge or off center in the frame, so I'm concerned that all that center sharpness won't count for much for my purposes. However, it sure would be nice to have that extra half stop and keep $400 in my wallet.