[Winder]

I realize this thread has pretty much run its course, however I don't recall the following link being posted here. Its a french website so I can only read it using an online translate page, however it is pretty much the only direct comparison I've found between these two lenses. Here it is:

Test_31ltd

I realize its easy to say I am biased based on the fact that I own the Sigma 30, however, I am of the opinion that it gets some additional critisism because it says Sigma on it.

I am curious how its negatives would be viewed if it had 'Pentax' written on it instead.

Either way, if anyone is after a fast normal prime, you can't go wrong with either. I chose the Siggy largely because of the extra half stop, being sharp at f1.4, and the price difference. (Not to mention 10yr warranty vs. 1 or 2)

Since getting the Sigma 50mm and 85mm F/1.4 lenses I have been a pretty big fan of Sigma glass. I tried the 30mm and as I posted above, it is an excellent lens for people who center everything. For the price difference I would have loved to have been happy with the Sigma. So far I am pretty ecstatic with the 31mm LTD. Edge to edge sharpness even wide open is very good, and much better than I expected. AF is quieter, faster, smother than I expected, and the lens required no micro-adjustment on my K-5. Even the CA wide open is less than I expected when I ordered it.

[Edgar_in_Indy]

I realize this thread has pretty much run its course, however I don't recall the following link being posted here. Its a french website so I can only read it using an online translate page, however it is pretty much the only direct comparison I've found between these two lenses. Here it is:

Test_31ltd

I've never seen that review before, but it's very interesting. I wish it was in English! Google translate leaves a lot to be desired in this case.

[snake]

It's pretty easy to read, even if you don't speak French (lots of international and related words in use), but the big thing are the examples posted and the final verdict.

Apparently, the Sigma not only held its own, but did better in several areas, especially PF. Apparently, the FA31 isn't so leaps and bounds better than most will lead you to believe. It's the same case I've seen with the FA35 vs the FA31.

Too bad; maybe I should have bought a Sigma 30 instead of my FA35.

[gtl]

I do agree on the purple fringe part and coming from the DA limiteds I was slightly disappointed by the fringing initially. But after fiddling with lightroom 4.1 purple fringe controls, it no longer bothers me. The sharpness of the lens across the frame is truly magnificent. And the bokeh versus the 35mm macro is smoother. But I have to say for its price, its too expensive for a 'normal' lens on APS-C. On FF however...

[snake]

Yeah, PF doesn't bother me, in the least. Many lenses do it. It was not so tough to dial it out prior to LR4, but a dream in LR4.

[Frogfish]

I realize this thread has pretty much run its course, however I don't recall the following link being posted here. Its a french website so I can only read it using an online translate page, however it is pretty much the only direct comparison I've found between these two lenses. Here it is:

Test_31ltd

I realize its easy to say I am biased based on the fact that I own the Sigma 30, however, I am of the opinion that it gets some additional critisism because it says Sigma on it.

I am curious how its negatives would be viewed if it had 'Pentax' written on it instead.

Either way, if anyone is after a fast normal prime, you can't go wrong with either. I chose the Siggy largely because of the extra half stop, being sharp at f1.4, and the price difference. (Not to mention 10yr warranty vs. 1 or 2)

That's a n excellent test - thank you for posting the link. Take a LIKE for that !

[sheld]

It's pretty easy to read, even if you don't speak French (lots of international and related words in use), but the big thing are the examples posted and the final verdict.

Apparently, the Sigma not only held its own, but did better in several areas, especially PF. Apparently, the FA31 isn't so leaps and bounds better than most will lead you to believe. It's the same case I've seen with the FA35 vs the FA31.

Too bad; maybe I should have bought a Sigma 30 instead of my FA35.

The only downside of the Sigma 30mm F/1.4 is that its sooo much bigger than the pentax pancakes. Now that I like shooting with the DA21+D70 combo, sometimes I wish I had bought an FA35. I think the Pentax 31mm limited is roughly the same size as the Sigma though. I would prefer the extra 1/2 stop in speed over the DAL35/2.4. Actually, why can't Pentax make an inexpensive 35mm APSC F/1.8 .lens, like Nikon?
- Sheldon

[gtl]

The only downside of the Sigma 30mm F/1.4 is that its sooo much bigger than the pentax pancakes. Now that I like shooting with the DA21+D70 combo, sometimes I wish I had bought an FA35. I think the Pentax 31mm limited is roughly the same size as the Sigma though. I would prefer the extra 1/2 stop in speed over the DAL35/2.4. Actually, why can't Pentax make an inexpensive 35mm APSC F/1.8 .lens, like Nikon?
- Sheldon

Because that would cannibalize the FA31mm. I would imagine the profit margin on that lens is much higher than a APS-C 35mm f1.8 would offer.

[snake]

The only downside of the Sigma 30mm F/1.4 is that its sooo much bigger than the pentax pancakes. Now that I like shooting with the DA21+D70 combo, sometimes I wish I had bought an FA35. I think the Pentax 31mm limited is roughly the same size as the Sigma though. I would prefer the extra 1/2 stop in speed over the DAL35/2.4. Actually, why can't Pentax make an inexpensive 35mm APSC F/1.8 .lens, like Nikon?
- Sheldon

I can recommend the FA35. It's nearly perfect in my usage. It has some quirks with AF in certain conditions, but once one understands them, they get easier and easier to work around.

The DAL 35 is no slouch, either. If I didn't get the FA35, I'd likely have gotten that, but have been dissatisfied because I'm bumping ISO6400 at f2.0 as it is with my FA35.

[Designosophy]

Fun to try to read the translation:

Google Translate

[Edgar_in_Indy]

It's pretty easy to read, even if you don't speak French (lots of international and related words in use)

Sure, you can get the meaning most of the time, but it makes it more of a chore to read than a pleasure. I love to pour over a good lens review, and this seems to be a very good one indeed.

[Arrvon]

Sure, you can get the meaning most of the time, but it makes it more of a chore to read than a pleasure. I love to pour over a good lens review, and this seems to be a very good one indeed.

I know someone posted that website here in the past, which is how I found it. As you said, the reviews are quite well done (aside from the language issues for us). There are a lot of other good Pentax comparisons on that site as well!

The bottom line I think is that no matter how good a lens is, none are perfect. They all seem to have drawbacks in some way or another, which, of course comes from their design. In almost all cases, for a lens to be good in one area, it has to give something up in another area, be it speed, focal range, size, weight, etc, etc. In the Sigma 30's case, it seems they gave up the corner sharpness at the fastest apertures when they designed it. If they tried to keep it sharp across the frame at f1.4-f5.6, who knows what other 'pros' they would have had to compromise. Likely the center sharpness right from f1.4 would have been one. I am anything but an expert in this, but for me, I just try and learn to play to my lens' strengths. If I want sharper corners for landscapes, etc., I know I will have to stop down to f8 or f11, and they will be just fine. It's the same reason I don't drag a lens like the 18-250 through the dirt. I realize they had to make design compromises to get that immense range into one fairly small lens. Again I just try and learn/remember to stop down to f8 to get better sharpness.

[Rondec]

The only downside of the Sigma 30mm F/1.4 is that its sooo much bigger than the pentax pancakes. Now that I like shooting with the DA21+D70 combo, sometimes I wish I had bought an FA35. I think the Pentax 31mm limited is roughly the same size as the Sigma though. I would prefer the extra 1/2 stop in speed over the DAL35/2.4. Actually, why can't Pentax make an inexpensive 35mm APSC F/1.8 .lens, like Nikon?
- Sheldon

The Sigma really isn't that much bigger than the FA 31, particularly considering that it is a good half stop faster. The only thing is that the FA 31 is a full frame lens (as is the DA 35 f2.4), while the Sigma doesn't really cover that size sensor.

[Nick Siebers]

The FA 31 is physically longer, and while the Sigma may be a little fatter it feels smaller, to me. I am not sure about weight, I would have a hard time calling the Sigma bigger than the FA31. Bigger than the pancakes, sure, but the FA 31 is no pancake.

[Digitalis]

Niether lens is supposed to be a pancake lens (30mm f/1.4\FA31) and IMO it is a tad unfair to compare them to smaller, slower lenses - because I have yet to come across a pancake lens as fast as f/1.4. Fast lenses are always going to be big and heavy, when compared to slower lenses. Unless you are shooting Leica, or other mirrorless cameras for instance: The Voigtlander 35mm f/1.2 is one stop faster and slightly smaller than the FA31.