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05-29-2016, 08:09 AM   #1
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Head to Head comparison between FA 31ltd and Sigma 30mm f/1.4

Looking for head to head comparison between the Sigma 30mm f/1.4 (I'd prefer the older screw drive version but the HSM version would be acceptable) and the FA 31 ltd. Other than being a stop faster I don't know any differences between these two lenses. There is a comparison review of sharpness and bokeh between the Sigma 35mm f/1.4 and the FA 31 ltd but that's all I could find.

NaCl(enquiring minds want to know)H2O

05-29-2016, 09:01 AM   #2
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QuoteOriginally posted by NaClH2O Quote
Other than being a stop faster I don't know any differences between these two lenses.
Price? Image circle?

This article compares all three (sort of):

Sigma 30mm F1.4 DC HSM "Art" Review - Introduction | Reviews


Last edited by stevebrot; 05-29-2016 at 09:10 AM.
05-29-2016, 09:05 AM - 3 Likes   #3
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I had the 31mm for a little while and now have the much cheaper (older withough HSM) Sigma 30mm 1.4.
First, the Sigma is APSC only, maybe it matters to you, maybe not. The 31mm is of course a FF compatible lens.
I haven't use the 31mm enough to give you a faire comparaison, so I won't do that. I'll however comment on sharpness and share some other random thoughts.
The Sigma is as sharp wide open as any f/1.4 lens I've seen. I will say however that I only use the lens wide open at relatively close range, for portraiture and similar application, so well within 8 meters. Beyond that, it's probably fine as well. Not that I would shoot at infinity and wide open. The center focus point is dead accurate on my K-5ii (I may have calibrated the lens, but that's something I do with all of my lenses anyway). I never noticed any problem with off center point either, but I mostly use center point. The focussing is about as fast a other screw drive lenses in that focal range, maybe a little slower than the DA 35mm 2.4, but nothing to complain about on my side.
As mentioned before, I use the Sigma for portraiture, low light indoor photojournalism and other indoor assignments. I never use this lens hoping to get edge to edge sharpness, so I wouldn't even be able to tell you how it fairs in that regard. Some people say corners and edge are terribles, I've never notice it, but my edges and corners are usually oof anyway.
About rendering, I absolutely love the shallow depth of field this lens provide and I haven't notice any problem in the bokeh either. I don't think it has a lot of character, meaning it seems "normal" most of time. To better explain, I'll try to compare with other lenses. The DA* 55mm 1.4 in comparaison sometimes offer Bokeh that will make you look twice and go "wait, what just happened?" because the Bokeh is either very nervous, or looks strange in some way. It's not a bad thing, but it happens. My 50mm f1.7 will also offer some strange, but lovely, Bokeh as well sometimes. It seems to me the Sigma is more constant in that regards, in the context I use it in anyway. I honestly think it doesn't offer anything crazy, but that it does offer very nice images for a good price and I'm perfectly happy with it. I will say however that I'm never tempted to use it outside in good light condition as I just don't think it would make the image pop as a limited like the 31mm would. But for indoor low light stuff, I think it rocks really good.

The FA 31mm offers a rendering that is more complex to me. I was looking at some shots I took wide open with it and couldn't help but look twice at most of the images. Most of them were snapshots of my kids doing their things, or picture in a book store, etc. I don't know if it was the colours, the contrast, or simply the presence of subtle chromatics aberrations in the transition from in focus to the out of focus zone that made the image special but truth be told, even after selling the lens, I could tell it produced some "special" images for me. Also, when I had it, I was more compelled to use outdoor - I think the coating made for better images of the outdoor colours.

I don't know what you would use the lens for (do tell us if you have an idea, it may help people offer you comparison), but I can recommend the Sigma for anything low light as I believe it offers good sharpness at 1.4 and pleasant bokeh, without being a complicated lens in my view, like some other lenses are. (For instance, I find hard to like the DA 70mm 2.4, but it sometimes just offer me that very nice picture that convince me to keep it, even if I own the 50-135mm that covers the 70mm focal length and is about as fast of a lens (although much bigger, of course!).
05-31-2016, 01:30 AM   #4
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I got only the older Sigma 30. Its the lens I attached if I want autofocus. Some of my best kid pictures were taken with that lens. Buy it if you can and you wont regret it. But if you are planning to use it on the K1, better choose a different lens.

05-31-2016, 02:17 AM   #5
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I can't really post comparison photos, as I owned the Sigma 30 for awhile, but sold it in favor of the FA 31. Biggest things that I didn't like about the Sigma were that the borders weren't sharp and stayed soft to f8 and the bokeh could be rough at times. Lots of messy octagons all over the place. I'm more used to Pentax's rounded highlights and I like that better.

As an added benefit, the FA 31 works quite nicely on the K-1.
05-31-2016, 05:01 AM   #6
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QuoteOriginally posted by NaClH2O Quote
Looking for head to head comparison between the Sigma 30mm f/1.4 (I'd prefer the older screw drive version but the HSM version would be acceptable) and the FA 31 ltd. Other than being a stop faster I don't know any differences between these two lenses. There is a comparison review of sharpness and bokeh between the Sigma 35mm f/1.4 and the FA 31 ltd but that's all I could find.

NaCl(enquiring minds want to know)H2O
06-01-2016, 08:59 AM   #7
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I don't have a FA 31 Ltd (YET, he said through clenched teeth), but I have both the Sigma 30 EX and the 30 Art. the Sigma 30 EX has a strongly curved plane of focus (globe of focus?), which causes the corners to be extremely soft. This can be useful for portraits and subject isolation, but not so good for applications where you want sharp corners. The Art 30 has more elements and is a little more corrected with a little smoother bokeh, but it is still soft-ish in the corners. Both have quite a bit more distortion than the 31Ltd, plus some issues with CA wide open. While the EX 30 makes very nice stars at f/5.6 and above, the 30 Art is extremely flare resistant, and will NOT "star" even if you want it to. I prefer the silent focusing of the 30 Art most of the time, but I kept the EX 30 for shooting Christmas lights (and because I believe LBA is an unappreciated art form).
06-01-2016, 07:11 PM   #8
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I had both the sigma 30 and the 31 at the same time and concur with pretty much what everyone else said. The sig 30 is really nice as a fast normal on crop. It does "the thing". The 31 is the 31. If you can afford it, yeah, it's nicer. It's got that pixie dust and better edge to edge sharpness. But the price difference is significant.


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