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09-18-2008, 11:07 AM   #1
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Sigma 30mm f/1.4?

Anyone have exprience/opinions about the Sigma 30mm f/1.4? I found one review in the lens database (9), any others? Popular Photography gives it an A+ SQF rating at 11x14" size but photozone hits it pretty hard and gives it only **.

Assuming I can't step up to the FA 31, the Sigma has speed and wider range compared to the FA 35, but that comes with weight, distortion and higher price. Thanks, FHPhotographer

09-18-2008, 11:35 AM   #2
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I have one... pretty much like it except for shots at F1.4 2..10m away.
Most likely its some kind of defect so most of lenses should be fine.
Mine, mounted on k100ds "likes backgrounds".. at the mentioned distances the lens does not back focuses, but if the subject is not large enough to completely cover whole selected focus point (and sometimes even if it is) it focuses to subject right behind it.
If there is nothing behind, the focus is dead on.
Some examples: Inbox Foto (foto.inbox.lv) (Exif shown at the right side)
Pictures containing IR/OK in title i considered to be focused as i wanted, those with GARAM/NAV are not.
Never had red of this kind of glitch before in internet, so decided some might be interested.
At first i taught it was my incompetence with F1.4, but after more careful testing the results were quite consistent.

In situations other that described, knowing the cons (CA's, distort., corner sharp.) the lens seems to be perfect.
Rich colors, no hunting, sharp in center, good weight balance on k100d, 3d feel in images. Actually i like it so much i dont mind the defect... well.. don't mind alot. But if i had to decide right now, i would rather spend my money on 35/2.
When im shooting with it, it almost seems the same as it was with 50mm helios on my Zenit-E.

Last edited by ytterbium; 09-18-2008 at 11:41 AM. Reason: update
09-18-2008, 11:37 AM   #3
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From what I've read it's very sharp in the center but soft near the edges. You may want to consider the new DA 35mm Macro Limited for around $389 with a UV filter from Prodigital2000. Another very good option is the Pentax FA 35mm F2 for 4300 from Adorama. The later is almost 95% as food as the Pentax FA 31mm Limited which goes for three times higher price.
09-18-2008, 11:41 AM   #4
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the sigma 28mm F1.8 is also a fantastic lens, and its FF compatible, only downside is its size.

09-18-2008, 12:02 PM   #5
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QuoteOriginally posted by Gooshin Quote
the sigma 28mm F1.8 is also a fantastic lens, and its FF compatible, only downside is its size.
Not to mention the 24mm f1.8 and the 20mm f1.8, getting progressively heavier (though not by much, once you're at the 28mm already), and with progressively more optical criticism in review, as a rule .
09-18-2008, 01:03 PM   #6
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QuoteOriginally posted by MrA Quote
Not to mention the 24mm f1.8 and the 20mm f1.8, getting progressively heavier (though not by much, once you're at the 28mm already), and with progressively more optical criticism in review, as a rule .
i dunno... i can pit the 28 against the FA31 and i'm quite confident that if one strips the exif people will be at a loss as to which is better or worse.
09-18-2008, 01:32 PM   #7
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What does "soft" at the edges mean?

QuoteOriginally posted by Stratario Quote
From what I've read it's very sharp in the center but soft near the edges. You may want to consider the new DA 35mm Macro Limited for around $389 with a UV filter from Prodigital2000. Another very good option is the Pentax FA 35mm F2 for 4300 from Adorama. The later is almost 95% as food as the Pentax FA 31mm Limited which goes for three times higher price.
I've always wondered about this: if a lens is "soft" at the edges, how much of the image is soft? For example, the following is a test shot from photozone for this lens (Sigma 30 f/1.4) with the 10% of the image greyed out. So, if the image were really cropped like that, would the remaining 90% be sharp edge to edge, or is the "softness" linear, decreasing at a steady rate moving toward the middle point?

FHPhotographer

Last edited by FHPhotographer; 09-18-2008 at 01:55 PM.
09-18-2008, 02:03 PM   #8
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QuoteOriginally posted by FHPhotographer Quote
I've always wondered about this: if a lens is "soft" at the edges, how much of the image is soft? For example, the following is a test shot from photozone for this lens (Sigma 30 f/1.4) with the 10% of the image greyed out. So, if the image were really cropped like that, would the remaining 90% be sharp edge to edge, or is the "softness" linear, decreasing at a steady rate moving toward the middle point? r
Also, isn't the 30mm a FF lens? If so, surely on a crop body, the soft edges are the bit you don't see anyway.

09-18-2008, 02:13 PM   #9
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QuoteOriginally posted by MrA Quote
Also, isn't the 30mm a FF lens? If so, surely on a crop body, the soft edges are the bit you don't see anyway.
Not a FF but it is soft in the corner even stopping down. The good thing about this lens is that it has the consistensy with image performance, hesistant AF from time to time but not that bad after all. I can assure you that people would sell after 1 year owning it. It is almost always the case.
09-18-2008, 02:58 PM   #10
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I'll Take That Bet

QuoteOriginally posted by Gooshin Quote
i dunno... i can pit the 28 against the FA31 and i'm quite confident that if one strips the exif people will be at a loss as to which is better or worse.
??? You really think that corner to corner, say at f2, the Sigma is going to stack up to the FA31? This lens and all of the Sigma wide primes have been criticized for soft corners at most apetures.
Post the photos and I will venture a guess
I don't have the Sigma 28mm but I have the FA31mm and it startles me how good every shot is. The FA31 is magic - worth every penny - worth $1,200 just like the Canon 35mm L glass.
Brick walls at 2 paces.... I am calling you out on that one!
09-18-2008, 04:13 PM   #11
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OP, let's go back to the original question...

QuoteOriginally posted by felix68 Quote
??? You really think that corner to corner, say at f2, the Sigma is going to stack up to the FA31? This lens and all of the Sigma wide primes have been criticized for soft corners at most apetures.
Post the photos and I will venture a guess
I don't have the Sigma 28mm but I have the FA31mm and it startles me how good every shot is. The FA31 is magic - worth every penny - worth $1,200 just like the Canon 35mm L glass.
Brick walls at 2 paces.... I am calling you out on that one!
Before this thread gets lost in a mine is better than yours back n' forth, can we keep this to either the original question I posted or the follow-up about what constitues corner softness for this particular lens?
Thanks,
FHPhotog
09-18-2008, 05:04 PM   #12
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QuoteOriginally posted by roentarre Quote
I can assure you that people would sell after 1 year owning it. It is almost always the case.
That certainly has been the case for friends of mine who have owned it (Canon & Nikon users). After an initial honeymoon period, the novelty wears off.
09-18-2008, 06:14 PM   #13
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After reading through this thread, I decided to go to Photozone and run through the optical quality ratings of all the Pentax lenses which had been tested. Needless to say, the 31mm f/1.8 is rated 4 star, and is highly recommended. Only four other Pentax lenses carry the same rating and recommendation, and one of them is the FA35mm f/2.0 mentioned above. The others are the DA 40mm f/2.8 ltd, the DA 70mm f/2.4 ltd., and the FA* 300 f/4.5. I was quite surprised to find that the highly touted DA* 50-135mm f/2.8 had only a 3 star rating. I guess that leads to the conclusion that there's more involved in the quality of a lens than the way it performs on a series of technical tests.

CN
09-18-2008, 06:24 PM   #14
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I have three of the Sigma fast wide primes: the 20/1.8, the 24/1.8 and the 30/1.4.

The 20/1.8 is the worst, so soft wide open (even in the center of the frame) that it's unusable unless stopped down till F/2.8. So what's the purpose of a fast 20mm lens if you have to use it at F/2.8?

Then comes the 30/1.4. As stated by others, it's quite soft at the edges, even when stopped down. I have no issues with focusing (maybe I got a lucky number) and the bokeh is pleasant. There is quite a bit of chromatic aberrations and distortion. I find edge sharpness and distortion are the main problems. They make this lens unusable for architecture or landscape. It would be suitable for portraiture but 30mm is not the best focal length for that in my opinion.

The 24/1.8 is the best of the bunch with no blatant issues. A good lens for everyday use as a widish normal lens on a crop format camera. Its close focus feature is very useful for close ups (museums). It remains perfectly usable at F/1.8 for low light interior shots. And when Pentax will finally release its full frame DSLR, it will turn into a great wide angle lens .

Cheers!

Abbazz
09-18-2008, 06:30 PM   #15
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QuoteOriginally posted by Clem Nichols Quote
...I was quite surprised to find that the highly touted DA* 50-135mm f/2.8 had only a 3 star rating. I guess that leads to the conclusion that there's more involved in the quality of a lens than the way it performs on a series of technical tests.

CN
Why continue to test with the K10D?
Testing with the K20D might yield better results.

Anyway whatever tests done relate to that specific lens being tested. It might be different with a different unit. To generalize from a single instance is a common philosophical fallacy.
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