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12-01-2009, 07:31 AM   #1
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Sigma AF 30 1.4 vs Pentax FA 31 1.8 questions

I've been searching and reading pentaxforums for several months (excellent infotainment!) and the contributors have helped me with the decision to purchase a K-7 with the typical 18-55 and 50-200 lens kit that I have been using to practice photography for a couple of months now. The kit lenses seem to be pretty good for most of my shooting experiences except for low light interior/people shots or video. I'm looking for some lens advice. I've been all over the place with the pros and cons of trying to make a decision on the first general use (if that's possible) prime FL I should buy with low light use in mind. I don't have a lot of money for a good range of primes so it's a 1 lens a year purchase I have to live with for now. I think the 30mm +- a couple FL seems to be the best compromise. So I've been exploring the potential of the Pentax FA 31mm F1.8 limited or Sigma's 30mm F1.4 EX DC HSM.

I'd like to get your opinions. Is the Sigma, at more than half the price of the Pentax FA, good value/investment or should I keep saving for the 31 FA?
OR am I going down the wrong path and need to look at other options.

thx Greg

12-01-2009, 09:08 AM   #2
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The Sigma 30/1.4 is a great lens at its asking price, though you have to understand that a) though well-built it's nowhere near the quality feel of a Limited series lens, and b) it has very soft edges wide open that only become "good" when stopped down. However, the center sharpness is extremely high from wide open. I get some nice results with mine:

12-01-2009, 10:03 AM   #3

The real question is...

Are you ready for manual focus yet?

If you are there are a bucket full of lenses you can get for the price of thoses lenses. That will give you wonderful results.

If not I have seen wonderful examples from the Sigma and of course the 31 is the Queen of all lenses... it all comes down to budget and patience.

If you aint got the budget, do you have the patience to save for it?

In the end, get what makes you happy, anything less... makes you less happy.

I myself would love a sigma 30 1.4, but would love the 31 ltd a little more.
12-01-2009, 10:09 AM   #4
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Keep in mind that the sigma 30/1.4 DC is digital only (no aperture ring), whereas the pentax 31 has an aperture ring and works with any K-mount camera.

Two fast-30mm-ish autofocus alternatives:
-- Sigma 28/1.8 DG
-- Pentax FA35 (longer than you want but still worth considering)

12-01-2009, 10:28 AM   #5
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Greg, if you want to stay within that focal length, I would also consider the FA 35mm F2.0 it is only slightly slower at F2.0 than the FA 31 ltd. And it is very sharp thru all aperture ranges. I would say that the major difference between the FA 35mm and the FA 31mm ltd is that the bokeh (out of focus areas) is much better on the 31, and there is the magical 3D effect that the 31 achieves. I will admit to 31mm ltd envy, if I could afford it I'd certainly own one, but that focal length is so useful for my type of shooting that I "make do" with the FA 35mm. Actually the lens is very very good except when compared to one of the best AF primes in ANY mount. sm-02-05-02
But if you can afford the 31mm ltd, go for it

NaCl(it's the only lens I really really really want)H2O
12-01-2009, 10:37 AM   #6
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One thing I didn't like about the Sigma 30/1.4 is that the minimum focus distance is quite far away, which means that close-ups and detail shots weren't really possible. That's not true of the FA35. Not sure about the FA31. This may not matter to you at all, but thought I'd mention it.

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