Fast fifties: Pentax vs Sigma

Since I take a lot of portraits (well, 'posed photos of people', I know that some people have a narrow technical definition of portrait ) I was planning to make a 50mm f1.4 lens my next purchase. This used to be a no-brainer: the Sigma was £100 cheaper than the Pentax and sharper wide open. Now SRS have gone and reduced the Pentax FA in their sale to less than the price of the Sigma, so I'm stuck again. Does anyone have experience of both lenses? (with the amount of time Pentax have been making that FA I'm guessing there might be!)

My primary concern with the Sigma (apart from the size, and whether what is now a higher price is worth it) is the reported focusing issues - although I understand these are a) More common on Canon bodies, where Sigma has always had problems and b) apparently/allegedly fixed in subsequent post-release batches.

Opinions?

The Pentax is a very fine lens. If you ever came to re-sell it then it would hold its value much better than the Sigma. Witness the way Samsung versions of Pentax lenses do not sell as well as Pentax ones, even though identical.

Apart from that the reasons for staying with marque lenses are well known.

Sounds like a no-brainer to me. I've rarely heard a bad word about the FA50 1.l4. And as John points out, as well as saving money now, it'll be a better long term investment!

I've not used it, but the Sigma is a much larger and heavier lens, so that means in theory at least that better optics could be built into it. The review of the the Canon-fit version on photozone.de is impressive.

The top class Sigma lenses hold their value well, and even go up in value.

I have a Pentax FA f1.4. It's excellent from f2.8, and nice and portable, but is not very sharp wide open.

A SMCP-FA 50mm for sale here if you are quick.

Pentax:

Smaller, lighter, arguably the best of the classic 50mm 1.4s and exhibits almost no distortion.

Sigma: Sharper wide open due to more modern design, but bigger, heavier, more expensive.


For me the beauty of a 50mm prime is they're so small and light that you have to have a good reason NOT to have one in your bag, so I'd go for the Pentax every time.

If you want absolute best possible image quality, consider the sigma in this case.

Devil's advocate mode on...

GET THE DA*55 f1.4

You won't regret it, sod the expense...

Devil's advocate mode off

If Pentax (or SRS) were to start offering an 'Xbox RROD'-style extended warranty on SDM failures I might think about it

SDM failures with the DA*55 :

How durable are SDM motors likely to be in the very long run? Lenses without motors will last a human lifetime if you don't do anything silly.

Indeed Pete, I hope they thought about that and made it easy serviceable

Indeed it is quite possible to mount certain lenses on our DSLRs which are already well on their way to their first human lifetime.

There are Takumars out there which are old enough to be my dad!

The sigma is better in almost everyway except for size.
Its price is kind of ridiculous when you think of what the price of FA 50 SHOULD be, and the price at which you can get so many fast manual fifties.

The street price of the current 50mm F1.4 AF lenses is not so far adrift from the actual Pentax street price.

There are a couple of plastic-construction f1.8 lenses from Canon and Nikon, but these are not made in the same way.

I've had two screw drive AF failures over the years, both involved repairs which cost around £50 each to fix. They were an FA 20-70 f4.0, which finally fell apart with elements separating (a common problem with that lens), and an FA 28-80 f3.5-4.7 Power Zoom which fell apart 3 times!

Pentax's FA series of "plastic fantastic" AF zoom lenses were not that wonderful and failed in all sorts of other ways, so screw drive is not a panacea for AF woes. Screw drive also has considerably more backlash than SDM, so consistent critical focus is more unreliable.

I've checked with Asahi Photo about SDM repairs for when my lenses are out of warranty. They can replace an SDM motor for around £65 which includes a general service and clean, if anything else is wrong, then naturally there would be extra costs.

SDM lenses hold no particular fears for me, but I do agree that maybe they should/could be faster considering they are (now) priced at the upper end of the market.

I do believe there could be other more serious issues than SDM, lens IQ manufacturing inconcistency and the long term durability of the internal cams, precision moving parts and seals concern me somewhat. But maybe I'm being paranoid!