[NicK10D]

I am looking to buy a lens for my k20 that opens up to 1.4 but I am not sure which one to get. I can get a used Pentax SMCP-FA 50mm f/1.4 Lens for a cheaper price than the sigma but i here the pentax is a little soft from 1.4 to 2.0 in the reviews. anyone have either of these lenses or know which one will preform better in low light?

Thanks

[rustynail925]

The pentax is indeed soft at wide apertures.
if weight is not an issue go for the sigma..

[Huwi]

I've got sigma, either of the lenses shoulb be good. I understand the 50mm pentax is roughly the same size and weight as the 35mm pentax. If you want lightweight, go for pentax. There might also be some focusing issues with the sigma, at least thats what i've heard. I like my gear a bit heavier, i think sigma was a good choice. Looks very professional too

[mikemike]

I've got the sigma and I have no complaints whatsoever. It is very sharp all the way through to 1.4. One of the things that made me hesitant about the pentax was people saying that pentax's motors are iffy which is something to consider especially when looking at a used copy.

[RBellavance]

One of the things that made me hesitant about the pentax was people saying that pentax's motors are iffy which is something to consider especially when looking at a used copy.

The FA50/1.4 does not feature an in-lens AF motor. The DA*55/1.4 does, however.

[noahpurdy]

My recommendation if you have the cash would be the DA* 55 f/1.4. Otherwise the Sigma and hope you get a good copy.

[pop4]

I got the Sigma 50mm F1.4 EX DG HSM "Sigmalux" last week, and I really really like it. Centre sharpness is good at f/1.4, and by f/1.8, it's already pretty good across the whole frame. Bokeh is lovely too. Oh, and the HSM is both fast and quiet, and IMHO, the HSM alone is almost reason enough to go for the Sigma.
But, apparently there have been a few issues with front/back-focusing with copies of this lens, so try to test the lens out beforehand, or buy from a place with a liberal return policy.

[NicK10D]

Thanks