[Shakey]

Looking for a good low light lens for my K-3.

I can buy a good used FA for a little more than a new DA. The FA could be used on a K-1 if I ever decide to step up. Which would you choose and why? I have read the reviews.

You advice would be appreciated. Thanks for taking the time.

[pathdoc]

The DA is a lovely lens capable of excellent work, but the FA has several advantages as they apply to my shooting style, and I will detail what these are. You can decide to what degree they apply to you.

1) It is full-frame designed and rated, and being an FA lens it has MTF program line data available at full frame setting if you ever do step up. Some people (but not others) have reported what to them are serious frame coverage/vignetting issues with the DA50/1.8 either on full frame or on film bodies that can manipulate the aperture. There is no such question with the FA.

2) It has an aperture ring, which is of value to me because (a) I also shoot film bodies that have no in-body aperture control (e.g. ME, MX, Ricoh XR-1) and (b) I use blind (non-data-passing, non-stepdown) extension tubes a lot (I have a deglassed PK-A/R 2X teleconverter, but that's sometimes too much extension tube for what I want to do). A set of cheap blind K-mount extension tubes is a wonderful and inexpensive way to get into close-up or true macro photography, and 50mm is one of the classic focal lengths to use in this setting. Extension tubes eat light fast, and having f/1.4 to start with at least makes focusing and composition easy before you clamp the tripod and stop down in Av mode for the shot.

3) On APS-C cameras, any second-rate optical behaviour at the edges will be ignored.

4) It does have that extra fraction of a stop. What that's worth in digital, I am not sure because I find things get a little bit soft at f/1.4, more than they get at f/1.8 on the DA. This may be of value if you want it for portrait work or other artistic effects. On film, it can sometimes make the difference between chancing a handheld shot and knowing I shouldn't bother.

Given the need to choose one or the other and a close enough price as makes no difference, I would therefore take the FA over the DA. It just does more.

[schnitzer79]

cant comment on the FA but I had the DA which i sold a few months ago. best bang for your buck plus it was tack sharp wide open. If i were to buy a 50mm now, id probably go for the FA 1.7.

[pathdoc]

If i were to buy a 50mm now, id probably go for the FA 1.7.

While I concur with this advice, I have only reputation to go on and also the OP doesn't have that option on the table right now.

[robthebloke]

FA43 limited would be my choice! Both of the 50mm options are good lenses, but you need to stop them down to get the best out of them, so it somewhat negates the difference in aperture. Both 50mm lenses work fine on the k-1. If I had to choose between the two, that's a tough call. I'd probably choose the 50mm f1.4 simply because the resale value would be higher, and by buying used you won't lose anything if you decide it isn't for you. (I actually think the DA50 is a slightly better lens optically, but the difference is negligible).

[pres589]

Seems like FA50 1.7's sell in the Bay of E for around $150 or so in excellent condition, right? DA 50's are $120ish new, $90ish used in mint condition? If the FA 1.7 is noticeably better, I could rationalize going to the FA 1.7 myself, but this is another one of those questions that everyone has to answer for themselves. In any case, I'm thinking about abandoning my M 50 1.4 due to wide-open softness, and my continued hit or miss ability with focusing manually with this lens.

[climit]

DA 50/1.8 is almost like FA 50/1.7, it is a very nice lens much better than the 50/1.4 up to f/4.

[pathdoc]

(I actually think the DA50 is a slightly better lens optically, but the difference is negligible).

Agree, but with more flexibility on the FA's side, depending on the photographer's particular interests, it can sometimes be a difficult choice.

[leekil]

Are you most interested in the fast aperture, to the exclusion of the focal length? A 50mm would be a significantly different field of view on a K-3 vs. a K-1.

[Fabian]

The DA does very well on the K-1. Very sharp. Well controlled chromatic aberrations and purple fringing. Pretty normal vignetting for a 50mm on full frame.

Negatives - awkwardly squeaking autofocus sound. Camera Raw correction profile will apply its aps-c correction on your full frame image from a k-1, so if you want 100% accurate correction you'll have to profile it manually.

[pepperberry farm]

are you only interested in AF?

[Pentax Syntax]

I have both lenses and prefer the 50 1.4 FA. It works much better on the K-1 and equally well in the K-3. Make sure you buy a hood for the FA 1.4 if you get it. The Pentax 49 rubber ones are nice. Makes a huge difference in contrast.

[clackers]

They are included in the forum comparison here, Shakey:

Pentax 50mm Prime Lens Shootout Review - Introduction | PentaxForums.com Reviews

[Shakey]

They are included in the forum comparison here, Shakey:

Pentax 50mm Prime Lens Shootout Review - Introduction | PentaxForums.com Reviews

Yes, I did read the shootout before posting but wanted opinions of those who owned the lenses.

---------- Post added 05-31-17 at 06:20 PM ----------

are you only interested in AF?

Yes, I'd like to have the option of AF.

---------- Post added 05-31-17 at 06:21 PM ----------

Are you most interested in the fast aperture, to the exclusion of the focal length? A 50mm would be a significantly different field of view on a K-3 vs. a K-1.

Fast aperture.

[gm4life]

Just call it a day and blow the wad on the DA 55 *, it is currently mounted on my K3II and am still blown away by the results. Again the other two are nice lenses but the DA 55 * is a few leagues above those two.