Originally posted by alamo5000 In very low light your learning how to 'read the light' is vital. And as for how to shoot, you will have a lot easier time with the 31mm merely because the DOF is easier to work with.
Not to be contrary, but the FA31 is one of two lenses I'd be careful saying this about (the other being the FA*24/2). While it's true that wider lenses give greater DOF at similar apertures, the FA31 has such a smooth transition from in focus to out of focus that missing your focus point at all can just give photos an overall blurry appearance. (The FA*24 has the opposite problem - it has perhaps the most obvious transition to OOF I've ever seen, so you want to make sure you get all important elements within the focus "plane.") And the IQ of the FA31 is good enough that it's tempting to shoot between f/1.8 and f/2.2 much of the time - thus compounding the problem by making the correct focus critical on many of your shots. It's surprising how shallow the DOF can still be on a wider lens around f/2 - especially when the subject is closer to the camera.
Having said that, sometimes I've found the FA31 very good for indoor photos of family, and perhaps my best lens for indoor video as well. But for some reason I use the FA*24 a lot more often these days (and it's good at f/2.2 - which is nice for such a "wide" lens).
Originally posted by alamo5000 I had to fiddle with my F50 f1.7 with the fine focus adjustment more than any other lens, but I shoot it wide open all the time and it mine is pretty darn sharp. I don't have to stop mine down. I do have to manual focus a lot of the time (when wide open) and I also have to be very aware of the super thin DOF produced with that lens and my f1.4 lens even more so.
Interesting - all my AF 50s are long gone, so I can't test this. Perhaps I would have had better results. But in the brief time I used the DA*55 it seemed to focus well and regularly achieve near-optimal sharpness and IQ and f/1.8, and often at f/1.6 (my FA*85 behaves very similarly to this). The only reason I don't own the DA*55 is it's hard to justify when I already have the FA43 and K50/1.2 (the truth is, I'm afraid I'll stop using them - especially the K50/1.2 - yet their good qualities are so nice I don't want to just put them aside).
I still believe the FA43 has better IQ than the AF 50s. But I have trouble believing I could ever get near-optimal IQ out of either AF 50/1.7 wide open, especially considering that both of them, plus the F50/1.4,
plus my MF A50/1.7
all needed to be stopped down to at least f/2.0 (and most of them - especially the 1.7s - at least f/2.2) in order to avoid significant loss of IQ, and
all behaved very similarly in this regard.
I think all four lenses I suggested are expensive for a reason - their performance is very impressive near wide open, and they produce nice images throughout the faster, lower-light stops.