Originally posted by Balog Well, my thinking is that the majority of the shots I take are inside at night casual pics of my wife/friends/dog etc. I have no other lens as suited to that application. I usually set it to 2.0 or 2.4 and turn up the iso a bit so I can get a fast enough shutter speed to shoot sharp handheld candids. But I hear turning it up a stop improves clarity, so if I had a 1.7 (or 1.4/1.2) I could go up a stop and still be close to what I use now. Or so is my thinking. I was just wondering if the improvement would be enough to justify the cost, or if I should use it to get a split focus screen/ 135mm 2.8 or some other bit of gear I've been wanting.
Take this for whatever you think it's worth... It is after all, just my opinion.
I personally don't think very highly of the 50mm f2.0. I'll give that it is compact, faster than the kit lenses, and simple to use, especially if you have the A version. In my experience with them however, they don't become sharp until you are at least at about f4 or slower. To replace your kit lens (assuming you have one) with a 50 f2.0 is a bit of a waste.
You can go back as long as I've been here. If anyone asks Which 50 to buy, my answer is almost Always the M or A 50 f1:1.7. They are the best of all compromises (in K mount) and won't break the new guy. With some patience, they can be found for less than $50. It's quite sharp wide open and at f2 - f2.8 it's one of the best out there. What the f1:1.4 will buy you is a thinner DOF and an extra stop over the f2.0. It is also very sharp stopped down to f2.0.
If you want to compare some of these lenses at Infinity,
Index of /Photos/50mmShootout
The first file in each directory is wide open, the last is fully stopped down (you'll see when you look).
Another worth considering if you want a fast 50 manual focus is the SMC 55mm f1.8, which is a K lens (predecessor to the M series). I would at the very least put it up there with the M50 f1:1.7 but it's more expensive due to the cult following of the K series primes.
As to a focus screen, depends on which camera you are using. I found them useful on the K10 and K20 cameras but with the K7 and now the K5, I find I don't need it as much. Especially with the Live View on those cameras.
135. completely different animal. It'll certainly increase your reach. Before purchasing and mounting one however, be sure to study the Ricoh Pin threads (so you're bargain 135 doesn't get stuck on the camera).