Quick introduction as I am a new member. I have been playing with cameras for about five years now, just for fun. The first 3 with three generations of point-and-shoots for snapshots, and the last two with a Canon t1i with kit lens, still casual mostly but starting to learn more about it. Recently (couple months ago) I sold the Canon and got the new K5 along with a DA 15mm limited. My interest is primarily travel photography, so more capturing a unique moment than finding artistic perspectives though I do enjoy that as well (even if I suck at it)
I'll be the first to admit it..I'm not that good, but I do take a lot of photos (45,000 so far) so I at least have some man hours behind it if nothing else
. I upgraded primarily because it seemed to be "worth it" given how many photos I take and because I had fun with the DOF/bokeh on a f/2.8 lens I rented. I've never owned a fast lens before (f/2.8 as the fastest I've ever shot, on the rental, before buying this lens) so please cut me a little slack if this post seems ignorant.
Long story short, I just purchased the FA 31mm from B&H photo and have 7 days left to try it out before I can return it. I've taken it out a couple times for some real world photos, and in the process a couple questions have come up. It might be that I am not used to the extreme DOF but some portraits I took seemed softer than expected and there was sometimes striking fringing/CA even in indoor lighting and visible in the scaled image.
Here are a few sample photos I took as a result:
f/1.8
f/2.8
f/1.8 center crop
f/2.8 center crop
Now, the two full size photos look okay scaled down but I would say there is a noticeable improvement at f/2.8, and a noticeable "out of focus-ness" to the f/1.8 photo when viewing it at 1920x1080. Both shots were taken on a fixed surface and I tried multiple shots both with manual focus and with AF adjustment and the f/1.8 version did not improve.
All I can compare it with is the DA15 and the kit lens, and while both showed some improvement when stopping down on the same test, the difference was not nearly as drastic across any of the apertures. Neither were as sharp as the FA 31 is at f/4 but I would call both sharp from wide open and onward.
So two questions:
1. Is this normal or does it not match your experience?
2. What aperature do you mostly shoot at with this lens? Is it common to shoot more in the f/2.2-2.5 range? I would say at f/2.8 it's pretty darn sharp.
I do like the way other elements of the photo render, but based on these results I can picture myself keeping it at f/2.8 or higher unless I really need a shallow DOF which seems like a waste. Low lighting is not really an issue with the K5 so I wouldn't say that is a factor.
Here is a photo that I thought turned out okay, but I still think the glasses would have maybe been better at f/2.8? It's been raining all week here so haven't really had a chance to get much variety in shots.
Any thoughts or ideas?
Last edited by mason; 03-22-2011 at 12:45 AM.