Originally posted by gatorguy Oh, and that FA31 I mentioned? Yeah that one too is now a fixture in my bag. This was from last weekend. Two great weekend shoots in a row, two of the three Amigos.
Nice job, however I do think you're missing out slightly with these lenses by not being on FF.
I have a K-1 and KP and thus regularly interchange the FA Ltds on these lenses, so you're right in a sense that they don't have to be purely shot on FF and can do well on Crop, but when using on crop it feels like you lose context around the subject, which is one of their strengths. With the FA's you're supposed to enjoy the out of focus parts of the scene as much as the focused parts because they render that stuff so gorgeously especially when using their widest apertures or close to it. It's literally this that causes the high prices and other lenses struggle to compete. If you shot stopped down with the FA77 and DA70 it gets harder to tell which took the shot, a little like comparing the DFA50/1.4 at F8 against some other 50's, but wide open it's lights out! Night and day difference.
So when you use the FA's on crop the out of focus parts suffer a little more due to the crop sensor/framing and distance to subject stuff.
With FF you can take the same lens and stand closer to the subject and take the shot, this closeness is what drives a more pronounced bokeh effect. To get the same framing and positioning with the subject on crop (with same lens) you must stand farther back, and thus the distance between yourself and the subject has increased and therefore their bokeh is now less pronounced (behind the subject).
I hope to do a test one day to illustrate this.
I had a visitor come to my house with his FA31 and K3, he had never seen what the FA31 was like on FF and his jaw did hit the ground. For the same kinda affect you would need a 21mm/1.8 on your K70.
Mind you, when you have the FA77 sitting on the K70 it's 'like' having a 115mm Ltd on a K-1, which of course we don't have.
But your FA31 is acting more like a FA43 on your crop (46.5mm equiv FoV), and your FA43 acting more like a FA77 (64.5mm FoV).
Lenses come first, you did the right thing, I would just consider your next purchase to being a FF one, if you have the funds and can grab a used K-1 for a good price I would lean that way. A K-1 + K70 with the FA Ltds is a fantastic line up of different FoV choices.