Originally posted by ElJamoquio OK, I thought it was about me when you brought up my D600.
There are certainly applications where APS-C is as good as FF. When starting from scratch, though, for most 'prosumers' (~F/5.6 or faster on FF) you have to spend more to get an APS-C system that can do the same thing... and even then it's at best debatable whether the APS-C camera has the same sharpness.
This is bang on true.
Having blown the lifetimes budget chasing the "try to make APS-C do what full frame does" nightmare . . . I still recommend those starting out . . .
1. Get an X20 or similar manual control point and shoot and shoot RAW and post-process for a couple of years first;
2. Research the hell out of the lenses you'd actually use on a full frame and then blow the budget on a D800e (or 5D MkIII) and fewer lenses, the ones you'd actually use regularly.
For me it should have gone . . . LX5 > D800e + 50/1.2 + 85/1.4G + 135/2 DC . . . perhaps a Siggy 35/1.4 Art and Nikkor 14-24/2.8.
As it stands I have a K-5, a K-5 IIs, a K-3 and over twenty lenses including the 31 and 77 FA Limiteds and K 50/1.2 and 100 WR Macro and 50/1.4 and 15/4 Limited and Siggy 8-16 and M-50/1.7 and Jupiter 11A (x2) and 21M, Helios 44M-4, 44M-7, 77M-4, Tair 11A, Meyer 135/2.8 (x2) and 200/4 and 300/4, Petri 28/2, Sun (awful) . . . oh and Carl Zeiss Jena DDR MC S 135/3.5 and CZJ DDR 50/1.8 Electric . . . there's more, I know there is . . . . oh yes, 2x dead Tamron XR 17-50/2.8's . . . .
All good fun. But a really expensive mish mash.rather than a coherent system of fewer lenses with greater all round capability. That said, the way I have the kit arranged, mobility is easy (I have three Lowepro bags).
Still need to sell a bunch to get the Pentax system down to something realistic. Most likely dump a lot of the old Soviet stuff and get a DA 60-250/4 instead. Trouble is that old Soviet bokeh is a real winner.