Originally posted by 08amczb Okey, so for those who has a K-1, but does not has a K-70/KP buying only a DFA28-105 is cheaper, then an APS-C body + a standard zoom. This is a point.
Altough I still think, a recent APS-C body + a standard zoom is more reasonable: you get a second body and it's more compact and light with aprroximetly the same IQ.
I am with you in principle. I have three models I shoot with for varying reasons- the KP (mostly), the K-5 IIs (usually for when I desire its control set), and the K-S2 (when I need smallest/lightest possible with smallest lenses). These serve my needs very well, and I've reached the conclusion that I really don't need a FF body, especially since now having the KP. I think that is essentially the nature of your question- why buy a FF outfit.
But as I mentioned, there are still some virtues the FF format offers. Just for example, take the very fine FA 43mm lens- it was designed for 35mm bodies (FF) to provide accurate "normal" perspective for scenes shot at "normal" distances. It will not do this when mounted on an APS-C body, although still a fine lens. To get the equivalent you have to go to a 28mm lens, but then you will not have f/1.9 capability, nor the quality of the Limited series. The same for the very fine FA 31mm Limited f/1.8- on APS-C it is no longer a wide angle FOV, and there is no equal of it for APS-C.
One vey good reason for buying a particular camera body is for the use of particular lenses. I have several such lenses. If I should decide to acquire the K-1 to employ the full benefits of having them, I would also include the D-FA 28-105mm DC WR zoom lens because it offers fine corner-to-corner sharpness, basically through its range, WR construction, and is compact for carrying, making the K-1 less of a bulky ensemble. In my case, for more tele range work, I'd then return to APS-C where I have some fine lenses for that at a much lower size/weight/price consideration.
When not wishing to shoot with the lenses I've bought the K-1 to use, I'd simply still go with the more compact APS-C equipment I have, which is very satisfying for my needs.