Opinion: The myth of the upgrade path
The past 18 months has seen a flurry of full frame cameras launched at lower prices than ever before. Suddenly it's no longer completely ridiculous to talk about 'affordable' full frame cameras, though it's still worth putting the word 'affordable' in single quotes. This new-found accessibility has had an interesting side-effect: it's made more people feel that they've already taken steps along an 'upgrade path'. And I think that's nonsense. I'd argue the 'upgrade path' to full frame is a myth.
There are two reasons I say this: firstly, it implies that full frame is the sole aspirational endpoint for everybody and secondly, that the purchases you've already made have taken you some way towards that goal. I believe both of these are false.
Fallacy 1: Full frame is the optimal end-point to aspire to
I'm not questioning the idea that it offers great image quality: if you line up the same framing and use the same shutter speed and f-number, a larger sensor will be exposed to more light than a smaller one and more light allows better image quality. If you want the best image quality but don't want to spend the money or carry the bulk of a Pentax 645Z, then your best chances are with a full frame sensor. However, if you go back and re-read that last sentence, you'll notice that it contains two important caveats: it can offer the best image quality if you like the size/price trade-off that it brings. And that's true of all formats.
|Full frame cameras can be incredibly capable but other formats can still be smaller or less expensive (especially once you've factored lenses in), allowing you to choose the size/price/quality balance that suits you.|
Sony in particular has done amazing things in the past year or so to redefine the price/size/quality balance that full frame offers, but it remains true that APS-C and Four Thirds can still be smaller, lighter and less expensive: so the optimal system for you depends on your requirements.
Fallacy 2: You're already part of the way there
However, I'd say the bigger myth is that there's a middle-ground between APS-C ownership and full frame ownership. This stems from the fact that you can mount full frame lenses on the many APS-C cameras. This, combined with the (broadly true) assumption that lenses are a long-term purchase but camera bodies will more quickly become obsolete, leads to some odd behavior and even stranger conclusions.
All too often I see APS-C users saying that they're not going to buy any more APS-C specific lenses because they plan to move to full frame at some point in the future. It's a decision that introduces awkward compromises to all future lens purchases.
Why? Because APS-C and full frame are not the same thing. There's a reason that manufacturers make specific lenses for APS-C cameras: the focal lengths that are useful on APS-C are totally different from the focal lengths that are useful on full frame.
|Too long for all-round use, a touch too short to be a really good portrait lens: you can mount a 50mm lens on an APS-C camera, but it probably wouldn't be your first choice, if there were other options.|
For example: a classic full frame 24-70mm lens acts as a 35-105mm equivalent when mounted on an APS-C camera, with a lack of wide-angle coverage limiting its effective use as a walkaround lens. Equally most wide-angle lenses for full frame offer very little wide-angle capability on APS-C. And don't get me started on the neither-one-thing-nor-another no-man's-land of 50mm lenses on APS-C.
This poor compatibility continues for almost any focal length you might care to name - if you're lucky then your lens may perform a useful function on both formats but it's unlikely to perform the same function. The only lenses that usefully serve the same purpose on both formats tend to be telephotos, and even then it's not unusual for photographers who've moved to full frame to be frustrated by how little reach their 70-200mm now offers.
The result is that, if you start buying full frame lenses while you're still shooting APS-C, you're either buying a lens that's not very useful now, or you're buying a lens that won't be as useful once you've made the switch. You might be willing to ignore the compromises or limit your shooting style to accommodate them, but you are either living with a compromise now or you're committing yourself to one once your new camera arrives.
Looked at from the perspective of APS-C lenses: while Nikon and Sony owners have the option to use their APS-C lenses after they move to full frame (which Canon EF-S lens owners can't), the effect of using them is to essentially hobble your expensive new full frame camera back to the level of an APS-C one, only with what's likely to be a lower pixel count. I'll guess this isn't what you were aiming for when you decided to move to full frame.
No path, just one big jump
Quite simply, I'd argue it doesn't make sense to buy many full frame lenses until you have a full frame body to mount them on and, by extension, that you shouldn't feel you're on the path to full frame until you're shooting with it. The benefit that comes from this way of thinking is that you may discover that you aren't limited to your existing system if you decide to make the jump.
|Canon's EF 40mm F2.8 is a great affordable prime for full frame users, but the 64mm equivalent focal length it offers on APS-C is hardly one that photographers often clamor for.||Thankfully Canon also makes an EF-S 24mm F2.8 that, not-coincidentally, gives a roughly 40mm-equivalent field-of-view on APS-C. Surely it's better to buy this lens now and sell it later than restrict yourself to full frame options?|
There are exceptions to this line of thinking, of course. If you've spent many years with one brand's cameras, you might appreciate the familiarity of the menus and behavior that you retain by sticking with what you know. Equally if you've spent a lot of money on flashguns or are particularly committed to the system in some other way, then being brand-loyal is a realistic consideration.
So are you saying I should or shouldn't upgrade?
Though this may sound odd, I'm not trying to argue for or against upgrading: it's the path and the assumption of destination that I'm questioning. Don't get me wrong, full frame cameras are lovely things that can give you the power to take much higher quality photographs. But don't let the manufacturers' marketing of a halo product trick you into thinking that it's the right answer for you or that you can make incremental steps towards it.
If you decide that full frame is definitely the right thing for you, step back and think about how committed you really are to your current system. Ask yourself how much of your current equipment is really going to be useful after the switch. Does it instead make more sense to sell your gear and start again with the full frame system that suits you best?