Not too long ago, getting a full frame camera actually mattered. It wasn’t just because real photographers have a collection of lenses that were meant for 35mm film but full frame sensors were actually different from their crop counterparts. Different and better.
Back then, a 12Mp APS-C sensor camera was fairly common. Canon, Nikon, Sony and Fuji had their own versions of the 12Mp DSLR. Those who had deeper pockets could go full frame. Although the resolution remained the same at 12Mp, the full frame sensors guaranteed better image quality especially in low light performance. The “affordable” and ancient Canon 5D and Nikon D700 can still hold a candle even against the latest full frame cameras of today.
It is quite frustrating that sensor development hasn’t really improved that much since then. Some full frame sensors are really just bigger crop sensors. Take the Nikon D800 36Mp full frame sensor for example which is just an enlarged D7000 16Mp APS-C sensor so we expect their performance to be the same (https://dtmateojr.wordpress.com/2014/03/08/debunking-the-myth-of-full-frame-superiority/):
(Image taken from dpreview.com)
Yes, there are other sensors such as the 24Mp of the D600 and the 16Mp of the D4 but if you compare their performance against the 7-year old 12Mp D700 sensor I would expect the huge technology gap to provide me with at least something that is visibly much improved. Have a look at the comparison below. Aside from the image size differences, the newer sensors have got nothing to say against the D700. In fact the D800 is visibly inferior:
(Image taken from dpreview.com)
So in terms of performance, my opinion is that full frame is NOT really any better than APS-C (D800 vs D7000) and newer is NOT necessarily better (D600 or D4 vs D700).
What then has full frame got to offer compared to smaller sensors?
In some cases, full frame is really just a waste of space (https://dtmateojr.wordpress.com/2013/12/11/resolution-and-sharpness/), so unless you make really huge prints, if you print at all, then there is no point in going for more megapixels.
Another issue that you have to deal with full frame cameras is depth of field. Shallow DoF, in the real world, is a problem NOT a feature. You will be forced to stop down to gain enough DoF and then you start dealing with diffraction issues.
Full frame cameras require bigger, more expensive lenses and bigger tripods. Bigger and heavier means lesser usage. Unless you have pre-planned trips, you will tend to leave your full frame in the closet. Everyone now has a camera. More people are bringing tiny m43 cameras that produce full frame quality images so you can’t afford to leave yours behind if you wish to be competitive. Of course, there is now a trend towards smaller cameras with full frame sensors. The problem here is that they require a new set of lenses unless you decide to go with their wonky adapters which essentially negate the whole point of having a smaller camera.
On a slightly different topic, I find it funny that Pentaxians are practically switching over to a different brand just to satisfy their full frame cravings. Even if it means selling all their Pentax gear to fund the purchase of an entirely new set of equipment. Even if it means losing a lot of money. Well if you really like something then buy it. There is no need for excuses. Thinking that switching to a full frame will help you make better photos is a thing of the past. It doesn’t apply anymore. I mean honestly, unless you already have a stash of full frame lenses, going full frame is no longer a good option.