There is little doubt that full-frame DSLR cameras offer the best image quality available outside of medium-format systems costly upwards of $10,000 USD. The main advantages are extremely low image-noise and shalow depth-of-field. What are the disadvantages are then? Some photographer colegues and I had this discussion recently and this is what came up:
- Total cost and weight increase more rapidly. The camera is more expensive and heaver and so are the lenses.
- Telephoto reach diminishes due to the larger sensor. It does get a little wider given the widest lens on a full-frame camera. Whether this is a disadvantage or advantage depens on photographic subject.
- Depth-of-field is shalower. It is an advantage for some types of photography and a disadvantage for others.
- Lenses tend to vignette much more, many of them significantly. Corner softness also increases.
- The larger mirror of full-frame DSLR cameras makes more noise, making such cameras less discreet.
- Although it is unlikely, certain upgrades from a cropped-sensor to a full-frame camera lose features. The most significant is upgrading from a 100% coverage viewfinder camera like the Nikon D300 or Olympus E-3 to one of the smaller full-frame cameras like the Nikon D700 or Canon EOS 5D Mark II. The only full-frame camera with 100% coverage viewfinder in a relatively compact body is the Sony Alpha A900.
- On Nikon, autofocus sensors are more clustered towards the center of the frame.