I'm a professional. I could do most of my work with cheap DSLR without much difference (although full frame vs. a crop sensor has some differences that couldn't be made up).
It's the edge cases where a top of the line camera/lens can become necessary. I've had church ceremonies where I've had to be at 6400 ISO at f/1.4. There are times where you need to work quickly and don't have time to get a perfect exposure, so having extra latitude in post production is key. There are also performance issues such as the ability to keep focus on a moving or dark target.
I'm primarily a photojournalist wedding photographer and I end up taking ~6000 pictures for a 10 hour wedding, and that'll get winnowed down to 1000 or less. The amounts are all over the place but that ratio is roughly what I've heard from other photographers. Don't feel bad about bad photos; the primary advantage to digital is that we can do that without wasting film.
It's the edge cases where a top of the line camera/lens can become necessary. I've had church ceremonies where I've had to be at 6400 ISO at f/1.4. There are times where you need to work quickly and don't have time to get a perfect exposure, so having extra latitude in post production is key. There are also performance issues such as the ability to keep focus on a moving or dark target.
I'm primarily a photojournalist wedding photographer and I end up taking ~6000 pictures for a 10 hour wedding, and that'll get winnowed down to 1000 or less. The amounts are all over the place but that ratio is roughly what I've heard from other photographers. Don't feel bad about bad photos; the primary advantage to digital is that we can do that without wasting film.