In the beginning for digital SLR cameras, all cameras were crop sensors.
The cost of a sensor per square inch meant that a sensor the same size as a 35mm strip of film would be very expensive, and the two main DSLR manufacturers (Nikon and Canon) initially didn't think there'd be enough interest in a camera in that price range.
Canon took the leap to full frame first with the EOS-1Ds back in 2002, but at $8,000 it was well out of reach for most hobbyists and semi-pros. Nikon didn't come out with their first full frame camera (the D3) until 2007.
Even though prices have come down some, the full frame cameras are still significantly more expensive than a similarly spec'd crop sensor camera.
For the average hobbyist the difference in image quality between a crop sensor camera and a full frame camera, just doesn't justify the cost. (Especially if you shoot only in good light or with studio strobes)
There are still quite a few professional photographers that continue to use crop sensor cameras.
However, in the world of Wedding Photography (and several other types of photography as well) full frame cameras now dominate.
The reason for that is due to the biggest single strength of a full frame camera over a crop sensor camera....(low light performance).
With all of the advances in sensor technology (from the switch from CCDs to much quieter CMOS sensors, to micro-lens arrays that channel more of the light directly to the individual pixels) the fact is that the single biggest factor in terms of noise at high ISO is still the size of the individual pixels and how much light they can gather, resulting in a greater signal to noise ratio.
A full frame DSLR can comfortably shoot at ISO 3200 to ISO 6400 without significant noise being present in the photos, and this has raised expectations across the board.
One result is that more and more churches are forbidding the use of flash. If you are in a typical church where you need at least ISO 5000 to get your shots and you aren't allowed to use flash, then no crop sensor camera will give you shots of high enough quality at those settings without extreme noise reduction in post processing (which robs you of sharpness)
However, that's still a side-case. The vast majority of churches still do allow you to use flash for photographing the ceremony. (at least for the official photographer)
With that being said, even for venues where flash is acceptable, the expectations have changed.
In the days of 35mm film (where ISO 3200 was the highest you could buy and it looked way too grainy for most people's tastes) photographers would generally choose a lower ISO like 400 or maybe 800, and then rely on the flash for the majority of the exposure.
Even with proper modifiers, and bounce flash techniques this resulted in a significant difference between the exposure of the subject(s) and the background. In other words the subjects would be perfectly exposed, but the background would be very dark.
This was not only acceptable, it was just plain expected.
However, now that full frame photographers can properly expose for the ambient light, and use their flash only for fill, and get high quality images where the exposure is consistent throughout the photograph, that has become the expectation.
It also allows for you to use a much lower intensity flash and your flash can provide more pops at a much faster rate.
This has several nice side affects:
1.) Your batteries last longer.
2.) No more missing that shot because your flash hadn't recharged quickly enough.
3.) Even if you do find yourself in rapid fire mode and somehow manage to get a shot off too quickly and your flash just doesn't go off. Since you aren't relying on the flash 100% for exposure, you will still get a useable image. (Even if it doesn't have the specular highlights and you have some shadows in places the fill flash would have helped fill.) Below I show an example of this.
The ability to shoot at extremely high ISOs and still get relatively noise free shots, and the corresponding ability to balance ambient light with your fill flash even in low light situations is a game changer.
Obviously if you shoot only out-door weddings, or in venues with very bright indoor lighting, this isn't a major factor and a crop sensor camera is more than adequate.
However, a full-time professional wedding photographer can't normally afford to turn down weddings that don't provide this kind of lighting, and more and more wedding photographers are finding that a full frame camera is practically a requirement.
This shot isn't from a wedding, but from a valentines day party. However, it demonstrates my point.
There were no lasers or other flashing lights. Yet, someone decided to turn out all the lights in the main room, so that the only light was in the room way behind them, and the room directly behind where I was standing.
The only light shining on my subjects was from the overhead lights in the room directly behind me. And this is no noise reduction of any kind in this shot.
This shot would not have been possible with a crop sensor camera because shots at ISO 16,000 would be unusable so I would have been shooting at a much lower ISO and using much more power from my flash on each shot.
That means that:
1.) It would have taken much longer to recharge my flash between shots, and it probably wouldn't have even fired for my 2nd and 3rd shots in this series to even make it to the 4th.
2.) Because the flash would have been providing most of the exposure, this shot where the flash didn't go off, would have been completely dark and unusable. No amount of tweaking in Lightroom or Photoshop would have saved it.
In my next post, I'll be returning to my little series on Gear that I use, and talking about my choice of lenses (specifically for Weddings)
I hope this was informative for someone. Please leave your comments and don't be afraid to like or share this post on Facebook, Google+ and/or Twitter.
And as always, please visit my personal web-site: Maranatha Wedding Photography