Here is a little review of the 5D3 that I posted on Facebook. I just copied and pasted. It is freaking amazing. I liked it so much I bought a second one as I love to have two of the same bodies for weddings.
5D Mark III Camera review. All people who don't care about gear should tune out now.
I'll make it a short review as not to bore you guys but here it goes. First I'll summarize and say that the 5D3 is everything I wished my 5D2 was. Its simply amazing.
I'm going to base my experience with the wedding I shot this past weekend as I've only had it for a week at this point. The autofocus is amazing. It works perfect in servo or one shot, almost every single time. I used servo at the reception which was very dark like normal and I was used to about 30% keepers in these conditions but with the 5D3 it was about 90%. The servo focusing system is simply able to track people wonderfully and is fully customizable to fit exactly your needs in any situation.
Second is the dual card slots. This wedding I shot about 91 gigabytes. All of my photos were backed up to the SD card as a 5.5 megapixel jpeg. I put a 32 gig card in there that should hold about 16K images without having to format it. Its a HUGE piece of mind knowing that if i have a memory card fail I instantly have a backup that I could print a 16x20 with. Between the dual card slots and the amazing autofocus I'd say the upgrade right there is worth it alone.
Image quality is better. Is it tons better than the 5D2? No. Is it better? Yes. As many of you know the 5D2 suffered from pattern noise and shadow noise especially when you adjust exposure up, the noise would come out of the shadows and its was ugggggg-lyyyyyy. Not a problem anymore. Period. This really helps the real world dynamic range of the sensor as with the 5D2 you got shadow noise even at ISO 200 and 400, heck even 100 at times if you boosted the exposure. The files out of the 5D3 are much more forgiving allowing significantly more flexibility. With the sensor improvements I'd say that I can easily shoot at ISO 6400, even 12,800 in a pinch. Its about a half to 3/4 stop better than the 5D2 I'd say and the noise is much, much less blotchy and with almost no banding so the noise that is there is easily tamed with Lightroom and is much more pleasing to the eye bearing a close resemblance to film grain instead of digital horror.
Ergonomics... Amazing. The level of customization you can do to the camera and all of its buttons is FREAKING AWESOME. I could write a huge post on this alone. It is so easy to use and lets me do things that I didn't even think of before with my 5D2. One such example is the ability to switch between servo and one shot focus with the press of a button. I made this function to be activated using the DOF preview button. Its crazy. Here's how it works. Lets just say that your at a wedding (or whatever) and the bride and groom are introduced mr and mrs smith, they are standing still and your in one shot focus mode. Then they start walking down the isle to leave the church towards you. As they started towards me I simply pressed the button and it switched from one shot to servo just like that! It switches between servo to one shot or one shot to servo, what ever mode you happened to be in, it goes to the opposite you can track a bird in flight with servo and as soon as it lands, you press the button and it goes right to one shot for that perfect tack sharp shot with the bird perched. You simply hold the button in to keep the focus mode switched and when you release the button it goes back to the original focus mode. Its brilliant. there are many, many features that I could go on about but you get the idea.
Then there is the amazing LCD you can see in bright daylight, the 100% coverage viewfinder. Also, The larger rubber cup around the viewfinder like on canons 1 series bodies is more comfortable, the mode dial locks (which some hate I know) but I no longer bump it from M to Av or Tv, it stays whrere I put it.
Then there is the flash compatibility with the new 600EXRT flashes. I'm now able to shoot in Gr (group) mode. At this past wedding I was able to set two flashes on stands at either side of the reception hall at 1/8th power and have my on camera flash on ETTL bouncing off the ceiling for fill... all using the built in radio for triggering. Previously I had to have them all in ETTL or manual, I couldn't mix the modes. Not anymore. It was so nice to set flash power on the flashes on the stands right from my camera(which I could do with my 5D2) and then shoot with ETTL on camera. It lit the room almost perfectly every time, tons of glorious light bringing out the detail and balanced with the ambient to still maintain the atmosphere and ambiance of the venue. LOVE IT!!!
These are just a few of the improvements that I noticed, there are many many more but this is already the longest post I've ever had on FB. If anyone has any questions please feel free to let me know and I'd be happy to try and help. Now its back to my new problem... sooooo many tack sharp photos to pick from from the wedding. Later gators. =)