Canon 5D Mark III HDR question

I currently have Canon 5D Mark II and a Canon G 1X Mark II. I do a lot of motorcycle riding so the Canon G 1X Mark II is my camera of choice give that it is compact and doesn’t take up a lot of storage room in the motorcycle. I shoot a lot of photos in HDR and I am pleased with the results from the Canon G 1X Mark II once the photos have been edited in Photoshop CS 6. I am now thinking of replacing my Canon 5D Mark II with the Canon 5D Mark III. I have ordered a Apple iMac Retina Screen so I want to have a higher resolution HDR file to go with the 5K iMac screen, hopefully a RAW photo. In reading reviews it appears that the Canon 5D Mark III takes the HDR photo in RAW and the converts it to JPEG? Can anyone tell me what the HDR file size is when the photo is shot in the Canon 5D Mark III HDR mode? Also any feedback on the quality of HDR photos taken with the Canon 5D Mark III would be appreciated. Thanks

The files are just standard 5DIII RAW files so around 27meg each (size varies depending on image) and then the camera creates the merged JPEG. You can set it to keep just the JPEG or to keep the source RAW files too. However no one who is serious about HDR actually uses the 5DIII HDR mode.

You get much greater freedom to edit by just shooting bracketed shots and processing in PS or Photomatix (or other HDR tool of your choice). Also the in camera HDR only shoot 3 exposures, while shooting bracketed allows you to take up to 7.

^^^ What he said. It's a nice to have feature in the 5D3, say family trip and you want to give a picture w/o having to do processing, then yes. Sometime, I use that instead of setting the camera to bracket and see how it goes. Most people who have 5D2 get 5D3 mainly for AF and convenience purpose. Image Quality isn't much, at high ISO say about a stop on RAW and maybe 2 stop on JPG. The AF does improve things, especially if you have shot w/ a 1D series where you have many AF points and you shoot differently instead of relying on center AF point. But overall, stuff like 2 card slots and higher FPS are nice-ity, not necessary. It's pretty much just a step under 1DX. So, don't buy it just for HDR.

Thanks for the information.