- Higher ISO than 1600 (3200 at least 6400 would be nice)
- 1/3 stop ISO settings (XT only does full stop)
- Less noise at ISO 800 and 1600 (XT is pretty noisy at 1600)
- Better focusing in low light
- More focus points
- Real spot metering
- ISO in viewfinder
- Full frame sensor (this isn't a requirement though I really want it!)
- Bigger LCD
- Better weather sealing
Turns out my new body did have most of what I wanted, here is what I am happy with in my 5D mark ii
- Full Frame - I just LOVE it, it is perfect for how and what I like to shoot.
- Megapixels - it was a nice jump to go from 4MP on myh P&S to 8MP on my rebel XT and then really nice to go to 21MP with this body. I don't think I need a lot more for what I shoot
- ISO - the low light image quality is great, especially when I nail my exposure. If they can make it better of course I would be happy, but I really don't think I need to be able to shoot at higher and higher ISOs, really I rarely need to go above 3200.
- Custom functions - I love the ability to change what all the buttons do. Especially using that nubbin thing to move my AF point, and using the AF-on button to stop AF for when I want to use manual focus for macros
- AF Microadjust - my 50L would be sunk without it!
- Video - I am actually glad that the body has video, I don't use it a lot, but the quality is amazing when I remember that it is an option. Now I just have to figure out what to do with those videos since I can't put them in a blurb book
- Weather sealing - I love that with an L lens I can feel safe taking my body out in a light drizzle for a couple of minutes to shoot some wet macros, or out in the snow, or out into the sandy desert in Egypt.
I guess that all begs the question why do I want to upgrade? In general I don't really need to upgrade. I would say overall I am very very happy with my 5D mark ii. I just hate using "old" technology so I know that when Canon does get around to annoucing the next in the series I will want it. Who doesn't want to be able to do just a bit more with what they have? Of course I want Canon to keep all the things I love and even update them a bit (like the megapixels, but really I think 28-30 is the max I would want and if they can make the high ISOs better, who am I to say no?), but what else would I like in my next body?
- Improved Autofocus - I just want more cross type points. Ideally the 19 that the 7D has. There are times when only my center point will be able to lock focus easily (some of the others will depending on which way they look for contrast) and it would be much easier if all of them did this better.
- Dual card slots - I know this isn't likely, unless I go insane and upgrade to a 1D series body (which likely will never ever happen, too many lenses to buy!) but it would be awesome for vacations to be able to shoot Large RAW on one card and a small JPG on the other that the ipad could handle so I could share photos on the road. Or I could use the second slot to backup the photos.
- More lens calibration options - I was just reading an article yesterday where someone mentioned this (here is the link, it is in the updated part, but read the whole article if you haven't before, awesome!) and it is a brillant idea.
- Built in Remote Flash Trigger - ideally radio signal based instead of IR, though then I would no longer need my PWs and I would probably need a new flash, but it would be handy! (canon did submit a patent for this actually).
Can you believe that is really it? I told you I was happy with my 5D mark ii.