5D Mark II or OMD EM5

In the past this decision would have been a no brainer with the mark ii be the coveted camera of choice, but these days Olympus has become quite an intriguing player. After using an Olympus EPL1 in the past I can testify to the superb almost perfect OOC JPEGs and fine quality primes. I currently own the XSI and only one lens: Canon 50 1.4. I love Canon as well so the decision is quite difficult, anyone else caught in this delima or able to provide some insight ? The one concern is definitely the DOF which is harder to achieve with m4/3rds, on the other hand I question just how much better the mark ii would be over my XSI in terms of IQ. If I went Olympus thinking body only and the 45 1.8.

Judging by photozone.de reviews with MTF numbers, the OM-D seems to deliver detail resolution on par with the larger frame size Canon APS-C bodies, but NOT up to par with Canon FF bodies. Olympus and Canon APS-C about 2500 line-pairs-per-frame-height, Canon FF about 3500...more detail (there's that 60% size factor once again, although in resolution a measured 40% advantage!), lower enlargement to make the same size print.

Having said that (as someone who had abandoned the 135 film for professional uses, due largely to film grain enlarged more with smaller formats -- using both medium format and large format cameras for jobs and only falling back on 135 when I needed absolutely fastest lenses of low light work), -- I find APS-C generally great enough in overall quality that I reserve my FF dSLR only for higher quality large print applications and for shooting with an 24mm OM shift WA lens.

IOW, I find that APS-C SLR quality is darned fine stuff and there isn't much to complain about, so the OM-D meeting that standard would make it darned fine stuff, too. That addresses IQ.

I have long loved the Olympus OM film camera system for its compact and light weight bodies and lenses, owning OM stuff since the mid-70's. Three issues for me, though, personally speaking...the EVF, the lesser ability to easily isolate the subject from the background, and the fact that there are few fast fixed aperture 4/3 zooms, most are variable aperture and relatively slow. That might be acceptable for snapshooting, but not for more serious work. I have an S95, which is fine for snapshots with an easily pocketable camera...the OM-D and lenses are large enough to no longer be pocketable, so I might as well hang my Canon APS-C from a bag on my shoulder! If Olympus made APS-C body and lens system, not 4/3 and micro 4/3, I would probably jump on it, as I have long lamented the large bodies of my Canon gear over the OM size bodies...

A very important question is....do you need a small body?

I own an Olympus simply because I want a small portable body that has similar to better IQ than any canon crop body. I only use the OM-d for slow/static family/friends photos.

The zuiko 45 f/1.8 is killer sharp and if you pixel peep the difference between a canon 85 f/1.8 on a canon crop body it'd be difficult to see any difference.

If you try to capture a child on a swing for example the OM-D would be a serious struggle while I can have a high percentage of keepers with my 5dmk2.

Specify your application and needs. Theres a big difference between phase detect af to contrast af. You'd get frustrated with the OM-D if your gonna need to shoot faster moving subjects at close distances.

OM-d with cheap 14mm f/2.5 is incredible. The 25 f/1.4 is also stellar.

I recently made the move from the Olympus 4/3rds system to Canon and for good reason. Among other things the Canon has far superior high ISO quality and faster burst mode (on the 7D). I had the E3's and E5's and almost all of the Super High Grade Lenses. I did not have the new OMD-EM5 but I did try it and it does have much improved Image quality and high ISO performance but from my experience with the 5DMkII and "L" lenses there is simply no contest. The 5DMkII with good lenses will bury the Oly in every catagory except size, it might size up to a crop camera but not a FF like the 5DMkII...

Go to DP Reviews and you can do a side by side of the two cameras to compare specs.