The biggest complaint about the E-5 is the noise levels when you shoot above 1600 ISO. So what! Not long ago this was the problem with most DSLR cameras. As soon as you drop below 800 ISO all cameras start to lose big time with DR, color, SNR, and overall picture quality. Visit DXO image sensor analysis and see for your selves. Shoot 200-400 ISO when ever possible with the E-5. Low noise has become a marketing hype. NOISE IS NO LONGER A PROBLEM...READ ON!
There are two types of noise: fixed and random. The random causes the most problem.
Today there are excellent program to handle noise. Here are some of the best and in no particular order:
DXO; PS CS5; Topaz DeNoise. Topaz state that they can retain detail and expand the photo range by 4 Stops!! I simply do not have that much noise. Topaz show examples of a Canon 5d MK II at ISO 25,400. Shooting a wedding reception with F2.2 with a 50 mm at 1/40 sec required an ISO of 5000 and after DXO I had no visible noise with my 5D Mk II. With the Olympus E-5 you could take the same shot at F2.8, SS-1/20, ISO 2500.
I have used DXO with outstanding results. It appears to me that you can shoot at 6400 ISO and remove the noise with one or all of the above. Olympus would have been wise to add 12,800 to the menu accordingly. I tackled a noisy E-510 1600 ISO image with great results in DXO alone.
If you can, shoot the image and over expose to the right side of the histogram as much as possible until you get to the bar. Never exceed the right side bar as you will blow out your highlights. This is called exposing to the right side of the histogram. Do this in all low light shots but do not clip the highlights. You can then bring the image back in DXO, CS5, ect. This is good advice even with a D3S. This is good advice for all shots!!
Remember, most of the image noise is in the shadows anyway. Blurring in PS will remove it. That is what our F1.4/F2.8 lenses do anyway. That is why we bought them in the first place- to blur the background.
The reason for doing this is two fold. You max the signal to noise ratio. Secondly and very important, the right quarter of the histogram contains 50% of your image information. Why lose that? To do this you might have to lower your shutter speed down to 1/20 of a second and use a small F stop like 1.8-2.2. You have to watch your DOF carefully and to not blur everything. Using DOFMaster, if the subject is 10 ft away at F4.0 you DOF is 6.5 ft to 28 ft. Using a 50mm this changes to a DOF of about 9 ft to 12 ft.
Because the E-5 has built in IS, you can tweak your shutter speed. If you are using a camera with no built in IS, SS become very important aspect to prevent camera shake if you are not using a tripod or monopod. Most and if not all of Canon prime lenses do not have IS.
Another trick is to shoot these shots with a lens setting below 50mm say 24mm. Here you get great DOF and the SS without IS is 1/20 sec. With the E-5 with IS, you might be able to shoot SS 1/10 but subject movement might occur. Therefore take several shots, it doesn't cost anything more with digital.
If you absolutely must have extreme ISO then buy a Nikon D3S FF along with their very expense F 1.4/F2.8 lenses. You will have a great camera that is rated slightly above the E-5 at 3X the price. The need for us to have this ISO range is so low and the time to remove the noise is so small, why pay $4000 more for a body and another $5000 more for a set of lenses above what it will cost to buy equal quality lenses from Olympus with better F stop range.
As a side note: Topaz Labs have done what no one else does. They sell their plug-ins at very reasonable prices. They even have just release InFocus to sharpen your out of focus images!!!!!!!!!!!!! I do not know of anyone else who does this. Also their ReMask 3 is the best that I have seen and is normally very fast except for those pesty backgrounds.