The Olympus OM-D E-M5 has a problem with the sun inside of the frame. Olympus digital PEN cameras also used to have the problem and it seems to manifest itself primarily with Panasonic lenses, and with none worse than with the expensive 7-14/f4.
What happens is, that strong light sources get reflected by the sensor, back to the inside the lens, and what happens then mostly depends on the internal coating of the lenses.
You see the effect as small, purple flares and sometimes also as a diffuse purple haze. Of course this is a common phenomenon of digital cameras. Sigma lenses on my Nikon D300 for instance produce small but bright flares, normally not purple but cyan. What actually happens is seemingly dependent on coating of lenses and sensors. Unfortunately Panasonic lenses and Olympus cameras go with each other much worse than the two maker’s association via the Micro Four Thirds standard would let you expect.
Interestingly enough it does not seem to be a problem the other way round. I’ve never heard of excessive ghosts and flares with Olympus lenses on Panasonic cameras.
Don’t get me wrong, you may never experience the problem at all, if you just heed common wisdom and don’t include the sun in your frame. It’s just that I can’t do that. For me “shooting into the light” is one of the biggest pleasures in photography. I see a bright sun and it magically attracts me. I’ve always loved those images and it is a passion that is central to my way of seeing. It’s not only an artistic device, not a style, for me it is a way to feel good. Thus I need a camera and lenses that allow me to follow my instincts.
The E-M5 with Olympus primes is pretty OK in that regard. Both images of today were taken with the 17/1.8. There is some purple haze in the Image of the Day, but that’s only because I didn’t only shoot into the light, no, I also overexposed the image. I think the behavior is still very acceptable.
The second image had no problem at all. It was properly exposed and while I still have added some overexposure and desaturation in the area of the sun, I’ve only done it to ease the roll-off in the highlights and to counter the HDR-ish effect of lightening up the shadows.
It would be interesting to know how the Panasonic 7-14 behaves on the new OM-D E-M1. After all, due to the phase detection pixels on the sensor it is necessarily a different sensor, it has no low-pass filter, thus it could as well have different reflection properties. I have sold my 7-14 a while ago and bought the Olympus 9-18 instead, a lens that I am entirely happy with. Therefore I can’t just go to a shop and try the combo. Is anybody of you in the position to make a test and shoot with an E-M1 and 7-14 into the sun? If so, please try too keep the sun off-center. I’ve asked the same question on Flickr, but so far I’ve got no answer.