Panasonic 7~14mm or Olympus 12mm ?

I am going to buy an Olympus OMD next week and I have been deciding what lenses to get with it. I use a Nikon D700 with some very nice glass but I want a good quality alternative that will allow me to carry lots of kit without the weight and bulk of an FF SLR.

So, I have been looking at the Olympus 12mm as my wide angle prime but I am a bit concearned that 24mm equivalent is not that wide. I use a Nikon 17~35 on my D700.

How does the Panasonic 7~14mm compare for IQ (to the Olympus 12mm)? I will have a 12~50 kit lens for snap shots so I am only asking about how it compares when I want the best IQ. If anyone has used both I would love to hear from you. How big is the Panasonic?

I realise it is more expensive.

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www.andrewsandersphotography.co.uk