Re: First see what you use already.
Guy Parsons wrote:
My initial answer is to get the 12-40mm lens, it is just so darn good.
But the sensible answer (not often seen here) is to first analyse what you already do and see where most of your lens use happens.
In my case I use (Windows) Exposureplot from http://www.vandel.nl/exposureplot.html to analyse say a month or a year of images to see what I'm doing.
Here's what 6 weeks of holiday in Ireland and UK did to me.....

Heavily used 12-40mm, hence the bumps at the ends of its zoom.
The 0 mm bump is the Samyang 7.5mm fisheye, used more than I thought I would, a great fun lens and highly recommended.
The 9mm bump is the 9-18mm lens at work, I didn't really need to carry that for the little use it got.
Then the tiny usage above 40mm up to 150mm is the Panasonic 45-150mm, small and light to carry so it is always in the bag for those relatively rare times that I use it.
If I were to be tempted to buy a prime lens (the 12-40mm has killed that lust) then my natural would be the 17mm as revealed by the hump in that vicinity.
Regards..... Guy
Thank you Guy for the time you took.
Love the small software (im a numbers guy-Engineering background-its amazing to see the graphs) that alone was as good as buying the lens.
Looking at the my OMD EM-5 pictures my highest range is between 14 mm and 50 mm.
Which already says a lot and makes me wanna get the 12-40 mm.
I have been eyeing the samyang fish eye for a couple of years, but have been so hesitant since i never used a fish eye other than the occasional Gopro scuba videos and snapshots. Which i often find so distorted and end up cropping or fixing the perspective on them.
My question is, is it worth it getting the samyang, or just wait and save and get the 7-14 mm pro lens to complete my kit ?
Have a good day
Sam