Fast prime help

rponiarski wrote:

I have the trio of Sigma primes (19mm, 30mm & 60mm), which I use quite often, but have been thinking of getting a faster prime lens for my E-P5 (they are fine for my E-P2 as that is used only in daylight). I have been thinking about the Olympus 25mm f1.8 or 17mm f1.8, or the Panasonic Leica 25mm f1.4 or 15mm f1.8. Pros and cons of each would be nice to hear. I tend to use my 12-32 Panasonic mostly for street shots, but would like something for interiors and lower light situations....

I think this is highly dependent on your preferred field of view.  Do you have kit zoom you can use with blue painters tape to "lock" the focal length into place so you simulate the fixed focal lengths?

If I had no other information to go on besides what you mentioned, I think I would have to go for the 17/1.8 as an all around lens.  I am interpreting your context for interiors as shooting indoors, rather than shooting interiors (architecturally).  If you actually need the lens for interior architecture shots, i would recommend a wider lens, such as a 12.

How do you like the 19mm FOV?  That is close.  For me, interiors, the 25 seems to be too tight.  I actually get by OK on the 20mm, but I would not recommend that lens with an E-P2.  I love it with my GX7, but the -4EV low light focus ability helps a lot with the 20mm.  Using the 20mm with my GH1 was painful at times in low light.