I don't like to test every lens, and probably only do this once or twice a year, but today I felt motivated. There is a lot of interest in this lens, particularly for the E-P1. I am a fast-glass junkie, so my alt glass for the E-P1 will all be fast glass like this. Really fast glass often is less than ideal wide open (witness the Canon EF 50/0.95 and the "dreamy look"), but I have always enjoyed learning how to use the effects to taste. One of the nice things about the micro-Four Thirds format is the smaller sensor just dealing with the sweet spot of the lens. You can see that here.
Observations: There is halation that reduces contrast and gives a bluish cast with this lens wide open. The L-R Deconvolution routine in Raw Processor was useful to clear that up a little, but you can still see it here. A little more contrast can help. Bottom line, the lens is *very* useful wide open. However, at f/1.4 the halation disappears and the images look great. By f/2.8, even the extreme corners are looking very good. Contrary to what you might imagine, the images continue to sharpen up, reaching peak sharpness at f/11. By f/16 you can see some very slight diffraction softening coming in.
The lens was obviously on my Olympus PEN E-P1. The camera was set at ISO 200, tripod mounted, anti-shock used (equivalent to a shutter delay and lock up combination to reduce any vibration). The images were converted with Raw Processor with the only adjustment being a round of sharpening using a R-L Deconvolution of 80,10.
The image below is a full-sized composite of 100% crops, 600x600 pixels. Beware, it's a 3.5MB jpeg file, so you want broadband to take a look at this one.
One very funky thing I discovered is that you can do "live" lens testing with the E-P1. Because you can zoom in on virtually any area of the screen, I zoomed in on the corners while in Live View, and then stopped it down and watched the detail sharpen up. That auto-gain on the display worked well, and it was bright enough that I never lost detail on the screen.
jhapeman wrote:
One of the nice things about the micro-Four Thirds format is the smaller sensor just dealing with the sweet spot of the lens. You can see that here.
That sweet spot is not often designed to take all those megapixels...
