I have had this ED 70-300mm f/4.0-5.6 lens for about 3 weeks now, and have had a great time learning to use it. I use it on my E-5 and Evolt-500, as well as on my E-M1, using the MMF-3 adapter.
There are some neat features about the lens that seem to get overlooked frequently. First, there is a switch on the side of the lens barrel, between the focus ring and zoom ring, which switches from AF mode to MF mode. When the lens starts to hunt for focus, I simply switch to MF mode, and I can achieve focus pretty easily. This switch works similarly to the MF mode of the 12-40 and 40-150 f/2.8 m-4/3 Pro lenses’ focus rings. The AF-MF switch also allows you to focus a little closer to your subject just like a macro lens does.
The second feature frequently ignored is the fact that the aperture assembly is a nine blade (circular blade) aperture set. Only the great lenses are configured with a 9 circular blade aperture assembly (ED 50-200mm f/2.8-3.5, ED 14-35mm f/2.0, ED 35-100mm f/2.0, 75mm f/1.8 m-4/3, 40-150mm f/2.8 Pro m-4/3, to mention a few). The nine blade circular set-up gives a truer circular highlight in your bokeh… generally regarded as higher quality. If you have specular highlights in your out of focus backgrounds, they show up as out of focus circles, so you have a bokeh. If you have no highlights in your background, you have a creamy background (of blurred greens and browns, etc) or a creamy bokeh… but it is really just a creamy background.
Anyway, I have worked at creating the specular bokeh, and creating a nice creamy background. This lens does a very good job of creating each. Good seperation from foreground subject to background features and a wider aperture are used to create the bokeh. My images have come out very sharp and crisp, with fine contrast… and colors so accurate, rich and saturated… nice creamy out-of-focus backgrounds and nice bokehs as well.
I tested the 70-300 lens on three cameras: the E-5, E-500, and the E-M1. The E-500 gave the poorest results, mainly because when shooting inside, under incandescent lamps, the lens would hunt and hunt for focus. Only images with High Contrast would focus. Outdoors, maybe an hour or less from sunset, focus started to fall off again. I got good results in broad daylight. With the E-5, I got good results under any condition. Focus hunting was rare. When I added the 1.4X converter, I had focus hunting maybe 1 image in twenty. So I felt comfortable with that result. With the E-M1 (and MMF-3 Adapter), I got just a few more instances where focusing was not so crisp, but results were very good, just not quite so good as with the E-5.
I had no problem with sharp focus and contrast at any focal length. I had good contrast and sharpness at 300 mm, 200 mm, 150 mm, 70 mm, anywhere in between. I really had fun learning how to use this lens. I have started leaving it on my E-5 in place of the 12-60, only because I leave the 12-40 Pro on my E-M1… so I can more quickly reach a camera with the focal lengths I need. (I keep the 11-22 or the 9-18 on the E-500).
I got really good sharpness corner to corner, as well as good contrast corner to corner. Some others don’t claim that result… maybe I did not test as strenuously or thoroughly as they did, but I consistently got these results… with both the E-5 and E-M1. My resolutions were really as good with the E-500, but only having an 8 MP sensor, results show up differently. And when I shoot an image at 300 mm, I usually have a focus distance of 3 to 6 feet, where others may have focus set near infinity.
This may be one of my best lenses for birding; but really, a nine circular blade aperture lens, for about $400… I see that as a bargain. This lens is a tool… you use to create a striking bokeh or creamy background, to enhance your photographs.
I wish I had bought this lens years ago. I don’t think anyone can go wrong getting one; if you use it on the Pen series, or OM-D series, you need the MMF-2 or MMF-3 adapter.
I owned, as brief as it was, the Olympus M.Zuiko 75-300mm. I realized quickly this lens was only going to be practical for about 10% (or Less) for my total photography needs. Therefore, I quickly returned it, and opted for a more "practical" lens, but I still needed a long lens for my trips to the Colorado mountains, bike rides along the South Platte River, and capturing fantastic vacation pictures on a southern California beach. I'm an OM-D E-M1 owner (absolutely love it by the way) and with the MMF-3 adapter, I can use this fantastic lens along with all the other 4/3 Zuiko lenses. Here's the secret...they are great lenses and they aren't quite as expensive as micro 4/3. The Micro 4/3 75-300mm is a great lens, but it's in excess of $500.00. If you decide to get that lens you will not be disappointed. However, the Zuiko ED 70-300mm is a great alternative and I am not noticing any quality compromises in the lens performance. It's bigger and more chunky than the micro 4/3 version, but it delivers the typical high standard of quality you expect form Olympus.