When I wanted an Olympus 40-150/2.8 but could not afford it I got an Olympus 50-200 SWD instead. And it has proved itself a great lens, especially for the price. I see them go for $300-350 (USD) and with a 43 to m43 adapter ($100-150) you can get a nice setup for a fraction 1/2 ~1/3 of a 40-150/2.8. I thought the SWD was only tele for me but of course fate has its own plans and I got really lucky with an auction and now I have a 40-150 as well. So let's look at the pros/cons of each lens: 50-200 SWD: + cost: 1/2 ~1/3 of a 40-150/2.8; + range: The 40-150 needs a 1.4 tc to match; + mechanical focusing: turning the focusing ring directly affects the focusing mechanism. - AF speed: acceptable with E-M1 & E-M5ii not with E-M5; - variable aperture: slightly annoying; 40-150: + AF speed: very fast with all bodies even the original E-M5; + size: internal zoom; + constant aperture; - cost; - range: needs a 1.4 TC to match the 50-200. With the 1.4 TC on the 40-150 and the adapter on the 50-200 they're pretty much matched in size. Subscribe to see EXIF info for this image (if available) The 50-200 zooms externally (trombones). Does it really matter? I think it's a personal preference. Subscribe to see EXIF info for this image (if available) While I always shoot jpeg + RAW, I rarely have the time to work on a RAW file and only do so when the photo really matters to me. Usually for a family pic to improve on it and/or if I have to crop a lot. For that reason all these comparisons are done with SOOC jpegs. 99% of my photos are SOOC jpegs and that's how I roll. When my kids go to college and I suffer from empty nest syndrome I promise I will only shot raw and massage each file to get the highest quality. So let's get on with the photos. Let's start with both lens near each end of the zoom range and widest aperture. Subscribe to see EXIF info for this image (if available) Subscribe to see EXIF info for this image (if available) Subscribe to see EXIF info for this image (if available) Not much to say for me, though to be honest I rarely use the lens this wide, but I'm more than happy with the quality. Subscribe to see EXIF info for this image (if available) Subscribe to see EXIF info for this image (if available) Same thing at 200mm. I'm more than happy with the output. The 40-150 has a slight advantage, but no so much to make or break a photo. Finally I mounted both to the E-Mii and took a photo in pixel shift. Both are at f/5.6 and 100mm for the 40-150 (with TC) and 92mm for the 50-200, ISO 200 and manual WB. So pretty close to mid zoom range, stopped down and cropped to the central area of the frame for the best quality. Subscribe to see EXIF info for this image (if available) Subscribe to see EXIF info for this image (if available) Here the advantage of the 40-150 becomes a bit more noticeable, the 50-200 seems a bit more noisy. Not sure how much this is due to the sub-optimal light in this test, but that's how it looks. In the end, and IMHO, I think the main difference between the two lens comes down to cost and focusing speed. If you want a budget setup and are okay with slightly slower AF speed, then the 50-200 is an amazing lens for the price. If you want to show off to your fellow photographers and/or compensate for other shortcomings (not my case) then get the 40-150. Hope this helps.