Hi, this afternoon I did a quick comparison of the background blur using different lenses. I wanted to do just a quick check, to pick the right lenses for the next shooting, so it is not a rigorous test. But the result was quite unexpected so I'm going to share it. Sorry for the ugly pictures. First I started with the olympus lenses, on the E-M10, the 60mm and the 40-150: E-M10    ---    60mm    f/2.8    1/25s    ISO 3200 E-M10    ---    102mm    f/5.0    1/3s    ISO 3200 There is not much difference and not much blur. So I tried with a couple of manual focus Nikon lenses, same lenght but faster: E-M10    ---    0mm    f/1.0    1/100s    ISO 3200 E-M10    ---    0mm    f/1.0    1/5s    ISO 3200 Well, not much difference here either. Maybe it's true: i need a bigger sensor So I picked up the Canon 5D and tried the only lenses available: 50mm 1.8 and 105 f/4.5 Canon EOS 5D    ---    105mm    f/4.5    1/2s    ISO 1600 Canon EOS 5D    ---    50mm    f/1.8    1/8s    ISO 1600 And...there is not much difference here either!! I know, I know, the framing (and the focus distance) is not identical, I should use a fast long lens on the Canon, etc. but I used what I got and I wanted to do a real-life comparison, where you cannot always choose the perfect focus distance and aperture. The most direct comparison 102 vs 105 has a very different framing. The point here is that I tried SIX different options and I got very similar results. Maybe the subject was just too close to the wall (about three meters). There ARE differences, but I expected a lot more. So what now? Not much. Either I buy a 24-70 2.8 or a 85 1.4 for the Canon or I'm not going to see much difference. Maybe tomorrow I'll do a couple more pictures with the canon, but I do not want to do a "scientific test", we have way too much of those and we already know THE answer. But I usually do not shoot in a lab so those test can be misleading, giving wrong expectations.