I have a question about lens converters, but not only in relation to m4/3. 4/3 lens have all sizes of filter diameter thread, but the same sensor size. For 17mmOly pancake I chose somthing like this - a 37mm lens adaptor. A cheap one. Here you can see results: Subscribe to see EXIF info for this image (if available) I don't care about distortion, but would like to eliminate gradual lack of sharpness off the centre. Subscribe to see EXIF info for this image (if available) It seems to add to background blur as you can see above. I wonder whether it just optical quality of this gadget, or its image format, as results remind me such lens, which are usually made for 1/3" sensor. Should I the get a stepup ring and screw on a larger than 37mm converter, ex. which could have larger image format, ex. this one?