Craftypics

Some lenses "show" the bigger aperture with the Speedbooster some dont Sigma 35mm F/1.4 Shows F/1.4 Canon 50mm F/1.4 shows F/1.4 Canon 40mm F/2.8 shows F/2.0 Canon 16-35 F/2.8 Mk2 shows F/2.0 Canon 70-200mm F/2.8 shows F/2.0 Tokina 11-16mm F/2.8 shows f/2.0 going to do some tests later today with the sigma 35mm f/1.4 and speedbooster wide open against the SLR magic 25mm M43 mount T0.95 which theortically should be similar apertures

Just received my EF - M43 Speedbooster and I cant check it out with my GH4 as that's currently out on a shoot , but I did check it with the Black Magic Pocket CInema Camera BMPCC. the Fit is REALLY tight on the BMPCC. Tried it with the 70-200mm F/2.8 II and its great. even at 200mm I can hold it handheld and get really decent stabilisation. Turn IS off and its a dreadfull. Will be another few days before my GH4 is returned so will be keen to see what the fit is like onto that. Can anyone tell me what the other little lever is on the side of the speedbooster ?