Thanks for all reply. If a poster "STEVE" is located far away which is invisible from the eye such that only one device is able to capture it, do you think it will be a
1) Panasonic SDR 26 max 2695mm? (1/8" sensor) Crop factor more than 20X
2) Canon SX10 max 560mm? (1/2.5" sensor) Crop factor 5X. Crop to the size of the poster after that.
3) Nikon 5000D with 50-150mm lens? Note that the previous two telephoto length are expressed after multiplying by the crop factor. For this one the max is 150mm and it is before cropping. The crop factor is 1.5X. After that crop to the size of the poster.