>>3328634Normally you double the bottom number in the exposure fraction. For 100mm don't shoot slower than 1/200. For 200mm don't shoot slower than 1/400 and so on. That is the cut off point for handheld usually. If you use macro tubes or bellows just add the mm of the tube/bellows to the mm of the lens. 100mm lens + 20mm tubes = 1/240exp With a zoom lens, always use the longest focal length for the lens as your guide regardless of the lens setting. So a 70-300mm lens should be 1/600exp.
A lot of people say it needs to be 1:1 where 50mm = 1/50, but that really doesn't cut it in my book, there always seems to be some motion blur with that though it will depends on a few factors. People with VR/IBIS or whatever pretty much don't need to care.
I'd also never go below 1/60 with handheld so to avoid blurring. Even then I use burst mode to ensure one gets no motion blur. I really prefer to go no lower than 1/125 since it is as close to my various camera LED frequencies.
