I just bought a Sigma 17-70 macro. Where do they measure from, when they say "minimum focusing distance - 20cm/7.9 in."? I was trying to take a close up shot of a couple of items and the lens almost touched the items (1/2 inch) and it would still focus and lock on. If I had the hood it would have touched it. Is this normal? I'm not complaining, I just didn't know what to expect.
hi ray- focusing distance is from the sensor plane. if you look at the top of your camera, you'll find a circle with a line through it. that's the sensor plane. measure 20cm from this point, and that should be the closest you can focus. ricky
Working distance, the distance from the front of the lens to the subject, is important to many macro shooters. That's why the longer lenses, 150, 180, 200, etc. are preferred by many of us. I love 50, 60, 85, etc macro lenses but they present real challenges when it comes to lighting. It's easy to block your own light with these shorter lenses and flash isn't always the answer (though it usually is).
