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Message: <blockquote data-quote="adrianf" data-source="post: 1471509" data-attributes="member: 14512">I stopped to think before I bought a macro lens. My schoolboy physics reminded me that a lens gives 1:1 reproduction at a distance of twice its focal length from the subject. This means that the 50/60mm macro lenses were going to require me getting far too close to my subjects. I also thought that the sensor on my Canon 40D is only 22mm X 15mm which means that at 1:1 anything bigger than that will be cropped. In the end I went for the excellent and reasonably priced Sigma 70-300 DG APO zoom which admittedly only manages 1:2 macro but a) it does that at over 2 feet range and b) it allows me to fit things like butterflies and dragonflies to fill the frame without being cropped. I can zoom to frame the scene too. It's also an excellent all-round lens for non-macro work and I got it on ebay for less than 100 quid.</blockquote>