I need to do some macro photography which will require about x5 magnification. I have the 180mm Canon macro lens which goes to life size, or x1 magnification. What extension tubes will I need to get to x5?Thanks.[a href=\"index.php?act=findpost&pid=223646\"][{POST_SNAPBACK}][/a]
A lot. rough approximation: magnification gain = ex tube length / lens focal length.So you want an additional 4x, which would be...720mm.I'm sure this approximate calculation falls apart long before that kind of extension, but you get the idea.Dave Chew[a href=\"index.php?act=findpost&pid=223697\"][{POST_SNAPBACK}][/a]
You could try the Canon 500D close up lens. I have one for a 70-200 zoom with a step down ring and it's sharp right across the zoom range, while a single element close up I tried was fine at 70mm and hopeless at above 120mm or so. I have a set of extension tubes and hardly use them as1) putting them on without filling the camera body with dust seems impossible2) by the time they are on the subject has died of old age3) the close up lens works just as well for most of my needs.You could probably borrow one from your camera store and try it out. I have no idea if it will do what you want. David[a href=\"index.php?act=findpost&pid=223750\"][{POST_SNAPBACK}][/a]
I thought the 500D focuses at 0.5m. How would one get a 5X magnification with this attached? I'm most curious since I have the same 500D.[a href=\"index.php?act=findpost&pid=223763\"][{POST_SNAPBACK}][/a]
Thanks Dave, yes I've looked it up and you're right, it's an unrealistic extension. Guess it's down to the x1-x5 macro 65mm; even though it's manual focus, the f2.8 aperture is calculated rather than real (so the image in the viewfinder is likely to be very dim), and I'll be too close to the subject for anything other than the ring flash![a href=\"index.php?act=findpost&pid=223713\"][{POST_SNAPBACK}][/a]
I think at 5x you're screwed no matter what.[a href=\"index.php?act=findpost&pid=223730\"][{POST_SNAPBACK}][/a]