what is the canon equvelent for the 105mm macro

[johnf3f]

Originally Posted by squishy

the 60 and 100mm should both give the same magnification surely. they're both 1:1 lenses. the only difference is the working distance.

If you go for a 'short' macro, look into the sigma 70mm f/2.8. Sigma themselves say that it's one of the sharpest lens they have ever produced.

I have heard v good things about the 70mm Sigma - forgot to mention it!

With my 100 macro I get 1:1 with my 5d Eos3 etc - exactly as specified, however my 1d (and 50d when I had it) also focus at the same distance with a smaller field of view (sensor) - hence apparenly higher magnification. Obviously the magnification of the lens has not changed - merely the part of the image recorded by the sensor. The 60mm gives 1:1 (APSC only) wheras the 100 gives it on full frame hence the discrepancy.

Hope this clarifies.

[squishy]

There is still no difference in magnification though. 1:1 simply means that the lens is projecting a life size image, i.e, the image is projects onto the sensor is the exact same size as the subject you are photographing.

The difference with the 60mm is that is projects a smaller image, so does not work on full frame, whereas the 100 projects a large enough circle to cover a 35mm sensor. So if the lenses are on an APS-C body, there is no difference in magnification.

[johnf3f]

Originally Posted by squishy

There is still no difference in magnification though. 1:1 simply means that the lens is projecting a life size image, i.e, the image is projects onto the sensor is the exact same size as the subject you are photographing.

The difference with the 60mm is that is projects a smaller image, so does not work on full frame, whereas the 100 projects a large enough circle to cover a 35mm sensor. So if the lenses are on an APS-C body, there is no difference in magnification.

You are quite right the 100mm lens goes to 1 to1 and thats it! However if you are using a smaller part of the image (than the lens produces) with a smaller sensor then you "apparently" have a longer lens at the same focal distance.
Just photographed a ruler with my Canon 100 macro on my 5d, focus manually set at minimum distance, visible part of the ruler was 35mm - exactly what you would expect. Repeated the procedure with my 1d - visible part of the ruler was approx 27mm again exactly what you would expect on the smaller sensor. Don't have an aps c sensor camera so cannot quote for that.
What this shows is that, with the smaller sensors, the image appears to be of higher magnification as smaller part of the image is used. This is very handy as you can use a longer working distance and still appear to have the same magnification of the full frame camera or work at the same distace and get apparently higher magnification. Obviously you are limited by the resolution of the lens but there a few cameras that can out resolve lenses though apparently there are some!
Try it for yourself and you'll see what I mean, it's simply the way my 600 looks like a 780 on my 1d and a 960 on a friends 20d - it's still a 600 but it "looks" longer!