Macro vs Normal Lens

[jgs001]

What's the difference between a Macro lens and a normal lens ? Is it just that the Macro lens is able to focus at much shorter distances ? I've done a little testing this morning, I have an old OM mount Sigma 80-200 with Macro mode, comparing against the 55-250 to find try and find out the differences. I mounted the camera on a tripod, set the camera to full manual control, to ensure I was really comparing the lenses. Ok, I think the Sigma is a bit softer than the Canon, but ignoring that, the only thing I could find, was that to get the same image scale on the Sigma in Macro mode as the Canon at Telephoto, I had to get the camera much closer to the subject. Is the Sigma with Macro mode, not really a macro lens at all so my little test is actually invalid ?

Thanks, trying to understand and failing dismally

 

[Canon Bob]

You've got it at the end there....the Sigma is not a macro lens and the "macro" tag is just a marketing thingy. True macro will put a 1:1 image on the sensor....ie, a 35mm wide object will fill a 35mm wide frame.

Manufacturers add the term macro to indicate that a lens will focus at a shorter distance than would be normal for a lens of the type.

Bob

 

[jgs001]

Cheers Bob, that explains why it didn't make any sense. For a true Macro lens, what sort of distance do the lenses achieve focus between subject and objective ?

 

[pxl8]

It varies but normally only a few inches from the front of the lens to the subject. Usually the distance in quoted as a focal so you need to subtract the length of the lens to find out how far away from the subject you'll be.

 

[jgs001]

great thanks for the answers. That's cleared things up for me. Looks like I'm on the downhill slide... I want a macro lens now...

 

[33L]

siggy 150mm is a good choice!

 

[jgs001]

Thanks for the pointer... have to have a look around.

 

[Spudgun]

Cheers Bob, that explains why it didn't make any sense. For a true Macro lens, what sort of distance do the lenses achieve focus between subject and objective ?

unsurprisingly, the distance will vary depending on the focal length of the lens. at 50mm you will be a few cms from the subject. iirc, the minimum focal length of my sigma 150mm is something like 34cm. what working distance you want will depend on subject; being further away is helpful when doing insect or animal macro. the working distance will also have an effect on perspective of your shot. however, the shorter lenses are easier to handhold than the longer ones, which usually require a tripod.

as for particular lenses, there aren't any bad macro lenses, just some are better than others. lenses like the tamron 90mm and the sigma 70mm and 150mm are highly thought of. they also have the advantage of being cheaper than they're equivalents from canon/nikon/etc. i'm sure you'll find plenty of threads here on this subject.