Macro Lens vs Extension Tube vs Both

Hello! I've just recently entered the DSLR world by purchasing a Canon 30D along with an EF 28-105 3.5-4.5 II USM lens.

Yesterday a friend was showing off his new Nikon P&S (not sure which model). We were at a table and wanted to see what our cameras could do for macro photography, so we grabbed a small mint from a candy jar and tested it out. I was amazed at how well his camera performed - he had his camera focusing right up against the object, and the mint filled the frame beautifully. My camera, on the other hand, performed terribly. The 28-105 has MACRO written on it, but advertises a close-focus distance of 0.5 meters... I focused at 0.5 meters and the mint was tiny in my frame.

How can they call this a macro lens, when it's close focus is so far away? I thought I had purchased a nice lens (well I still think it's nice) but that little P&S blew me out of the water. If this is how things work, why aren't ALL lenses called macro?

So that's my first question:

1) Why do they bother calling it macro in the first place?

My other questions are:

2) If I want to be serious about macro photography, should I purchase a *true* macro lens (something that can close focus better than my 28-105) or should I use extension tubes instead, or a combination of both?

3) What are the basic rules for extension tube length (assuming there are any), so that I can apply this to the use of my 28-105 lens?

4) For understanding/purchasing extension tubes or diopters, how do I interpret the numbers of the charts on this page (see link below) which detail extension tubes and diopters?

http://www.bobatkins.com/photography/eosfaq/closeup.htm

I know those are a lot of questions - even if you just post a reference to another site/article that I was too stupid to find, I would appreciate it! Thanks!

First I'de get a book about macro photgraphy.
I would also get an extension tube set and a 2x telecnverter, both of which can be used(together even) on most any lense.
Mark.
ps.
Some point and shoots can focus on things as close as the end of the lens.(good luck lighting these) That is amazing. lense distortion is horrible but probably not noticed shooting a mint.

http://forums.photographyreview.com/...ad.php?t=28035

http://forums.photographyreview.com/...ad.php?t=21833

read them threads ... Loupey is the man around here when it comes to all this stuff...

the 2nd one is a great thread ... and the 1st he just got a macro lens and compares them to his tubes ...

Welcome to the site Crucifix. When you compare a DSLR to a P&S, it's kind of like comparing apples to oranges. They really don't work the same. Although your lens says macro on it, I don't believe it is a true macro lens. I think that where it says macro on your lens, is just there to tell tell you what your close focusing distance is. A true macro lens will have a much shorter min focusing distance. Also, your lens is listed as having a magnification of 1:5.3. A true macro lens will have a magnification of 1:1. A magnification of 1:1 equals life size. This means that the mint in your case, would be the same size on the sensor of your 30D as it would be in real life. What you are getting with your current lens is only 1/5 of life size.

One of our members, and a co-moderator of the Nature and Wildlife fourm loves his macro work,and has posted a couple threads with some great experiments that he's done with both tubes, and now a dedicated macro lens. Check out the two links below and they should give you a pretty good idea of what you can accomplish with tubes, or a macro lens.

http://forums.photographyreview.com/...ad.php?t=21833

http://forums.photographyreview.com/...ad.php?t=28035

Thanks for the responses everyone!

Any recommendations here for books on macro photography?

Quote:

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Originally Posted by Crucifix

Thanks for the responses everyone!

Any recommendations here for books on macro photography?

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http://www.amazon.com/gp/product/cus...283155&s=books

I just odered one for less than $17 myself. I read a copy of this 11 years ago and it pretty much covers everything. its old and out of print, but is as complete a manual as there is on the subject.
As an aside, for every syestem I have(cannon AE1P, KM MAXUM 7, Nikon D70) I have a three tube set and 2x teleconverter. I also have a tokina 100mm f2.8 macro for the D70 (an older version that only goes to1/2 life size, not 1/1 as a true macro would) that I bought used for $178. It serves me well.
Good luck and happy shooting,
Mark.

John Shaw has published some excellent nature/macro books. It's been a while since I bought a book so I don't know if his books are still on the bookshelves. I learned from him.

All manufacturers use the term "macro" loosely. Far too many lenses have that inscribed on the lens barrel - mostly for marketing purposes. It just means that that particular lens focuses closer than their other model of similar focal length.

To get you started, I would indeed recommend the tubes. Cheap, easy, and fun to use. You can see if you like this macro stuff before buying a true macro lens. To get the best from them, it is better to have a good prime though (like a 50mm, 85mm, 100mm, 135mm). But I have used them on my 24-85mm and 24-70mm - the results aren't spectacular but acceptable once you know which focal length/extension tube combinations work best for any particular lens.

Here is the formula of extension tubes to magnifications:

Magnification = total extension tube ÷ focal length of main lens
(with lens focused at infinity)

So a 25mm extension tube mounted on a 50mm lens will provide 1/2 life size image on the sensor.

Quote:

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Originally Posted by mjs1973

Welcome to the site Crucifix. When you compare a DSLR to a P&S, it's kind of like comparing apples to oranges. They really don't work the same. Although your lens says macro on it, I don't believe it is a true macro lens. I think that where it says macro on your lens, is just there to tell tell you what your close focusing distance is. A true macro lens will have a much shorter min focusing distance. Also, your lens is listed as having a magnification of 1:5.3. A true macro lens will have a magnification of 1:1. A magnification of 1:1 equals life size. This means that the mint in your case, would be the same size on the sensor of your 30D as it would be in real life. What you are getting with your current lens is only 1/5 of life size.

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FWIW, a true macro lens also has a flat field that "normal" lenses do not. This can be extremely important for some macro subjects. Extension tubes can't change a curved view to flat field.
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