Compare: Canon 180mm f/3.5 macro and 70-200 f/4 w/ ex tubes

Please forgive me if this is too far off, but I'm still new to the world of extension tubes. But what advantages would one of these have over the other? Would the optics on the 70-200 make it a better choice? But the 180 is a prime and dedicated macro. What makes a lens a dedicated macro?

Theory? Actual comparisons? Am I just nuts for thinking of this?

Teach me!

Not sure we'll get too mcuh help but i'm interested too. Thinking about buying a set for my 70-200.

A true macro lens will let you get closer to your subject, usually close enough to give you a image size the same size as what you are taking a picture of (1:1), while still keeping the ability to focus to infinity.

With extention tubes you get the ability to move closer to your subject (and increase the image size on the sensor) but loose you ability to focus out to infinity.

How much depends on the length of the extention tube compared to the focal length of the lens you attach it to.

You also loose some light with extention tubes.

One thing that keeps getting said about dedicated macro lens is that the are as a general rule some very high quality lenses, shaper than zooms and very competative against high quality primes.

I have been useing extention tubes and find them very usefull and inexpensive but I am currently looking to buy a macro lens.

When would anyone need to focus at infinity while shooting macro???

A macro lens doesn't always have to be used to shoot things close up. I use my Tamron 90mm quite often as a mid-tele on my 10D. It's as sharp or sharper than my 16-35L and 200L at all focus distances.

some shots from the Tamron 90mm...
http://nobot.2y.net …res/20041031-yosemite/?37 (infinity)
http://nobot.2y.net …res/20041031-yosemite/?49 (mid)
http://nobot.2y.net …res/20041031-yosemite/?42 (macro)

Exactly, thats when you take off the extension tubes .

As a friend of my explained it.

It is nice to be able to go from taking a picture of the entire flower arangment to taking a picture of a single bud with only having to move the tripod / camera.

I am pondering the same question. I currently have the 70-200 2.8L, which I love. When shooting with my extension tubes, I lose quite a bit of light, making it harder to shoot at the the smaller apertures. I always use a tripod, but the slower shutter speed leaves you vulnerable to wind gusts and movement by the subject. I have taken some good shots with this setup, but would be curious to hear the experience from anyone who has used both.

Thanks

Putting on extension tubes changes your focussing distance in discrete steps; depending on the lens and tube lengths, you may or may not have continuous coverage between the lens' closest (normal) focus and the closest focus possible with all tubes.

Not all extension tubes will provide full auto capabilities on your system, whereas you know the macro lens will work exactly the same electronically at 1:1 and infinity.

Also, the macro lens is corrected to provide maximum image quality across the full focussing range from infinity to 1:1. As you add extension to other lenses, you move them away from their optimally corrected ranges.

Bill, have you any pictures with your setup?
I'm consdiering adding some tubes to my 70-200 and it would be great to see some examples

Martin

I have recently acquired the Sigma 180 macro and (a few days later ) the 1.4x TC. Having previously used mainly the 500D close-up lens and occasionally extension tubes.

The dedicated macro does make it much easier to get greater magnification. This gallery has some examples of the 180 macro along and this one with the 1.4xTC. The picture of the Loonie 5 buck coin is around 1.5x magnification.

There are some picture in this gallery taken using the 500D on a variety of lenses.

Personally, if you don't want to get a dedicated macro lens, I think the 500D is a much better bet with a 200mm lens than extension tubes - less hassle, better working distance and greater magnification unless you really stack the tubes.

Regards,

I have used extension tubes quite a bit on my 70-200/2.8. I don't have a 180 mm macro lens to compare it to, but do have a Sigma 105 mm macro lens.

The most obvious comparison is that the macro lens is somewhat sharper than the zoom with extension tubes. This is quite noticeable if you make big enlargements.

The next inconvenience comes when you try to compose and then focus. You have to use the right length of extension tubes since the focus ring on the lens does not provide much of a range for focusing. With the macro lens you can focus at any distance from minimum to infinity so you don't have to play around with finding the right combination of extension tubes. To be fair, you can focus a zoom lens on extension tubes by turning the zoom ring. Changing the focus ring will allow you to focus, but it also changes composition. This is also somewhat of a problem with most macro lenses because you will find that composition changes slightly when you focus very close. They probably also achieve close focusing by changing the effective focal length a bit. This is especially true with internal focusing designs.

Carrying extension tubes with your zoom lens is an economic method of starting macro photography and/or saves weight if you are hiking and don't want to cart an extra lens. If you become very serious about macro shooting I believe you would be happier with a true macro lens.

That said, my favourite combination for butterfly photos is a long extension tube on a Sigma 50-500 lens. The wide zoom range allows using the zoom ring for focusing and the long telephoto length allows photos without chasing the bugs away.

Scott, Roger, great info, thanks,
Martin

Martin,
Most of the macro work was done before I went digital last month. I have a couple with my 20D which I will try and post. I don't have a place on the internet to upload them but am working on it.

ScottE is dead on as far as focusing with the tubes. It can be work to get composition and focus. However, I don't regret buying mine. It allowed me to get started into Macro. I carry them in my bag all the time, and have taken shots when on a location and wasn't planning to shot Macro.

Just to provide a little wrap up . . .

I have been taking macro using extention tubs and a 100-400L zoom lens. I was happy. Good pictures, not to hard to work with.

But I was still considering getting a true macro lens. Talked to a friend who has both the 100 Canon and the 180 Sigma macro lense. In the end he let me borrow the 180 for a test spin.
WOW the difference was just more than I had expected. I am now totaly convinced and have to buy my own 180 macro lens.

Things that I noticed -
image through the viewer was so much brighter.
even with a 12+20+36 on 100mm the image is not 1:1 and 1:1 is very big and very cool
very sharp