Macro Lens Vs. Standard Lens

nico · Aug 20, 2007

Could use a little insight:

Looking at the Canon Macro lens (http://www.usa.canon.com/consumer/co...modeli d=7400)
My big question, besides theadded zoom range, how does this macro lens differ from the standard 18-55 mm Canon len? (http://www.usa.canon.com/consumer/co...odeli d=10512)

I thought the big thing about macro lenses is the closest focusing distance. In this instance, it seems the 18-55 lens is better (.92 to infinity)?

JeannetteK · Aug 20, 2007

Great question. I'd love to know the answer as well.

lifeafter2am · Aug 20, 2007

Macro lenses produce an image that is the same size in real life as it is on the sensor. Basically a true macro lens has a 1:1 magnification or higher.

http://en.wikipedia.org/wiki/Macro_photography

Don Simon · Aug 20, 2007

Well there are a few things to mention.

Firstly the 100mm macro does not have any added zoom range, in fact it has no zoom range at all... "zoom" does not mean longer, it means the lens has more than one focal length; it means the focal length is variable. Therefore a 10-20, an 18-55, a 70-200, anything with a hyphen is a zoom. The 100mm however only has that fixed focal length of 100mm. A fixed focal length lens is often also known as a "prime" lens.

As the previous poster said, a true macro lens will be 1:1 magnification or higher. Generally this does require a closer focusing distance. Now the 18-55mm may have a closer focusing distance than the 100mm, but this is because it covers shorter focal lengths with a wider angle of view. The longer 100mm lens is a telephoto which also has a short minimum focusing distance, so it is still much better... the 18-55 may get physically slightly closer to the subject, but the 100mm macro will still be a much better lens for magnification of small subjects...
... perhaps the best way to understand that is this: consider that using a 100mm lens at normal distances would appear to bring you much closer to the subject than using an 18mm or 50mm lens from the same spot. Now imagine having that ability at very short distances.

In addition to the different focal length and the macro capability, the 100mm will also be significantly different from the 18-55mm in terms of the optical quality. Because it is a prime (which are easier to design to a higher standard than a zoom), and one designed for macro use, it will give higher resolution, be far less prone to various aberrations, and generally be of a higher quality.

TCimages · Aug 20, 2007

nico said:
Could use a little insight:

Looking at the Canon Macro lens (http://www.usa.canon.com/consumer/co...modeli d=7400)
My big question, besides theadded zoom range, how does this macro lens differ from the standard 18-55 mm Canon len? (http://www.usa.canon.com/consumer/co...odeli d=10512)

I thought the big thing about macro lenses is the closest focusing distance. In this instance, it seems the 18-55 lens is better (.92 to infinity)?

the 18-55 will only allow you to get close up images, not true macro. As posted above, 1:1 is true macro. When you select the Macro switch on the 18-55, it allows you to focus at a minimum focus distance (280mm), but at this distance, your magnification is only 55mm.
The 100mm macro allows a shorter minimum focus distance (149mm), but at this distance the magnification is at 100mm.

So, the 100mm is not only a greater magnification, but it's a greater magnification at a closer minimum focus distance.

I hope this helps. I think you may have misread the minimum focus distances of the lenses. The 18-55 is .09 ft or (280mm), the 100mm is 149mm. If you are interested in true macro, a dedicated macro lens is the way to go.

*edit* The below poster is correct, but this is film plane to subject, In the overview and in my own personal experience, the minimum focus distance is around 6 inches which is approx. 149mm .

Don Simon · Aug 20, 2007

According to the Specifications sheet the closest focusing distance on the 100mm macro is 31cm or 1 foot. This would be in line with most macro lenses of similar focal length.

Sideburns · Aug 20, 2007

Well, those two in particular...
the macro is 699 CAD, the 18-55 is about 100 CAD with the kit...
You get what you pay for.
You can make tiny things seem huge, and you can bring little barely noticeable details into your everyday pictures.
Also, you can get in closer to your subject because of the added focal length, not to mention the magnification...

Don Simon · Aug 20, 2007

Oh and I forgot to mention... the 100mm is f/2.8. The kit lens is f/3.5 to f/5.6 depending on focal length. Larger max aperture on a longer lens is pretty much always going to cost more.

TCimages · Aug 20, 2007

ZaphodB said:
According to the Specifications sheet the closest focusing distance on the 100mm macro is 31cm or 1 foot. This would be in line with most macro lenses of similar focal length.

I think it's .31m or 1ft, but this is film plane to subject.

nico · Aug 20, 2007

Wow, lot's of explanations.
I think I get the idea.
To clarify, I already have the 18-55 when I bought the Rebel XT. I'm considering getting the macro 100mm in a month or so and was just wondering how "good" it was. When I read about the closest focus distance I got a little confused (since I knew macro lens are supposed to be superior in high quality, up close and personal shots).

I even went as far to see how close my 18-55 could get before the AF would get a little wacky. So for example, if I took a penny and got really close with my 18-55 and focused on it, and did the same with the 100mm, the 100mm would come out the winner?

lifeafter2am · Aug 20, 2007

The 100mm would make a MUCH larger image. For instance you could focus in on just the eye of Lincoln on the penny vs the whole penny.

Some Examples

You can get really nice and very magnified images with this lens. Look at the bug pics, and just imagine how small those bugs are!

TCimages · Aug 20, 2007

nico said:
Wow, lot's of explanations.
I think I get the idea.
To clarify, I already have the 18-55 when I bought the Rebel XT. I'm considering getting the macro 100mm in a month or so and was just wondering how "good" it was. When I read about the closest focus distance I got a little confused (since I knew macro lens are supposed to be superior in high quality, up close and personal shots).

I even went as far to see how close my 18-55 could get before the AF would get a little wacky. So for example, if I took a penny and got really close with my 18-55 and focused on it, and did the same with the 100mm, the 100mm would come out the winner?

Yes, If you want a full frame penny, the 100mm macro would be the best. This lens is an amazing lens. I will add this tho, Macro takes practice to master lighting and aperture. If you haven't already done so, learn how aperture affects DOF (depth of field), it's critical. In fact, the one thing about the 100mm that makes it an amazing portrait lens is the F2.8, but this is almost useless in the world of macro. The closer you get, the more shallow the DOF. Sorry for info overload, but it's a subject I love most.

If you can handle looking at insects, check out my site, most all of them are taken with the 100mm macro.

Good luck.

nico · Aug 20, 2007

Dude the dragonfly rocks. How'd you get him to stay still?
My gf has a huge amount of land, so I can only imagine what type of critters and wildlife are out there. It's one of the big reasons I was interested in Macro lenses in the first place.

Garbz · Aug 20, 2007

Dragon flies tend to sit still after a while. It gives you ample time to photograph them. My last attempt though I moved slightly before clicking and the autofocus couldn't keep up. It wasn't the eyes in focus but the dragonfly's tail, and I didn't realise till I got home >_<

Macrophotography is hard, it requires patience to do, I highly recommend a tripod or a flash unit or both to go with it but once you master it you'll fell like nothing else in life matters anymore

And you will quite literally look at the world through different eyes: http://farm2.static.flickr.com/1422/1048970286_6f09ea4fc9_b.jpg

TCimages · Aug 21, 2007

nico said:
Dude the dragonfly rocks. How'd you get him to stay still?
My gf has a huge amount of land, so I can only imagine what type of critters and wildlife are out there. It's one of the big reasons I was interested in Macro lenses in the first place.

Thank you. This guy was actually more cooperative than normal. It takes a lot of patience, but very rewarding. I'm happy to hear your interest. It opens up a whole new world of photography with an endless supply of subjects.

Best of luck to you. If I can be of any help, just ask.