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12-27-2009, 06:46 AM   #1
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Please define: Wide-Angle. Macro.

These are the most basic of photography questions.

As I search and shop for lenses I find I really don't know what the drawbacks are to these two types of lenses.
I understand my k1000 looks at a 35mm lens as a ff camera would see a 50mm lens.

But it seems to me that all 28mm or 35mm lenses are considered "Wide-Angle". When I think of wide-angle I think 'distorted' shot.

Macro is a bit trickier. IF a Macro lens is to be used for shooting small subjects, (flowers and insects etc) can it ALSO be used to shoot normal subjects in distance without any problems or distortion?

How are these lenses constructed differently and what's the drawback to having them as a 'normal' lens?

12-27-2009, 07:41 AM   #2
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Winnie,

I am not an expert and I'm sure folks will correct me if I'm wrong but "wide angle" is a somewhat arbitrary term. It's all relative. A 35mm lens is wider than a 50mm and a 17mm is wider than a 35mm. I think you might mean a fisheye lens when you mention distortion although zooms will typically have some barrel distortion at the wide end.

As for macro. This is a lens that has the ability to focus at some distance and give a 1:1 image size (note that many of the so-called macro zooms do not quite achieve 1:1 but simply allow a very close focusing distance). A 70mm macro will give this 1:1 image at a fairly close distance to the subject. A 300mm macro allows you to stand off a further distance and still have the 1:1 image. I'm not sure if the macro lens has any limitations if used for "normal" photography.

WD
12-27-2009, 09:59 AM   #3
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When you say 1:1 image...you meeeean?
12-27-2009, 10:34 AM   #4
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Macro lens.
Macro lenses in recent years have settled on 1:1, also known as "life size", as the criteria for a lens being a true macro lens. In former years, such as when my SMC Pentax-M 100mm f/4 macro was built, 1:2 or "half life size" was the norm. The real criteria of a macro lens is that in addition to the ability to focus very closely to the subject it is optically designed to take pictures of close objects with little or no distortion.

So, in short, a macro lens is one that will take pictures of something very small and fill the viewfinder frame with it. I know of only one exception to the rule that the macro lens will also focus to infinity, and that is the Canon lens that provides magnifications from 1:1 through 1:5 only. It is a very expensive, very specialized, and very, very good lens.

Wide angle.
A wide angle lens is one that takes a picture that is wider than the field of view of the human eye, basically. A "normal" lens is one with a focal length approximately the same as the diagonal measurement of the sensor or film gate. As the focal length becomes shorter, the field of view of the lens becomes wider - you can get more and more of the mountain into your picture.

Telephoto or Long lens.
As the focal length becomes longer, the field of view narrows, and distance objects are larger than seen with the naked eye.

Zoom lens
A zoom lens has a variable focal length. The photographer changes the focal length with a control. Zoom lenses are then categorized as "normal" "wide angle" "super zoom" and "telephoto" zoom lenses. A normal zoom lens includes the focal length of a normal lens and goes somewhat wider and somewhat longer. On 35mm film cameras, a normal zoom would have numbers like 24-90 or 28-75. On digital SLR cameras with the smaller (APS-C size) sensor, which is 2/3 the size of the 35 mm negative, "normal" zooms have focal ranges such as 18-55 or 16-50. Telephoto zooms would be 50-135 or 50-200. A super zoom is along the lines of 18-250, and has a "super" range of focal lengths built in.

Prime lens
A "prime" lens is mentioned from time to time as well. This simply means that it is a single focal length lens.

Signature lenses

In my signature below, you will see that I have a DA 12-24 zoom. This is called an ultra wide zoom because it has a very large field of view. My 16-50 is a "normal" zoom, and a recent look at my pictures showed me that it took over 40% of my images. My 50-135 is a telephoto zoom. The field of view is always narrower than normal, which makes distant subjects such as soccer players appear closer in the image than they are, just like a pair of binoculars. There are also two film range zoom lenses for my film cameras, a 28-80 and a 24-90. I have a macro lens, the 100mm f/4 lens and a super telephoto, the 400mm f/5.6.

12-27-2009, 12:10 PM   #5
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to further extrapolate the meaning of 1:1 magnification - if the subject (say a bug) is 1cm long, then at closest focus the bug will be viewed at the sensor level as 1cm across, or actual size.
12-27-2009, 06:49 PM   #6
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Great explanations. Thanks guys.
12-30-2009, 09:07 AM   #7
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On a FF or 35mm camera, a 50mm lens used to be the standard 'kit' lens. Reason for this was that this lens gives a similar view as the human eye has (very slightly tele compared to the human eye). Anythong longer is considered tele and anything shorter is considered wide.

Divide this by 1.5 for an APS-c sensor and you get around 35mm. The confusion is that all specifications/advertisements that I have seen still refer to a 35mm as a wide angle lens, even if the lens is dedicated for APS-c cameras.
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