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09-21-2009, 11:47 AM   #1
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Macro basics

A few macro questions. I have seen the macro gallery. Amazing!!! So, to get some nice macro shots, what are the basic needs? For a first macro lens for say... insects, what focal length would be best 50, 100 or some other length. Are bellows similar to macro extension tubes? Why is a 50 2.8 macro good, while 2.8 n
'normal' 50 isn't that fast? Thanks

09-21-2009, 12:02 PM   #2
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First, I'd recommend goign to a library or bookstore and getting a good basic guide to photography; these typically cover questions like this, as well as the inevitable questions that you'll have next after getting to the answers to these :-)

But FWIW:

- A longer focal length allows you to shoot from farther away for the same magnification. In this sense, macro photography is no different than non-macro photography. Take your kit lens, set it to 18mm, fill the frame with an object, then zoom to 55mm, and you'll have to step back to fill the frame the same way.

- Since insects typically don't respnd well to having lenses stuck right in their faces, that means longer is usually better. I wouldn't be messing with anything shorter than 100mm, personally.

- Bellows are like adjustable extension tubes, yes.

- Large apertures (eg, f-numbers less than f/2.8) are useful for shooting in low light, because they allow faster shutter speeds, but the tradeoff is very shallow DOF. With macro photography, DOF is already incredibly shallow; far to shallow to be useful a f/2.8, normally. So even if your lens had f/2 or f/1.4, you wouldn't want to use it - you'll normally stop down to f/8, f/11, or even f/16 or more. This often means you'll you'll need flash to provide enough light, but the alternative is a picture with just a tiny bit in focus. Sometimes that's a ncie effect, but it gets old quickly.

- Google "Raynox 150" (including disucssions here) and consider whether that might not be a good way to get started without spending much money.
09-21-2009, 01:32 PM   #3
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Bryan Peterson, author of "Understanding Exposure", which many on this and other forums recommend highly, has another book, "Understanding Close-Up Photography". In it, he covers the differences between using a true macro lens, close-up filters ("silly, useless, optically inferior and ridiculously cheap") and extension tubes. He uses the same writing techniques and style to explain close-up and macro photography that he used to explain exposure in the previous book.

He doesn't discuss bellows, but, in my mind, they are optically, more or less equivalent to extension tubes. They have no optics and merely move the lens further from the image plane, just as extension tubes do. Bellows are more bulky and perhaps more difficult to carry around, but they are infinitely variable, whereas extension tubes can only be used in a finite number of combinations.

I think that many macro lenses are slower than comparable non-macro versions because macro shots are almost always done in controlled lighting situations or at least in moderately bright lights. No one does macro photography in a night club or theater. So, macro lenses don't have to be fast. Macro lenses are designed with extended focusng mechanisms, to allow the close focusing in the first place, and the optics are designed to be sharp at close distances. Its all in the compromises that the lens designer made. In the case of a macro lens, the compromises are all to put the design and production costs into getting the sharpest possible image at very close distances, whereas a "normal" lens is compromised to get the best results at more common shooting distances, like 10 feet to infinity.
09-28-2009, 01:12 PM   #4
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QuoteOriginally posted by Marc Sabatella Quote
First, I'd recommend goign to a library or bookstore and getting a good basic guide to photography; these typically cover questions like this, as well as the inevitable questions that you'll have next after getting to the answers to these :-)

But FWIW:

- A longer focal length allows you to shoot from farther away for the same magnification. In this sense, macro photography is no different than non-macro photography. Take your kit lens, set it to 18mm, fill the frame with an object, then zoom to 55mm, and you'll have to step back to fill the frame the same way.

- Since insects typically don't respnd well to having lenses stuck right in their faces, that means longer is usually better. I wouldn't be messing with anything shorter than 100mm, personally.

- Bellows are like adjustable extension tubes, yes.

- Large apertures (eg, f-numbers less than f/2.8) are useful for shooting in low light, because they allow faster shutter speeds, but the tradeoff is very shallow DOF. With macro photography, DOF is already incredibly shallow; far to shallow to be useful a f/2.8, normally. So even if your lens had f/2 or f/1.4, you wouldn't want to use it - you'll normally stop down to f/8, f/11, or even f/16 or more. This often means you'll you'll need flash to provide enough light, but the alternative is a picture with just a tiny bit in focus. Sometimes that's a ncie effect, but it gets old quickly.

- Google "Raynox 150" (including disucssions here) and consider whether that might not be a good way to get started without spending much money.
..or Raynox DCR-250 for that matter.

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