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Re: Help > Macro photography

Craig Bailey wrote:
>I'm interested in trying some close-up photography using my Canon AE-1
>Program.
>
>I have a Canon 50mm lens and wondered what the best approach would be:
>Do I need to purchase another lens? Or would extension tubes for my
>existing lens serve the same purpose?

What kind of images do *you* want to make???

Diopter supplementary lenses, reverse rings, using a short lense
(say 50mm) as a diopter by mounting it reversed in front of a
longer lense, extension tubes, bellows, tripods, focusing rails,
ring flash units, "macro" zoom lenses that can do 1:4
magnification, macro prime lenses that can do 1:1 magnification,
flat field lenses, and using enlarging lenses... are all topics
related to different kinds of photomacrography.

There is a huge difference in what to talk about if the intent
is to take pictures of very small, very flat, or 3 dimensional
items.

With a regular 50mm lense there are a few characteristics that
you'll want to know about, because they restrict what it can do.

Your 50mm lense will almost certainly need something to help it
focus closer, and either a bellows (which will put it into
manual mode only) or extension tubes (which can be either manual
or can provide automatic functions too) will work well.

Supplementary (diopter) lenses that mount like filters do not
have as much effect with shorter focal length lenses, hence only
a very strong diopter would work and of course the stronger the
diopter the more it degrades the sharpness of the lense, hence
that would probably not be as productive.

With extension tubes or a bellows, a short focal length like
50mm will have a very short working distance, but give
significant magnification. Not Good, if you want pictures of
rattle snakes, for example. And you'll be so close that most
insects will flee in terror, so that's out too.

It will not have a very flat field either. And it will probably
have a very distinct decline in sharpness if the aperture is
anywhere near either wide open or fully closed. Basically
you'll only get sharp images at f/8 and maybe f/11 or f/5.6.
That means you cannot get much depth of field for 3 dimensional
objects, and yet it isn't very versatile for flat objects
either.

Some of the limitations do have work arounds though. For fairly
large objects, such as flowers, a 50mm lense with a short
extension tube will do just fine if you can set the aperture to
f/8 and vary exposure in other ways. A tripod and focusing rail
might be handy, especially if natural light and long exposure
times are used. Or two or more flash units can be used
creatively too.

What kind of pictures do you want to take? Tell us that, and
folks will describe the easiest ways, the cheapest ways, and the
most versatile ways. All different, and probably all both fun
and productive to some degree.

--
Floyd L. Davidson
Ukpeagvik (Barrow, Alaska) floyd@apaflo.com
 

Article References :

Help > Macro photography
 

See Also : Re: macro questions

On 2006-07-25 16:06:20 -0400, "Cisco Kid" said:

> I'm thinking of buying a macro lens but I have a few questions. Looking
>
> at some sites, I noticed macro photography is much more than just
> buying and using a macro lens. In a generic, explanantion-friendly way
> - what is macro photography? I'm not looking for a scholarly these
> paper on the subject.
>
> Also, why can't I just use a telephoto lens? What does a macro lens do
> better than a telephoto lens?
>
>
> Lastly, being that I am mainly a landscape/nature photographer, what
> kind of subjects are we talking about - small bugs and plants/flowers?
>
>
> CK


Classically, Macro Photography was a photograph of an object taken at
1:1 magnifaction or greater (that is life size). Dispense with that
notion. It commonly is used to refer to close up photography. Back
in ancient history (the 60's and 70's) a Macro 35mm lens was generally
used to refer to a lens which had between a 1:1 and a 1:2 reporduction
ratio at its closest focus. At 1:1 a bee photographed on a flower,
would be the actual size on the negative or slide that it was in real
life. at 1:2, the bee would be half its real life size. Macro lenses
were also gernerally corrected for flatness of field. ALL normal lens
have a curved field. That is the, the focus plane is not the same
across the entire width of the lens. On really good lenses, this
curvature of field is minor and we consider the lens to have excellent
edge to edge sharpness. When photographing 3-dimensional objects more
than a couple of feet from the camera, these issues are not visible.
However, when taking a close up of a coin, at 1:1, this curvature of
field is an issue. So, true macro lenses contained elements to correct
this. This holds true for fixed length macro lenses for SLRS'' (i.e.
Nikon, Canon, Minolta, Pentax etc.)

Then life got muddied. The marketers got in the way of engineering.
Some bright bulb discovered he/she could add 50 bucks or more on the
the price of a zoom lens by adding a "macro" setting. At best, that
really was a closer focus lenses than the equivalent non-macro version,
at worst is was printing on the box, and extra engraving on the lens
barrel, but no real "macro" added. Again things progress. The
computer engineering that was not available to the lens designers of
y'or, allow todays engineers to produce zoom lenses which have
credible close focusing capability. Notice, I did not say macro.
Compensating for curvature of field is , I don't believe, yet possible
in a complex zoom lens.

I own two macro lenses. On is the Nikkor 55mm macro (which Nikon
confusingly calls micro) and the Nikon 105mm F4 macro (also confusingly
called micro). The flatness of field in the 55mm is extraordinary.
However, at 1:2 with the lens, the front of the lens is about 2 inches
from the subject. Makes photographing bugs nearly impossible. I don't
know of any "cooperative" bugs or bugs holding out on a modeling
contract (and hense cooperative subjects ) The distance doubles
with 105. It is much more convenient for wildlife photography. Better
yet would be the 200 Micro.

The other issue is lens speed. At macro range, or even close focus,
the depth of field is very shallow, measured in fractions of an inch.
You need a small aperature to compensate. Even then, its still
fractions of an inch. Also, focusing at close distances is tough,
even for AF systems. Most zooms do their "macro" at the full zoom
extension. If your zoom is a variable aperature, this means the thing
may at F4.5 or 5.6 (or worse). F4.5 is marginal for focusing
accurately at close focus, and for my eyes F 5.6 is impossible.

What do you need? Certainly you can take lots of great flower shots
with a decent close focusing telephoto or zoom lens. With some work
and careful selection of subject you can take some amazing ones. Bugs?
or other small objects, I would opt for a 100mm or better true macro
lens. The choices will depend on your camera brand. Taking really
good macro shots requires time and patience and every issue that
effects every photograph is magnified greatly. You might as well
remove one thing form the equation and get a decent macro lens. BTW
there is an added benefits. Most 100-110mm macros are F2.8 or there
abouts. The 100mm focal length makes a great portrait lens on 35mm and
an OK one on 1.6x digitals. The faster speed makes for some better low
light portraits and because of wide aperature, it is easier to throw
the backgorund out of focus.... dual purpsoe lens.

Sorry for the long essay.. I hope it was of some help.

--
Jim