Someone please explain MACRO lenses to me

Hi folks, I feel a bit like an idiot because I don't know this, but it's
never come up. I'm not sure I understand the idea of macro (close-up)
lenses. A bit of searching on the internet always turns up the same info:

"Continuous focusing from infinity to life-size"
"Maximum Reproduction Ratio (Macro Setting): 1:1"
"high resolution from infinity to close-ups down to x.x inches"

..but I'm honestly not sure what this means. Don't all lenses have
"continuous focusing"?

In other words, what's the difference in the photo? For example, they always
seem to show a picture of a flower. What is the difference between shooting
with, say, a 105mm macro lens and a 105mm non-macro lens? I assume you can
get quite close to the subject to shoot with these lenses, but what's the
benefit? Is there any reason to choose a 60mm macro lens to shoot something
closeup, versus a 200mm non-macro lens a bit further away?

Thanks in advance,
G

greg wrote:
Hi folks, I feel a bit like an idiot because I don't know this, but
it's never come up. I'm not sure I understand the idea of macro
(close-up) lenses. A bit of searching on the internet always turns up
the same info:

"Continuous focusing from infinity to life-size"
"Maximum Reproduction Ratio (Macro Setting): 1:1"
"high resolution from infinity to close-ups down to x.x inches"

.but I'm honestly not sure what this means. Don't all lenses have
"continuous focusing"?

No. For example, on the Minolta A2 there is a restricted range at which
its macro settings work. In fact, there are two ranges, one for
wide-angle and one for telephoto. I don't have the figures in front of
me, but it mean that (for example) you could only take pictures from 3
inches to 4 inches, 7 inches to 8 inches, and 15 inches or further
(Non-macro).

In other words, what's the difference in the photo? For example, they
always seem to show a picture of a flower. What is the difference
between shooting with, say, a 105mm macro lens and a 105mm non-macro
lens?

In theory, none, but the non-macro lens may not allow you to focus close
enough (some 28 - 200mm zooms can only focus down to 2 metres), and it may
not be as sharp. The macro lens will be designed to wrok close up, and
may focus better over the whole subject (i.e. it has a flatter field).

[Cross-posting trimmed]

Cheers,
David

Macro is one of those terms which has been misused by lens manufacturers, so
it's not surprising you are confused. So, to clear things up, a true macro
lens generally focuses to life size, or 1:1. That means that the object is
reproduced actual size on the film. The image of one centimeter object in
real life will measure one centimeter on the neg or slide.

Not all lenses have continuous focusing, no. Some specialized lenses don't
focus to infinity, for example, like the old Minolta macro zoom, which went
to 3 times life size.

Hi resolution is meaningless in differentiating a macro from anything else.
More marketing babble. You can have a high resolution non macro lens too.

The difference between a 100mm macro and non macro will be the minimum
focusing distance. A non-macro may get to you within several feet. A 100mm
macro with lifesize capability (1:1) will get you to 100mm, more or less,
probably less due to lens oddities.

Most lenses claiming macro anymore are consumer zooms which will focus down
to 1/4th life size. Nice, but hardly macro.

Mike

"greg" wrote in message
news:cR3Tc.98306$gE.62708@pd7tw3no...
Hi folks, I feel a bit like an idiot because I don't know this, but it's
never come up. I'm not sure I understand the idea of macro (close-up)
lenses. A bit of searching on the internet always turns up the same info:

"Continuous focusing from infinity to life-size"
"Maximum Reproduction Ratio (Macro Setting): 1:1"
"high resolution from infinity to close-ups down to x.x inches"

.but I'm honestly not sure what this means. Don't all lenses have
"continuous focusing"?

In other words, what's the difference in the photo? For example, they
always
seem to show a picture of a flower. What is the difference between
shooting
with, say, a 105mm macro lens and a 105mm non-macro lens? I assume you can
get quite close to the subject to shoot with these lenses, but what's the
benefit? Is there any reason to choose a 60mm macro lens to shoot
something
closeup, versus a 200mm non-macro lens a bit further away?

Thanks in advance,
G

Macro is one of those terms which has been misused by lens manufacturers, so
it's not surprising you are confused. So, to clear things up, a true macro
lens generally focuses to life size, or 1:1. That means that the object is
reproduced actual size on the film. The image of one centimeter object in
real life will measure one centimeter on the neg or slide.

Not all lenses have continuous focusing, no. Some specialized lenses don't
focus to infinity, for example, like the old Minolta macro zoom, which went
to 3 times life size.

Hi resolution is meaningless in differentiating a macro from anything else.
More marketing babble. You can have a high resolution non macro lens too.

The difference between a 100mm macro and non macro will be the minimum
focusing distance. A non-macro may get to you within several feet. A 100mm
macro with lifesize capability (1:1) will get you to 100mm, more or less,
probably less due to lens oddities.

Most lenses claiming macro anymore are consumer zooms which will focus down
to 1/4th life size. Nice, but hardly macro.

Mike

"greg" wrote in message
news:cR3Tc.98306$gE.62708@pd7tw3no...
Hi folks, I feel a bit like an idiot because I don't know this, but it's
never come up. I'm not sure I understand the idea of macro (close-up)
lenses. A bit of searching on the internet always turns up the same info:

"Continuous focusing from infinity to life-size"
"Maximum Reproduction Ratio (Macro Setting): 1:1"
"high resolution from infinity to close-ups down to x.x inches"

.but I'm honestly not sure what this means. Don't all lenses have
"continuous focusing"?

In other words, what's the difference in the photo? For example, they
always
seem to show a picture of a flower. What is the difference between
shooting
with, say, a 105mm macro lens and a 105mm non-macro lens? I assume you can
get quite close to the subject to shoot with these lenses, but what's the
benefit? Is there any reason to choose a 60mm macro lens to shoot
something
closeup, versus a 200mm non-macro lens a bit further away?

Thanks in advance,
G

greg ) wrote...
Hi folks, I feel a bit like an idiot because I don't know this, but it's
never come up. I'm not sure I understand the idea of macro (close-up)
lenses. A bit of searching on the internet always turns up the same info:

"Continuous focusing from infinity to life-size"
"Maximum Reproduction Ratio (Macro Setting): 1:1"
"high resolution from infinity to close-ups down to x.x inches"

.but I'm honestly not sure what this means. Don't all lenses have
"continuous focusing"?

Yes, all lenses have continuous focusing, as you put it, but all
lenses also have a minimum focus distance - that is a point where if
you move any closer to the subject you will not be able to focus on
it.

Some specialist macro lenses, however, are so tuned to macro
photography that they will not focus out to infinity (e.g. the Canon
MP-E65mm)

In other words, what's the difference in the photo? For example, they always
seem to show a picture of a flower. What is the difference between shooting
with, say, a 105mm macro lens and a 105mm non-macro lens?

Nothing, except with a proper Macro lens you will be able to get
closer to the flower (and thus get more of it to fill your frame)
than with the non-macro lens.

It gets a bit confusing because "Macro" as a term is often abused.
My 28-70mm zoom lens has a "macro" end of the focusing scale, but is
only capable of 0.22 x lifesize.

Life size (or 1:1) means that the size of the subject on the film is
the same size as in real life. So, assuming you have a 35mm film
camera, at "life size" an object 35mm across will fill the frame.

So my "macro" setting on my lens will mean that at the minimum
focusing distance an object 35mm / 0.22 = 160mm wide will fill the
frame. In other words, if I want a frame-filling photo of a bumble
bee, this is not the lens to do it!

I assume you can
get quite close to the subject to shoot with these lenses, but what's the
benefit? Is there any reason to choose a 60mm macro lens to shoot something
closeup, versus a 200mm non-macro lens a bit further away?

The advantage of a longer focal length macro lens is that you have
more working distance between you and the object in question. This
can make lighting it a bit easier, as you are less likely to be
casting your own shadow over it.

Ian
--
Ian Riches
Bedford, UK

"high resolution from infinity to close-ups down to x.x inches"

.but I'm honestly not sure what this means. Don't all lenses have
"continuous focusing"?


No. I can recall aftermarket lenses in the late 70's / early 80's that
required the user to move a 'shift cam' to select the macro range. Some
of the Vivitar Series 1 were like this.

"high resolution from infinity to close-ups down to x.x inches"

.but I'm honestly not sure what this means. Don't all lenses have
"continuous focusing"?


No. I can recall aftermarket lenses in the late 70's / early 80's that
required the user to move a 'shift cam' to select the macro range. Some
of the Vivitar Series 1 were like this.

In article , Mike
Lipphardt writes

The difference between a 100mm macro and non macro will be the minimum
focusing distance. A non-macro may get to you within several feet. A 100mm
macro with lifesize capability (1:1) will get you to 100mm, more or less,
probably less due to lens oddities.

A 100mm lens at 1:1 reproduction ratio will have a subject to lens
(front nodal plane) distance of 200mm and a lens (rear nodal plane) to
film distance of 200mm. (Bear in mind, though, that some complex designs
will have the nodal planes outside the physical limits of the lens.)
--
David Littlewood

In article cR3Tc.98306$gE.62708@pd7tw3no, greg writes
Hi folks, I feel a bit like an idiot because I don't know this, but it's
never come up. I'm not sure I understand the idea of macro (close-up)
lenses. A bit of searching on the internet always turns up the same info:

"Continuous focusing from infinity to life-size"
"Maximum Reproduction Ratio (Macro Setting): 1:1"
"high resolution from infinity to close-ups down to x.x inches"

.but I'm honestly not sure what this means. Don't all lenses have
"continuous focusing"?

In other words, what's the difference in the photo? For example, they always
seem to show a picture of a flower. What is the difference between shooting
with, say, a 105mm macro lens and a 105mm non-macro lens? I assume you can
get quite close to the subject to shoot with these lenses, but what's the
benefit? Is there any reason to choose a 60mm macro lens to shoot something
closeup, versus a 200mm non-macro lens a bit further away?

Thanks in advance,
G

With apologies if there is some overlap with other replies.

1 With a normal (i.e. non-macro) lens, the closest focus may get you to
a magnification of say 0.2 - that is, a subject 1cm in length will be
0.2cm on film or sensor (referred to hereinafter as "film"). Now you can
make any lens give a larger magnification by moving it further from the
film. This can be done by using extension tubes - metal tubes which fit
between lens and camera body - or bellows. However, this is
inconvenient, as you have to keep stopping and switching bits in and out
for differing magnifications. One of the advantages of a true macro lens
is that it will go to 1:1 in one continuous rotation of the focus ring
without you having to mess about with tubes. Hence "continuous focussing
from infinity to life-size". Yes, all (well, most) lenses have
"continuous focussing", but not down to life size.

2 Reproduction ratio is the size of the image of an object on film
divided by its true size. Thus 1:1 reproduction ratio, or 1.0
magnification, is "life size". Note that in purist terms
photomacrography only *starts* at magnifications of 1.0, and goes up to
about 50 or 60x or so (beyond which you really start to need a compound
microscope, and are in the realms of photomicroscopy). Also note that
the words macrophotography and microphotography mean something else
entirely (very big and very small photographs - like microdots -
respectively). Not that you used these terms, but just FYI...

3 All lenses have to be designed to give the best balance of the various
aberrations - image faults - for a given size, maximum aperture, price
and application. Aberrations will vary, and require different
corrections, at different combinations of subject distance and image
distance. Lenses for normal use are corrected to give best performance
at a subject distance of typically about 20x focal length. To get decent
performance down to M = 0.2 often requires things like aspherical
elements, floating element groups (i.e. groups which move relative to
other groups as you focus) etc.

4 To get down to M = 1.0 in one lens, yet still have decent performance
with a subject at infinity, is difficult. Something has to give, and
that is usually price and maximum aperture. That is why a true macro
lens will typically be 1.5-2x the price of a "normal" lens of similar
focal length, and about 1-1.5 stops slower.

5 The other thing which matters a lot more for a macro design than for a
normal lens is field flatness. With an ordinary lens, if you focus a
flat subject, the image plane of best sharpness will typically be
slightly curved. This normally does not matter, as most subjects are not
flat planes anyway. For a macro lens this is more important, as
photographing stamps, documents or works of art is a common application.
Thus a good macro lens will have a flat field, which also adds another
constraint.

6 The advantage of a longer length lens - say a 200mm macro - is that it
places you further away from the subject. For example, with the 200mm
lens at M = 1.0 the subject will be about 400mm away, compared with
100mm away with a 50mm macro. With a nervous subject, or a nervous
photographer of say venomous snakes, this can be an advantage. However,
there are costs: first, such lenses tend to cost 2-4 times as much,
second they tend to be 2-4 times as heavy, and third they are 2-4 times
as long. Incidentally, I don't think the fact that they have a longer
focal length in itself makes them significantly harder to hand-hold -
camera shake is mostly* a function of image magnification, not focal
length as such, and if you are working at 1:1 the magnification is the
same. Perspective and depth of field will be different, which may be a
plus or a minus under different circumstances.

*I think it's a bit more complex than that, but this is going too far
for this reply.

David
--
David Littlewood

In article cR3Tc.98306$gE.62708@pd7tw3no, greg writes
Hi folks, I feel a bit like an idiot because I don't know this, but it's
never come up. I'm not sure I understand the idea of macro (close-up)
lenses. A bit of searching on the internet always turns up the same info:

"Continuous focusing from infinity to life-size"
"Maximum Reproduction Ratio (Macro Setting): 1:1"
"high resolution from infinity to close-ups down to x.x inches"

.but I'm honestly not sure what this means. Don't all lenses have
"continuous focusing"?

In other words, what's the difference in the photo? For example, they always
seem to show a picture of a flower. What is the difference between shooting
with, say, a 105mm macro lens and a 105mm non-macro lens? I assume you can
get quite close to the subject to shoot with these lenses, but what's the
benefit? Is there any reason to choose a 60mm macro lens to shoot something
closeup, versus a 200mm non-macro lens a bit further away?

Thanks in advance,
G

With apologies if there is some overlap with other replies.

1 With a normal (i.e. non-macro) lens, the closest focus may get you to
a magnification of say 0.2 - that is, a subject 1cm in length will be
0.2cm on film or sensor (referred to hereinafter as "film"). Now you can
make any lens give a larger magnification by moving it further from the
film. This can be done by using extension tubes - metal tubes which fit
between lens and camera body - or bellows. However, this is
inconvenient, as you have to keep stopping and switching bits in and out
for differing magnifications. One of the advantages of a true macro lens
is that it will go to 1:1 in one continuous rotation of the focus ring
without you having to mess about with tubes. Hence "continuous focussing
from infinity to life-size". Yes, all (well, most) lenses have
"continuous focussing", but not down to life size.

2 Reproduction ratio is the size of the image of an object on film
divided by its true size. Thus 1:1 reproduction ratio, or 1.0
magnification, is "life size". Note that in purist terms
photomacrography only *starts* at magnifications of 1.0, and goes up to
about 50 or 60x or so (beyond which you really start to need a compound
microscope, and are in the realms of photomicroscopy). Also note that
the words macrophotography and microphotography mean something else
entirely (very big and very small photographs - like microdots -
respectively). Not that you used these terms, but just FYI...

3 All lenses have to be designed to give the best balance of the various
aberrations - image faults - for a given size, maximum aperture, price
and application. Aberrations will vary, and require different
corrections, at different combinations of subject distance and image
distance. Lenses for normal use are corrected to give best performance
at a subject distance of typically about 20x focal length. To get decent
performance down to M = 0.2 often requires things like aspherical
elements, floating element groups (i.e. groups which move relative to
other groups as you focus) etc.

4 To get down to M = 1.0 in one lens, yet still have decent performance
with a subject at infinity, is difficult. Something has to give, and
that is usually price and maximum aperture. That is why a true macro
lens will typically be 1.5-2x the price of a "normal" lens of similar
focal length, and about 1-1.5 stops slower.

5 The other thing which matters a lot more for a macro design than for a
normal lens is field flatness. With an ordinary lens, if you focus a
flat subject, the image plane of best sharpness will typically be
slightly curved. This normally does not matter, as most subjects are not
flat planes anyway. For a macro lens this is more important, as
photographing stamps, documents or works of art is a common application.
Thus a good macro lens will have a flat field, which also adds another
constraint.

6 The advantage of a longer length lens - say a 200mm macro - is that it
places you further away from the subject. For example, with the 200mm
lens at M = 1.0 the subject will be about 400mm away, compared with
100mm away with a 50mm macro. With a nervous subject, or a nervous
photographer of say venomous snakes, this can be an advantage. However,
there are costs: first, such lenses tend to cost 2-4 times as much,
second they tend to be 2-4 times as heavy, and third they are 2-4 times
as long. Incidentally, I don't think the fact that they have a longer
focal length in itself makes them significantly harder to hand-hold -
camera shake is mostly* a function of image magnification, not focal
length as such, and if you are working at 1:1 the magnification is the
same. Perspective and depth of field will be different, which may be a
plus or a minus under different circumstances.

*I think it's a bit more complex than that, but this is going too far
for this reply.

David
--
David Littlewood