[pcarfan]

Ok, 1:1 means a bug the exact size of the sensor will fill the sensor, so the size of the image on the sensor is the exact 1:1 replica of the actual size of the bug, but why does this matter ???

If I take this shot and print it on paper, now the bug will be the size of my paper choice, no ?

Also, if displayed on a screen then it would depend on the screen size and resolution.

Who care if the bug is a different size on the sensor ?, I just don't get it.

I understand the importance of perspective in photgraphy, but not this 1:1 in macro. Can someone please explain why it is important ?

Thanks

My take on it...

So many manufacturers say macro on their lenses, that really are just close focusing lenses. It can be a bit misleading

So if a lens is 1:1 macro, you have a real sense of its actual macro capabilities. So you really know what you are getting.

[pcarfan]

I think there is more to it than setting a standard. My hunch is it has something similar to perspective, and I think a 1:1 macro reflects reality more...but, I don't know exactly how.

A lens close to 50mm puts things in a picture that are at different depths in a similar relationship to what the human eyes sees, a telephoto lens on the other hand will bring the far away object closer than what the human eye sees...the angle of view is another matter also.

But, 1:1 just is a sensor phenomenon, and definitely sets the standard so everyone knows by just looking at the uncropped picture of how large the subject is, .....but is that all ???? just can't be, from all this fuss that goes into it.

I am hoping someone would say that a 1:1 macro keeps the size of the eye, the antenna, the leg, the tail in the same size proportions , OR the petal, the stem, the pollen etc. maintain the same realtive size eventhough they are all at differnet distance from the sensor ...does it ????

1:1 is a ratio. In film days it would yield a life size image on the film. 1:2 would give you a 1/2 size image on the film. By the same reasoning it will yield a s/s image on the sensor, what the software does with it I am not sure

[rayallen]

For me, it is about getting in close to the subject.
Here's shot taken with a Tamron 70-300 LD Di Macro 1:2 -



Here's another shot of the same flower taken with an f4/50mm Macro-Takumar 1:1 -



Does that explain the difference? The Tamron just can't get in that close.

[slomojoe]

Ok, 1:1 means a bug the exact size of the sensor will fill the sensor, so the size of the image on the sensor is the exact 1:1 replica of the actual size of the bug, but why does this matter ???

If I take this shot and print it on paper, now the bug will be the size of my paper choice, no ?

Also, if displayed on a screen then it would depend on the screen size and resolution.

Who care if the bug is a different size on the sensor ?, I just don't get it.

I understand the importance of perspective in photgraphy, but not this 1:1 in macro. Can someone please explain why it is important ?

Thanks

I may be misunderstanding your question, but basically it's an issue of resolution of the sensor/film. Just like your ability to crop a a picture from a standard lens to obtain the same effect of a tele is limited, so it is for close-up subjects. If your subject is only reproduced at a magnification of, say, 1:4 on your sensor/film, there is only so much resolution of detail you can obtain by simply enlarging/cropping the picture. Usually, 1:1 is consider a sufficient enlargement to resolve fine detail in the conventional macro subjects (e.g. insects, flowers etc). If you were interested in even smaller subjects with even finer detail (e.g. snow flakes, or very small bugs), then you'd need an even higher magnification ratio, e.g. 5:1 or larger. Some people call that "super-macro". Anything below 1:1 should not really be called "macro", I think, though people do.

[pcarfan]

I may be misunderstanding your question, but basically it's an issue of resolution of the sensor/film. Just like your ability to crop a a picture from a standard lens to obtain the same effect of a tele is limited, so it is for close-up subjects. If your subject is only reproduced at a magnification of, say, 1:4 on your sensor/film, there is only so much resolution of detail you can obtain by simply enlarging/cropping the picture. Usually, 1:1 is consider a sufficient enlargement to resolve fine detail in the conventional macro subjects (e.g. insects, flowers etc). If you were interested in even smaller subjects with even finer detail (e.g. snow flakes, or very small bugs), then you'd need an even higher magnification ratio, e.g. 5:1 or larger. Some people call that "super-macro". Anything below 1:1 should not really be called "macro", I think, though people do.

Thank you. I understand it now.

I was thinking all along the focus distance to be the only indicator of how close one can get to the subject, obviously the magnification matter also.

So, a lens that focus as close as 10cm with 1:2 macro will show the same close up detail as a lens that can focus only to 20cm but 1:1 macro, right ? So, it is always a combination of the two.

Also, another related question...how will the dof work in the above example. The lens that is at 20cm and 1:1 macro will have a narrower dof compared to one that can focus as close as 10cm but 1:2 macro, or is it ?...if this is true I'll take the closer focusing lens with 1:2 as I would want a wider dof.

Thanks

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Last edited by pcarfan; 01-28-2009 at 02:16 PM.

[Venturi]

My understanding (for what that's worth) on the technicalities of it is that:

a) Macro begins at 1:1 and goes to 10:1
b) Micro begins at 10:1 goes to 100:1
c) anything under 1:1, like 1:2, is merely "close up". Where things change from close up to "normal" I don't know...
d) anything over 100:1 is really frikkin small, dude!

So, lenses marketed as "macro" or "tele-macro" with ratios of 1:2 or 1:3.9 aren't technically macro at all. They merely have close focus (under 18" or so) capability.

[Blue]

My understanding (for what that's worth) on the technicalities of it is that:


b) Micro begins at 10:1 goes to 100:1

Unless it is a Micro Nikkor which are just 1:1.

[Ron Boggs]

Until you work with 1:1 and get a feel for how really close and magnified that is, you really can't know what it means. I had used extension tubes and such for years before getting a 1:1 macro--and several since. The images are really stunning and detailed, stuff you will typically not see with the naked eye and definitely not capture through a conventional lens. The two flower views posted above are a great example.

The big deal about 1:1 is that signifies a lens that has been corrected for close focusing. So aberrations at wide apertures are far better controlled than in conventional lenses--even AL and ED ones. To get marketable perfomance at 1:1, the lens has to have better than normal optical performance and top-level optical engineering. Lenses with less than 1:1 magnification may or may not have super engineering. Lenses that get to 1:1 virtually always have killer optics and great control of abberations, thus generally better performance (IQ wise) than conventional lenses whether at high magnification or at more traditional shooting distance. That's why lots of folks use macro lenses for general shooting as well. They tend to be killer lenses!

[newarts]

Here's another take on the significance of 1:1; things get harder to do as you magnify beyond 1:1 - not only harder, but different. It is because of the physics involved.

The distance from the back of the camera to the subject goes through a minimum at 1:1; as magnifcation gets bigger than 1:1 the camera back moves *away* from the subject fast so elaborate helicon movements, bellows, or extension tubes are required to get the sensor far enough from the lens.

Another example is Depth of Field as a % of Width of Field; at high magnifications it stops changing, while at low magnifications it changes with magnification.

For most casual close-up work it is more useful to talk in terms of field width rather than magnification now that there are small sensor cameras around.

Dave

[pcarfan]

So, how is magnification (1:1), min. focussing distance and dof related.

As in what is the effect on dof for a lens that can focus to 'x' distance and 1:2 VS a lens that can only focus to 2*x but 1:1 macro, and

Thanks.

[slomojoe]

Thank you. I understand it now.

I was thinking all along the focus distance to be the only indicator of how close one can get to the subject, obviously the magnification matter also.

So, a lens that focus as close as 10cm with 1:2 macro will show the same close up detail as a lens that can focus only to 20cm but 1:1 macro, right ? So, it is always a combination of the two.

No. The magnification ratio refers to the original linear dimensions of the subject, so a one-inch worm will be reproduced as a one inch long image if you are using a 1:1 lens at its closest focus distance, and as half-inch if you are using a 1:2 lens at its closest focus distance, regardless of what that distance may be (it could be 10 cm for the 1:2, and 20 cm for the 1:1).

Also, another related question...how will the dof work in the above example. The lens that is at 20cm and 1:1 macro will have a narrower dof compared to one that can focus as close as 10cm but 1:2 macro, or is it ?...if this is true I'll take the closer focusing lens with 1:2 as I would want a wider dof.

Thanks

As a general rule, yes, depth of focus will increase with focus distance, so a lens focusing at 10 cm will have a shallower dof than a lens focusing at 20 cm, but decrease even more pronouncedly with longer focal length (which you will need to achieve higher magnification at further distances). There are calculators to figure this out, but for instance in your case, you could have something like a 200 mm 1:1 macro lens focusing at 50 cm at f/16, which will have a dof of 0.24 cm (on a K20D), vs a 50 mm 1:2 lens also at f/16 focusing at 25 cm, for which the dof will be 1.28 cm.

But depth of focus is not the only consideration in choosing a macro lens. If you want to take pictures of bugs, for instance, it can often be a problem to get very close, and you may be better off with a longer lens.

[pcarfan]

No. The magnification ratio refers to the original linear dimensions of the subject, so a one-inch worm will be reproduced as a one inch long image if you are using a 1:1 lens at its closest focus distance, and as half-inch if you are using a 1:2 lens at its closest focus distance, regardless of what that distance may be (it could be 10 cm for the 1:2, and 20 cm for the 1:1)........

WOW! thank you...now my understanding is complete, and I really appreciate your help.

[pcarfan]

Also, a big thank you to all others who filled in the gaps with information and especially by posting the pictures. Greatly appreciated.