Macro, what is it and what does it mean.

[tayl0124]

So I am seen a lot of stuff on macro shots, but as far as I can tell it is just close up shots, usually of flowers and model's (cars, buildings, etc.) That being said what is the purpose to have a 70-210 1:4 Macro. And does the 1:4 mean that I have to be at least 4 ft away??

[danic]

Not too sure exactly on the 1:4, perhaps it's the magnification of the lens. The purpose of the 70-210 macro is to give you a cheap alternative to a dedicated macro lens.

The minimum focus distance of the lens will tell you how close you can get to the subject. Typically, for a DSLR lens it's usually 30cm, but it can vary. With a dedicated macro, you can get a lot closer. However, the longer the focal length, the farther away you can be.

Whilst macro is usually of flowers and bugs, they don't always have to be that. Macro lenses open up another world of photography. Personally, I think macro is more about light, textures and DOF than almost any other type of photography. But that's only my opinion.

I have a Sigma 105mm macro lens, and I've attached some photo's taken with it. Hopefully it will persuade you to get into macro! The last two photo's were taken with a set of extension tubes fitted as well.

[mjs1973]

A lot of companies have started using the word "macro" as a marketing tool. Just because your lens can focus close, doesn't make it a true macro lens. A true macro lens should give you a 1:1 ratio. This ratio represents the size of the image on your sensor (or film) compared to the actual size of the object.

For example, lets say you were to take a photo of a penny at a ratio of 1:1. If you were to lay that penny on top of your sensor (or film) the penny and the image on the sensor would be the same size, 1:1.

If you were to take a picture of the penny at a ratio of 1:4 and then placed the penny on the sensor, the actual penny would be 4 times as large as the image on the sensor. This is not something I would consider a "macro" photo.

[mwfanelli2]

Often forgotten is that true macro lenses are also "flat field", normal lenses, even with macro abilities, are not.

[mjs1973]

Often forgotten is that true macro lenses are also "flat field", normal lenses, even with macro abilities, are not.

Thanks Michael. I have never heard the term "flat field" used before. I did a quick search and this is what I found. Thanks for helping me learn something new!

"One type of lens is called "flat field", and this means that it is in focus on a planar area. If you want to take pictures of flat things, like pages of a book, or other photos, or coins, or paintings, you'll want a flat field lens. Other lenses are exactly in focus on a curved surface in space. Since the vast majority of photographic subjects aren't flat, it doesn't matter much whether most lenses are flat-field -- you'll just look through the viewfinder and make the best possible tradeoff. But if you're shooting a printed page, it's a real bummer to have the words in the center readable while those at the edges are not."

[freygr]

The 1:4 just means at the closest focus distance the size on film or sensor is 1/4 life size, 1:2 is half size and 1:1 is full size meaning object is 1" wide the image will be 1" wide on the film or sensor. There are exposure compensations which you will need to use if you do not have a through the lens metering system.

[icicle]

Sorry in advanced, I didn't take the time to fix these pictures nor the time to set up a nice back ground. I used my mat cutter to hold the ruler in place, And double sided tape to hold the quarter to the ruler.

These were taken using a Canon Xt, 50 mm F/2.5 macro lens
first picture 1:10 2 ft.

next is 1:8 1.645 ft.

next is 1:6 1.333 ft.

next is 1:5 1.167 ft.

next is 1:4 1.038 ft.

next is 1:3 .887 ft

next is 1:2.5 .815 ft

And the last one 1:2 .749 ft



Hope this help you some what.
And again sorry for being so long.

[danic]

A lot of companies have started using the word "macro" as a marketing tool. Just because your lens can focus close, doesn't make it a true macro lens. A true macro lens should give you a 1:1 ratio. This ratio represents the size of the image on your sensor (or film) compared to the actual size of the object.

I guess it depends on what your definition is, which you have stated in your post, but I have omitted it.

"Macro" is Greek for large.

Nikon call their range of "macro" lenses "Micro".

I guess it really does depend on semantics and how you define it.

For me, anything that is close up I would consider "Macro".

[OldClicker]

I guess it depends on what your definition is, which you have stated in your post, but I have omitted it.

"Macro" is Greek for large.

Nikon call their range of "macro" lenses "Micro".

I guess it really does depend on semantics and how you define it.

For me, anything that is close up I would consider "Macro".

A common definition I have seen is macro= 1:1 to about 10:1. Micro= > 10:1 (i.e. through a microscope) - TF

[Sushigaijin]

Also, A 1:4 magnification can be quite a bit higher than 1:4.

The actual magnification (tested) is not likely to be 1:4. That's the same way that a 2gb compact flash card is actually 1.7 or 1.8 gb. The posted magnification is probably pretty close but I wouldn't bet my life on it. I know for sure that my 1:2 macro lens is actually more like 1:1.7.

Regardless of which final number you come up with, the camera output magnification is probably higher. You didn't mention which body you have it strapped on but if it is an APS model (most dslrs) than you need to multiply the magnification by the crop factor.

In my case, the 1:2 macro has an actual magnification of 1:2, or half life size. Since I'm shooting on a 2x crop sensor, the output files have a lifesize image (1:1). Your sensor might have a 1.5x crop, so a 1:4 magnification might actually be about 1:3 (one third life size) on the final image. On a full frame camera it would still be 1:4, of course.

Yet another reason why crop sensors are better for macro

[freygr]

clip..........
You didn't mention which body you have it strapped on but if it is an APS model (most dslrs) than you need to multiply the magnification by the crop factor.

Crop...........

The sensor size does not affect the micro rating 1:2 1:4 1:1 as it is calculated by the image size on the film or sensor and the physical size of the item, size of film/sensor does not factor in. But the size of the sensor/film DOES mater on the apparent focal length (angle of view) APS sized sensor has a factor of angle of view of 1.5. Example a 50mm 35mm film lens will have the angle of view of a 75mm 35mm film lens due to cropping of the image circle of the lens. Now the lenses made for APS sized sensor digital camera if installed on a full fame sensor digital camera will not cover the sensor and you will have a image circle on the film/digital file.

[Sushigaijin]

The sensor size does not affect the micro rating 1:2 1:4 1:1 as it is calculated by the image size on the film or sensor and the physical size of the item, size of film/sensor does not factor in.

that's right, the macro/micro rating is determined by the lens, and not the sensor. However, a crop sensor takes a crop of the full frame image which is smaller than the macro rating.

In other words, if you take a 50% crop of a 1:2 image, you have a 1:1 image (in the case of the 50/2 Zuiko macro). If you have an APS camera with a siggy 150 1:1, your photo is a crop of the 1:1 and is actually more like 1.5:1. Put that same siggy on a full frame camera and the magnification is only 1:1.

The sensor doesn't make the lens longer, it just takes a smaller chunk of the projected image circle. A smaller chunk of a 1:1 circle is higher magnification than 1:1!

[icicle]

I was talking to a friend the other day and ask about macro and this is how he explained it to me.

in the days of film, 35mm if you could fit a 35 frame on to a 35mm frame that would be 1:1.
if you could fit two frames on to a 35mm frame that would be 1:2 and so forth.

[freygr]

that's right, the macro/micro rating is determined by the lens, and not the sensor. However, a crop sensor takes a crop of the full frame image which is smaller than the macro rating.

In other words, if you take a 50% crop of a 1:2 image, you have a 1:1 image (in the case of the 50/2 Zuiko macro). If you have an APS camera with a siggy 150 1:1, your photo is a crop of the 1:1 and is actually more like 1.5:1. Put that same siggy on a full frame camera and the magnification is only 1:1.

The sensor doesn't make the lens longer, it just takes a smaller chunk of the projected image circle. A smaller chunk of a 1:1 circle is higher magnification than 1:1!

I'm sorry that you think the size of the sensor makes a difference and that is NOT in the Laws of PHYSICS. The size of the projected image is the only factor in determining the micro/macro ratio. The angle of view doesn't change the ratio as a 1" object will have a projected image of 1" at 1:1 ratio (one to one) even if the sensor is smaller than 1".

[Loupey]

The sensor size does not affect the micro rating 1:2 1:4 1:1 as it is calculated by the image size on the film or sensor and the physical size of the item, size of film/sensor does not factor in.

This is correct. It is important as it is a source of confusion. Macro magnification, by definition, is only concerned with the reproduced image size, at the imaging plane, and so it is independent of the format used.

A 1:1 image is life size whether it is with a 1.6x digital sensor, 35mm film, or large format sheet film.

Sorry, but here's another visual My 180mm macro set at closest distance for a 1:1 image and locked in position with a tripod and manual focus. Simply switching the body out between a 5D full frame and 50D APS-C.

These two images are proportional in size. Since the 5D is reduced here to 533 x 800 pixels in size, the 50D is reduced to 331 x 497 pixels. Both show the same life-size image as expected.

[Sushigaijin]

Loupey,

Your photos clearly show higher magnification on the 50d than the 5d. All other things equal, the 5d's scrimshaw shows the top and sides, while the 50d is so close that it is just the ship.

I understand that the actual projection on the image plane is still 1:1. The projection doesn't matter. Only the photo. So maybe this should be a discussion about apparent magnification, just like our 35mm equivalent comparisons that we make with crop sensors (100mm on an aps is apparently 150mm, etc.)

A 15mp aps sensor will give you a closer look than a 15mp full frame sensor, with the lens set to closest focus distance.

The problem here is that we are talking about like and dislike dimensions. If the 5d has 15mp (arbitrary), and the 50d has 15 mp, they both have the same size film. Now if the 50d's pixels are smaller, how can we possibly compare these two? The output area is the same, but the input area is very different. So two files, same dimensions, but different sensor dimensions...the smaller sensor will show more apparent magnification because it is a crop of the larger sensor. So in practical terms, a crop sensor will put more pixels on a smaller area and output to the same size as a full frame sensor. Also from a practical standpoint, a crop sensor gives you a photo with higher magnification (all other things being equal.)

[Sushigaijin]

I'm sorry that you think the size of the sensor makes a difference and that is NOT in the Laws of PHYSICS. The size of the projected image is the only factor in determining the micro/macro ratio. The angle of view doesn't change the ratio as a 1" object will have a projected image of 1" at 1:1 ratio (one to one) even if the sensor is smaller than 1".

This doesn't have anything to do with physics. Geometry, more like.

[mjs1973]

Loupey,

Your photos clearly show higher magnification on the 50d than the 5d. All other things equal, the 5d's scrimshaw shows the top and sides, while the 50d is so close that it is just the ship.

This is not showing a difference in magnification, only a difference in the crop do to the sensor size difference. If you were to take both of these images, and lay the 50D image on top of the 5D image, you will see that in fact the ship is the same size in both photos. I have done this, but since Loupey asked not to repost his photos, I won't post it, unless he says it's OK. You are seeing more in the 5D image because of the bigger sensor.

[Dylan8i]

the actual magnification (1:1) does not change between full and crop sensor ( as loupey shows.) however as sushiaijin states the APPARENT magnification does. since i don;'care how large the output of the two sensors are ( IE if i'm going to print at 8x10, or 12x18, i'm going to no matter what sensor size) the aps sensor DOES make the subject larger, hence more magnification.


and actually we did study optics in out physics class.

[freygr]

The apparent magnification does not affect the ratio of the lens 1:1 or what ever the ratio is, unlike Sushigaijin is saying the ratio changes if you change senor/film size. That is the point. It is like saying the printing a large print changes the focal length of the lens used in taking the picture.

[Dylan8i]

thats true, however look at it this way. if i wanted an 8x10 close up of a salamander. and i had a full frame, or an aps sensor. and the same macro lens. the aps sensor is going to appear larger for that print, and thus be more magnified than the full frame at an 8X10. That is also basic physics.


that result is what really matters, not what size is actually hitting the sensor, because unlike film you can't see the image at that size, and it is instantly enlarged.... so that is the size we need to compare.

[OldClicker]

I see macro as magnification and magnification is the amount of detail the lens provides at the sensor. No matter what size the sensor or how big/small the crop, you are not going to see things that require 1:1 to be visible with a 1:2 lens. If you want to see bacteria, you are going to need the magnification of a microscope’s lenses, not just smaller sensors or different crops. - TF

[Dylan8i]

I see macro as magnification and magnification is the amount of detail the lens provides at the sensor. No matter what size the sensor or how big/small the crop, you are not going to see things that require 1:1 to be visible with a 1:2 lens. If you want to see bacteria, you are going to need the magnification of a microscope’s lenses, not just smaller sensors or different crops. - TF

now your bringing resolution in to the situation. resolution is being able to differentiate between two different objects. the human eye (unaided) has something like 0.2um resolution (i can't remember exactly so don't quote me). that means that any two object close than that together the human eye will see as 1 object. with that resolution, no matter how large you magnify it, it will still appear as 1 object. with that said, microscopes have much higher resolution than the human eye, thus distinguishing the 2 objects as two objects and magnifys them which the human eye then sees.

a large magnification with out enhanced resolution, of bacteria (assuming they are close together) will just appear as a blurry blob. resolution in a camera is determined by how close the pixels are together on the sensor. so with a same MP camera the crop sensor will have them closer together (maybe smaller pixels), thus producing a greater resolution photo. albeit it, usually full frame has greater MP.

[Sushigaijin]

The apparent magnification does not affect the ratio of the lens 1:1 or what ever the ratio is, unlike Sushigaijin is saying the ratio changes if you change senor/film size. That is the point. It is like saying the printing a large print changes the focal length of the lens used in taking the picture.

I never said the apparent magnification affected the lens, only the photo. In fact, I CLEARLY stated several times that the output (photo) was different than the input (default lens magnification). The laws of physics do require actually reading the post. But in all seriousness, please do go back and re-read it. If we're going to have a discussion, we have to be on the same page and it is TOUGH to communicate effectively on the interweb.

And to build on what Dylan said, If I were printing an 8x10 from a 10mp full frame camera, and also from the same lens on a 10 mp APS camera, and a tree fell in the forest, which photo would have more magnification (apparent)? Pixels don't care about inches, millimeters or formats.

[tayl0124]

Wow, I didn't mean to start an argument!!