# Does macro lenses of different focal lengths give the same image?



## RAKAMRAK (May 1, 2014)

Let me explain my question a bit further. I have seen/used only two macro lenses till date Canon 100mm L and sigma 150mm OS. That also at a distance of more than 1 year. So I had no opportunity to test this question of mine.

What I am asking is, let's say I am photographing a small flower (pretty small) which is not going to occupy the entire image at 1:1 (let's say on a full frame camera). Now if I use different macro lenses - 50mm (Canon), [60mm (Tamron or Canon)-APS-C only], 70mm (Sigma), 90mm (Tamron), 100mm (Canon), 105mm (Sigma), 150mm (Sigma) or 180mm (Canon/Sigma/Tamron) - at 1:1 magnification focusing distance (varying the distance between the flower and my camera, of course) would I get the same image (not talking about sharpness here)? Probably this may be framed slightly differently, what is the importance and significance of the angle of view of different macro lenses at their minimum (or comparable magnification) focusing distances? 

In case any of you have used more than one lenses at the same time you may have some idea about this. Any comment will be highly appreciated. Even better is if any of you have images like this to demonstrate the difference/similarities.


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## Deleted member 91053 (May 1, 2014)

If a macro lens gives 1:1 magnification (note the 50mm Canon does not) the the image size will be the same despite the different focal lengths, what changes is the minimum focus distance from your sensor to the subject.
As a general rule of thumb the longer macro lenses are better for subjects that my fly/run off, for static/inanimate subjects then the focal length is more down to personal preference/price.


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## RAKAMRAK (May 1, 2014)

Right, at 1:1 the same object will occupy exactly the same area of the image. Till this my understanding is clear. But ten things get a bit fuzzy for me. 

Do you mean that the focal length difference of macro lenses have no effect on the 'image' (for example from the point of view of perspective) at 1:1 magnification other than the usability (that is subject to lens front distance while capturing the photogrpah)?


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## Deleted member 91053 (May 1, 2014)

I have not really noticed a difference in perspective at 1:1, though I believe to longer lenses will give a shallower depth of field at 1:1 - I am not an expert here.
Note the minimum focus distance is measured from the sensor/film - this is indicated on the top of your camera by a circle with a line through it. As the longer focal length lenses tend to be physically longer the front of the lens may not be that much further away, from the subject, than a shorter lens - but it all helps with skittish insects etc.


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## RAKAMRAK (May 1, 2014)

John thank you for the replies. 
Correct, the distance is from the film/sensor (the phi type symbol). I was kind of brushing over those issues (the 50mm needs an extender type thing as well for 1:1).

You are quite right that it that longer macros will have shallower depth of field. But I am specifically looking info about perspective - no one talks about that - may be because it is not important as such. But still.....


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## Deleted member 91053 (May 1, 2014)

I don't know, but I suspect, that the difference in perspective would be more noticeable at lower magnifications. I think it's time for a trip to the camera shop and have a play with a few lenses!


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## Random Orbits (May 2, 2014)

If the subject is the size in the frame, then objects in the foreground and background will be different sizes using lenses of different focal lengths. See example at 

http://www.the-digital-picture.com/Reviews/Canon-EF-100mm-f-2.8-L-IS-USM-Macro-Lens-Review.aspx


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## privatebydesign (May 2, 2014)

The subject, as you say, will be the same size in the different images.

The perspective will be different in the images, that is the apparent shape of an object will appear more rounded with a shorter focal length and flatter with a longer focal length. This effect of perspective is vastly reduced in macro shooting.

At the same aperture value the different images, if framed the same, will have the same dof.

The most apparent difference between the images will be the background, the longer the focal length the more blurred it will appear, though that is an optical illusion, things in the background will be much bigger and less "busy".


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## neuroanatomist (May 2, 2014)

Random Orbits said:


> If the subject is the size in the frame, then objects in the foreground and background will be different sizes using lenses of different focal lengths. See example at
> 
> http://www.the-digital-picture.com/Reviews/Canon-EF-100mm-f-2.8-L-IS-USM-Macro-Lens-Review.aspx



+1, that's the main difference (other than working distance, which has already been discussed). Longer FL tends to give more pleasing backgrounds at 1:1.


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## e17paul (May 2, 2014)

If you go to http://www.the-digital-picture.com/Reviews/Canon-EF-100mm-f-2.8-L-IS-USM-Macro-Lens-Review.aspx and scroll down to the background blur comparison photos, you can see the comparitive depth of field. 

You can also see the slight difference in perspective of the subject. If there were any objects visible in the background, they would show a more obvious change in perspective. 

Paul


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## Keem (May 2, 2014)

If all the lenses can go down to 1:1 magnification; the subject will have the same size in the frame if you shoot at minimum focusing distance. However, the background will change slightly ; moreover lenses having a longer focal length can give you two advantages:

i- better, creamy blur, BOKEH
ii- allow a longer working distance (distance between the front of the lens and subject)

(ii) can be important if you are shooting shy creatures (insects etc.) plus will give you more options on lighting.


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## danski0224 (May 2, 2014)

The main difference I have noticed is working distance. This is distance from camera to object and the available depth of field. Longer focal length sure seems to have less depth of field.

The field of view also changes, or it sure seems like it. An object at 1:1 with a 100mm lens fills less of the viewfinder than the same object at 1:1 with a 150mm or 180mm lens.

I prefer the 150mm focal length for macro, given a choice between 100, 150 and 180.


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## Tanispyre (May 2, 2014)

danski0224 said:


> The field of view also changes, or it sure seems like it. An object at 1:1 with a 100mm lens fills less of the viewfinder than the same object at 1:1 with a 150mm or 180mm lens.



It is correct that the field of view changes, however the size of an object at the point of focus will be the same at 1:1. It is objects in the background that change. Brian over at The Digital Picture has an exellent example of this in his macro lens review: http://www.the-digital-picture.com/Canon-Lenses/Canon-Macro-Lens.aspx

Scroll down and look at the photos of the purple flower. They are taken at different focal lengths with the same magnification. As you can see the size of the flower is the same, however the background is quite different due to the narrow field of view of the longer focal length lenses.


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## StudentOfLight (May 2, 2014)

The images will all be different. Whenever you change sensor size or focal length the results will change.

There is a difference between image framing on full-frame vs Crop. If you shoot the same lens on APS-C and full-frame, with the same image framing, you would shoot from further back with the APS-C camera and as a result you will have more depth-of-field.

If you shoot with two different focal lengths, at the same magnification on the same body then the longer focal length will show less of the background. This gives you more control of your image by being able to eliminate possible background distractions. This is very important in macro.


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## StudentOfLight (May 2, 2014)

danski0224 said:


> The main difference I have noticed is working distance. This is distance from camera to object and the available depth of field. Longer focal length sure seems to have less depth of field.
> 
> The field of view also changes, or it sure seems like it. An object at 1:1 with a 100mm lens fills less of the viewfinder than the same object at 1:1 with a 150mm or 180mm lens.
> 
> I prefer the 150mm focal length for macro, given a choice between 100, 150 and 180.



I'm hoping Canon replaces their 180mm L Macro with a lighter (and-hopefully-not-more-expensive) 150mm f/2.8 IS Macro... and their 135mm f/2 with a 100mm f/1.4. That would make my year (of the lens).


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## RAKAMRAK (May 2, 2014)

Thank you CRians. So my hunch was more or less right that the background will be slightly different. But from your replies it seems that such difference won't really matter in most cases (in few cases it might though). What will matter mainly is the subject to front element distance - which is generally longer for longer FL macro lenses.

Anyway, day before yesterday I received my Sigma 150mm OS. Waiting for the weekend to explore its abilities at the local park.


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## 100 (May 3, 2014)

At 1:1 most macro lenses don’t have the focal length given in the specification. 
The Canon 100L for instance is at 1:1 a 75mm lens (source: http://www.photozone.de/canon_eos_ff/458-canon_100_28is_5d)
You need to know the real focal length for each lens to compare them. 
Look at the minimum focus distance of each lens. 
The Canon 100L has a minimum focus distance of 30cm
The Sigma 150mm OS has a minimum focus distance of 38cm
If you compare specified focal length the difference between the two is 50%
If you compare minimum focus distance the difference between the two is less than 30%


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## RAKAMRAK (May 3, 2014)

@100 Thanks for the link. But do you know any other source where I can get the 'effective focal length' information for the macros. The photozone website seems to have the information is only for the 100mm lenses. I will google it. But in case you know any other website please let me know. This is a very interesting piece of information.


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## sulla (May 3, 2014)

A macro lens is nothing special. You will have the same type of differences with the small objects as you would have with a large objects, say, a building:
With a shorter focal length (macro but also non-macro) you will have to move closer (building with a 28mm lens) and with a longer focal length lens (building with a 200mm lens) you will have to back up, but you can fit the building on the sensor in either case. The perspective changes (for macro and for non-macro lenses alike), and you will get different DOF (for macro and for non-macro lenses alike).
If you just shoot flat subjects you won't notice any difference at all: A 2D test chart looks the same with a 600mm and a 14mm lens, a stamp will look the same with a 60mm or a 200mm macro lens. The difference only can be seen when you shoot 3D objects - huge buildings or tiny flowers.

But the biggest difference, for macro and for non-macro lenses alike, will be the greater distance from the subject, and this will make a huge difference with scary subjects and only a small difference with flowers.

Personally, I have the 100mm Canon macro and would really like a longer lens like the 180 Canon macro, because the working distance gets so immensly short at 1:1...


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## 100 (May 3, 2014)

RAKAMRAK said:


> @100 Thanks for the link. But do you know any other source where I can get the 'effective focal length' information for the macros. The photozone website seems to have the information is only for the 100mm lenses. I will google it. But in case you know any other website please let me know. This is a very interesting piece of information.



I don’t know if this applies to every optical design but if you take the minimum focus distance in mm and dived that by 4 you get the effective focal length in mm.

The old EF 100mm f/2.8 USM macro has a minimum focus distance of 310mm => 310/4=78mm
The new EF 100mm f/2.8 USM L IS macro has a minimum focus distance of 300mm => 300/4=75mm
The Sigma 150mm f/2.8 Macro OS has a minimum focus distance of 380mm => 380/4=95mm 
The EF 180mm f/3.5L has a minimum focus distance of 480mm => 480/4=120mm

The minimum focus distance is the distance from the subject to the sensor. The working distance however is from the front of the lens to the subject so you also need to consider the length of the lens and the flange distance (distance between the front of the lens mount and the sensor). The flange distance for EF-mount is 44mm.

The EF 100mm f/2.8 USM L is 123mm long. The minimum focus distance is 300mm. So the working distance is 300-123-44=133mm
The Sigma 150mm f/2.8 Macro OS is 150mm long. The minimum focus distance is 380mm. So the working distance is 380-150-44=196mm
The EF 180mm f/3.5L is 187mm long. The minimum focus distance is 480mm. So the working distance is 480-187-44=249mm.


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## 100 (May 3, 2014)

sulla said:


> A macro lens is nothing special. You will have the same type of differences with the small objects as you would have with a large objects, say, a building:
> With a shorter focal length (macro but also non-macro) you will have to move closer (building with a 28mm lens) and with a longer focal length lens (building with a 200mm lens) you will have to back up, but you can fit the building on the sensor in either case. The perspective changes (for macro and for non-macro lenses alike), and you will get different DOF (for macro and for non-macro lenses alike).
> If you just shoot flat subjects you won't notice any difference at all: A 2D test chart looks the same with a 600mm and a 14mm lens, a stamp will look the same with a 60mm or a 200mm macro lens. The difference only can be seen when you shoot 3D objects - huge buildings or tiny flowers.
> 
> ...



When you get to 1:1 things change because the effective focal length is no longer equal to the specified focal length.


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## danski0224 (May 3, 2014)

Interesting. How does the background change while the flower in these examples does not? 






Tanispyre said:


> It is correct that the field of view changes, however the size of an object at the point of focus will be the same at 1:1. It is objects in the background that change. Brian over at The Digital Picture has an exellent example of this in his macro lens review: http://www.the-digital-picture.com/Canon-Lenses/Canon-Macro-Lens.aspx
> 
> Scroll down and look at the photos of the purple flower. They are taken at different focal lengths with the same magnification. As you can see the size of the flower is the same, however the background is quite different due to the narrow field of view of the longer focal length lenses.


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## sulla (May 3, 2014)

yes, the effective focal lenghts change to some other figure - by the way, this is true with every lens, not just macro lenses - but still, the perspectives, DOF and so on still behave like with every other lens.


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## sulla (May 3, 2014)

The background changes, because a different focal length causes a different angle of view. To keep the flower the same size, you have do change the distance, which changes the background.
Just as with every lens.


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## 100 (May 4, 2014)

sulla said:


> yes, the effective focal lenghts change to some other figure - by the way, this is true with every lens, not just macro lenses - but still, the perspectives, DOF and so on still behave like with every other lens.



The largest change in effective focal length you get at the minimum focus distance and that’s where you are if you shoot macro. You compared it to shooting buildings and you don’t shoot buildings at the minimum focus distance of any lens unless the buildings are tiny scale models you have to shoot with a macro lens. 

Another difference is the effective f-stop at macro distances. 
To get the effective f-stop you can use the next formula:
Effective f-Stop = f-Stop x (1 + magnification / pupil magnification)
With a pupil magnification of 0.5 like the EF 180mm f/3.5L at 1:1 you get an effective f-stop 3 times greater than what you see in your camera. You won’t notice it because the camera’s metering compensates for that automatically, but it will affect the DOF. 

Because the effect on the image at macro distances is much greater you can’t really say they behave like every other lens.


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## steven kessel (May 4, 2014)

As I understand it both my old 100mm f.28 non-L and my 180mm f3.5L produce 1:1 images. The difference is that I must get much closer to my subject with the 100 in order to get 1:1 image size than with the 180. 

I do mostly wildlife photography and I find the 180 to be ideal for that purpose. Being able to back off a bit means that my subjects -- often insects -- are made less uptight and tend not to be so skittish as when I'm photographing with the 100. The 180 also functions as a superb short/medium telephoto. I've made a whole series of hummingbirds in flight shots using the 180 in lieu of my 70-200 f4 L and the difference in sharpness is astonishing. The 180 is simply a MUCH better lens for that type of work.

I love my 180 and I was surprised to read somewhere recently that Canon is going to discontinue it. I probably take more pictures with that lens than with all of my other L lenses combined.


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## danski0224 (May 4, 2014)

StudentOfLight said:


> I'm hoping Canon replaces their 180mm L Macro with a lighter (and-hopefully-not-more-expensive) *150mm f/2.8 IS Macro...* and their 135mm f/2 with a 100mm f/1.4. That would make my year (of the lens).



In case you didn't know... Sigma makes one of those 150mm IS f2.8 macro lenses


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## Antono Refa (May 4, 2014)

Unless the object is flat, say a coin or a medallion, and the background is empty, say a flat colored background, the photos will not be the same.

It's just like portrait photography, with the nose looking too big relative to the ears when shooting from a short distance - perspective works for the front & back parts of the subject same as it works for the subject itself being in the foreground and other stuff being farther away in the background.

Therefore, if you shoot a diamond ring with the diamond facing the camera and the band away from it, the shorter the focal length the larger the diamond will look compared to the band.


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## surapon (May 4, 2014)

RAKAMRAK said:


> Let me explain my question a bit further. I have seen/used only two macro lenses till date Canon 100mm L and sigma 150mm OS. That also at a distance of more than 1 year. So I had no opportunity to test this question of mine.
> 
> What I am asking is, let's say I am photographing a small flower (pretty small) which is not going to occupy the entire image at 1:1 (let's say on a full frame camera). Now if I use different macro lenses - 50mm (Canon), [60mm (Tamron or Canon)-APS-C only], 70mm (Sigma), 90mm (Tamron), 100mm (Canon), 105mm (Sigma), 150mm (Sigma) or 180mm (Canon/Sigma/Tamron) - at 1:1 magnification focusing distance (varying the distance between the flower and my camera, of course) would I get the same image (not talking about sharpness here)? Probably this may be framed slightly differently, what is the importance and significance of the angle of view of different macro lenses at their minimum (or comparable magnification) focusing distances?
> 
> In case any of you have used more than one lenses at the same time you may have some idea about this. Any comment will be highly appreciated. Even better is if any of you have images like this to demonstrate the difference/similarities.




Dear friend RAKAMRAK.
Most of our friends, the PRO and the Experts are already explain to you, The Question that you ask, and I do not want to repeat the great answers.
BUT, in my IDEAs of the usage of my 4 Items of Macro Photography equipment :

1) The : TUBE = So cheap and Great, that If our friends want to borrow my Macro Lenses, I just let them Borrow my " TUBE" and use with their Lenses, Any Lens that they have-----Well, YES, MY RULES are= Never let my friends borrow 3 things that I have , 1 = My Guns, 2= My Lenses and my Cameras, 3 = my wife----Ha, Ha, Ha---YES, that 3 items that my friends can screw up and damage my properties, and in that case, I will lose my dear friends.BUT the Best Idea that I might get the new young wife----Ha, Ha, Ha.

2) Canon MP-E 65 mm, F/ 2.8 Maxcro 1X-5X-----I use when I have the dead insect or Frozen insects( that I put in Zip-Lock Bag in Ref. for 30 minutes, Let them Hybernate = No movement, But Not Dead yet)---And I can shoot as close as 1/4 Inches or 3-5 mm. from the front of lens with out damage my high cost lens from their saliva----Ha, Ha, Ha.

3) Canon EF 100 mm. F/ 2.8 Macro, USM. my 15 years old Super Macro lens , that I not use any more, But I try to let my Son to borrow, and to use for his Portrait Photography. Yes, He hate the Insects and the Bugs.

4) my Dear EF 100 mm. F/ 2.8 L Hybrid IS, MACRO, USM---Yes, I use to shoot the Great Smell Flowers and The harmless Butterfly in closed distant that I can enjoy the smell of beautiful flowers or catch the movement of butterfly in the air---Yes, With or with out get the best Macro Photos----I do not care about the photos, But I get beautiful sun tan on my upper body---With out pay the money to Sun Tan salon----Ha, Ha, Ha.

5) My favorite EF 180 mm. F/ 3.5 L Macro USM.----Yes, This is my best---To use for shoot the Hungry/ Super Mad Bees or Hornets Far away from them, when I try to capture and know their secret locations of their sweet honey at the best beautiful flowers---Yes, I can use this lens as far as 1/4 miles from the mad/ angry insects, and safe from my nose that point to them.----Ha, Ha, Ha.
The Point is This 180 mm. Lens can use about= 48 CM. or 1.6 Foot from the angry bees---Compare to only min. distant 30 CM, or 1 Foot---That not safe distant for my beautiful nose or sharp , good old Lips.

Just for FUN , to talk to my dear friends.
Have a great Sunday.
Surapon


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## surapon (May 4, 2014)

Just for FUN , to talk to my dear friends.
Have a great Sunday.
Surapon


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## RAKAMRAK (May 5, 2014)

Antono Refa said:


> Unless the object is flat, say a coin or a medallion, and the background is empty, say a flat colored background, the photos will not be the same.
> 
> It's just like portrait photography, with the nose looking too big relative to the ears when shooting from a short distance - perspective works for the front & back parts of the subject same as it works for the subject itself being in the foreground and other stuff being farther away in the background.
> 
> Therefore, if you shoot a diamond ring with the diamond facing the camera and the band away from it, the shorter the focal length the larger the diamond will look compared to the band.



This is actually the answer that I was looking for when I wrote the question. I had a hunch, but probably could not put my question properly. Thank you.


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