September 30, 2014, 08:22:47 AM

Author Topic: Does macro lenses of different focal lengths give the same image?  (Read 4324 times)

RAKAMRAK

  • Canon 70D
  • ****
  • Posts: 305
    • View Profile
Re: Does macro lenses of different focal lengths give the same image?
« Reply #15 on: May 02, 2014, 04:39:23 PM »
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.
Need to learn a lot more.
My Flickr Page

canon rumors FORUM

Re: Does macro lenses of different focal lengths give the same image?
« Reply #15 on: May 02, 2014, 04:39:23 PM »

100

  • Rebel T5i
  • ****
  • Posts: 124
    • View Profile
Re: Does macro lenses of different focal lengths give the same image?
« Reply #16 on: May 02, 2014, 08:09:18 PM »
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%

RAKAMRAK

  • Canon 70D
  • ****
  • Posts: 305
    • View Profile
Re: Does macro lenses of different focal lengths give the same image?
« Reply #17 on: May 02, 2014, 11:20:58 PM »
@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.
Need to learn a lot more.
My Flickr Page

sulla

  • PowerShot G1 X II
  • ***
  • Posts: 40
    • View Profile
    • my flickr page
Re: Does macro lenses of different focal lengths give the same image?
« Reply #18 on: May 03, 2014, 03:07:53 AM »
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...
« Last Edit: May 03, 2014, 03:10:55 AM by sulla »
5D & EF 8-15 f/4L, EF 16-35 f/2.8L II, EF 24-70 f/2.8L II, EF 40 f/2.8 STM, MP-E 65 f/2.8 Macro, TS-E 90 f/2.8, EF 100 f/2.8L IS Macro, EF 70-200 f/2.8L IS II

100

  • Rebel T5i
  • ****
  • Posts: 124
    • View Profile
Re: Does macro lenses of different focal lengths give the same image?
« Reply #19 on: May 03, 2014, 05:52:59 AM »
@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.

100

  • Rebel T5i
  • ****
  • Posts: 124
    • View Profile
Re: Does macro lenses of different focal lengths give the same image?
« Reply #20 on: May 03, 2014, 06:00:13 AM »
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...

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

danski0224

  • 6D
  • *****
  • Posts: 533
    • View Profile
    • Some of my Work in Progress
Re: Does macro lenses of different focal lengths give the same image?
« Reply #21 on: May 03, 2014, 07:40:45 AM »
Interesting. How does the background change while the flower in these examples does not?





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.
Some of my Work in Progress..... www.dftimages.com

canon rumors FORUM

Re: Does macro lenses of different focal lengths give the same image?
« Reply #21 on: May 03, 2014, 07:40:45 AM »

sulla

  • PowerShot G1 X II
  • ***
  • Posts: 40
    • View Profile
    • my flickr page
Re: Does macro lenses of different focal lengths give the same image?
« Reply #22 on: May 03, 2014, 09:41:07 AM »
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.
5D & EF 8-15 f/4L, EF 16-35 f/2.8L II, EF 24-70 f/2.8L II, EF 40 f/2.8 STM, MP-E 65 f/2.8 Macro, TS-E 90 f/2.8, EF 100 f/2.8L IS Macro, EF 70-200 f/2.8L IS II

sulla

  • PowerShot G1 X II
  • ***
  • Posts: 40
    • View Profile
    • my flickr page
Re: Does macro lenses of different focal lengths give the same image?
« Reply #23 on: May 03, 2014, 09:42:40 AM »
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.
5D & EF 8-15 f/4L, EF 16-35 f/2.8L II, EF 24-70 f/2.8L II, EF 40 f/2.8 STM, MP-E 65 f/2.8 Macro, TS-E 90 f/2.8, EF 100 f/2.8L IS Macro, EF 70-200 f/2.8L IS II

100

  • Rebel T5i
  • ****
  • Posts: 124
    • View Profile
Re: Does macro lenses of different focal lengths give the same image?
« Reply #24 on: May 03, 2014, 08:17:53 PM »
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. 

steven kessel

  • EOS M2
  • ****
  • Posts: 191
    • View Profile
Re: Does macro lenses of different focal lengths give the same image?
« Reply #25 on: May 03, 2014, 10:43:30 PM »
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.

danski0224

  • 6D
  • *****
  • Posts: 533
    • View Profile
    • Some of my Work in Progress
Re: Does macro lenses of different focal lengths give the same image?
« Reply #26 on: May 04, 2014, 08:21:33 AM »
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  :)
Some of my Work in Progress..... www.dftimages.com

Antono Refa

  • PowerShot G1 X II
  • ***
  • Posts: 68
    • View Profile
Re: Does macro lenses of different focal lengths give the same image?
« Reply #27 on: May 04, 2014, 10:06:15 AM »
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.
« Last Edit: May 04, 2014, 10:42:02 AM by Antono Refa »

canon rumors FORUM

Re: Does macro lenses of different focal lengths give the same image?
« Reply #27 on: May 04, 2014, 10:06:15 AM »

surapon

  • Canon EF 300mm f/2.8L IS II
  • *******
  • Posts: 2283
  • 80% BY HEART, 15% BY LENSES AND ONLY 5% BY CAMERA
    • View Profile
Re: Does macro lenses of different focal lengths give the same image?
« Reply #28 on: May 04, 2014, 12:28:32 PM »
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
« Last Edit: May 04, 2014, 12:41:41 PM by surapon »

surapon

  • Canon EF 300mm f/2.8L IS II
  • *******
  • Posts: 2283
  • 80% BY HEART, 15% BY LENSES AND ONLY 5% BY CAMERA
    • View Profile
Re: Does macro lenses of different focal lengths give the same image?
« Reply #29 on: May 04, 2014, 12:38:49 PM »
Just for FUN , to talk to my dear friends.
Have a great Sunday.
Surapon

canon rumors FORUM

Re: Does macro lenses of different focal lengths give the same image?
« Reply #29 on: May 04, 2014, 12:38:49 PM »