Macro lenses: Field of view, MFD, Aperture.


Shen siung

Senior Member
May 21, 2008
2,597
0
36
#1
Hi All,

Feeling to get myself a macro lens. Will be my 1st try. And I would like to double up this lens as a portrait lens.

Would like to ask for your kind clarification about some of the things related to macro lens...

1. field of view (FOV)
For a macro lens of 100mm, its field of view (how 'wide / narrow') will be identical to any other 100mm lenses? Just FOV, regardless of MFD. I want to use other lens to justify which focal length i will like.

2. Aperture
I read from somewhere else, when the distance to the subject getting closer until the minimum focus distance, the maximum aperture of the lens will be different when the lens is far away from a subject?

If a 100mm f2.8 macro lens, at it's MFD, the max aperture is actually >f2.8 (say f3.5, f4...)?

Thanks for your kind input :)
 

Last edited:

Dream Merchant

Moderator
Staff member
Jan 11, 2007
9,659
6
38
#2
1) If two lenses have an identical focal length, their FOV will be the same.

2) From a certain point/focusing distance, the closer a lens is focused, or the further an objective is moved away from a focal plane, the more light is lost.
 

Numnumball

Senior Member
Mar 6, 2009
13,899
0
0
Central
#3
Hi All,

Feeling to get myself a macro lens. Will be my 1st try. And I would like to double up this lens as a portrait lens.

Would like to ask for your kind clarification about some of the things related to macro lens...

1. field of view (FOV)
For a macro lens of 100mm, its field of view (how 'wide / narrow') will be identical to any other 100mm lenses? Just FOV, regardless of MFD. I want to use other lens to justify which focal length i will like.

2. Aperture
I read from somewhere else, when the distance to the subject getting closer until the minimum focus distance, the maximum aperture of the lens will be different when the lens is far away from a subject?

If a 100mm f2.8 macro lens, at it's MFD, the max aperture is actually <f2.8?

Thanks for your kind input :)
1. FOV remains reagrdless so long its 100mm

2. should be greater than >2.8

Some find macro lens (including me) to be too unflattering (sharp and too constrasty) for portraiture work :0
 

Shen siung

Senior Member
May 21, 2008
2,597
0
36
#4
Thanks Numnumball and Dream Merchant :)

Yes I mean smaller aperture, or greater than 2.8 (f3.5,f4....) , he he. Error.

So that means, for all macro lens, when it is at MFD, the aperture might be only maximum at, say f4? Thanks
 

titleist

New Member
May 18, 2009
99
0
0
#5
Thanks Numnumball and Dream Merchant :)

Yes I mean smaller aperture, or greater than 2.8 (f3.5,f4....) , he he. Error.

So that means, for all macro lens, when it is at MFD, the aperture might be only maximum at, say f4? Thanks
The size of the aperture doesn't change when its at the minimum focus distant or at infinity. The only thing about macro lens is that you will likely set it above f/8 due to the thin dof. Basically the aperture doesn't change like that of a zoom lens.
 

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