Originally Posted by
William W
If I only had a choice of one lens it would be a fast, non-varying aperture zoom in the range of a little wide to a little telephoto: what is termed 'a standard zoom lens' or 'a normal zoom lens': for example a 24 to 70/2.8 on the ‘full frame’ Nikon that you intend to buy.
Why a zoom - flexibility of many Focal Lengths from which to choose.
Why a fast zoom – flexibility of many Apertures from which to choose.
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I often use my macro lenses for Portraiture. Macro lenses are (usually) very crisp. But, in consideration of above the macro lens is set at one Focal Length: that might be OK for one Portrait shot, but not for another.
There is no such thing as "A Portrait Lens".
Many Lenses and many Focal Lengths can be used to make a Portrait Photograph.
The choice of Focal Length to use mainly depends upon the shooting situation and also the artist's vision.
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My opinion is: that is a silly comment to make and is probably based more on regurgitated internet nonsense rather than experience shooting Portraiture.
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If it is fact that the fixed Focal Length of the lens is the element which forces you to think more about composition, then a zoom lens and a roll of GAF tape would be a better value for money purchase for learning Composition.
A zoom lens is like having many primes all in one. You could set the zoom at a particular Focal Length and tape it at that FL. Then shoot all day, all week all month, just at that one Focal Length.
When you get bored with learning about composition at that Focal Length, you could start a whole new lesson on composition at a different Focal Length.
However I don't think that a Prime Lens is necessarily a good tool for making one concentrate better on COMPOSITION: if you only have a Prime Lens, you can only change the PERSPECTIVE of THE SHOT and you CANNOT change the FIELD of VIEW. (read below).
A better tool for concentrating on Composition is to (initially) have a structured and methodical approach to setting up The Shot: for example choose the VIEWPOINT of the camera to set the PERSPECTIVE that you want; then set the FOCAL LENGTH to set the FIELD of VIEW that you want; then FRAME the SUBJECT to finish the COMPOSITION that you want.
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Moving the Camera's Viewpoint (changes the PERSPECTIVE), and doing so is NOT the same as zooming (which changes the FIELD OF VIEW).
Performing one of those maneuvers is NOT the same as performing the other.
To compare those two variables, is akin to comparing apples to horses.
WW