50mm "Normal" Lens... Ok, but "Normal" on FF or APS-C Sensor?

Started Nov 10, 2012 | Discussions thread
tkbslc Forum Pro • Posts: 12,627
Re: Not the 50mm myth again. That one is tough to kill!
1

ljfinger wrote:

tkbslc wrote:

ljfinger wrote:

tkbslc wrote:

If you want to debate "normal" should we also try to debunk "wide angle" and "telephoto"?

Telephoto has a specific meaning - the lens' physical length is shorter than its focal length.

So what about wide angle, then? And Telephoto's definition has extended to mean any lens longer than a normal prime, regardless of the construction of your lens. A 300mm prime that is 300mm long would still be called a telephoto by most.

And most would be using the term incorrectly. That doesn't make it right.

So how do you describe a lens longer than 50mm?

You still haven't answered about wide angle.  What makes it wide?  When would a lens start becoming described as wide and why?


We are really not talking FOV as much as we are perspective.

And perspective is a function of shooting location, and not focal length.

It's just as easy to work backwards from that function.   I can't use  a 300mm lens to stand 1 foot from a person and exaggerate their face because the shot would be out of focus and only contain their nose.

The normal prime does keep things sized as we expect when shot at the same distance we view them.

Only if you view the final image at a distance that provides the same subtended angle as did the original scene. These days, with big monitors and us sitting closer to them, the "natural" (I'm loathed to use the term "normal") focal length is closer to 30mm

How can viewing size and position change the relative size of objects in a two-dimensional photo?  Are you implying that just by printing bigger, I can change the perspective?  Wouldn't all objects scale equally, thus preserving the size and spatial relationships?

When going into telephoto territory, we start to see the background compressed as would be unnatural with the naked eye.

No, that's just entirely false. The "compression" is caused by being far away, not by using a long lens. If you view a long focal length shot encompassing a small visual angle, it will still be "natural".

You are right technically, but in practice once rarely achieves noticeable compression with a wide angle because the size of the objects are both such a small portion of the frame that neither are magnified.   Also, framing limits on telephoto lenses prevent actually crating a natural looking perspective.   It's a matter of real world results vs being technically correct.

When moving into wide angle territory, we start to see foreground objects unnaturally large. It's pretty easy to observe with only a few minutes of experimenting.

And, again, that's because of the location, not the focal length, and if you view that final image from close up so that the image subtends the same angle in your view as did the original shot, it will again be "natural".

And again, that's not how people use cameras.

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