Nikon Lens Magnification Factor on Red

[Digital Island]

Evin and Community,

Correct me if I am wrong, with Nikon 35mm still lenses on Red shooting 4K Redcode Raw, then the magnification factor is 1.65.

So a 135mm Nikon AIS f/2.0 lens is closer to 223mm?

[Evin Grant]

No. But this is a little hard to get your head around. It might be described as a crop factor that affects your FOV but in reality all lenses behave the same for any format provided their image circle covers it. But your sensor size does affect your field of view. So in relation to 35mm still format, yes there is a 1.63x crop factor. But compared to 35mm motion picture there is none. Magnification is a relationship to life size so that is not an accurate term.

[Damien Molineaux]

In 35mm still format, a 50mm lens is considered as reproducing a normal angle of view.
In 35mm motion picture, a 35mm lens is considered as reproducing a normal angle of view.
With Red, you have a sensor of the same size as 35mm motion picture film, so the result with any given lens will correspond to what you get on a 35mm motion picture camera, wether you use still or cine lenses.

Maybe some people forget the size of the image on the negative is larger on a still camera than on a motion picture camera, although they use the same size negative, but still is length wise while motion pictures only use the width.

Cheers,
Damien

[Digital Island]

Thanks for the help, guys. I knew something seemed awry with that calculation (the use of the word 'magnification' instead of when I meant FOV already got me off to a wrong start). I'd better stick with Brook's advice on his Red FAQ:


This is another problem with conversion formats. Not only is it annoying to constantly have to translate focal lengths on set, the user will never learn. If you're constantly thinking of one focal length in terms of another one, what are you learning? All conversion factors do is complicate the situation.

[Dominique Grenier]

In 35mm still format, a 50mm lens is considered as reproducing a normal angle of view.
In 35mm motion picture, a 35mm lens is considered as reproducing a normal angle of view.

So, basically, a 50mm is a 50mm whatever the format you're working with, all that it is changed, is the way you use it. If I want a wide angle, I'll have to use lower value such as 14 or 18mm, instead of say, a 24mm on 35mm still?

You just change the way you think about it, rather than doing some conversion. There's only a crop factor when you compare both format, but one format or the other, by itself, doesn't have a crop. 35mm still have a certain FOV for a 50mm, and 35mm motion have another.

Am I correct?

[Martin Drew]

You are correct. We commonly use the focal length as a shorthand for FOV, but that is always dependent upon format.

M

[Dominique Grenier]

You are correct. We commonly use the focal length as a shorthand for FOV, but that is always dependent upon format.

Would there be a better way of refering to FOV without using focal length?

I mean, " Gimme the ultra-wide-angle! No, this is the ultra-ultra-wide-angle, I want the ultra-wide-angle! ", sorta thing isn't really practical.. :biggrin: