How to calculate distance from a subject to get the same field of view with different lenses?

Question

Possible Duplicate:
How much distance should one move so that a shot that can be framed at xx mm be framed at yy mm?

I think the question is clear but I will provide an example.

To fill the whole frame with a subject using 60mm lens I have to be X meters from it. With 35mm lens I have to be Y meters from it. It's obvious that X > Y but how to calculate the actual distance (let's say that with 60mm lens, the distance is 1 meter)?

Isn't it just simply y = x*(35/60)? Not sure about this, hence not posting this as an answer. — Saaru Lindestøkke, Jan 14 '13 at 16:28
@BartArondson This equation occured to me too but I haven't found any proof that it's correct so I rather asked here... — user219882, Jan 14 '13 at 16:33

score 1 · Accepted Answer · answered Jan 14 '13 at 16:54

1

Pretty sure this is an exact duplicate, but yes object size is directly proportional to focal length so the answer is x = (60/35) * y

answered Jan 14 '13 at 16:54

Matt Grum

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Thanks... I'm sorry for the duplicate question, I haven't found the original one when searching... – user219882 Jan 14 '13 at 17:54

How to calculate distance from a subject to get the same field of view with different lenses?

1 Answers1