What is the use of the focal plane mark on a camera body?

Question

My camera body has a small marking on one side, indicating the position of the image sensor. (The manual even makes a point of explaining that this mark exists, and what it means.)

What possible reason would I have for knowing this? Why would I care exactly where the sensor is? It's buried deep within the body anyway, so...?

This is a pretty clear duplicate of the question referenced by mattdm. — Michael C, Feb 27 '16 at 04:46
The body of the other question ends with, "What does this symbol mean, and what is it used for?" — Michael C, Feb 27 '16 at 04:47

score 7 · Accepted Answer · edited Jul 25 '18 at 22:24

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Macro shooters sometimes need to know the distance between their subject and the image (film/sensor) plane, because that's how the minimum focus distance of a lens is measured. The mark gives you an easy way to determine whether you're inside or outside of that distance.

edited Jul 25 '18 at 22:24

Kevin Ghaboosi

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answered Feb 25 '16 at 19:59

inkista

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score 0 · Answer 2 · edited Feb 27 '16 at 17:22

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I often take images of file art for reproduction prints. Aligning focal planes can help eliminate distortions due to improper prospective. Both the target and image sensor should be parallel planes.

edited Feb 27 '16 at 17:22

BobT

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answered Feb 27 '16 at 15:47

Dave L vt

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The marker seems way to small to accurately define a a proper line (let alone a proper plane). How do you use it? – xenoid Jul 26 '18 at 13:29

What is the use of the focal plane mark on a camera body?

2 Answers2

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