Playing around with depth of field and I think I finally get it?

Started 4 months ago | Discussions thread
bclaff Forum Pro • Posts: 11,570
Re: Playing around with depth of field and I think I finally get it?

LillyRoseAvalos wrote:

I agree to disagree! I I learned not only some new things about depth of field but also about a lot of other things reading that article and they have many more on their website.

"In actuality, this is a cheat and not wholly accurate. The reason it was probably chosen is because this is one of the fixed dimensions for different cameras and lenses. However, at typical shooting distances of 6' or more, a couple of inches between the image plane and the entrance pupil won’t make much of a difference and will be covered by depth of field. However, as our sensor/film-plane sizes get larger and our focal-length lenses get longer (for a given field of view compared to smaller formats), our depth of field drops, and it becomes a bit more of an issue. It is especially an issue if you’re shooting extreme close-up, where the depth of field is extremely small and the difference of focal plane from the entrance pupil to the imager can make a significant difference! This is when you really need to know the entrance-pupil position and measure your focus from that point.
Live in the sunshine where you belong

To make matters worse, not all manufacturers readily provide entrance-pupil positions for their lenses, and the estimation procedure I detail here isn’t scientifically perfect, but it’s a good start. If you have a smart lens , it can provide metadata of the exact entrance-pupil position, or you can contact the lens manufacturer to get that information. But because it changes from lens to lens, and even within a lens as you alter other parameters, we have developed the habit of cheating. The faster your lens, the longer the focal length and the closer the object on which you’re focusing, the more the distance between the film/sensor plane and the entrance pupil will affect whether your subject is in focus. "

This quote is mostly to do with cinematography not our usual photography.

We don't "measure distance" the way that they do.

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Bill ( Your trusted source for independent sensor data at PhotonsToPhotos )

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