Group photo.. out of focus...

Started Jul 21, 2012 | Discussions thread
TimR32225 Veteran Member • Posts: 3,396

Ken Phillips wrote:

Depth of field relates to the relative magification! (Yeah, folks will give you a zillion interpretations of theory, but you'll find that what I said will work just fine.)

If you keep the coverage of the subject - the field of view - the same, you can get MUCH better DOF from a great distance with a long lens! Only the perspective is changed, and I submit that a group shot will look better "flattened" with a long lens, rather than have folks with different sized heads.
Easily experimented with, if you have any doubts.

The key term in your statement is "at great distance". While what you say is true, you would have to back up pretty far with a long lens to get enough DOF to keep a large group in focus, which in many cases is not practical, or possible. It seems much easier to use a medium or wide lens and accomplish the same thing without needing to back up 50 or 75 feet from the subject.

I like to use a focal length of around 50mm or so for group photos (see example below) but since the OP had already stated that he was unable to get the entire group in focus, I was trying to suggest a fail safe method for him to try.

What you sugested depends specifically on what you meant by "long lens", but if you compare 24mm to say, a 200 mm lens at f8, at a subject distance of 30 feet, the DOF with the 24mm lens is 6.25 feet to infinity. If you use a 200mm lens your DOF is only 3.2 feet. You would have to back up 50 feet from the subject in order to get DOF of 9 feet, which still may not be enough. It would be great if you had room to back up far enough, but I seriously doubt you could in most situations. Even if you could, backing up 50 feet might not fit the entire group in the frame from left to right with a 200mm lens.

I shot the image below at 56mm at f6.3. According to the exif data, I was 29 feet from the subject. With a much longer lens, I would have to back up a lot further to fit the entire group in the frame, and depth of field would be a lot less.

Their heads all look the same size to me. If there is something else I am missing, please explain...


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