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Herb Houghton wrote:
Nice set of little birds. I tend to disagree that the "aperture doesn't matter. " When filling the frame with a little bird, I'd rather have the whole bird in focus, head to tail. It's not uncommon for me to fill the frame with a little guy and stop down from f11- f16. Your 1/4 inch dof would turn into 2-5 inches of dof, allowing the whole bird to be in focus and sharp. Now I would only do this with clean, far away BGDs, not while they're in the midst of branches or other BGD parts that you...Show more →
Herb and Cincy
I am trying to understand what your saying. I appreciate your input and want to here your thoughts. I wrote:
My goal is always to get pictures suitable to print large. The number of pixels on the bird is important.
I want 16 x 20, 16 x 24, 20 x 30. I'm not getting bigger than that without a full frame camera. This means I need many pixels on the bird. Anytime you extrapolate pixels, for example with photoshop, then you lose something. You can't make something out of nothing without losing something. So, please think - print large.
Harry C asked can you explain why you are using extension tubes for these please?
That was to get closer than the minimum focusing distance. More pixels on the bird. I simply could not get full frame images without it.
First, I rechecked the DOF calculator and at the distance I am at, DOF is 0.36" (not 1/4", sorry). At F16 it is .72". That is fairly insignificant. However, the DLA for the camera is F6.8. F8, F9 doesn't really matter. F16 does. You can see the softness set in. Blow that picture up to 16 x 24 and that just makes the softness worse. Shooting at F16 is not going to help. DOF change is not significant and the images will be soft.
Second, the option is to move back from the bird. More distance equal greater DOF. At F8 doubling the distance to 32 feet, the DOF is .84". So, now we are up to more than 3/4" DOF. Still very thin. Double the distance again and DOF is 3.36" Now we are in the range you're talking about. But, moving back 4 times the distance means 1/4 x 1/4 = 1/16 the pixels on the bird (pixels are two dimensions). That is going to be one tiny bird.
So there is the dilemma. F16 is going to add a fraction of an inch to DOF and the diffraction will be noticeable printed large. Moving back far enough to get decent DOF means the pixels on the bird will be unsuitable for printing large.
Maybe I did the math wrong and someone can correct me or maybe I don't understand this well. I know I need maximum pixels on the subject and seek advise on how to do this. Please correct me if I get this wrong.
I know people say they blow up 6 MP images to 24 x 36, or whatever, and are happy with it. I'm not going to be happy with that. Anytime you make up data out of the sky, you lose something. Resolution matters.
Thank you for any advise you can provide.