There is a new Depth of Field page at Want to blur and hide the background? Comparing Depth of Field of Two Lenses
It has a new DOF calculator, but it was not done to be general purpose. DofMaster is already a very good one.
Specifically it computes Circle of Confusion at the background behind the subject, in concern about blurring and eliminating the background. The calculator compares situations of two lens regarding this (CoC at the background, and DOF at the subject).
It could be said to be an anti 50mm f/1.8 article.
Actually it just shows a much better plan. DOF also depends on other factors than aperture, also focal length and subject distance. We can use that too.
It does make the point that the 50 mm f/1.8 is NOT best plan. Novices get the notion it is, but we won't see many pros suffering that way (they tend to want their work to sell). There will be better results to stand back with a longer lens. Instead of 50mm f/1.8 at 6 feet, instead maybe 200mm f/4 at 24 feet. Or even 100mm at 12 feet with f/2.8. Generally we're outside and have lots of room so this is no issue. But there may not always be enough room indoors.
200mm is 4x longer than 50mm, so if standing back 4x farther, it has exactly the Same Field of View as the 50 (at the subject). And if at the same aperture there, the Same DOF too (at the subject) - the adage about the "same image" has same DOF, etc. (at the subject, it does).
But the background is certainly NOT the same then... most of it is zoomed and gone missing (you want it excluded right?), but what's left is in more blurred focus (assuming that is a plus here)... due to focal length and distance to the background. In regard to the background, the longer lens standing back has a vastly larger Circle of Confusion (the blur circle diameter) at the background, computed by this new calculator. The actual CoC number isn't so useful, but it being LARGE is the point and this benefit. And then if opening the 50 to f/1.8 to help blur the background, the subject DOF goes to pot too.
Here is the default and the example shown in images.
Anyway, it makes the point that standing back with the longer lens will be better results, sometimes much better,
in regard to blurring the background, (your plan is to blur it, right?)
and in regard to simply excluding most of the background, (you want the clutter eliminated, right?)
and in regard to better DOF at the subject. (f/1.8 certainly needs better DOF at the subject, right?)
A major point is that since the telephoto background is so much smaller area, we can easily and simply slightly move the camera sideways to select the best (least objectionable) part of it to be shown in the picture.
We could add that that standing back with a longer lens is much better portrait perspective too... 50 mm is too short for head and shoulders work.
You should try it. It works.
It has a new DOF calculator, but it was not done to be general purpose. DofMaster is already a very good one.
Specifically it computes Circle of Confusion at the background behind the subject, in concern about blurring and eliminating the background. The calculator compares situations of two lens regarding this (CoC at the background, and DOF at the subject).
It could be said to be an anti 50mm f/1.8 article.
Actually it just shows a much better plan. DOF also depends on other factors than aperture, also focal length and subject distance. We can use that too.It does make the point that the 50 mm f/1.8 is NOT best plan. Novices get the notion it is, but we won't see many pros suffering that way (they tend to want their work to sell). There will be better results to stand back with a longer lens. Instead of 50mm f/1.8 at 6 feet, instead maybe 200mm f/4 at 24 feet. Or even 100mm at 12 feet with f/2.8. Generally we're outside and have lots of room so this is no issue. But there may not always be enough room indoors.
200mm is 4x longer than 50mm, so if standing back 4x farther, it has exactly the Same Field of View as the 50 (at the subject). And if at the same aperture there, the Same DOF too (at the subject) - the adage about the "same image" has same DOF, etc. (at the subject, it does).
But the background is certainly NOT the same then... most of it is zoomed and gone missing (you want it excluded right?), but what's left is in more blurred focus (assuming that is a plus here)... due to focal length and distance to the background. In regard to the background, the longer lens standing back has a vastly larger Circle of Confusion (the blur circle diameter) at the background, computed by this new calculator. The actual CoC number isn't so useful, but it being LARGE is the point and this benefit. And then if opening the 50 to f/1.8 to help blur the background, the subject DOF goes to pot too.
Here is the default and the example shown in images.
Anyway, it makes the point that standing back with the longer lens will be better results, sometimes much better,
in regard to blurring the background, (your plan is to blur it, right?)
and in regard to simply excluding most of the background, (you want the clutter eliminated, right?)
and in regard to better DOF at the subject. (f/1.8 certainly needs better DOF at the subject, right?)
A major point is that since the telephoto background is so much smaller area, we can easily and simply slightly move the camera sideways to select the best (least objectionable) part of it to be shown in the picture.
We could add that that standing back with a longer lens is much better portrait perspective too... 50 mm is too short for head and shoulders work.
You should try it. It works.
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