Effect of a TC on DOF

MatBin

MatBin

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Am I correct in thinking a TeleConverter has no effect on DOF, assuming same aperture, focus distance etc.
Namely if I put a 2x converter on a 70/200 and shoot at max focal length and an aperture of f4 I'll get the same dof with or without the converter i.e. the appropriate dof of f4 on a 200mm lens and not the dof of a 400mm lens at f8. I would be using the same focus distance but the image is somewhat bigger in the frame of course when using the converter.

Matt
 
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MatBin said:
Am I correct in thinking a TeleConverter has no effect on DOF, assuming same aperture, focus distance etc.
Namely if I put a 2x converter on a 70/200 and shoot at max focal length and an aperture of f4 I'll get the same dof with or without the converter i.e. the appropriate dof of f4 on a 200mm lens and not the dof of a 400mm lens at f8. I would be using the same focus distance but the image is somewhat bigger in the frame of course whe using the converter.

Matt
Click to expand...

No. If you put a 2x converter on a 200mm f/4 lens, it becomes 400mm f/8.
 
MatBin said:
Am I correct in thinking a TeleConverter has no effect on DOF, assuming same aperture, focus distance etc.
Namely if I put a 2x converter on a 70/200 and shoot at max focal length and an aperture of f4 I'll get the same dof with or without the converter i.e. the appropriate dof of f4 on a 200mm lens and not the dof of a 400mm lens at f8. I would be using the same focus distance but the image is somewhat bigger in the frame of course whe using the converter.

Matt
Click to expand...


sorry,i can't really understand what u mean?
example if u have 70-200mm F4 lens and put a 2x TC to it and shooting at the most tele end of 200mm,after putting in the TC u will be shooting at 400mm F8(max aperture).

but then if u were comparing the DOF when shooting at 200mm F4 vs 400mm F8,i guess the DOF should be the same. the subject at 400mm ofcourse will look bigger.
iam not exactly sure though,just my gut feel about it.
 
HoppyUK said:
No. If you put a 2x converter on a 200mm f/4 lens, it becomes 400mm f/8.
Click to expand...

So I would get less dof by using a converter?
 
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