DOF/Focal length relationship
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The Reverend JT
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google
HIMUPNORTH
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Start here: http://en.wikipedia.org/wiki/Focal_length
EOS_JD
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Depth of field I believe is not affected by the focal length per se - it's more to do with the magnification of the subject on the sensor or film. kinmd of similar but the magnification takes into accout focal length and distance to subject.
Look at the online depth of field calcualators too to help.
www.dofmaster.com/dofjs.html
Look at the online depth of field calcualators too to help.
www.dofmaster.com/dofjs.html
alastairb
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it is also worth noting that for images framed the same on an aps-c (1.6x) sensor will have 1.5 stops more dof when compared to full frame (aka f/1.7 on aps-c will have the same dof as f/2.8 on full frame) , and an aps-h sensor will have 0.5 stop more dof when compared to full frame
HoppyUK
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As EOS JD says, the significant factor is magnification, not just focal length per se. Subject distance also affects magnification.
In other words, if you frame a portrait at say 2m, but then move back to 4m with a lens of double the focal length, the subject remains the same size on the sensor (same magnification) and depth of field also remains the same.
And yes, you get more depth of field with the smaller formats of crop sensor DSLRs compared to full frame, and with compacts with much smaller sensors still, there is so much DoF it's quite hard not to get everything sharp all the time.
The difference in DoF between formats is equal to the crop factor, so with a Canon having a 1.6x crop factor relative to full frame, the difference is about one and a quarter stops. In the example quoted above, f/1.7 on a crop camera would give the same DoF as f/2.7 (1.7 x 1.6 = 2.72). The 1.5x crop factor on Nikon/Sony is virtually the same.
Canon 1D series cameras have a 1.3x crop factor which is just under one stop difference. The 2x crop factor of Four-Thirds format is two stops. Compacts are usually around 5x crop factor.
In other words, if you frame a portrait at say 2m, but then move back to 4m with a lens of double the focal length, the subject remains the same size on the sensor (same magnification) and depth of field also remains the same.
And yes, you get more depth of field with the smaller formats of crop sensor DSLRs compared to full frame, and with compacts with much smaller sensors still, there is so much DoF it's quite hard not to get everything sharp all the time.
The difference in DoF between formats is equal to the crop factor, so with a Canon having a 1.6x crop factor relative to full frame, the difference is about one and a quarter stops. In the example quoted above, f/1.7 on a crop camera would give the same DoF as f/2.7 (1.7 x 1.6 = 2.72). The 1.5x crop factor on Nikon/Sony is virtually the same.
Canon 1D series cameras have a 1.3x crop factor which is just under one stop difference. The 2x crop factor of Four-Thirds format is two stops. Compacts are usually around 5x crop factor.
Bendihossan
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You're helpful aren't you?
Anyway, to the OP: check out the wiki page linked above as well as this site: http://www.dofmaster.com/ Hope that helps
You're helpful aren't you?
Anyway, to the OP: check out the wiki page linked above as well as this site: http://www.dofmaster.com/ Hope that helps
the 2nd result on google...
The Reverend JT
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You're helpful aren't you?
Anyway, to the OP: check out the wiki page linked above as well as this site: http://www.dofmaster.com/ Hope that helps
1) It was a question which could have been typed into google and would have been answered within 2 minutes of searching.
2) When I want people to run about after me on the internet because i'm too lazy to type it into google and read up about that first - i generally say please.
was that explanation helpful enough for you?
