Do lens focal length and sensor size influence depth of field

[fjrabon]

Since I can get the same magnification with different focal lengths (just alter distance), then focal length is not directly a factor in DOF. Is that going to work?

Yes, sure that works, that's exactly what direct versus indirect causation means. A direct cause causes something... directly. An indirect cause causes something through its influence on another factor.

The direct factors are aperture and magnification.

But if it could be that simple then you should be able to run variants on the DOF Master calculator using different focal lengths and as long the magnification is the same you should get the same DOF -- you'll get the same total DOF but you'll get different front/back distributions so focal length isn't really canceled out.

DOF = f/stop + magnification. (I even have that as the right answer on an exam!) But the caveat is that it's an oversimplification. When you break down magnification you can't say that the specific factor values cancel as long as they add up to the same magnification value -- it's not that clean; be nice if it was. So we at least have to write this: DOF = f/stop + magnification*

And when you flesh out that asterisk the sub factors carry weight.

Joe

Sure, but I thought we were solely talking about total DoF (what I think most people mean when they talk about DoF in my experience), not front/back distributions. Front/back DoF ratios are obviously solely a function of focal point distance in relation to the hyperfocal distance.

also im sure at this point the op is sufficiently confused by this when im pretty sure we are more or less ultimately in agreement since im sure we both ultimately understand how DoF works in all its gory detail.

 

[Ysarex]

Since I can get the same magnification with different focal lengths (just alter distance), then focal length is not directly a factor in DOF. Is that going to work?

Yes, sure that works, that's exactly what direct versus indirect causation means. A direct cause causes something... directly. An indirect cause causes something through its influence on another factor.

The direct factors are aperture and magnification.

But if it could be that simple then you should be able to run variants on the DOF Master calculator using different focal lengths and as long the magnification is the same you should get the same DOF -- you'll get the same total DOF but you'll get different front/back distributions so focal length isn't really canceled out.

DOF = f/stop + magnification. (I even have that as the right answer on an exam!) But the caveat is that it's an oversimplification. When you break down magnification you can't say that the specific factor values cancel as long as they add up to the same magnification value -- it's not that clean; be nice if it was. So we at least have to write this: DOF = f/stop + magnification*

And when you flesh out that asterisk the sub factors carry weight.

Joe

Sure, but I thought we were solely talking about total DoF (what I think most people mean when they talk about DoF in my experience), not front/back distributions. Front/back DoF ratios are obviously solely a function of focal point distance in relation to the hyperfocal distance.

OK -- just keeping it to total DOF helps simplify it, but it still doesn't entirely cancel the magnification sub factors into insignificance -- for example you still have infinity to deal with when accounting for focal length.

P.S. Did you notice that the OP was brand new and this was 1st post? You know it's possible we just got trolled.

Joe

 

[fjrabon]

Since I can get the same magnification with different focal lengths (just alter distance), then focal length is not directly a factor in DOF. Is that going to work?

Yes, sure that works, that's exactly what direct versus indirect causation means. A direct cause causes something... directly. An indirect cause causes something through its influence on another factor.

The direct factors are aperture and magnification.

But if it could be that simple then you should be able to run variants on the DOF Master calculator using different focal lengths and as long the magnification is the same you should get the same DOF -- you'll get the same total DOF but you'll get different front/back distributions so focal length isn't really canceled out.

DOF = f/stop + magnification. (I even have that as the right answer on an exam!) But the caveat is that it's an oversimplification. When you break down magnification you can't say that the specific factor values cancel as long as they add up to the same magnification value -- it's not that clean; be nice if it was. So we at least have to write this: DOF = f/stop + magnification*

And when you flesh out that asterisk the sub factors carry weight.

Joe

Sure, but I thought we were solely talking about total DoF (what I think most people mean when they talk about DoF in my experience), not front/back distributions. Front/back DoF ratios are obviously solely a function of focal point distance in relation to the hyperfocal distance.

OK -- just keeping it to total DOF helps simplify it, but it still doesn't entirely cancel the magnification sub factors into insignificance -- for example you still have infinity to deal with when accounting for focal length.

P.S. Did you notice that the OP was brand new and this was 1st post? You know it's possible we just got trolled.

Joe

sure, ive sorta thought for the last 5-6 replies "none of this is at all helpful to the OP, but its TPF, so lets go with it."

 

[Ysarex]

Since I can get the same magnification with different focal lengths (just alter distance), then focal length is not directly a factor in DOF. Is that going to work?

Yes, sure that works, that's exactly what direct versus indirect causation means. A direct cause causes something... directly. An indirect cause causes something through its influence on another factor.

The direct factors are aperture and magnification.

But if it could be that simple then you should be able to run variants on the DOF Master calculator using different focal lengths and as long the magnification is the same you should get the same DOF -- you'll get the same total DOF but you'll get different front/back distributions so focal length isn't really canceled out.

DOF = f/stop + magnification. (I even have that as the right answer on an exam!) But the caveat is that it's an oversimplification. When you break down magnification you can't say that the specific factor values cancel as long as they add up to the same magnification value -- it's not that clean; be nice if it was. So we at least have to write this: DOF = f/stop + magnification*

And when you flesh out that asterisk the sub factors carry weight.

Joe

Sure, but I thought we were solely talking about total DoF (what I think most people mean when they talk about DoF in my experience), not front/back distributions. Front/back DoF ratios are obviously solely a function of focal point distance in relation to the hyperfocal distance.

OK -- just keeping it to total DOF helps simplify it, but it still doesn't entirely cancel the magnification sub factors into insignificance -- for example you still have infinity to deal with when accounting for focal length.

P.S. Did you notice that the OP was brand new and this was 1st post? You know it's possible we just got trolled.

Joe

sure, ive sorta thought for the last 5-6 replies "none of this is at all helpful to the OP, but its TPF, so lets go with it."

OK -- well then the asterisk after magnification applies -- the factors don't cancel cleanly. It's an appropriate simplification and one I use myself, but when it's fleshed out the factor values matter.

Joe

edit: But we're both shooting Fuji X cameras now so we have to stay friends.

 

[fjrabon]

Since I can get the same magnification with different focal lengths (just alter distance), then focal length is not directly a factor in DOF. Is that going to work?

Yes, sure that works, that's exactly what direct versus indirect causation means. A direct cause causes something... directly. An indirect cause causes something through its influence on another factor.

The direct factors are aperture and magnification.

But if it could be that simple then you should be able to run variants on the DOF Master calculator using different focal lengths and as long the magnification is the same you should get the same DOF -- you'll get the same total DOF but you'll get different front/back distributions so focal length isn't really canceled out.

DOF = f/stop + magnification. (I even have that as the right answer on an exam!) But the caveat is that it's an oversimplification. When you break down magnification you can't say that the specific factor values cancel as long as they add up to the same magnification value -- it's not that clean; be nice if it was. So we at least have to write this: DOF = f/stop + magnification*

And when you flesh out that asterisk the sub factors carry weight.

Joe

Sure, but I thought we were solely talking about total DoF (what I think most people mean when they talk about DoF in my experience), not front/back distributions. Front/back DoF ratios are obviously solely a function of focal point distance in relation to the hyperfocal distance.

OK -- just keeping it to total DOF helps simplify it, but it still doesn't entirely cancel the magnification sub factors into insignificance -- for example you still have infinity to deal with when accounting for focal length.

P.S. Did you notice that the OP was brand new and this was 1st post? You know it's possible we just got trolled.

Joe

sure, ive sorta thought for the last 5-6 replies "none of this is at all helpful to the OP, but its TPF, so lets go with it."

OK -- well then the asterisk after magnification applies -- the factors don't cancel cleanly. It's an appropriate simplification and one I use myself, but when it's fleshed out the factor values matter.

Joe

edit: But we're both shooting Fuji X cameras now so we have to stay friends.

speaking of fuji and complications to DoF calculations, you got hold of one of those new 56mm f/1.2 apd lenses?

 

[Braineack]

Since I can get the same magnification with different focal lengths (just alter distance), then focal length is not directly a factor in DOF. Is that going to work?

Yes, sure that works, that's exactly what direct versus indirect causation means. A direct cause causes something... directly. An indirect cause causes something through its influence on another factor.

The direct factors are aperture and magnification.

But if it could be that simple then you should be able to run variants on the DOF Master calculator using different focal lengths and as long the magnification is the same you should get the same DOF -- you'll get the same total DOF but you'll get different front/back distributions so focal length isn't really canceled out.

DOF = f/stop + magnification. (I even have that as the right answer on an exam!) But the caveat is that it's an oversimplification. When you break down magnification you can't say that the specific factor values cancel as long as they add up to the same magnification value -- it's not that clean; be nice if it was. So we at least have to write this: DOF = f/stop + magnification*

And when you flesh out that asterisk the sub factors carry weight.

Joe

Sure, but I thought we were solely talking about total DoF (what I think most people mean when they talk about DoF in my experience), not front/back distributions. Front/back DoF ratios are obviously solely a function of focal point distance in relation to the hyperfocal distance.

OK -- just keeping it to total DOF helps simplify it, but it still doesn't entirely cancel the magnification sub factors into insignificance -- for example you still have infinity to deal with when accounting for focal length.

P.S. Did you notice that the OP was brand new and this was 1st post? You know it's possible we just got trolled.

Joe

I only think one of you.got trolled here.

using tapatalk.

 

[dennybeall]

Braineack? two AM!!! I wonder what's going on back home in NorVA?????

 

[Designer]

P.S. Did you notice that the OP was brand new and this was 1st post? You know it's possible we just got trolled.

More like; he'll not return.

 

[ruifo]

P.S. Did you notice that the OP was brand new and this was 1st post? You know it's possible we just got trolled.

More like; he'll not return.

Indeed.
The # of newcomers posting just once and desapearing seems to be growing fast these days.

 

[astroNikon]

Braineack? two AM!!! I wonder what's going on back home in NorVA?????

I thought he was in vegas buying me a 150-600 tamzooka?

 

[fjrabon]

P.S. Did you notice that the OP was brand new and this was 1st post? You know it's possible we just got trolled.

More like; he'll not return.

Indeed.
The # of newcomers posting just once and desapearing seems to be growing fast these days.

Haha, or a lot post and simply forget they ever asked the question. I remember one that asked something about a starter camera and i asked a question and was essentially going to offer my old 7D for free, but they never answered my question and never came back.

 

[Designer]

Too bad for him!

 

[Bebulamar]

Uhm I hate it when someone just post a question to test us.

 

[Derrel]

Uhm I hate it when someone just post a question to test us.

We must chalk this thread up as being yet another successful trolling pass made.

 

[Ysarex]

Yes, sure that works, that's exactly what direct versus indirect causation means. A direct cause causes something... directly. An indirect cause causes something through its influence on another factor.

The direct factors are aperture and magnification.

But if it could be that simple then you should be able to run variants on the DOF Master calculator using different focal lengths and as long the magnification is the same you should get the same DOF -- you'll get the same total DOF but you'll get different front/back distributions so focal length isn't really canceled out.

DOF = f/stop + magnification. (I even have that as the right answer on an exam!) But the caveat is that it's an oversimplification. When you break down magnification you can't say that the specific factor values cancel as long as they add up to the same magnification value -- it's not that clean; be nice if it was. So we at least have to write this: DOF = f/stop + magnification*

And when you flesh out that asterisk the sub factors carry weight.

Joe

Sure, but I thought we were solely talking about total DoF (what I think most people mean when they talk about DoF in my experience), not front/back distributions. Front/back DoF ratios are obviously solely a function of focal point distance in relation to the hyperfocal distance.

OK -- just keeping it to total DOF helps simplify it, but it still doesn't entirely cancel the magnification sub factors into insignificance -- for example you still have infinity to deal with when accounting for focal length.

P.S. Did you notice that the OP was brand new and this was 1st post? You know it's possible we just got trolled.

Joe

sure, ive sorta thought for the last 5-6 replies "none of this is at all helpful to the OP, but its TPF, so lets go with it."

OK -- well then the asterisk after magnification applies -- the factors don't cancel cleanly. It's an appropriate simplification and one I use myself, but when it's fleshed out the factor values matter.

Joe

edit: But we're both shooting Fuji X cameras now so we have to stay friends.

speaking of fuji and complications to DoF calculations, you got hold of one of those new 56mm f/1.2 apd lenses?

Fascinating lens -- looks like a game changer. All those FF shooters can start drooling immediately.

Personally I lean the other way as I don't do much portrait work anymore and am more inclined to grab a short lens for landscape and general walkabout photos.

Joe