spreadsheet showing why M8 and FF have same DOF

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according to DOF Master online, the LX3 should give about 6 cm total DOF, while the 5D should give about 30 cm total DOF, assuming focus is at 1m, and would be even less at a shorter focal point.

Sure looks like the LX3 has a little more DOF, doesn't it?

He clearly moved much closer to the cans to take the second picture so the comparison is pointless. You can even see his hat's shadow in the second picture.
 

I agree, but Pickett's photos should be the other way around! The LX3 @ 24mm will have less in focus than the 5D at the same aperture and focus distance. The comparison is misleading because he's changed the focus distance to get the same field of view.

That's all from yours truly on the subject.
 
He'll write another book: "Snapshots of the Gods." :)

Yes but I'm not sure even he could explain a one dimensional photo focused at infinity

His website claims he is the world's most successful non-fiction writer of all time but doesn't offer any proof
 
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Was there an original question? I thought there was just an Excel file full of math which ampguy posted.

Yes, there is an original question. What is the focal length and F-stop required to provide a normal field of view on a 35mm camera with enough depth of field so that you do not need to worry about focusing the camera?

FORTY-TWO.

42mm lenses used at F42 have infinite depth of field that encompasses the entire galaxy. So no matter how far out you hitchhike, you will still be in focus even if you are so far away that you are a point-source object.
 
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according to DOF Master online, the LX3 should give about 6 cm total DOF, while the 5D should give about 30 cm total DOF, assuming focus is at 1m, and would be even less at a shorter focal point.

Sure looks like the LX3 has a little more DOF, doesn't it?

You are using the tool wrong.
Panasonic LX-3, 24mm (35mm equiv), f/2.8
24mm (35mm equiv) on LX-3 is 5.1mm actual focal length.
http://www.dpreview.com/reviews/panasonicdmclx3/
Lens • 2.5x zoom
• f=5.1-12.8mm (35mm Equiv.: 24-60mm)

So now input-
LX3 @ 5.1mm / f2.8 / 3ft subject distance
DOF = 5.5ft

Canon 5d @ 24mm / f2.8 / 3ft subject distance
DOF = 0.8ft

This lines up with what we see in the picture.

Now your statement can be both wrong or right depending on interpretation.

Facts
Effective focal length, on different sized sensors, has wildly different DOF.
Actual focal lengths, on different sized sensors, have same DOF.

Actual focal length
Put a 28mm summicron on an M8 and a 24mm on an M9, you get same DOF and the M8 looks cropped.

Now effective focal length
Put a 28mm summicron (28*1.33=37.24 effective focal length) on the M8 and a 35mm summicron on the M9. This will give you approximately the same angle of view. However, the DOF will be different. The M8 will look like the DOF of a 28mm, that has been cropped.

Note the sensor crop is small enough that the difference is 1.28ft 28-on-M8 vs 1.06ft 35-on-M9 for f2.0 @ 6ft.

But please understand how to use the tool before you go around shouting about its failure.
 
Yes, there is an original question. What is the focal length and F-stop required to provide a normal field of view on a 35mm camera with enough depth of field so that you do not need to worry about focusing the camera?

FORTY-TWO.

42mm lenses used at F42 have infinite depth of field that encompasses the entire galaxy. So no matter how far out you hitchhike, you will still be in focus even if you are so far away that you are a point-source object.

That only works with M42 lenses, though.
 
I'll check it on the St-801.

Do DOF calculations correct for the Theory of Relativity, or are they based on Newtonian Physics? Somehow I get the feeling that DOF changes if you are traveling at close to the speed of light.
 
I'll check it on the St-801.

Do DOF calculations correct for the Theory of Relativity, or are they based on Newtonian Physics? Somehow I get the feeling that DOF changes if you are traveling at close to the speed of light.

Well clearly doppler shift, would have a profound effect if one were photographing ones relatives ...
 
I'll check it on the St-801.

Do DOF calculations correct for the Theory of Relativity, or are they based on Newtonian Physics? Somehow I get the feeling that DOF changes if you are traveling at close to the speed of light.

I think you would want Quantum Field Theory. It will give you a fast answer, but I am uncertain where you will find it. The Theory of Relativity will just tell you DoF does not work in meadows.
 
I think you would want Quantum Field Theory. It will give you a fast answer, but I am uncertain where you will find it. The Theory of Relativity will just tell you DoF does not work in meadows.

Or in Windows. NOTHING works in Windows, at least not first time...

Cheers,

R.
 
Given the inverse-square law (light dimishes with the square of the distance), infinity-focus isn't really all that it's cracked up to be.

~Joe
 
yes it will

yes it will

while mass goes towards zero as you approach the speed of light, even throwing a baseball can be measured slightly smaller when moving than at rest.

I'm wondering if this might be an easier to see and photograph phenomena than the move the barrel on m8 1 stop hyperfocal setting :p

I'll check it on the St-801.

Do DOF calculations correct for the Theory of Relativity, or are they based on Newtonian Physics? Somehow I get the feeling that DOF changes if you are traveling at close to the speed of light.
 
... throwing a baseball can be measured slightly smaller when moving than at rest. ...

Measured? I don't think so.

My 'back of the envelope' calculations say the Lorentzian contraction of a baseball thrown at 100 mph would be on the order of 10^-16 meters. Current thinking in holographic theory precludes a measurement that small.
 
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