Depth of Field (Bokeh) lesson

[Ysarex]

^^^^
Now I'm gonna have to carry around a Fuji lens in my pocket for reference.

Silly. They print paper tables for you.

Joe

Tables that once I gain enough experience to be able to use become more or less obsolete because I already have enough experience to know pretty much what I need without looking it up.

Handy. But hey, maybe in the future we can skip all this garbage and just post a link to the tables instead. BAM. Problem solved.

I did that back on page 2 -- problem solved.

Joe

 

[astroNikon]

^^^^
Now I'm gonna have to carry around a Fuji lens in my pocket for reference.

Silly. They print paper tables for you.

Joe

 

[Ysarex]

^^^^
Now I'm gonna have to carry around a Fuji lens in my pocket for reference.

Silly. They print paper tables for you.

Joe

From that photo looks like you need them too. You can download them free off the Internet.

 

[Tim Tucker]

Practical application time, this is what I found with APS-C systems.

As you approach the hyper-focal distance to infinity the dof may increase more but once you hit it then the increase in dof slows. The larger format doesn't until it too hits the hyper-focal distance to infinity. When it does and the subject is within the dof range then there is no advantage in dof in the smaller format.
The smaller format however will aways be able to take the shot at a faster shutter speed. However opening the aperture up will not result in reducing the dof much until you get back below the hyper-focal distance to infinity which the larger format will hit first. Therefore the larger format will always have a greater range of dof control for the f-stops available.
This is the problem I found with APS-C and landscapes, not in getting enough dof, but reducing it as in good light with distant vistas because one past the hyper-focal distance to infinity f-stop does not behave in such a linear manner. I really found that it became more like a point-and-shoot with the kit lens.
At certain practical limits the relationships that govern things like dof change and are no longer linear or proportional either within the same camera or between formats. These have a very real practical application and can define the strengths of the various formats and their weaknesses. Trying to invent and force all formats across all ranges to conform to one rule because it's easier to understand can mask why certain formats are more suited to certain styles of photography than others.

 

[petrochemist]

As you approach the hyper-focal distance ....

The hyper focal distance of course varies with all the same parameters that DOF varies, other than object distance. Yet you seem to be taking it as a fixed distance.

 

[Ysarex]

As you approach the hyper-focal distance ....

The hyper focal distance of course varies with all the same parameters that DOF varies, other than object distance. Yet you seem to be taking it as a fixed distance.

I think what he's saying is that, with smaller format cameras, hyperfocal distance is too close to the camera to allow precise control over DOF -- it ramps up too quickly.

Joe

 

[chuasam]

DOF is a result of Focal Length, Aperature and Distance to Subject.
Sensor size does not matter. DOF for a 18mm f/1.8 is the same on a micro43 as it is on an 8x10
the view is just a lot larger on a 8x10

You can change bokeh. You can clip on shapes on the front element. Defocus control lenses can also change bokeh.
Bokeh also changes with your aperture.

 

[Ysarex]

DOF is a result of Focal Length, Aperature and Distance to Subject.
Sensor size does not matter. DOF for a 18mm f/1.8 is the same on a micro43 as it is on an 8x10
the view is just a lot larger on a 8x10

Incorrect.

Explanation can be found further back in the thread.

Joe

You can change bokeh. You can clip on shapes on the front element. Defocus control lenses can also change bokeh.
Bokeh also changes with your aperture.

 

[chuasam]

DOF is a result of Focal Length, Aperature and Distance to Subject.
Sensor size does not matter. DOF for a 18mm f/1.8 is the same on a micro43 as it is on an 8x10
the view is just a lot larger on a 8x10

Incorrect.

View attachment 131147

Explanation can be found further back in the thread.

Joe

You can change bokeh. You can clip on shapes on the front element. Defocus control lenses can also change bokeh.
Bokeh also changes with your aperture.

Weird...intuitively it should not change.
Just imagine a lens and the image.
Only thing that changes is the sensor size...why should the DOF change?

 

[pixmedic]

DOF is a result of Focal Length, Aperature and Distance to Subject.
Sensor size does not matter. DOF for a 18mm f/1.8 is the same on a micro43 as it is on an 8x10
the view is just a lot larger on a 8x10

Incorrect.

View attachment 131147

Explanation can be found further back in the thread.

Joe

You can change bokeh. You can clip on shapes on the front element. Defocus control lenses can also change bokeh.
Bokeh also changes with your aperture.

Weird...intuitively it should not change.
Just imagine a lens and the image.
Only thing that changes is the sensor size...why should the DOF change?

 

[snowbear]

Weird...intuitively it should not change.
Just imagine a lens and the image.
Only thing that changes is the sensor size...why should the DOF change?

It's that circle of confusion thing. It's like the speed of light from a moving object being exactly the same speed as light from a stationary object, to the same observer . . . science is jammin' interesting.

 

[chuasam]

Weird...intuitively it should not change.
Just imagine a lens and the image.
Only thing that changes is the sensor size...why should the DOF change?

It's that circle of confusion thing. It's like the speed of light from a moving object being exactly the same speed as light from a stationary object, to the same observer . . . science is jammin' interesting.

Did you know that light is both a Particle and a wave but not both at the same time.

 

[snowbear]

Yep.
I've always referred to physics classes as "Math, with toys."

 

[Ysarex]

DOF is a result of Focal Length, Aperature and Distance to Subject.
Sensor size does not matter. DOF for a 18mm f/1.8 is the same on a micro43 as it is on an 8x10
the view is just a lot larger on a 8x10

Incorrect.

View attachment 131147

Explanation can be found further back in the thread.

Joe

You can change bokeh. You can clip on shapes on the front element. Defocus control lenses can also change bokeh.
Bokeh also changes with your aperture.

Weird...intuitively it should not change.
Just imagine a lens and the image.
Only thing that changes is the sensor size...why should the DOF change?

Because DOF is not calculated at the sensor/film. This is a common misconception because if you think about it as a phenomenon that occurs when the image is formed on the film/sensor then, yes, logically you'd think the size of the film/sensor wouldn't matter, it's just focal length, aperture and focus distance. But DOF is defined on the final print and DOF comparisons need to be made comparing like-image prints. When you do that the sensor/film size plays a role. In all the DOF calculations the size used for the circle of confusion is predicated on the sensor/film size and so influences the calculation results.

Joe

 

[The_Traveler]

Déjà vu