Shooting in Dx mode

[Griffym]

This is one of those topics.Depth of field calculators make different assumptions. I do have the app for that calculator.
The following article may be of interest:

Depth of Field Myths: The Biggest Misconceptions

photographylife.com

It is possible to find articles which claim different things too. I think it depends who you believe.

 

[Griffym]

Check out this dof calculator. Keep all the same except compare a full frame like a d850 to a crop like a d500. I think the calculator assumes the size of the images will be equal.

Depth of Field (DoF) calculator | PhotoPills

This Depth of Field (DoF) calculator will help you get the creative control on the design of your photos. Decide the zone of sharpness you need to tell the story you want and get your message across.

www.photopills.com

The assumptions in the app (Yes I have it) are probably why we think differently on this. See the article on depth of field myths on my post.

 

[bleirer]

This is one of those topics.Depth of field calculators make different assumptions. I do have the app for that calculator.
The following article may be of interest:

Depth of Field Myths: The Biggest Misconceptions

photographylife.com

It is possible to find articles which claim different things too. I think it depends who you believe.

Good article, a quote from it: indeed, if you crop a photo and display the final images at the same print size, it’s even arguable that you will see a shallower depth of field in the cropped image, since any out-of-focus regions would be magnified;

 

[bleirer]

This is one of those topics.Depth of field calculators make different assumptions. I do have the app for that calculator.
The following article may be of interest:

Depth of Field Myths: The Biggest Misconceptions

photographylife.com

It is possible to find articles which claim different things too. I think it depends who you believe.

A quote from another PL article: at the same distance from your subject, at the same physical focal length and aperture setting, a camera with a smaller sensor will have shallower depth of field than the one with a larger sensor. The images will have the same perspective, but different fields of view (framing)

Sensor Size, Perspective and Depth of Field

photographylife.com

 

[bleirer]

I think dof comes down to the concept of circle of confusion - the largest blur that still looks like a sharp point. I think this is not a single entity, but varies with the visual acuity of the viewer as well as the viewing distance and related image size. So if I viewed an 8x10 image at arms length there would be a certain c of c. If I cropped to 4x5 but kept viewing it at arms length the c of c would not change, but if I looked at it from a closer distance or if I resized the cropped area back to 8x10 then the c of c would change resulting in less dof.

My main point is that there is a cost to cropping, no free lunch. For example we can't take a close up from farther away where the dof is better and think we can crop closer but keep the better dof. We lose the dof advantage when cropping.

 

[Griffym]

It is difficult to be correct about DOF unless all the factors are fully explained.
As I understand it ; If you compare a crop sensor image and a full frame image where the subject is the same size in the picture because the photograph had been taken from different places, then DOF will be different. If the camera does not move but the user presses a button to switch to DX mode instead of FX, then the closest acceptable sharpness point will not change etc.
DOF raises lots of challenges and delights. For example:
I was photographing a tiny migratory bird on a beach with a 500 F4 on a D500 crop sensor body. As the bird moved close to my minimum focus distance, the DOF got very very thin. When I bought my Z 180-600 lens, a key part of that decision was looking on the minimum focus distance at 600.

 

[bleirer]

It is difficult to be correct about DOF unless all the factors are fully explained.
As I understand it ; If you compare a crop sensor image and a full frame image where the subject is the same size in the picture because the photograph had been taken from different places, then DOF will be different. If the camera does not move but the user presses a button to switch to DX mode instead of FX, then the closest acceptable sharpness point will not change etc.
DOF raises lots of challenges and delights. For example:
I was photographing a tiny migratory bird on a beach with a 500 F4 on a D500 crop sensor body. As the bird moved close to my minimum focus distance, the DOF got very very thin. When I bought my Z 180-600 lens, a key part of that decision was looking on the minimum focus distance at 600.

Check out this advanced dof calculator, the way the circle of confusion changes and as a result the dof changes as you change one variable at a time. For example viewing distance or image size or crop vs. Full frame or visual acuity. Point being that c of c is variable and if we crop or use dx mode or use a crop camera but choose to view the crop at the same size image as the full frame it affects the dof.

https://www.photopills.com/calculators/dof-advanced#page

 

[Griffym]

Thanks for the link. The discussion about DOF and sensor size could go on indefinitely. There are multiple ways to look at it because there are multiple ways to change between FX and DX and that is why it is called the circle of confusion.