Samsung 45mm vs Rokinon 85mm?

causey wrote:

Those are contradictory statements.

The truth is this:

Shoot a subject with a 50mm lens at f 5.6

Switch to a 100mm Lens and 5.6

Move back so the subject fills the frame to match the 50mm

The DOF will be the same. Only the distance has changed. The DOF looks different on longer lenses because the magnification crops out more of the image so you can't see all of the DOF.

https://luminous-landscape.com/dof2/

You changed two parameters, not one: focal length and focal distance. You say, "Shoot with a 50mm at 5.6, then switch to 100mm/ 5.6, move back; only the distance has changed,"--but if you want to prove that focal length doesn't affect DoF you should be able to say that only the focal length changed. However, you changed the focal distance in addition to changing the focal length...

More generally, if you want to see how a function of three factors varies when one factor varies, you must keep the other two constant.

Thus, if you want to see how DoF varies when aperture varies, you keep focal distance and focal length constant. Similarly, if you want to see how DoF varies when focal length changes, you need to keep aperture and focal distance constant.

It seems you're keen on contradicting me, which is fine, but if you are fond of arguing it doesn't make sense for me to try to explain anything. So, I guess, this is my last reply on this topic. I think you have enough elements to understand what I'm saying.

Now that you've successfully put an end to this argument, is there any chance you could respond to my inquiry about using the 85mm Rokinon without focus peaking?