[Robert Ellis]

If the depth of field is the same for a given configuration, and being a former photog I can believe that, there must be math to go with it? Is there a formula that one can use to determine the DOF at a given distance for a given aperture and magnification?

Further, if I do bite that DOF is related to configuration and nothing else, why is the 8x32 SE touted as having a huge DOF and the 8x32 LXL criticized for having a slightly narrow DOF? IS this perception that arises from the focus rate as resistence? I seem to remember a BVD article about the BL Elites, criticized for having a narrow DOF but in reality Mr. Ingraham found it was equal to the rest of the bunch and blamed the very rapid focus for the perception.

I also remember my camera lenses having markings for focus depth, which did get wider as one stopped down. There has to be a calculation somewhere for this optical phenomenon, but who is to say what is in focus and what is not?

Then again birders tend to proclaim larger apertures give a longer DOF which is opposite of a camera lense. Wha? IT seems we would have to know the f ratio of each binocular before we can make statements like that. Maybe the little LX is faster than the big LX, yielding a narrower DOF but not due to the size of the lense alone?

What we need more than the math would be a table of the focal lengths of all our binoculars, then we could quicly figure out which would have better DOF than others.

[Robert Ellis]

I've been reading up on it some more, it seems using the paerture to determine DOF is hollow, what one really needs to know to make a guess at performance in this aspect is the focal ratio of the binocular.

[Atomic Chicken]

Robert,

I don't know if what you are looking for is here or not, try this thread:

http://www.birdforum.net/showthread.php?t=41596&page=1

Best wishes,
Bawko

[Robert Ellis]

Good find, where the heck was I in September that I forgot about that thread already?

[Robert Ellis]

Geez, I even posted to that thread and forgot about it. Getting old is a drag.

I have found some photog sights that give some math, but all is for naught without focal length numbers available.

[Migaloo]

G'day,

Just a passing comment relating to DOF .... some first-time users state that a deep DOF gives a somewhat "2-dimensional" or "picture-like" impression.

[Robert Ellis]

Can we have this thread deleted? I must have hit my head this week to have completely forgotten about the earlier thread.

[Pileatus]

Originally Posted by Robert Ellis

If the depth of field is the same for a given configuration, and being a former photog I can believe that, there must be math to go with it? Is there a formula that one can use to determine the DOF at a given distance for a given aperture and magnification?

Further, if I do bite that DOF is related to configuration and nothing else, why is the 8x32 SE touted as having a huge DOF and the 8x32 LXL criticized for having a slightly narrow DOF? IS this perception that arises from the focus rate as resistence? I seem to remember a BVD article about the BL Elites, criticized for having a narrow DOF but in reality Mr. Ingraham found it was equal to the rest of the bunch and blamed the very rapid focus for the perception.

I also remember my camera lenses having markings for focus depth, which did get wider as one stopped down. There has to be a calculation somewhere for this optical phenomenon, but who is to say what is in focus and what is not?

Then again birders tend to proclaim larger apertures give a longer DOF which is opposite of a camera lense. Wha? IT seems we would have to know the f ratio of each binocular before we can make statements like that. Maybe the little LX is faster than the big LX, yielding a narrower DOF but not due to the size of the lense alone?

What we need more than the math would be a table of the focal lengths of all our binoculars, then we could quicly figure out which would have better DOF than others.

I believe the perception that the SE has superior DOF is the result of:

1. The SE's extremely clear and precise level of detail (i.e. extreme sharpness) coupled with a large, relaxing sweet spot.
2. Increased depth perception due to wider objective spacing.
3. Enhanced 3D (see number 2).
4. Minimal focusing requirement...the SE snaps into focus with little or no need for adjustment. Unknowingly, people who fine focus in/out a lot stress their eyes, negatively impacting eye function and overall image quality.

Combine all these factors and you have a sharpness zone that appears quite large. Many users will perceive and report this as exceptionally good DOF.

John