Monarch X 8.5x45- how is the depth of field? (1 Viewer)

Hi,

Monarch X 8.5x45- how is the depth of field?

That's what I'm wondering.

Thanks

Martin,

Great question about the Monarch X. I own this binocular and am a huge fan of this field-ready optic. Depth of Field/Focus is a non-quantitative spec so it is hard to comment with specifics. Nevertheless, I find the depth of field to be somewhere between a Monarch and a Nikon EDG. To me this means it is more than sufficient. Nikon in the past has always been known for shallow depth of field which has allowed for some of the sharpest (if not THE sharpest) images on the market. This is why people rave over the Premier SEs.

I find depth of field a bit odd because it really can differ from one set of eyes to another. When I focus on a subject and then immediately look past (while keeping the focus knob still) it takes a millisecond for my eyes to adjust, but then the scenery/subject farther back comes into perfect focus. How far back you might ask? That is once again hard to estimate, but I can say that the increased DOF is noticeable with my 8.5x45 Monarch X. Did all of that make sense?

Best,
Mike Freiberg
Nikon Birding Market Specialist

I think most people here now agree that real depth of field varies only with magnification. So these should have a slightly smaller DoF than an 8x bin but more than a 10x bin.

But what most people describe as depth of field seems to be an interesting mix of focusing speed, field curvature, their own accommodation (which varies with age) and perhaps other phenomena.

A search will find more details.

Thanks Mike and Kevin.

I know that depth of field is a factor of magnification but it does seem to vary between bins of the same mag. I say "seem" very deliberately because of the other factors of focus speed, etc.

Depth of field is something of an illusion or an impression.

I guess the only way to really know, is to try them out. I'll try to track some down.

Kevin Purcell said:

I think most people here now agree that real depth of field varies only with magnification. So these should have a slightly smaller DoF than an 8x bin but more than a 10x bin.

But what most people describe as depth of field seems to be an interesting mix of focusing speed, field curvature, their own accommodation (which varies with age) and perhaps other phenomena.

Click to expand...

Thank you, Kevin. I had missed the conclusion that the issue had been put to rest -- that the laws of optics have indeed not changed. *whew!* The factors you cite make perfect sense of the apparent differences among individual binoculars of the same magnification.
Howard

I've yet to see someone convince me that the true DoF depends on anything other than magnification (and a lot has been written about DoF here and elsewhere).

The problem is perceived "depthoffield" isn't the same as technical definition of depth of field. There are lots of ergonomic and perceptual things going on which vary a lot with the individual as well as the bin design.

Kevin Purcell said:

I've yet to see someone convince me that the true DoF depends on anything other than magnification ...

Click to expand...

I would also add target distance to the equation, with DoF being deepest near infinity focus and becoming shallowest at close focus. Bino specs are usually computed at infinity, so that is where any comparisons should be made.

RJM said:

I would also add target distance to the equation, with DoF being deepest near infinity focus and becoming shallowest at close focus.

Click to expand...

Right, and those of us who've used 35mm lenses with DOF scales on them know this optical principle very well. Our eyes work the same way.

So yes, there is the perceived (per individual binocular design) vs. "real."

Thanks. I can relax now.

RJM said:

I would also add target distance to the equation, with DoF being deepest near infinity focus and becoming shallowest at close focus. Bino specs are usually computed at infinity, so that is where any comparisons should be made.

Click to expand...

That is a given ... I was thinking in terms of DoF normalized to the target distance which is a constant for a given magnification (which might also change on focusing too).

It's a problem of being trained as a physicist so every parameter can be scaled from 0 to 1.0 if you choose the right constants