Maven B1.2 10x42 depth of field (1 Viewer)

[Harber8]

I have been observing with the B1.2 10x42's for a few weeks now. The more I look through them, the more I like them. There's no one thing that completely stands out, they just work. Pretty much good everything. I had an older SLC 10X42 for a while, and optically I would say it was a just a bit more perfect overall, but not much. Same with a new Habitch 10X42 binocular, but those were unreal sharp and clear. But overall, I'm more happy looking through the Mavens- the large, sharp fov, good balanced colors and very good sharpness and brightness all work together very well. What I wanted to perhaps get some opinions on was how different are some 10x42's at this price point as far as depth of field goes? The Mavens have a very nice focuser, but it does seem that you have to fine-tune quite a bit as you move around to different objects. Its not bad, but when compared to some other binoculars I have used, maybe not quite as good a depth of field? I'm not sure. I've read in several places the Conquest 10x42 glasses might be a bit shallow as far as that goes, but they are very highly regarded. Is there a real difference there between different models and brands, or is depth of field simply determined by magnification? Or focal length? From what I have read so far, any 10x42 roof prism binocular should have pretty much the same depth of field, yet some individuals keep reporting that this or that model is not as good in that respect. I'm not quite understanding how that could be the case.

 

[Upland]

All binos of the same configuration has the same dof. However just as binos have differing amount of fov that is In Focus the same applies to dof. I’ve had dozens of binos and noticed this with certainty. Be prepared for the experts here to tell you there is absolutely no difference in dof

 

[Harber8]

All binos of the same configuration has the same dof. However just as binos have differing amount of fov that is In Focus the same applies to dof. I’ve had dozens of binos and noticed this with certainty. Be prepared for the experts here to tell you there is absolutely no difference in dof

Thank you for clarifying that. I didn't know if there could be different results in depth of field based on some way of designing a particular model of 10x42's. I guess with a bit more magnification, that's an unavoidable result.

 

[Upland]

Lots of folks here have disagreed with me on that but no one has been able to explain why. They are all stuck on the fact that all binos of the same configuration have the same dof. No arguement from me on that part.

 

[BKoh]

Depth of field (DOF) was discussed in depth (pun intended) on Cloudy Nights some years ago. After experiments, some experienced observers agreed with theoretical calculations that DOF depends only on magnification.

As to why the area that is in focus appears different in different binos of the same power, field curvature could be one answer. Depending on the scene in question, field curvature could increase or decrease the area in focus.

Suppose the bird is nearby on the top of a large bush, and there is only sky behind and above the bird. With the bird centred, parts of the bush will be nearer to the observer, and the sky is far away. In such a case a strongly curved field would result in both the bird and the bush being in focus. A flat field binocular may have only the bird and the part of the bush next to it in focus.

On the other hand, suppose the observer is looking at a group of birds eg wading shorebirds or birds on a fence, and they form a line roughly perpendicular to the observer ie they are equidistant. When the observer focuses at the birds in the centre of the group, birds at the edge of the field of view will also be in focus in the flat field binocular, but may be out of focus in the normal binocular.

Both binoculars have the same DOF, but the DOF is on a plane for the flat field bino, and on a curved surface for the normal binocular. When the objects happen to lie along the relevant plane/surface, they are all in focus at the same time. So sometimes the flat field bino is better, sometimes the normal bino is better. The only exception is astronomy, where flat field is always better since all objects are effectively at infinity.

 

[Harber8]

Depth of field (DOF) was discussed in depth (pun intended) on Cloudy Nights some years ago. After experiments, some experienced observers agreed with theoretical calculations that DOF depends only on magnification.

As to why the area that is in focus appears different in different binos of the same power, field curvature could be one answer. Depending on the scene in question, field curvature could increase or decrease the area in focus.

Suppose the bird is nearby on the top of a large bush, and there is only sky behind and above the bird. With the bird centred, parts of the bush will be nearer to the observer, and the sky is far away. In such a case a strongly curved field would result in both the bird and the bush being in focus. A flat field binocular may have only the bird and the part of the bush next to it in focus.

On the other hand, suppose the observer is looking at a group of birds eg wading shorebirds or birds on a fence, and they form a line roughly perpendicular to the observer ie they are equidistant. When the observer focuses at the birds in the centre of the group, birds at the edge of the field of view will also be in focus in the flat field binocular, but may be out of focus in the normal binocular.

Both binoculars have the same DOF, but the DOF is on a plane for the flat field bino, and on a curved surface for the normal binocular. When the objects happen to lie along the relevant plane/surface, they are all in focus at the same time. So sometimes the flat field bino is better, sometimes the normal bino is better. The only exception is astronomy, where flat field is always better since all objects are effectively at infinity.

That makes sense- thanks for that information. I looked at that conversation on dof in Cloudy Nights. A bit too much math for me! I enjoy what both the binoculars I have now do well, and hopefully I will have enough sense to keep both. The B1.2's are brighter, clearer and just a bit sharper, but the little E11's are plenty of all that as well, but with breathtaking 3D effect, and huge dof. The image can be incredibly "real" at times, especially with several birds at a feeder. Both wonderful binoculars.

 

[Swedpat]

Justified question by Harber8. I wondered about this myself, because I know DOF is related to the magnification and I read some have claimed that two binoculars of same configuration still have different DOF.

 

[Binocollector]

Short version: Magnification and aperture (or the resulting exit pupil) determine DoF.
Long version: The binocular forms an optical system with the human eye so pupil dilation has to be taken into account. So when using a 7x35 or a 7x50 in the daytime and your pupils are only 2.5 mm -- there will be no difference in DoF since the entrance pupil of the eye doesn't reach the size of the exit pupil of the binoculars. Since the human pupil will only open up more in dusk, dawn or at night, for all intents and purposes there will be no difference between them and only magnification is the factor.
But, let's say you are using a 7x21 and compare it to a 7x35 when your pupils are dilated to 5mm (the exit pupil of the 7x35) then the 7x21 should have slightly more DoF than the 7x35. Similar to photography where DoF is determined by the diaphragm of the lense.
So I'd say, yes, different people can perceive the DoF of binos with the same specifications differently not just because of accomodation but also because of their pupil dilation. And there can even be very small differences when the same person is using the same bino under different lighting conditions. But the problem with this is probably that the darker, the harder it becomes to even notice any differences in DoF. But in theory an 8x56 should have a larger DoF in the day than during dusk or dawn or at night. The question is whether that is perceptible.
Also -- the FoV plays a role here, too, as a larger FoV will increase the amount of light hitting your eye and the pupil will contract, so slightly more DoF will be the result compared to a bino with similar specs but smaller FoV. My guess is however, that those effects are so small, you will probably not even notice it. There are mathematical formulas for all that but my math is not nearly good enough.
There are still a few other factors like the general optical quality of the bino -- sharpness for example. Paradoxically a bino with a more "fuzzy" image can be perceived as having better DoF as everything in the image is not really sharp. So differences between sharpness in different distances might be perceived as being smaller than they actually are because there is no really sharp area of the whole FoV that one can use to compare to.

So long story short: only when the entrance pupil of the eye is smaller than the exit pupil of the bino is there an effect on DoF insofar that binos with the same specs might have a slightly different DoF. In any other case (human pupil is the same or larger than exit pupil of bino) binos with the same specs (magnification and aperture) have the same DoF.

Unfortunately I only found a really good explanation of all of this on a German astro forum. I'll post the link anway.

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