10x20is binoculars won't converge at close range

[ericgaren]

I just bought a pair of 10x20is binoculars.  The two images converge fine when viewing objects at a distance, but when I view objects 7-10' away, I need to twist the objective lenses all the way to the center to get the image to even come close to converging.  Is this normal, or did I get a bad pair?

[Denis314]

Do you really twist the OBJECTIVE lenses? If yes, No idea. If no, is your interpupilary distance too small for the binos? To check have someone with a larger interpupilary distance see if they have the same problem. If they do not have the problem, then you may need different binos.

[Tintype_18]

Never needed to use binos for short distances. Would the 10X have anything to do with your concern? 20 seems to be small for a 10X binos. Can't help otherwise.

[Stephen]

Maybe it wasn't quite far enough? The the specs from the MANUAL say the closest focusing distance is approximately 2m (6 1/2 ft).

Stephen_0-1785760286819.png

[SignifDigits]

Make/model of binos?  Are you wearing glasses?  Do they have adjustable eye cups for varying eye relief?  If you're talking about getting concentric circles at a distance then that changing when you do close focus it could be normal for your brand and quality of optics, and you might be expecting to have gotten a better result than the product it capable of.  In other words it could be a "feature" rather than a "problem".  Here is an AI answer for you to explore:

>>>>>>>>>>>>>>>>>>>>>>>>

When the single combined circle of view breaks apart into two separate concentric circles or images at close range, your eyes are struggling to merge the offset angles of the binocular barrels. This usually points to an interpupillary distance (IPD) mismatch, a close-focus limit violation, or physical miscollimation.

Causes and Fixes for Image Separation:

• IPD Mismatch: The distance between your eyes does not match the hinge setting of the barrels. Adjust the hinge until both fields of view fuse into one clean circle.

• Close-Focus Limit: You are standing closer to the subject than the binoculars are physically capable of focusing (often 10 to 25 feet). Step back from the object. 

• Miscollimation (Alignment): The internal prisms or lenses are misaligned, which strains your eyes and splits the image when shifting focus or viewing angles.

• Eye Relief / Eyecup Position: Your eyes are positioned too close or too far from the eyepieces, cutting off the edges of the exit pupil. Twist the eyecups up or down.