Most problems with binocular eyepieces are minor and easily fixable at home. If one or both of your binocular eyepieces is wobbly, dirty, or out of focus, you can repair it yourself.
Other more serious issues may require the help of an expert repairer or replacement of the lens or eyepiece.
How To Fix Wobbly Eyepieces?
One of the most common problems that arise when using binoculars is the eyepieces getting wobbly.
The entire focusing mechanism also gets wobbly and doesn’t work well. With time, the shakiness gets so bad that it feels like the eyepieces might fall off.
Luckily, this is an easy problem to fix. There’s a screw on the main/central focus that you need to tighten.
Locate a cap above the focusing thumbscrew. It’s between the two eyepieces.
Use a flathead screwdriver or anything with a thin edge to pry the cap off.
Once the cap is off, you should see the screw. Use a Philip’s head screwdriver to tighten this screw. Do not overtighten as that could strip the threading that holds the screw in place.
Check that the eyepieces and the focusing mechanism are no longer wobbly.
Put the cap back on. To make sure the cap is secure, put a tiny bit of glue on one spot then place the cap on top. This will ensure you can still take the cap off in the future if you need to tighten the screw again.
Here’s a video showing the repair process for wobbly binocular eyepieces.
How To Fix Blurry Binocular Eyepieces
If the view through your eyepieces appears blurry or if you are getting a double image, it’s probably because the binoculars are out of alignment.
This can happen over time as the binoculars get bumped around. It can also happen if you drop the binoculars or if you lend them to someone and they change the focus.
To get the eyepieces working right again, you’ll need to align the binoculars. It only takes a couple of minutes.
Go outside and pick an object about 15 metres away like a streetlight or a birdhouse.
Raise the binoculars to your eyes and close your right eye. Alternatively, just cover the right objective lens with your hand.
Look at the object through the left eyepiece and use the central focusing ring to bring the object into sharp focus.
Open both eyes and see if you can now see a clear image. If it’s still blurry, you need to focus the other side with the diopter ring.
Close your left eye or cover the left objective lens. Use the right diopter ring to bring the image on your right eyepiece into sharp focus.
Open both eyes. You should now have a sharp and clear image. Lock the diopter ring and only use the central ring to adjust focus.
If, after alignment, you still get blurriness or a double image, the binoculars may need to be collimated. You cannot do this yourself. Send the binoculars back to the manufacturer for repair.
How To Fix Cloudy or Foggy Binocular Eyepieces
If the eyepieces appear cloudy or foggy, it’s likely that the lenses inside are dirty. This can be from oil smudges, dust, or grit.
Resist the temptation to wipe away at the dirt with any piece of cloth or tissue. You can easily scratch the coatings on the lens.
Once you damage the coating, the lens is pretty much useless.
We highly recommend getting a lens cleaning kit like this one from CamKix. Most of these are made for camera lenses, but they work just as well on binocular lenses.
They typically consist of an air blower, a soft brush, microfiber cleaning cloths, and a cleaning solution.
Jack Bennett is the founder and editor of Stargazing in the UK. He lives in London and have started this blog about stargazing and amateur astronomy for beginners to keep track of his attempts to explore the Universe.