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Focus Your Binoculars by Adjusting the Diopter

Binocs won't help you unless you can see through them clearly. Adjusting the diopter the right way makes all the difference.

Even the best (read extravagantly expensive) binocular on the market will give you a fuzzy view of the world until you correctly set the diopter ring. This adjustment, typically found on the right eyepiece or center-focus knob, fine-tunes the binocular settings to compensate for any visual differences between your eyes. Set properly, a diopter will not only max out the performance of a high-end binocular but even boost the sharpness of budget glass. 

[A] Set the diopter ring to the center of the adjustment scale. This is most likely marked with a zero; on some models it might be indicated with a hash mark or some other symbol. Cover the right lens barrel with a lens cap or duct tape.

[B] Pick an object in the middle distance zone, about 50 yards away. Keeping both eyes open, move the focus ring until the image is at its sharpest. Although you are focusing only with the left eye, keep both eyes open and relaxed. Do not squint.

[C] Switch the lens cap or duct tape to the other lens barrel. Look at the same object, and turn the diopter ring (see inset) to bring the object into sharp focus. Make sure the focus knob doesn’t change. Keep both eyes open; do not squint.

[D] Remove the lens cap or duct tape and look through both lens barrels. The image should remain sharp. Make a note of the diopter-ring setting, or place a small dot of fingernail polish on the correct adjustment. If your visual acuity changes during the year, you may need to reset the diopter.

Comments (14)

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from rabbitpolice88 wrote 2 years 43 weeks ago

That is 100% correct! I have been doing what the article says for years now. Most folks think you just mess around with the big knob on top. what you are really doing when you adjust the one eye piece and the top knob is making a pair of magnifying glasses specifically for your eye sight. It like a perscription pair of glasses.

+2 Good Comment? | | Report
from alozzi wrote 2 years 43 weeks ago

im definatly gonna have to try that

+2 Good Comment? | | Report
from MNhunter23 wrote 2 years 42 weeks ago

great advice, tried it and worked great

+1 Good Comment? | | Report
from Brian W. Thair wrote 2 years 42 weeks ago

Don't ignore this method. Much more restful on the eyes if you're glassing all day. Binoc heads on microscopes are exactly the same.

+2 Good Comment? | | Report
from 2Poppa wrote 2 years 42 weeks ago

That is one reason to purchase new binoculars and read the directions ... and memorize them!

As Brian W. Thair posted, it's easy on the eyes!

+2 Good Comment? | | Report
from Keith Shively wrote 2 years 39 weeks ago

This is very helpful information!!

+1 Good Comment? | | Report
from Peter Planz wrote 2 years 34 weeks ago

Wow, that was simple and really works well. This does work for all kids as I have a "budget" pair and I'm impressed!!

+1 Good Comment? | | Report
from Jere Smith wrote 2 years 31 weeks ago

Very good information here!

+1 Good Comment? | | Report
from 270WSM wrote 2 years 28 weeks ago

GOOD INFORMATION. BEEN DOING THIS FOR YEARS. I WOULD BE VERY FRUSTATED WITH MY BINOS IF I DID NOT USE THIS METHOD.

+1 Good Comment? | | Report
from bgddy wrote 2 years 24 weeks ago

I cant believe this article is here,I was trying to figure this out just yesterday, I was trout fishing and was checking my rods from 70 yards away,(washing the car).very helpful, thanks

+1 Good Comment? | | Report
from HunterGreene wrote 2 years 3 weeks ago

Good tip.

0 Good Comment? | | Report
from gfr2395 wrote 1 year 25 weeks ago

Great article!

0 Good Comment? | | Report
from chrishinson1971 wrote 1 year 25 weeks ago

this was very informitive thanks for the help now i know what to do.

0 Good Comment? | | Report
from Woods Walker wrote 8 weeks 3 days ago

It never ceases to amaze me how many people do not know this basic adjustment - I have to explain it frequently when people look through some pricy bins and then complain that they do not focus for them! Great info - thanks for posting this!

Now for one more tip - how many people know that you can reverse the bins and, looking through the "front" lens, use them as a microscope? Especially useful for a quick scan of the fine print in the regulation book ;) Being a biologist, I find this feature to be almost as useful as using them for distance viewing.

0 Good Comment? | | Report

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from rabbitpolice88 wrote 2 years 43 weeks ago

That is 100% correct! I have been doing what the article says for years now. Most folks think you just mess around with the big knob on top. what you are really doing when you adjust the one eye piece and the top knob is making a pair of magnifying glasses specifically for your eye sight. It like a perscription pair of glasses.

+2 Good Comment? | | Report
from alozzi wrote 2 years 43 weeks ago

im definatly gonna have to try that

+2 Good Comment? | | Report
from Brian W. Thair wrote 2 years 42 weeks ago

Don't ignore this method. Much more restful on the eyes if you're glassing all day. Binoc heads on microscopes are exactly the same.

+2 Good Comment? | | Report
from 2Poppa wrote 2 years 42 weeks ago

That is one reason to purchase new binoculars and read the directions ... and memorize them!

As Brian W. Thair posted, it's easy on the eyes!

+2 Good Comment? | | Report
from MNhunter23 wrote 2 years 42 weeks ago

great advice, tried it and worked great

+1 Good Comment? | | Report
from Keith Shively wrote 2 years 39 weeks ago

This is very helpful information!!

+1 Good Comment? | | Report
from Peter Planz wrote 2 years 34 weeks ago

Wow, that was simple and really works well. This does work for all kids as I have a "budget" pair and I'm impressed!!

+1 Good Comment? | | Report
from Jere Smith wrote 2 years 31 weeks ago

Very good information here!

+1 Good Comment? | | Report
from 270WSM wrote 2 years 28 weeks ago

GOOD INFORMATION. BEEN DOING THIS FOR YEARS. I WOULD BE VERY FRUSTATED WITH MY BINOS IF I DID NOT USE THIS METHOD.

+1 Good Comment? | | Report
from bgddy wrote 2 years 24 weeks ago

I cant believe this article is here,I was trying to figure this out just yesterday, I was trout fishing and was checking my rods from 70 yards away,(washing the car).very helpful, thanks

+1 Good Comment? | | Report
from HunterGreene wrote 2 years 3 weeks ago

Good tip.

0 Good Comment? | | Report
from gfr2395 wrote 1 year 25 weeks ago

Great article!

0 Good Comment? | | Report
from chrishinson1971 wrote 1 year 25 weeks ago

this was very informitive thanks for the help now i know what to do.

0 Good Comment? | | Report
from Woods Walker wrote 8 weeks 3 days ago

It never ceases to amaze me how many people do not know this basic adjustment - I have to explain it frequently when people look through some pricy bins and then complain that they do not focus for them! Great info - thanks for posting this!

Now for one more tip - how many people know that you can reverse the bins and, looking through the "front" lens, use them as a microscope? Especially useful for a quick scan of the fine print in the regulation book ;) Being a biologist, I find this feature to be almost as useful as using them for distance viewing.

0 Good Comment? | | Report

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