[Coues22]

Hello All. I wanted to pose a question to the optics experts, or anyone else for that matter. First a little background. I own a pair of Ultravid 10x50 that is almost exclusively used on a tripod for long distance wildlife viewing. After about 4 days of looking at accumulated dust I decided to clean the objectives. Both lenses are now very clean except for a small (1mm) blemish on the right objective (barely noticeable). I don't think it is a scratch but who knows. Do small blemishes as noted impair image quality? The reason I ask is that I have a friend that uses 10x50 SLC and if you looked at his front objectives you would be horrified. When you look through his binoculars they seem as clear as a brand new pair. I normally would not worry about such things and I wonder if most of these theoretical image issues we have with binoculars are even perceptable to human vision. Just wanted a few opinions on the subject. Great forum.
Darin

[FrankD]

...... don't think it is a scratch but who knows. Do small blemishes as noted impair image quality?

I am not an expert as some of the folks that frequent this forum are but I can relate a bit of info that I picked up while frequenting here over the last two years. Dust, marks, etc... on the objectives have much less of an impact on image quality than the same issues on the eyepieces. Someone might be able to clarify why this occurs as I cannot.

[Otto McDiesel]

Frank D is correct. Dirt on the objectives is not visible, dirt/scratches on the oculars is immediately visible. As far as cleaning those Ultravids: that spot may go away with the help of a moist tissue or optics tissue ($3/box at your wallystore, Zeiss brand, at the eyeglass department). as far as cleaning, there is a useful thread here somewhere.

[matt green]

A blower brush from a photography store is always a handy thing to have.

It saves you pushing dust and dirt around on the surface of the lense with a cloth.

Matt

[Alexis Powell]

The only viewing problems that can arise from dirt on the objectives are that it reduces brightness (by blocking light; rarely a significant factor) and that it reduces contrast when lit up and scattering light as when the objective has direct sunlight shining on it (can be a problem at times). I only clean my scope objective with more than a blower bulb about once a year. Getting grease or salt spray on the objective DOES reduce contrast and clarity significantly, so it must be removed more regularly than dust/dirt.
--AP

[scampo]

Originally Posted by Coues22

Hello All. I wanted to pose a question to the optics experts, or anyone else for that matter. First a little background. I own a pair of Ultravid 10x50 that is almost exclusively used on a tripod for long distance wildlife viewing. After about 4 days of looking at accumulated dust I decided to clean the objectives. Both lenses are now very clean except for a small (1mm) blemish on the right objective (barely noticeable). I don't think it is a scratch but who knows. Do small blemishes as noted impair image quality? The reason I ask is that I have a friend that uses 10x50 SLC and if you looked at his front objectives you would be horrified. When you look through his binoculars they seem as clear as a brand new pair. I normally would not worry about such things and I wonder if most of these theoretical image issues we have with binoculars are even perceptable to human vision. Just wanted a few opinions on the subject. Great forum.
Darin

Getting rid of that last little speck can sometimes be difficult. As others have said - it won't impair the view at all. Make sure it's on the outside, though - if it's on the inside it can be cleaned under warranty.

Zeiss make an excellent cleaning kit with a special solvent included that really does seem to clean everything. If you cannot get hold of this, have you tried to use a cotton earbud with pure methanol or isopropanol? That usually works.

[Coues22]

Thanks for the replies. As far as trying to clean the blemish, I think I will wait until my binos need another cleaning in about 6-12 months. To be honest, the blemish is nothing to be overly concerned about. I brought up the topic because I think people get carried away with keeping their binos lenses "sterile." I know guys who use their binoculars and spotting scopes in the harshest conditions imaginable and due to this they need almost daily cleaning. I have looked through these samples and can see no image loss. I have learned through many years not too get too concerned over the small stuff. Use your equipment but don't abuse it. All the major brands will continue to function at a very high level.
Darin

[Pileatus]

Originally Posted by Coues22

Hello All. I wanted to pose a question to the optics experts, or anyone else for that matter. First a little background. I own a pair of Ultravid 10x50 that is almost exclusively used on a tripod for long distance wildlife viewing. After about 4 days of looking at accumulated dust I decided to clean the objectives. Both lenses are now very clean except for a small (1mm) blemish on the right objective (barely noticeable). I don't think it is a scratch but who knows. Do small blemishes as noted impair image quality? The reason I ask is that I have a friend that uses 10x50 SLC and if you looked at his front objectives you would be horrified. When you look through his binoculars they seem as clear as a brand new pair. I normally would not worry about such things and I wonder if most of these theoretical image issues we have with binoculars are even perceptable to human vision. Just wanted a few opinions on the subject. Great forum.
Darin

I clean my lenses in the field and at home. I probably clean eyepieces once a week…I hate distractions and a spot of dried spittle on an eyepiece is a major distraction. Objectives don't seem to get dirty as fast as eyepieces, but when there's a smudge of any sort near the center of an objective I remove it post haste. The proper technique will enable you to clean your lenses daily without causing any harm.
John

[Sancho]

Just should it ever become necessary, the lens elements on high-end optics can actually be replaced by the manufacturers. This comes as no surprise to the experts, but it left me gobsmacked, and pleasantly so.... Swarovski changed the eyepiece lens on my scope eyepiece after I foolishly dropped and scratched it, leaving a little notch way off-centre that didn´t really affect the target, but annoyed the hell out of me (as it reminded me of my foolishness). They charged me practically nothing for the service (probably felt sorry for me, the way one does for a clown...). Hope it won´t be necessary in the case of your bins, but it´s worth bearing in mind, and very comforting; even a bad scratch is not the end of your optics.