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Is heat a problem, and cleaning optics?

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#1 Guest_**DONOTDELETE**_*

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Posted 14 January 2004 - 02:46 AM

It's been pretty quiet around here the last few days :sleepy:... So I though I would ask a couple of questions related to binos:

Firstly, is heat a bad thing when it comes to binoculars (not direct sunlight, but say in a car glovebox)?

Could this sort of heat expansion and contraction affect the optical alignment?


Secondly, I understand that cleaning multicoated optics (or any optics for that matter) is best kept to a minimum, but if it is necessary (a fingerprint smudge, etc) what is the safest/best method to use?

I currently use a gentle rub with a lens microfiber cloth. I have also have heard that lens pens are great, but they apparently have a carbon powder paste or something on the suction cap that aids cleaning - is this a good thing and does this affect the multicoating?

P.S. For the many people that have tirelessly helped me along in my journey towards selecting a bino for astronomy, I have ordered a pair of Pentax DCF SP 10x43's that should arrive tomorrow :grin: I hope... I'll post a review (hopefully to a sufficiently high standard given the company on this forum) as soon as I have had a chance to "play" :jump:

#2 Tom L

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Posted 14 January 2004 - 11:36 AM

And what made you finally decide on those binoculars??? Congrats, Frilby!

#3 KennyJ


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Posted 14 January 2004 - 01:24 PM

Hi Frilby,

First of all may I say how genuinely pleased I am that you have finally taken the brave decision to order your first ever "real" binocular.

I will be surprised , very surprised in fact , if you are not very pleased with them once they arrive.

Given your expressed preference for the superior "edge" of this Pentax model as opposed to wider field of the Swift
I think you have made the correct choice ( as I was TRYING to steer you towards by my referenc to Barry Simon's comments BEFORE you realised the Swift eyecups would be problematic.

I still hold a SLIGHT reservation about your ability to hold a 10x image perfectly steady when aimed at the stars --but you'll soon find out if I was right or not -- and in any case so long as you like every thing else about the image you can always go tripod at times ( which I would recommend even for 7x binos for certain types of viewing)

From the moment you first get these binos Frilb --take special care of them -- natural to do with anything that is brand new -- but often standards tnd to slip once a few grease or scuff marks start to appear on them.

If you continue to look after them like a new born baby --you won't even have the grease or scuff marks to deal with.

Being a hands-on engineer , my fingers and hands get dirty often , so I always keep a pack of disposable vinyl gloves in my vehicle and put them on before handling my Zeiss.

As regards your questions , my advice is NEVER leave the binos in a hot place --excessive heat can ruin both coatings and the glue that holds prisms together.

Leaving good quality binos in an unattended vehicle at all is risky business.

Keep any dust covers ON ( if they'll stay on ! )when no using the binos -- this will help minimise dust on the lenses -- and keep them in the case when not using them.

BEFORE using ANY kind of CLEANING device , het yourself a couple of cans of compressed air aerosols -- and give both the objective lenses and the oculars a little blast as often as you can after using them . This should remove any tiny particles of dust , sand or salt that can easily scratch the lens surfaces.

ALWAYS blow them with the air BEFORE any other kind of cleaning operations , which are better kept to an absolute minimum . Binocular lenses are generally quite forgiving and a bit of a tiny smudge is actually very unlikely to affect the image quality.

These lens pens come highly recommended , but I've never actually used one myself.

If and when I feel I MUST clean the lenses , I've never had any trouble using lens tissues with a VERY soft -handed circular motion , so as not to damage the coatings.

If you are married or have a partner you may be familiar with the motions necessary.


Many people recommend breathing on the lenses after this gentle cleaning operation , to add a touch of moisture , which should then also be very gently wiped away.

Probably not a great idea if you're smoking a cigar at the time , which I sincerely hope you never would be.

Enjoy your binoculars Frilby.

I look forward to your first attempt at a semi -serious review !

If you feel pressurised trying to write a review -- do what I do -- fill it out with waffle and keep it light -hearted !

and a special wish for CLEAR SKIES !


#4 Guest_**DONOTDELETE**_*

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Posted 14 January 2004 - 01:34 PM

Regarding heat, I have found that prolonged exposure to direct sunlight can rot the rubber on some binoculars, esp. the eye tubes.

As for cleaning, I agree that the less the better. I would not use a microfibre cloth or a lens pen. I suspect both will cause micro-scratches in the coatings. In fact I would suggest that both items are rubbish and to be avoided at all costs.

IMO a better way to clean optical surfaces is as follows:

1)Clean the larger bits of crud from the surface using a a hand blower. If the optics are very dirty e.g. mud encrusted, then - assuming waterproof bins - just hold them under a running tap until the more obvious dirt has gone. Shake dry. (Don't use a cloth to dry the optics. It'll scratch them.)

2) Apply a couple of drops of lens cleaning fluid the to an optical surface. Isopropyl alcohol is good. Eyeglass cleaning fluid from opticians is bad as there are too many impurities. Obtain some cottol wool that you know is free from dirt and has been stored in a sealed bag. Tear off a small piece and using one of the freshly exposed surfaces that you have not toucheded GENTLY wipe the surface a few times. Don't apply pressure. Don't polish. The aim is to remove dirt. Throw away the piece of cotton wool. Pull off another piece of cotton wool and again using a clean surface give a few more light wipes. The surface should be relatively free of grit and hard bits of dirt. If not, repeat. All that's left should be grease and very fine dirt.
3) Repeat 2 but this time apply a little more pressure when wiping, but don't press hard, and don't polish.

That's it. It's a lot easier than it sounds, and takes a few minutes per surface. It's easy to make up a little cleaning kit to take with you in the field.

The essential thing to bear in mind when cleaning is that any grit on the surface of the cleaning pad or the optical surface will cause scratches and so it must first be removed. That's why I think microfibre cloths and lens pens are worse than useless.

#5 KennyJ


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Posted 14 January 2004 - 04:07 PM

Whilst not being an expert on glass coatings of any description I do wonder sometimes about what differences there must be between the actual glass and coatings applied to eye glasses and those applied to binoculars.

I only started wearing glasses last September.
I have two pairs --one ( the distance ones I wear all day for driving etc ) having coated optics to reduce glare that cost me an additional £55 ( raising the overall cost to way above what most people seem to be paying for 4 or 5 pairs of 15 x 70 Chinese binoculars ! )

Coming from a family blessed with good natural eyesight , (apart from one daughter who wears contact lenses) I had no previous experience of or with glasses ,so at the time I sought advice about cleaning mine from a work colleague who has been wearing them for 40 years.

His advice was " forget what everybody else might TELL you or try to SELL you -- just do THIS " - - ->

Every evening when you get home ( usually from very dusty and greasy environments), blow them over with aeroduster( compressed air in a small can that we use every day at work) put on some vinyl gloves ,(which we wear most of the time for work), then squeeze a tiny amount of regular washing -up liquid onto both sides of both lenses , and adding a small amount of tepid water ,VERY gently rub in a circular motion the soapy , liquid -filled lenses between gloved thumb and forefinger for about 30 seconds , then rinse off completely with cold water and leave to dry naturally.

If necessary , dab off any excess water with clean soft kitchen roll.

Thus far , I must confess that the glasses are as clear , brlliant and smooth as new -- not the slightest sign of any scratches ! -- the difference in clarity between " before and after" this daily ritual really has to be seen to be believed !

Now according to the wise men of optics -- if anyone tried doing this kind of thing to ANY kind of telescope or binocular lens -- even if the unit WAS waterproof , then the lenses would have been ruined beyond repair months ago !

This may well be true -- but if it is -- WHY ?

What is SO different about the two examples given ?

Regards -- Kenny.

#6 EdZ


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Posted 14 January 2004 - 04:53 PM

My regular use cleaning solution for all my arstronomy optics is a mixture of about 1oz. water, 2oz. 92% alcohol and several drops of dishwashing cleaner without additives. The cleaner helps break the surface tension. I apply it sparingly with a Qtip and clean off with dry Qtips or cotton balls. Sometimes very gently brushing off to get off any residual cotton fibers. I clean whenever I need too. Springtime May-June is the worst. One night out with the optics and the next morning they can be observed to be coated with pollen.


#7 Guest_**DONOTDELETE**_*

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Posted 14 January 2004 - 08:19 PM

Thanks everyone...

I certainly won't be leaving my binos intentionally in the heat, but was just interested in what the possible effects may be if this occurred.

I handle all my "optics" with great care (I have an SLR camera kit that travels everywhere with me that is over 12 years old and has taken an estimated 20,000+ pictures and it is still in immaculate condition).

I am a firm believer in using a tool for its intended purpose... There is no point wrapping something up in cotton wool for fear of harming it, if as a result you never get the pleasure from it that was intended through normal use. However, I strongly temper this with common sense, and care to ensure that my investment lasts me as long as it can... :waytogo:

The same will go for my new binos... Any suggestions on a name for them?

That's an interesting idea actually... has anyone ever given their binoculars a name? And no, I'm not crazy :crazy:, although I'm sure Kenny, Brock, Tom and a few others may beg to differ on this point :)

As far as cleaning optics is concerned, it sounds like pure alchohol is a safe option with multicoatings, with the abvious caution with rubbing the lense surface... I was never sure about using alchohol (or any chemical, cleaner, etc) for fear of damaging the coatings which is why I stuck with a simple cloth (but it sounds like this may not be the best idea with regard to micro-scratches).

The learning process continues... :thinking:

#8 Tom L

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Posted 14 January 2004 - 08:23 PM

Frilby, on the top of the reflectors forum there is a thread about cleaning mirrors. There is a link there for a cleaning solution that you should look into.

Every time I have held a pair of roof binocs in my hands I liked them very much! Enjoy your new binoculars. I've never thought of naming them...would they be considered twins??? :D

#9 edcannon


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Posted 14 January 2004 - 08:49 PM

The instructions for my Orion Ultraviews specifically say not to use ordinary tissue or household cleaning fluids (probably including "Windex"?). They don't name any specific brands to use. They say, interestingly, that leaving dust on them can promote mold growth, which can then harm the coatings. They have the document online:


My sister gave me a little kit that's specifically for optics, with a little squeeze-bulb blower and fine hair brush, plus special paper and a cleaning solution.

One difference with eyeglasses is that of course they are waterproof.

Ed Cannon - ecannon@mail.utexas.edu - Austin, Texas, USA

#10 Guest_**DONOTDELETE**_*

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Posted 15 January 2004 - 11:43 AM

Do bear in mind that eyeglasses are quite different form binocular optics. Firstly most people tend to replace eyeglasses every few years so damage is less critical. Secondly, I get a noticeable loss of contrast when viewing through binoculars with eyeglasses than with the naked eye. No doubt this is a combination of uncoated eyeglass lenses, and fine scratches on the lens surfaces. I suppose I should do like Kenny and pay for anti-reflection and hard coatings on my eyeglasses and then just take more care of them.

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