Re: Lens Cleaning

Discussion in 'Digital Photography' started by Peter Irwin, Nov 26, 2011.

  1. Peter Irwin

    Peter Irwin Guest

    rdoc <> wrote:
    >
    > I tried using my regular lens cleaner with only marginal success.
    >
    > What can I use on the glass that will not harm the multicoating? Alcohol?
    >

    Modern lens coatings are not likely to come off in alcohol.

    I would suggest dipping q-tips in either alcohol or Windex
    and work gently, changing q-tips frequently. There should
    never be enough liquid at the front of the lens that there
    is a risk of some seeping inside, you can alternate wet
    and dry q-tips. The real risk is scratching the lens or
    coating, a little bit of grit can do quite a bit of harm.

    A single big scratch is actually nearly harmless, but lots
    of tiny scratches will ruin the definition of a lens. People
    sometimes do make lots of tiny scratches, so be sure to change
    q-tips very frequently, especially at the start.

    Peter.
    --
    Peter Irwin, Nov 26, 2011
    #1
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  2. Peter Irwin

    Peter Irwin Guest

    rdoc <> wrote:
    >>

    >
    > I was thinking about one thing and typed another originally... it is not on
    > a K1000... it is an 'A' lens on a Program Plus. As to my original concern...
    > how modern does multicoating have to be, to be modern enough to tolerate
    > alcohol or whatever? Shame there are no real camera shops anywhere around
    > these days.
    >

    It shouldn't be a problem with any multicoated pentax lens. Some
    early coating technologies (1940s) were quite "soft" and delicate,
    and while the coatings used in the 1950s and 1960s were supposed
    to be quite durable, some of them are easier to damage in practice
    than they are supposed to be.

    The Magnesium Flouride used in single coatings is NOT actually
    soluble in alcohol, but people do sometimes harm some old
    coatings by careful cleaning anyway. The materials used for the
    outer layer of multicoatings tend to be quite durable. The real
    thing to avoid is rubbing dirt into the lens.

    Peter.
    --
    Peter Irwin, Nov 26, 2011
    #2
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  3. Peter Irwin

    Wally Guest

    On Sat, 26 Nov 2011 10:03:19 +0000 (UTC), Peter Irwin <>
    wrote:

    >rdoc <> wrote:
    >>
    >> I tried using my regular lens cleaner with only marginal success.
    >>
    >> What can I use on the glass that will not harm the multicoating? Alcohol?
    >>

    >Modern lens coatings are not likely to come off in alcohol.
    >
    >I would suggest dipping q-tips in either alcohol or Windex
    >and work gently, changing q-tips frequently. There should
    >never be enough liquid at the front of the lens that there
    >is a risk of some seeping inside, you can alternate wet
    >and dry q-tips. The real risk is scratching the lens or
    >coating, a little bit of grit can do quite a bit of harm.
    >
    >A single big scratch is actually nearly harmless, but lots
    >of tiny scratches will ruin the definition of a lens. People
    >sometimes do make lots of tiny scratches, so be sure to change
    >q-tips very frequently, especially at the start.


    Q-tips are made of cotton, a natural product, which therefore can
    contain natural impurities. That can include stuff like sand (quartz),
    which can leave scratches on the glass.

    Instead of using product made for babies, it's best to use products
    intended for cleaning photographic lenses.

    Wally
    Wally, Nov 26, 2011
    #3
  4. Peter Irwin

    Peter Irwin Guest

    Wally <> wrote:
    >
    > Q-tips are made of cotton, a natural product, which therefore can
    > contain natural impurities. That can include stuff like sand (quartz),
    > which can leave scratches on the glass.


    Maybe they could, but do they generally? People use q-tips and surgical
    cotton for cleaning front surface mirrors which are much more
    delicate than lenses.

    > Instead of using product made for babies, it's best to use products
    > intended for cleaning photographic lenses.


    What product made specifically for lens cleaning would you suggest
    for a very dirty lens? Moistened lens tissue, even if harmless in
    itself, will very quickly pick up abrasive dirt from the lens. The
    gadgets known as "lens pens" work wonderfully for removing fingerprints,
    but I wouldn't dream of using one on a lens that wasn't already pretty
    clean.

    Peter.
    --
    Peter Irwin, Nov 26, 2011
    #4
  5. Peter Irwin

    Wally Guest

    On Sat, 26 Nov 2011 18:23:14 +0000 (UTC), Peter Irwin <>
    wrote:

    >Wally <> wrote:
    >>
    >> Q-tips are made of cotton, a natural product, which therefore can
    >> contain natural impurities. That can include stuff like sand (quartz),
    >> which can leave scratches on the glass.

    >
    >Maybe they could, but do they generally? People use q-tips and surgical
    >cotton for cleaning front surface mirrors which are much more
    >delicate than lenses.
    >
    >> Instead of using product made for babies, it's best to use products
    >> intended for cleaning photographic lenses.

    >
    >What product made specifically for lens cleaning would you suggest
    >for a very dirty lens? Moistened lens tissue, even if harmless in
    >itself, will very quickly pick up abrasive dirt from the lens. The
    >gadgets known as "lens pens" work wonderfully for removing fingerprints,
    >but I wouldn't dream of using one on a lens that wasn't already pretty
    >clean.


    I pretty well never have to clean very dirty lenses because mine never
    get that dirty... but I would consider commercial lens cleaning paper,
    folded a couple times and then torn across, which gives a very
    absorbent and safe medium -- or microfiber lens cleaning cloth should
    work great (but I have no experience with it).

    You will most likely need a liquid to help lift the grunge off a very
    dirty lens. I'm pretty sure water, isopropyl alcohol, or naphtha
    (lighter fluid, varsol, some paint thinners, etc) are all harmless to
    glass or lens coatings. But one needs to use a minimum so as to keep
    the liquid from penetrating at the edges.

    Which liquid to use? Depends on the dirt. I would first try breathing
    on it (suck in slightly before the breath so you don't get any
    aspirated saliva on it). If the dirt is fatty, water won't help much,
    so try IPA, which will lift some fat. Naphtha is better for that, but
    some kinds leave a residue. Never use stuff like lacquer thinner,
    acetone or turpentine.

    There is of course also commercial lens cleaning liquid, but I don't
    have recent experience with it.

    As you say, rubbing on a lens surface can cause scratches from the
    dirt on the lens. That probably happens less with more absorbent
    tissue/cloth, but it is still a peril. I also agree with you about
    lens pens.

    Wally
    Wally, Nov 26, 2011
    #5
  6. Peter Irwin

    nick c Guest

    Wally wrote:
    > On Sat, 26 Nov 2011 18:23:14 +0000 (UTC), Peter Irwin <>
    > wrote:
    >
    >> Wally <> wrote:
    >>> Q-tips are made of cotton, a natural product, which therefore can
    >>> contain natural impurities. That can include stuff like sand (quartz),
    >>> which can leave scratches on the glass.

    >> Maybe they could, but do they generally? People use q-tips and surgical
    >> cotton for cleaning front surface mirrors which are much more
    >> delicate than lenses.
    >>
    >>> Instead of using product made for babies, it's best to use products
    >>> intended for cleaning photographic lenses.

    >> What product made specifically for lens cleaning would you suggest
    >> for a very dirty lens? Moistened lens tissue, even if harmless in
    >> itself, will very quickly pick up abrasive dirt from the lens. The
    >> gadgets known as "lens pens" work wonderfully for removing fingerprints,
    >> but I wouldn't dream of using one on a lens that wasn't already pretty
    >> clean.

    >
    > I pretty well never have to clean very dirty lenses because mine never
    > get that dirty... but I would consider commercial lens cleaning paper,
    > folded a couple times and then torn across, which gives a very
    > absorbent and safe medium -- or microfiber lens cleaning cloth should
    > work great (but I have no experience with it).
    >
    > You will most likely need a liquid to help lift the grunge off a very
    > dirty lens. I'm pretty sure water, isopropyl alcohol, or naphtha
    > (lighter fluid, varsol, some paint thinners, etc) are all harmless to
    > glass or lens coatings. But one needs to use a minimum so as to keep
    > the liquid from penetrating at the edges.
    >
    > Which liquid to use? Depends on the dirt. I would first try breathing
    > on it (suck in slightly before the breath so you don't get any
    > aspirated saliva on it). If the dirt is fatty, water won't help much,
    > so try IPA, which will lift some fat. Naphtha is better for that, but
    > some kinds leave a residue. Never use stuff like lacquer thinner,
    > acetone or turpentine.
    >
    > There is of course also commercial lens cleaning liquid, but I don't
    > have recent experience with it.
    >
    > As you say, rubbing on a lens surface can cause scratches from the
    > dirt on the lens. That probably happens less with more absorbent
    > tissue/cloth, but it is still a peril. I also agree with you about
    > lens pens.
    >
    > WallyI


    IMO, you have offered some good advice. I would like to offer a
    suggestion that I have found to be worthy of note. I shun commercial
    lens cleaning paper. My experience with such items has not been good. I
    prefer to use a microfiber cloth. I have used a cotton dish drying towel
    but much prefer to use a microfiber cloth.

    Wash the cleaning/drying cloth in Woolite soap&water solution to remove
    any dirt and residue that may be in the cloth. When washed in Woolite,
    the cleaning cloth will be free from dirt, oil, and old soap residue.
    I've found nothing yet that's as good as Woolite to clean cloths to be
    used to wipe optical lens glass or plastic.

    The lens is generally the item that is looked at to see if any oily
    substance or hard particulate may be on the lens. I've learned that
    people just assume the cloth they intend to use is contaminant free.

    Save the Woolite cleaned cloth in a plastic Zip-lock bag to be used for
    future lens cleaning needs. I keep a 10 in x 6 in microfiber cleaning
    cloth (80% Polyester and 20% Polyamid), which I always wash in Woolite,
    that my wife bought at the local super-market for about 0.60 cents just
    for cleaning optical lenses.

    Nick
    nick c, Nov 27, 2011
    #6
  7. Peter Irwin

    Bruce Guest

    nick c <> wrote:

    >IMO, you have offered some good advice. I would like to offer a
    >suggestion that I have found to be worthy of note. I shun commercial
    >lens cleaning paper. My experience with such items has not been good. I
    >prefer to use a microfiber cloth. I have used a cotton dish drying towel
    >but much prefer to use a microfiber cloth.



    It depends on what type of microfibre cloth. There are a huge variety
    of products that go under the name of 'microfibre cloth' and huge
    variations in the type of thread used to make them.

    The sort of microfibre cloth that is designed for use on camera lenses
    should be fine, however many microfibre cloths designed for domestic
    and industrial cleaning are quite abrasive and would be likely to
    damage a camera lens.
    Bruce, Nov 27, 2011
    #7
  8. Peter Irwin

    Martin Brown Guest

    On 26/11/2011 14:14, Peter Irwin wrote:
    > rdoc<> wrote:
    >>>

    >>
    >> I was thinking about one thing and typed another originally... it is not on
    >> a K1000... it is an 'A' lens on a Program Plus. As to my original concern...
    >> how modern does multicoating have to be, to be modern enough to tolerate
    >> alcohol or whatever? Shame there are no real camera shops anywhere around
    >> these days.
    >>

    > It shouldn't be a problem with any multicoated pentax lens. Some
    > early coating technologies (1940s) were quite "soft" and delicate,
    > and while the coatings used in the 1950s and 1960s were supposed
    > to be quite durable, some of them are easier to damage in practice
    > than they are supposed to be.


    IPA of a suitably pure grade should be tolerated by most optics - it is
    very nasty in eyes though to handle with care. Pure ethanol is harder to
    get without residual junk in it (for booze tax reasons). Methanol is
    sufficiently aggressive that it may damage plastic parts.

    Isopropanol is the alcohol of choice for cleaning optics. There is also
    a celluloid in ether method that is much older and trickier to use.

    Whatever cleaner you decide to use do a spot test on a piece of glass to
    see how clean it really is when evaporated to dryness. There is no point
    at all cleaning good optics with dirty alcohol - and often stuff that
    has been stored in plastic bottles will have leached enough plasticiser
    out of its container to be effectively useless!
    >
    > The Magnesium Flouride used in single coatings is NOT actually
    > soluble in alcohol, but people do sometimes harm some old
    > coatings by careful cleaning anyway. The materials used for the
    > outer layer of multicoatings tend to be quite durable. The real
    > thing to avoid is rubbing dirt into the lens.


    In fact unless it is *really* bad you can easily do more harm by trying
    to clean them. In particular you don't want to put any scratches into
    the surface that will harm the point spread function - that is with a
    circular scrubbing motion. Too many people do this! Linear radial motion
    with the smallest pressure you can get away with on a fine brush wet
    with alcohol is about as good as anything and dry off as much of the
    residual with lens tissue to take the oils and gunge with it.

    Regards,
    Martin Brown
    Martin Brown, Nov 27, 2011
    #8
  9. Peter Irwin

    Peter Irwin Guest

    Martin Brown <|||newspam|||@nezumi.demon.co.uk> wrote:
    >
    > Isopropanol is the alcohol of choice for cleaning optics. There is also
    > a celluloid in ether method that is much older and trickier to use.
    >

    I'm pretty sure you are thinking of collodion, which is
    nitrocellulose in ether. Reliable people have reported
    problems using that method with coated optics.
    see: <http://www.cloudynights.com/item.php?item_id=1304>

    It is also seldom really necessary to get a lens _that_
    clean, since the front of the lens will quickly return
    to the state of being very slightly dirty in any case.

    Thanks for your information, you seem to know your stuff.

    Peter.
    Peter Irwin, Nov 27, 2011
    #9
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