That 8mm Zuiko that John H. mentioned is pretty much sealed. Focussing, such as
it is, is achieved by racking the entire lens assembly out. But there is
something really weird going on in the small air space between the tiny rear
doublet and the small third element, which are seated snugly in a tube with
spacer rings.
John - no chance that the third element could be repolished and recoated? Or
does that 'milkiness' go really deep?
Andrew Fildes
afildes@xxxxxxxxxxxxx
On 25/01/2011, at 10:17 AM, Moose wrote:
> On 1/20/2011 11:04 AM, George Themelis wrote:
>> 2. Are zoom lenses more susceptible to haze vs. fixed focal length lenses?
>>
>> And what causes this internal haze?
>
> I see this has been addressed, but one factor not yet mentioned. None of the
> lenses you are talking about are sealed. So
> when the elements move, air is pushed around, both redistributing anything in
> it to begin with and 'pumping' air in and
> out of the lens.
>
> As a general rule, prime lenses have less element movement than zooms and
> short focal lengths have less movement than long.
>
> Sooo. Things that cause haze, fungus spores, moisture for them to sprout,
> dust, dispersed petroleum fractions from
> helical grease breakdown, smoke, smog, cigarette smoke, etc. are more likely
> to be found in some lenses than others.
>
> Use a wide range, long, single control zoom actively, and you cycle lots and
> lots of outside air through it. All the
> detailed bits inside act like filter elements. So shoot only in dry, clean
> air. :-)
>
> A. Movable Moose
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