Correct name for "pinhole lens" used in covert cameras?
Alison J
I want some info on the optical quality of the lenses used in small
digital camera units lie this: http://tr.im/onwK.
Many sites call that a "pinhole lens" but when I search for
"pinhole lens" I get hits for lenses created by making a pinhole in
a card.
Is this tiny glass or plastic lens more correctly called by some
other term which I can use for a search?
Thank you.
AJ
PS---I would appreciate any links to info on the typical optical
quality and specification of these lenses. (Usual angle of view,
typical low light sensitivity, depth of focus, etc.) I can guess
these are probably low spec but how low?
John Navas
<9C299D502...@newsfarm.ams2.highwinds-media.com>:
>Can I ask you specialists some questions about digital cameras.
>
>I want some info on the optical quality of the lenses used in small
>digital camera units lie this: http://tr.im/onwK.
When you use URL redirection without preview you'll lose much of your
audience, since that's how spammers and scammers work. Instead:
<http://preview.tinyurl.com/kshygw>
>Many sites call that a "pinhole lens" but when I search for
>"pinhole lens" I get hits for lenses created by making a pinhole in
>a card.
>
>Is this tiny glass or plastic lens more correctly called by some
>other term which I can use for a search?
Try "pinhole camera"
>PS---I would appreciate any links to info on the typical optical
>quality and specification of these lenses. (Usual angle of view,
>typical low light sensitivity, depth of focus, etc.) I can guess
>these are probably low spec but how low?
<http://en.wikipedia.org/wiki/Pinhole_camera>
--
Best regards,
John
Panasonic DMC-FZ28 (and several others)
nospam
<spamf...@navasgroup.com> wrote:
> When you use URL redirection without preview you'll lose much of your
> audience, since that's how spammers and scammers work. Instead:
> <http://preview.tinyurl.com/kshygw>
or just use the original url. if it's properly delimited with angle
brackets, it can span multiple lines and remain clickable.
Matt Ion
You can search on "pinhole camera", as Navas suggests (and in fact, as
is suggested by the title of the page you linked to), or you can add
"CCTV" to your original search: http://lmgtfy.com/?q=cctv+pinhole+lens
daveFaktor
The camera is known as : "Camera Obscura" Not sure it that's spelt
correctly but it sound right.
PatM
You are hurting my brain, but IIRC that type of lens is called a
"Pancake Lens".
Matt Ion
That is spelled correctly, but that's not what he's talking about.
That's what his searches keep finding, it's not what he's looking for.
dj_nme
> Can I ask you specialists some questions about digital cameras.
>
> I want some info on the optical quality of the lenses used in small
> digital camera units lie this: http://tr.im/onwK.
>
> Many sites call that a "pinhole lens" but when I search for
> "pinhole lens" I get hits for lenses created by making a pinhole in
> a card.
That's called "'pinhole lens" because the hole the video camera needs
for it's lens to poke through is very small, it looks a bit like a
pinhole and can sometimes be concealed behind a pop-rivet or what looks
like a hole left by a missing srew.
> Is this tiny glass or plastic lens more correctly called by some
> other term which I can use for a search?
The lens could perhaps be better described as an "afocal lens", because
everyting appears to be in focus (or at least equally blurred) and thus
does not need to be focused during installation.
PatM
Here is the DSLR version of a pancake lens, which they say in
knicknamed a pin lens:
http://www.loreo.com/pages/products/loreo_lenscap.html
It might be what you are looking for.
The Correction Police
>Alison J wrote:
>> Can I ask you specialists some questions about digital cameras.
>>
>> I want some info on the optical quality of the lenses used in small
>> digital camera units lie this: http://tr.im/onwK.
>>
>> Many sites call that a "pinhole lens" but when I search for
>> "pinhole lens" I get hits for lenses created by making a pinhole in
>> a card.
>
>That's called "'pinhole lens" because the hole the video camera needs
>for it's lens to poke through is very small, it looks a bit like a
>pinhole and can sometimes be concealed behind a pop-rivet or what looks
>like a hole left by a missing srew.
>
>> Is this tiny glass or plastic lens more correctly called by some
>> other term which I can use for a search?
>
>The lens could perhaps be better described as an "afocal lens", because
>everyting appears to be in focus (or at least equally blurred) and thus
>does not need to be focused during installation.
>
Yet the more mechanically inclined user will take that small video-camera
apart or find the small focusing-helix collar and refocus that lens to
ensure pixel-edge-sharp details--maximizing their potential. It's the first
thing I do before I ever install or make use of one. (First use an x-acto
blade to carefully scratch/chip-away the small clear-green daub of
Loctite�.) My wide-angle IR nighttime wildlife surveillance video-cam at
home does just fine (now) at being able to discern the difference between a
raccoon or fox at 200 ft. in the pitch-dark. (A pair of plain old 100-watt
incandescent yard-floods when covered with IR filters put out massive
amounts of IR-only, even when not turned up full on their light-dimmer.)
The same optical quality is true for the miniature lenses in any
inexpensive laser-pointer collimation-lens assembly. The manufacturer's
costs often saved in alignment and focusing time spent because this is
generally a manual labor issue; dependent on the perception, patience, and
dexterity of humans. I'm more than happy to take one apart to pick up where
they left off. Taking a <5mW $10 green laser-pointer's optics and finely
tuning it to <1.05 mRads divergence. As long as I'm in there fiddling with
things I will also ramp-up the output to ~75mW. (They only set them for
low-output so as to legally sell them to the U.S.A., getting them through
customs.)15 minutes of my time brings me a $130-$250 laser for $10.
That aside, some of these small pinhole digital-cameras work great for
turning an optical microscope into a digital-microscope for just pennies,
compared to a digital microscope-ocular that might be sold at outrageous
cost by the microscope manufacturer themselves. Just because they are small
doesn't mean they aren't of high quality. Many a microscope owner would
regard the idea that "small can only be trash-optics and blurry" as instant
nonsense. Lenses of this nature are generally mass produced by only a
handful of companies; supplying to a wide range of industrial, research,
and home-use applications. High-quality microscopy being one of them. Sell
a single lens element at $70 to a research lab or microscope company
because they expect that price and are willing to pay it, then sell an
identical one to a "pin-hole" camera or laser-pointer mfg. for <$0.20 each
because they expect that price too and will pay no more than that for a
mass-quantity order. They're not going to re-design their whole
manufacturing line just to ensure that they produce one larger order of
inferior lenses. Anton van Leeuwenhoek would also disagree with you, when
he was able to obtain sharp magnifications up to 500x by the use of only
one of these miniature lenses, hand-ground. This also happening over 350
years ago. Much has changed and improved since then.
Segue to r.p.d.: It is far, far, by far, easier to get a perfect figure on
a smaller lens than any larger one. The same holds true for all camera
lenses. This is precisely why larger diameter camera lenses will invariably
perform their worst at widest apertures. It is impossible for them to
figure glass that large to the proper curvatures, at any
consumer-acceptable costs that is. With smaller camera lenses this is
wholly possible, easily accomplished minute-by-minute, camera-by-camera.
Bob Larter
> they left off. Taking a <5mW $10 green laser-pointer's optics and finely
> tuning it to <1.05 mRads divergence. As long as I'm in there fiddling with
> things I will also ramp-up the output to ~75mW.
HAHAHAHAHAHAHAAHAHAHAhahahahahahaha!
--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
The Correction Police
wrote:
>The Correction Police wrote:
>> they left off. Taking a <5mW $10 green laser-pointer's optics and finely
>> tuning it to <1.05 mRads divergence. As long as I'm in there fiddling with
>> things I will also ramp-up the output to ~75mW.
>
>HAHAHAHAHAHAHAAHAHAHAhahahahahahaha!
Oh ye of such vast ignorance, with an attention-deficit deeper than the
Mariana Trench. Google for laser pot mod Some people adjust their's
higher, to 150mW output, but I feel that that will shorten their life
greatly. I do have one set that high, just for the life-expectancy
experiment. It readily ignites a phosphorous match in under a second. It's
still working two months later, but for how long. Granted it is only used
intermittently.
The ones I buy direct from China are actually $8 each, shipping incl., (not
$10, but some people can't get them that inexpensive), all easily adjusted
for a 75mW output. Their heat-sink is more than adequate to be tuned that
high. The emergent beam of light clearly visible in a sunlit room after the
exceptionally simple modification.
Every time I am engaged in a group astronomy discussion (which invariably
happens a dozen times a year while photo-trekking or at home) I like to
hand a laser to each so that they may easily point out objects they are
curious about. It's much less time-consuming than playing, "Where? There?"
"No, over there, see where I'm pointing my finger?" "Wait, let me line up
my eye with your arm..." This is also a good time to educate any young
children that might be present on the dangers of lasers this powerful. They
too get to use them to ask about things in the sky. It's a wonderful
opportunity for them to display and learn adult-level responsibility. A
multi-faceted lesson. I teach the adults an important lesson too. All
adults in attendance are more than willing to keep explaining safety issues
to their children, they are motivated by fear of being permanently blinded
by their own child. It's "grow up" time for all. With fun astronomy info
thrown in for good measure.
(Imagine a world were every person was given an atomic weapon when born,
you useless sub-human idiots would all grow up immediately.)
Educate yourself before you make a fool of yourself, yet again. It's
getting tiring watching you do it so relentlessly, so predictably.
There's nothing sadder in the world than someone who chooses to remain as
ignorant as you. Something tells me that you'd be the one out of
one-hundred-thousand that I would hesitate to hand a 75mW laser to. You
appear to be the type that could never learn, no matter your age. The kind
of life-form where your genetics should be prevented from continuing.
John Navas
in <130620091222391744%nos...@nospam.invalid>:
Not necessarily -- it will still be broken in many news clients.
John Navas
<t...@knowldegeisgood.com> wrote in
<ki3935pl4alvh9hdv...@4ax.com>:
>Segue to r.p.d.: It is far, far, by far, easier to get a perfect figure on
>a smaller lens than any larger one. The same holds true for all camera
>lenses. This is precisely why larger diameter camera lenses will invariably
>perform their worst at widest apertures. It is impossible for them to
>figure glass that large to the proper curvatures, at any
>consumer-acceptable costs that is. With smaller camera lenses this is
>wholly possible, easily accomplished minute-by-minute, camera-by-camera.
While most relatively large lenses aren't at their best wide open, the
better ones are quite close, with superb optical quality, and at their
best closed down by only 2-3 stops, which contradicts your claim. And
their worst performance may well be stopped all the way down due to
diffraction.
nospam
<spamf...@navasgroup.com> wrote:
> >> When you use URL redirection without preview you'll lose much of your
> >> audience, since that's how spammers and scammers work. Instead:
> >> <http://preview.tinyurl.com/kshygw>
> >
> >or just use the original url. if it's properly delimited with angle
> >brackets, it can span multiple lines and remain clickable.
>
> Not necessarily -- it will still be broken in many news clients.
then the news client is broken. this is 2009, it's time to update.
plus those services don't necessarily maintain the url reference
forever and if someone finds the post on google groups some time in the
future, the link will be dead and they'll have no way to load the page.
John Navas
in <140620091109226249%nos...@nospam.invalid>:
>In article <8v3a35lqb9m66t4qh...@4ax.com>, John Navas
><spamf...@navasgroup.com> wrote:
>
>> >> When you use URL redirection without preview you'll lose much of your
>> >> audience, since that's how spammers and scammers work. Instead:
>> >> <http://preview.tinyurl.com/kshygw>
>> >
>> >or just use the original url. if it's properly delimited with angle
>> >brackets, it can span multiple lines and remain clickable.
>>
>> Not necessarily -- it will still be broken in many news clients.
>
>then the news client is broken. ...
[shrug]
I deal with the world as it is, not what I'd like it to me,
but as always, YMMV.
nospam
<spamf...@navasgroup.com> wrote:
> >> >or just use the original url. if it's properly delimited with angle
> >> >brackets, it can span multiple lines and remain clickable.
> >>
> >> Not necessarily -- it will still be broken in many news clients.
> >
> >then the news client is broken. ...
>
> [shrug]
>
> I deal with the world as it is, not what I'd like it to me,
> but as always, YMMV.
translated: i'm stuck using primitive software and refuse to upgrade.
ymmv.
How Ironic
Translation, nobody is stupid enough to follow any of your lame troll's
advice.
Paul Furman
> Can I ask you specialists some questions about digital cameras.
>
> I want some info on the optical quality of the lenses used in small
> digital camera units lie this: http://tr.im/onwK.
http://www.google.com/products?hl=en&q=spy+camera+lens
It's inherently going to be a very small low resolution camera requiring
bright light to form an image through a tiny hole. Tiny hole means tiny
amount of light. Even if you could focus such a lens on the sensor of a
high performance camera, diffraction would limit resolution severely.
Tru pinhole photography requires very long exposures due to the tiny
amount of light passing.
This one for example:
http://www.spyville.com/3213ccdbwcam.html
$69.99
1/3" CCD Image Sensor (4.8mm x 3.6mm, the very smallest)
512 x 492 pixels
Min Illumination: 0.1 Lux
Lens Pin Hole: 5.5mm, f/3.5
Size: 32mm x 32mm
Probably a clear glass/plastic cover, an open pinhole would let dust in.
The diagonal of that sensor is 6mm so the 5.5mm lens is a normal lens,
with a field of view comparable to a 50mm lens on a 35mm format camera.
The aperture of f/3.5 means 5.5/3.5 = 1.6mm diameter opening. That's
probably too big for an actual pinhole so perhaps there is an actual
lens in there. If so, it's probably nothing fancy because diffraction
will wipe out most of the detail anyways. It wouldn't be worth putting a
better sensor in there either.
I have a pancake lens for 35mm format, the opening is 16mm dia. which is
45mm f/2.8 capable of very high resolution images in low light.
> Many sites call that a "pinhole lens" but when I search for
> "pinhole lens" I get hits for lenses created by making a pinhole in
> a card.
>
> Is this tiny glass or plastic lens more correctly called by some
> other term which I can use for a search?
>
> Thank you.
> AJ
>
> PS---I would appreciate any links to info on the typical optical
> quality and specification of these lenses. (Usual angle of view,
> typical low light sensitivity, depth of focus, etc.) I can guess
> these are probably low spec but how low?
--
Paul Furman
www.edgehill.net
www.baynatives.com
all google groups messages filtered due to spam
oh my
wrote:
Go study up on "diffraction limits" of microscope objectives, maybe you'll
really figure it out someday.
Thanks for playing. Now go educate yourself some more so you don't appear
so foolish the next time.
Paul Furman
Go to hell, I was in the ballpark.
And I doubt there are any infinity focus microscope lenses with a 1.5mm
dia. front element <g> so you haven't contributed anything here but
bile, as always.
While it may be technically possible to get more resolution from such a
tiny lens (I'd estimate 2MP), it's certainly not common. I challenge you
to find anything with a 1.5mm front opening that captures more than 640
pixels wide (1/3 of a megapixel) if even that. Go up to a 6mm opening
(1/4 inch) & you can do a lot better.
This place lists a 2.6mm diagonal sensor lens that does about 100 lppmm
but with a sensor that's only 2mm wide, that's not much resolution:
http://www.enplas.co.jp/english/business/opto/product/iop_list.html
It's designed for CIF (352�288 pixels - 1/10th of a megapixel) and would
have a 0.5mm dia. aperture at f/2.8.
They also list a 1.5mm aperture lens 'for Mega" presumably meaning a 1
megapixel sensor 4.8mm wide which is perhaps just barely possible at 80
lppmm.
> Thanks for playing. Now go educate yourself some more so you don't appear
> so foolish the next time.
>
>>
>>> Many sites call that a "pinhole lens" but when I search for
>>> "pinhole lens" I get hits for lenses created by making a pinhole in
>>> a card.
>>>
>>> Is this tiny glass or plastic lens more correctly called by some
>>> other term which I can use for a search?
>>>
>>> Thank you.
>>> AJ
>>>
>>> PS---I would appreciate any links to info on the typical optical
>>> quality and specification of these lenses. (Usual angle of view,
>>> typical low light sensitivity, depth of focus, etc.) I can guess
>>> these are probably low spec but how low?
The Correction Police
wrote:
On the contrary, what you state precisely supports what I said and in no
way contradicts it. NO larger diameter camera lenses (i.e. DSLR glass) are
figured well enough to perform best at widest aperture. Well figured glass
will continuously provide a sharper and sharper image as the aperture is
enlarged (go study up on Dawes' Limit, something that few if any around
here comprehend). If you are using a 16" diameter diffraction limited
telescope mirror and stop it down to 6" the level of detail will degrade,
just as it should, limited by the diffraction. As you open up the aperture
the resolution gets better and better until you reach the full 16" diameter
lens, from which you can open the aperture no further. The highest
resolution available at the full 16" dia. aperture. This is how precision
optics are supposed to act. If their lenses cannot perform best at widest
aperture then that means that is not diffraction limited optics, = CRAP
GLASS. Smaller camera lenses do not suffer from this problem. The only
thing that degrades their image is by stopping down the lens, not opening
it up. Those smaller lenses are always butting up against the very limits
of diffraction (the limits of precision optics and the physics of light
itself). Just as what happens in precision diffraction-limited telescope
optics. Diffraction limited optics = the best of the best. The softness in
larger lenses is just due to poorly figured glass all around at all
apertures.
Really, go take a remedial course in optics and physics or something.
Trying to educate you fools is so fuckingly tedious.
Bob Larter
> On Sun, 14 Jun 2009 20:56:58 +1000, Bob Larter <bobby...@gmail.com>
> wrote:
>
>> The Correction Police wrote:
>>> they left off. Taking a <5mW $10 green laser-pointer's optics and finely
>>> tuning it to <1.05 mRads divergence. As long as I'm in there fiddling with
>>> things I will also ramp-up the output to ~75mW.
>> HAHAHAHAHAHAHAAHAHAHAhahahahahahaha!
>
> Oh ye of such vast ignorance, with an attention-deficit deeper than the
> Mariana Trench. Google for laser pot mod Some people adjust their's
> higher, to 150mW output, but I feel that that will shorten their life
> greatly. I do have one set that high, just for the life-expectancy
> experiment. It readily ignites a phosphorous match in under a second. It's
> still working two months later, but for how long. Granted it is only used
> intermittently.
>
> The ones I buy direct from China are actually $8 each, shipping incl., (not
> $10, but some people can't get them that inexpensive), all easily adjusted
> for a 75mW output. Their heat-sink is more than adequate to be tuned that
> high. The emergent beam of light clearly visible in a sunlit room after the
> exceptionally simple modification.
This is a complete & utter load of bullshit. Cheap Chinese laser
pointers do not use >75mW rated laser diodes. Attempting to put that
much power through one will kill it stone dead instantly. You obviously
don't have the faintest idea how to measure the output of a laser.
The Correction Police
wrote:
I built my own power-meter from one of the better DIY methods (uses an
inexpensive IR thermometer and an easy to fabricate sensor, in a sealed
environment). It's accurate to within 5%. Good enough for what I need it
for. YOU however are just an idiot troll desperate for my attention.
Now run along little boy. Go educate yourself or have your mommy do it for
you. Better yet, try the potentiometer modification (pot mod) on a cheap
Chinese laser and look into it. Tell me what you see.
I've only given you attention this long because I felt so sorry for how
desperate you are for it. Go latch onto someone else to get your much
needed attention. Consider yourself scraped out of the cleat of my boot,
just like any other dogshit I might have accidentally stepped in.
Rich
wrote:
>Anton van Leeuwenhoek would also disagree with you, when
> he was able to obtain sharp magnifications up to 500x by the use of only
> one of these miniature lenses, hand-ground. This also happening over 350
> years ago. Much has changed and improved since then.
Leeuwenhoek microscopes (on hand, few that there are) went up to about
266x. It is theorized he had them up to 500x. In addition, it is
very possible his lenses were ground aspherical, unlike small
spherical lenses you can buy today so the correction across the field
with his would have been superior. Which is how he was able to
observe small things in detail and even bacteria and detect Brownian
motion, while those using compound microscopes with spherical lenses
had no hope of seeing things in that detail, in those days.
Bob Larter
Rubbish. You're making the whole thing up.