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How can smartphone cameras work thru scratched lenses?



 
 
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  #21  
Old June 1st 18, 04:21 PM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default How can smartphone cameras work thru scratched lenses?

In article , Eric Stevens
wrote:

Perhaps it's to do with something like the focal length or depth
of
focus?

Simple, the image focal point is nowhere near the scratched area so
it
behaves more or less like a very mild diffusion filter at worst.

no.

Yes. I see this question all the time dealing with camera lenses.

i'm sure you do, but that doesn't mean you understand it.

there's a very big difference between a scratch on a cellphone lens
versus a scratch on an slr lens, for reasons that should be immediately
obvious.

there are also other factors involved as to why smartphone cameras do
as well as they do (and have been mentioned, eric).

Here is what nospam has written in this thread so far:

1. it's built to withstand it, usually with a sapphire crystal lens
cover or similar.
....
mostly because digital is much better than film, particularly when
it's mixed with highly sophisticated image processing.

2. no.

3. actually no.

a scratch on a tiny lens would be much more than a 'mild diffusion
filter', and it's actually *very* difficult to scratch the lens
because it has a protective cover (usually sapphire crystal),
which does not scratch easily, even if one tries.

4. i'm sure you do, but that doesn't mean you understand it.

there's a very big difference between a scratch on a cellphone
lens versus a scratch on an slr lens, for reasons that should be
immediately obvious.

there are also other factors involved as to why smartphone cameras
do as well as they do (and have been mentioned, eric).

5. yes it most certainly is.

It's the ancient laws of optics. Several people have already
given the correct explanation.

they might think they have, but they have not, and the 'ancient
laws of optics' actually say the *opposite* of what you think they
do.

I expect you to say "no". If you really believe that it is
modern technology please explain what the technology is and how
it works.

i already did.

Extracted from this is the valid point that cellphone lenses tend not
to be scratched because they are behind a layer of saphire crystal
glass.


read it again and extract the other key point.


I would rather leave it to the author. What do you regard as the other
key point?


cop out.

it's very clear what it is and you don't have to read very far to find
it either.
  #22  
Old June 1st 18, 10:24 PM posted to rec.photo.digital
Ken Hart[_4_]
external usenet poster
 
Posts: 569
Default How can smartphone cameras work thru scratched lenses?

On 06/01/2018 02:11 AM, RichA wrote:
On Thursday, 31 May 2018 21:03:14 UTC-4, nospam wrote:
In article ,
RichA wrote:


Simple, the image focal point is nowhere near the scratched area so it
behaves more or less like a very mild diffusion filter at worst.

no.

Yes. I see this question all the time dealing with camera lenses.

i'm sure you do, but that doesn't mean you understand it.

there's a very big difference between a scratch on a cellphone lens
versus a scratch on an slr lens, for reasons that should be immediately
obvious.

Deep DOF?


that has nothing to do with scratches


Deep DOF might make dirt or scratches on surfaces far from the focal plane have GREATER impact on the image than if the camera had a large sensor and shallow DOF. This is WHY people stop-down lenses when looking for evidence of sensor dust.


That "sensor dust" part doesn't make sense to me; I agree totally with
the sentence before. I've taken pictures through chain link fences with
the lens up against the fence- wide open, the fence doesn't show. Stop
down, and the fence appears.

Any object (dust) on the sensor should just block light from hitting the
sensor pixel(s) behind it. DOF shouldn't have anything to do with it.
Although stopping down may make it easier to see the dust, depending on
what you are looking at.

--
Ken Hart

  #23  
Old June 1st 18, 10:34 PM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default How can smartphone cameras work thru scratched lenses?

In article , Ken Hart
wrote:

Deep DOF might make dirt or scratches on surfaces far from the focal
plane have GREATER impact on the image than if the camera had a large
sensor and shallow DOF. This is WHY people stop-down lenses when looking
for evidence of sensor dust.


That "sensor dust" part doesn't make sense to me; I agree totally with
the sentence before. I've taken pictures through chain link fences with
the lens up against the fence- wide open, the fence doesn't show. Stop
down, and the fence appears.


and can disappear:
https://www.theverge.com/2017/5/17/1...-object-remova
l-feature-demo

Any object (dust) on the sensor should just block light from hitting the
sensor pixel(s) behind it. DOF shouldn't have anything to do with it.
Although stopping down may make it easier to see the dust, depending on
what you are looking at.


https://photographylife.com/why-sens...le-at-small-ap
ertures
  #24  
Old June 1st 18, 11:42 PM posted to rec.photo.digital
Eric Stevens
external usenet poster
 
Posts: 13,611
Default How can smartphone cameras work thru scratched lenses?

On Fri, 01 Jun 2018 11:21:00 -0400, nospam
wrote:

In article , Eric Stevens
wrote:

Perhaps it's to do with something like the focal length or depth
of
focus?

Simple, the image focal point is nowhere near the scratched area so
it
behaves more or less like a very mild diffusion filter at worst.

no.

Yes. I see this question all the time dealing with camera lenses.

i'm sure you do, but that doesn't mean you understand it.

there's a very big difference between a scratch on a cellphone lens
versus a scratch on an slr lens, for reasons that should be immediately
obvious.

there are also other factors involved as to why smartphone cameras do
as well as they do (and have been mentioned, eric).

Here is what nospam has written in this thread so far:

1. it's built to withstand it, usually with a sapphire crystal lens
cover or similar.
....
mostly because digital is much better than film, particularly when
it's mixed with highly sophisticated image processing.

2. no.

3. actually no.

a scratch on a tiny lens would be much more than a 'mild diffusion
filter', and it's actually *very* difficult to scratch the lens
because it has a protective cover (usually sapphire crystal),
which does not scratch easily, even if one tries.

4. i'm sure you do, but that doesn't mean you understand it.

there's a very big difference between a scratch on a cellphone
lens versus a scratch on an slr lens, for reasons that should be
immediately obvious.

there are also other factors involved as to why smartphone cameras
do as well as they do (and have been mentioned, eric).

5. yes it most certainly is.

It's the ancient laws of optics. Several people have already
given the correct explanation.

they might think they have, but they have not, and the 'ancient
laws of optics' actually say the *opposite* of what you think they
do.

I expect you to say "no". If you really believe that it is
modern technology please explain what the technology is and how
it works.

i already did.

Extracted from this is the valid point that cellphone lenses tend not
to be scratched because they are behind a layer of saphire crystal
glass.

read it again and extract the other key point.


I would rather leave it to the author. What do you regard as the other
key point?


cop out.

it's very clear what it is and you don't have to read very far to find
it either.


It seems I don't have to read it at all if I'm relying on you to
explain it.
--

Regards,

Eric Stevens
  #25  
Old June 1st 18, 11:57 PM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default How can smartphone cameras work thru scratched lenses?

In article , Eric Stevens
wrote:


there's a very big difference between a scratch on a cellphone lens
versus a scratch on an slr lens, for reasons that should be immediately
obvious.

there are also other factors involved as to why smartphone cameras do
as well as they do (and have been mentioned, eric).

Here is what nospam has written in this thread so far:

1. it's built to withstand it, usually with a sapphire crystal lens
cover or similar.
....
mostly because digital is much better than film, particularly when
it's mixed with highly sophisticated image processing.

2. no.

3. actually no.

a scratch on a tiny lens would be much more than a 'mild diffusion
filter', and it's actually *very* difficult to scratch the lens
because it has a protective cover (usually sapphire crystal),
which does not scratch easily, even if one tries.

4. i'm sure you do, but that doesn't mean you understand it.

there's a very big difference between a scratch on a cellphone
lens versus a scratch on an slr lens, for reasons that should be
immediately obvious.

there are also other factors involved as to why smartphone cameras
do as well as they do (and have been mentioned, eric).

5. yes it most certainly is.

It's the ancient laws of optics. Several people have already
given the correct explanation.

they might think they have, but they have not, and the 'ancient
laws of optics' actually say the *opposite* of what you think they
do.

I expect you to say "no". If you really believe that it is
modern technology please explain what the technology is and how
it works.

i already did.

Extracted from this is the valid point that cellphone lenses tend not
to be scratched because they are behind a layer of saphire crystal
glass.

read it again and extract the other key point.

I would rather leave it to the author. What do you regard as the other
key point?


cop out.

it's very clear what it is and you don't have to read very far to find
it either.


It seems I don't have to read it at all if I'm relying on you to
explain it.


it's clear as can be.

you're arguing just to argue, as usual.
  #26  
Old June 2nd 18, 01:41 AM posted to rec.photo.digital
PeterN[_7_]
external usenet poster
 
Posts: 1,161
Default How can smartphone cameras work thru scratched lenses?

On 5/31/2018 6:37 PM, nospam wrote:
In article , Eric Stevens
wrote:


If 99% (or more) of the lense is producing a sharp image the 1% (or
less) which is the scratch is producing no image but only a relatively
faint diffuse illumination of the film plane which may never be
noticed.


exactly the point,

now compare the size of a scratch to the size of a cellphone lens.

keep in mind that cellphones are designed for abuse and usually have a
sapphire crystal which is *significantly* harder to scratch than an slr
lens, which has no protection unless the user adds a uv filter on their
own.


All true. However a scratch, no matter how, small relative to the size
of the lens, will cause some aberration, if light hits it at the right
angle.

--
PeterN
  #27  
Old June 2nd 18, 04:34 AM posted to rec.photo.digital
Eric Stevens
external usenet poster
 
Posts: 13,611
Default How can smartphone cameras work thru scratched lenses?

rOn Fri, 01 Jun 2018 18:57:10 -0400, nospam
wrote:

In article , Eric Stevens
wrote:


there's a very big difference between a scratch on a cellphone lens
versus a scratch on an slr lens, for reasons that should be immediately
obvious.

there are also other factors involved as to why smartphone cameras do
as well as they do (and have been mentioned, eric).

Here is what nospam has written in this thread so far:

1. it's built to withstand it, usually with a sapphire crystal lens
cover or similar.
....
mostly because digital is much better than film, particularly when
it's mixed with highly sophisticated image processing.

2. no.

3. actually no.

a scratch on a tiny lens would be much more than a 'mild diffusion
filter', and it's actually *very* difficult to scratch the lens
because it has a protective cover (usually sapphire crystal),
which does not scratch easily, even if one tries.

4. i'm sure you do, but that doesn't mean you understand it.

there's a very big difference between a scratch on a cellphone
lens versus a scratch on an slr lens, for reasons that should be
immediately obvious.

there are also other factors involved as to why smartphone cameras
do as well as they do (and have been mentioned, eric).

5. yes it most certainly is.

It's the ancient laws of optics. Several people have already
given the correct explanation.

they might think they have, but they have not, and the 'ancient
laws of optics' actually say the *opposite* of what you think they
do.

I expect you to say "no". If you really believe that it is
modern technology please explain what the technology is and how
it works.

i already did.

Extracted from this is the valid point that cellphone lenses tend not
to be scratched because they are behind a layer of saphire crystal
glass.

read it again and extract the other key point.

I would rather leave it to the author. What do you regard as the other
key point?

cop out.

it's very clear what it is and you don't have to read very far to find
it either.


It seems I don't have to read it at all if I'm relying on you to
explain it.


it's clear as can be.

you're arguing just to argue, as usual.


You are plagiarising Peter N
--

Regards,

Eric Stevens
  #28  
Old June 2nd 18, 05:02 AM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 24,165
Default How can smartphone cameras work thru scratched lenses?

In article , Eric Stevens
wrote:


I would rather leave it to the author. What do you regard as the other
key point?

cop out.

it's very clear what it is and you don't have to read very far to find
it either.

It seems I don't have to read it at all if I'm relying on you to
explain it.


it's clear as can be.

you're arguing just to argue, as usual.


You are plagiarising Peter N


nope, and you've just confirmed that's exactly what you're doing.
  #29  
Old June 2nd 18, 06:18 AM posted to rec.photo.digital
David Taylor
external usenet poster
 
Posts: 1,146
Default How can smartphone cameras work thru scratched lenses?

On 01/06/2018 23:42, Eric Stevens wrote:
[] It seems I don't have to read it at all if I'm relying on you to
explain it.


Use the kill-file, Eric. Save yourself (and everyone else) a lot of
needless effort! You know you'll never be able to answer Mr. (Im)Perfect.

--
Cheers,
David
Web: http://www.satsignal.eu
  #30  
Old June 3rd 18, 10:49 AM posted to rec.photo.digital
Eric Stevens
external usenet poster
 
Posts: 13,611
Default How can smartphone cameras work thru scratched lenses?

On Sat, 02 Jun 2018 00:02:01 -0400, nospam
wrote:

In article , Eric Stevens
wrote:


I would rather leave it to the author. What do you regard as the other
key point?

cop out.

it's very clear what it is and you don't have to read very far to find
it either.

It seems I don't have to read it at all if I'm relying on you to
explain it.

it's clear as can be.

you're arguing just to argue, as usual.


You are plagiarising Peter N


nope, and you've just confirmed that's exactly what you're doing.


Prove it.
--

Regards,

Eric Stevens
 




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