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#21
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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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