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CCD size and low light sensitivity
There is something aboutt CCDs that I need to understand. It is
in conjunction with Digital Cameras. Photography people who are mostly familiar with film based may not be so with CCD so let me ask the questions here. One CCD has 5 megapixel capability with 9mm size. Another CCD has 2 megapixel capability with 12.5mm size. Using F2.8 lens. Is there evidence that the CCD with bigger size sensor (that I presume in the 2megapixel/12.5mm combo) is more sensitive to light such that using the same target at night such as indoor object with flourescent light, it should produce a brighter image using the same shutter speed of 1/30 secs and iso rating for example?? Thanks. Matt |
#2
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CCD size and low light sensitivity
As far as I am aware no. The brightness of the resultant image is
dependant entirely on the iso setting. Yes the larger pixels will collect more light, but the resultant charge will be amplified by a smaller amount to obtain the required brightness levels as determined by the iso setting. What should improve is the signal to noise ratio. There has been a lot of discussion on many camera forums recently about this subject, and the general feeling is that when comparing cameras with similar chips but different sizes, then the ones with larger pixels tend to give cleaner images with less of the random noise that one can see particularly in low light,long exposure images. Phil Bishop Matthew wrote: There is something aboutt CCDs that I need to understand. It is in conjunction with Digital Cameras. Photography people who are mostly familiar with film based may not be so with CCD so let me ask the questions here. One CCD has 5 megapixel capability with 9mm size. Another CCD has 2 megapixel capability with 12.5mm size. Using F2.8 lens. Is there evidence that the CCD with bigger size sensor (that I presume in the 2megapixel/12.5mm combo) is more sensitive to light such that using the same target at night such as indoor object with flourescent light, it should produce a brighter image using the same shutter speed of 1/30 secs and iso rating for example?? Thanks. Matt |
#3
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CCD size and low light sensitivity
Phil wrote in message ...
As far as I am aware no. The brightness of the resultant image is dependant entirely on the iso setting. Yes the larger pixels will collect more light, but the resultant charge will be amplified by a smaller amount to obtain the required brightness levels as determined by the iso setting. What should improve is the signal to noise ratio. There has been a lot of discussion on many camera forums recently about this subject, and the general feeling is that when comparing cameras with similar chips but different sizes, then the ones with larger pixels tend to give cleaner images with less of the random noise that one can see particularly in low light,long exposure images. Phil Bishop Hmm... supposed I want to take the shot of the moon (to be astronomy related or other low light indoor object) using the hand and I have to increase the shutter from the default 1 second exposure (as set by an average digital camera such as the 9mm Sony P10) to 1/30 sec or more to prevent blurred images from the hand shake with ISO both fixed at 100. What design changes in the CCD can give a brighter image? I'm evaluating what model can give a brighter image using similar ISO setting. Or if you are right in your comment that it is dependent entirely on ISO. In other words, you mean bigger CCD sensor can produce higher ISO with cleaner image such that it can create clean ISO 400 images compared to the ISO 100 using small CCD sensor? The digital cameras of years past all use bigger CCDs as it was then difficult to produce smaller ones. This means those cameras of years past are of greater quality that those now and could produce higher cleaner ISO image (?) Matt Matthew wrote: There is something aboutt CCDs that I need to understand. It is in conjunction with Digital Cameras. Photography people who are mostly familiar with film based may not be so with CCD so let me ask the questions here. One CCD has 5 megapixel capability with 9mm size. Another CCD has 2 megapixel capability with 12.5mm size. Using F2.8 lens. Is there evidence that the CCD with bigger size sensor (that I presume in the 2megapixel/12.5mm combo) is more sensitive to light such that using the same target at night such as indoor object with flourescent light, it should produce a brighter image using the same shutter speed of 1/30 secs and iso rating for example?? Thanks. Matt |
#4
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CCD size and low light sensitivity
While its true to say the older ccd's may have been bigger with bigger
pixels, you have to remember that there have been major advances in chip construction and design. Newer ccd's require less power, so there is less heat produced by the circuits (and heat is a major contribution to noise,)and they tend to be more efficient, so the signal to noise ratio is better. Also, with consumer cameras (and I am most familiar with the Nikon SLR's), a lot of effort has gone into the post capture processing hardware and software. This means that the newer cameras are considerably better than the older ones in terms of colour reproduction, noise, and overal image quality. Have a look at http://www.dpreview.com/ . Its the one camera review site I've found which tests cameras from a technical rather than subjective point. Phil Matthew wrote: Phil wrote in message ... As far as I am aware no. The brightness of the resultant image is dependant entirely on the iso setting. Yes the larger pixels will collect more light, but the resultant charge will be amplified by a smaller amount to obtain the required brightness levels as determined by the iso setting. What should improve is the signal to noise ratio. There has been a lot of discussion on many camera forums recently about this subject, and the general feeling is that when comparing cameras with similar chips but different sizes, then the ones with larger pixels tend to give cleaner images with less of the random noise that one can see particularly in low light,long exposure images. Phil Bishop Hmm... supposed I want to take the shot of the moon (to be astronomy related or other low light indoor object) using the hand and I have to increase the shutter from the default 1 second exposure (as set by an average digital camera such as the 9mm Sony P10) to 1/30 sec or more to prevent blurred images from the hand shake with ISO both fixed at 100. What design changes in the CCD can give a brighter image? I'm evaluating what model can give a brighter image using similar ISO setting. Or if you are right in your comment that it is dependent entirely on ISO. In other words, you mean bigger CCD sensor can produce higher ISO with cleaner image such that it can create clean ISO 400 images compared to the ISO 100 using small CCD sensor? The digital cameras of years past all use bigger CCDs as it was then difficult to produce smaller ones. This means those cameras of years past are of greater quality that those now and could produce higher cleaner ISO image (?) Matt Matthew wrote: There is something aboutt CCDs that I need to understand. It is in conjunction with Digital Cameras. Photography people who are mostly familiar with film based may not be so with CCD so let me ask the questions here. One CCD has 5 megapixel capability with 9mm size. Another CCD has 2 megapixel capability with 12.5mm size. Using F2.8 lens. Is there evidence that the CCD with bigger size sensor (that I presume in the 2megapixel/12.5mm combo) is more sensitive to light such that using the same target at night such as indoor object with flourescent light, it should produce a brighter image using the same shutter speed of 1/30 secs and iso rating for example?? Thanks. Matt |
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