Toralf Lund wrote:

>>> as has been pointed out many times there are perhaps 40,000 photons 
>>> available to be counted
>>
>> Wouldn't the number of photons vary considerably with exposure time
>> (shutter speed)?
>>   
>It's also a question of the number of electrons available. When a photon 
>hits the sensor, its energy will be used to move an electron from one 
>place to another, thus building up a charge (in an ideal senor - I think 
>a practical one will sometimes require more than one photon.) There is, 
>however, a limit to the number of electrons that may "jump" and/or be 
>held as a charge (no, not "held in charge"...). This limit is believed 
>to be approximately 40000 per pixel or photosite for the 10MP sensor.

This limit "is believed to be" 40000 per pixel?
Who believes this and why?
 
-- 
Mark Roberts Photography & Multimedia
www.robertstech.com
412-687-2835

-- 
PDML Pentax-Discuss Mail List
[email protected]
http://pdml.net/mailman/listinfo/pdml_pdml.net

Reply via email to