Originally posted by Angel Perez Next point, going full frame adds one stop to your shot because it's a larger sensor. This helps tremendously in low light. If you go to a 645 you increase your iso by two stops because of this larger sensor. So a medium format camera at f5.6 is equivalent to a full frame at f4 and a cropped sensor at f2.8.
Originally posted by pathdoc Codswallop.
This equivalence thing is a load of horse you-know-what - the reason there is a difference is because with a different sized sensor behind the same focal length lens, the field of view changes, the distance changes, and the depth of field changes with it IF YOU MAINTAIN THE SAME COMPOSITION.
Pathdoc, it seems like you are unnecessarily bringing focal length equivalence and depth of field equivalence into a discussion about how larger sensors provide cleaner pictures at given ISO levels.
Originally posted by pathdoc But the light at f/4 on one sensor is the same as the light at f/4 on any other sensor; the difference is in the nature of the pixels and the signal processing gear behind the sensor.
It's pretty clear that if all else is held equal, including the generation of sensor tech and the megapixels, then a larger sensor will produce a cleaner picture at any given ISO level. This is simply due to larger sensors having more surface area exposed to light, and they therefore have more information from which to build the image. Are you really arguing otherwise?
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I see you mention "nature of the pixels". Is that a reference to pixel density? If your argument requires that pixel-density be held the same, then you could be right. But in the real world, that is kind of a meaningless point.
So a FF sensor has approximately 30x the surface area of the common 1/2.3" compact camera sensor. So if you wanted to say that a 1/2.3" sensor at 1MP produces an image just as clean as a FF sensor at 30MP since the pixels will be equal sized, and each pixel will be exposed to the same amount of light, then you may be right.
But in the real world, sensor resolution (pixel density) does not scale up at a constant rate with sensor size. If we did that, then small sensors would be limited to ridiculously low resolutions with almost no detail, or large sensors would output large resolutions that would be nearly unworkable on most computers.