Comparing optical zoom to MP

[akelley 0]

Is there a formula for determining the optical zoom equivalent of an MP image? For example, for a 3MP camera, its equivalent optical zoom is X (assuming the same lens on each camera) before the digital zoom degrades significantly? Or can you really not compare the two?

[shropna 0]

Is there a formula for determining the optical zoom equivalent of an MP image? For example, for a 3MP camera, its equivalent optical zoom is X (assuming the same lens on each camera) before the digital zoom degrades significantly? Or can you really not compare the two?

Hm. This is the simple calculations.... Just compare pixels quantity

But this is not true

Optical resolution for megapixel cameras is more difficult issue, then the pixels quantity

[akelley 0]

That's what I was thinking, but was hoping someone had a magical formula

 

Is there a formula for determining the optical zoom equivalent of an MP image? For example, for a 3MP camera, its equivalent optical zoom is X (assuming the same lens on each camera) before the digital zoom degrades significantly? Or can you really not compare the two?

Hm. This is the simple calculations.... Just compare pixels quantity

But this is not true

Optical resolution for megapixel cameras is more difficult issue, then the pixels quantity

[Soundy 1]

Apples and oranges, here. "Optical zoom" in cameras refers only to a ratio of the shortest to the longest focal length of a lens. For example, a 4-8mm variable focal length lens would be a "2X" zoom. 4-12mm would be 3X. So would 3-9mm, or 5-15mm. 2-12mm would be 6X... and so on.

 

Megapixel cameras typically use the same style of lenses as analog cameras, often with the same size sensor. Either way, the ratio remains the same. A 2.5-10mm lens on a 1/4" sensor would give about the same maximum field of view (at 2.5mm) as a 4mm-16mm lens on a 1/2" sensor - close to 90 degrees either way... yet both lenses have a "4X" zoom factor.

 

For that matter, a lens of any given focal length will produce the same size image on a 1/3" analog sensor as it would on a 1/3" megapixel sensor... the latter would just have more detail to that image.