Hello everyone, I am new here so forgive me if this is a question that has been answered 5000 times on this site already. I have an Olympus C-720 which is old as dirt. I am considering purchasing a Nikon D50 but I am undecided on what focal length lens I want to get. The one thing I like about about SLR-like digital cameras is the amount of optical zoom they boast. My Olympus has 8X zoom so I want to make sure I have at least the same amount of "reach out and touch something" power. I have recently stumbled across the term, focal length multiplier or FLM for short. My understanding of how to get this number is by taking the diagonal measurment of 35mm film (43.3mm) and dividing the diagonal measurement of the digital sensor into it.
Olympus C-720
Sensor size - 5.27 X 3.96 = 6.592 diagonal ----------- 43.3 / 6.592 = 6.56X FLM.
Actual focal length - 6.4mm - 51.2mm ---------- 6.56((6.4)(51.2)) = 41.984mm - 335.872mm.
335.872 / 41.984 = 8 times optical zoom exactly.
Olympus puts the 35mm equiv. of this lens at 40mm - 320mm, which divided gives 8X
So what I get with the camera above is fantastic zoom with only a 6.4mm - 51.2mm lens because of the ridiculously small sensor that produces a very cropped image. Now lets look at the Nikon D50.
Nikon D50
Sensor size - 23.7 X 15.5 = 28.3185 diagonal ------------- 43.3 / 28.3185 = 1.529X FLM.
Example DSLR lens - 70mm - 300mm ---------- 1.529((70)(300)) = 107.03mm - 458.7mm.
This is the part that confuses me. I can use the same method that was used to determine the power of the C-720 or I can use the method that consist of taking the telephoto end of the focal length and dividing that by 50mm (what the human eye sees).
C-720 method - 458.7 / 107.03 = 4.23 times optical zoom
/ 50mm method - 458.7 / 50 = 9.174 times optical zoom
Which is right??? My reasoning leads me to determine that with a 300mm zoom lens on the Nikon D50 I would have more zoom than the C-720 does. Something else just occured to me - If I take the FLM focal length of the C-720 and divide that by 50 it gives me 6.72 times optical zoom. So does the C-720 have 8X zoom or 6.72X zoom? Thanks alot! Sorry this is so long.
Nathan