# Is Gamma Still Needed?: Part 9 - Processing In Floating Point

Floating-point notation and gamma are both techniques that trade precision for dynamic range. However they differ fundamentally. Gamma is a non-linear function whereas floating point remains linear. Any mathematical manipulations carried out on floating-point encoded data will be correct whereas manipulations of gamma-encoded luma cannot be. Gamma was intended to linearize a cathode ray tube whereas floating point encoding was designed from the outset for mathematical manipulation.

Fig.1 The transfer function of a 16-bit quantizer is shown at a). If a sixteen bit number is expressed to 12-bit accuracy, the steps b) become four times larger. In floating point this can only happen in the presence of a signal, so the approximation is masked.

Fig.2 A five-bit exponent has 32 combinations. The ends of the scale denote zero and infinity, leaving fourteen negative values, zero and fifteen positive values for the exponent.

Fig.3 Addition first requires the exponents to be the same. Then the mantissae are added and the result is re-normalized.

Fig.4. When a mantissa is shifted right, three bits shifting from the end are considered. These are the guard, round and sticky bits that are used to optimize the normalization.

# Creative Analysis: Part 22 - Cinematographer Jonathan Furmanski On Search Party

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# HDR: Part 24 - Creative Technology - Artificial Intelligence

Every decade has had a buzzword. Watch a 1950s educational movie and realize how dated the term “atomic” sounds now, and not only because the downsides of nuclear power have since become so painfully apparent. Since then, we’ve been sold …

# HDR: Part 23 - DOPs: How Useful Is The iPhone Really For Professional Production?

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# Essential Guide: Flexible IP Monitoring

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# Creative Analysis: Part 21 - Cinematographer Markus Förderer On Bliss

Speculative fiction is something that’s often hovered on the borders of drama, fantasy and sci-fi, and one of the huge benefits of the streaming media revolution is that much more of the genre has found a way in front o…