How Do I Measure Noise Using Photoshop? And What Is A Significant Change?

Started 2 months ago | Discussions thread
photonut2008 Veteran Member • Posts: 4,962
Re: How Do I Measure Noise Using Photoshop? And What Is A Significant Change?

FingerPainter wrote:

MrBrightSide wrote:

to measure the noise in a photograph.

The usual measurement for noise in a photo is Signal to Noise Ratio (SNR), expressed in decibels (dB). The SNR of images taken with modern digital cameras tends to track the square root of the exposure (in lux seconds) closely.

Measurement of S/N for some part of the scene which will have a range of signal strengths that constitute the dynamic range (DR) of the scene.

Question 2: Once the noise is measure what constitutes a significant difference in the noise level? Does it fall at 1 percent noisier? 10 percent? 100 percent?

A 3dB difference, which represents the change in noisiness related to a change of 1 stop of exposure, can often be detected by the human eye, but perhaps not without pixel peeping.

It could also be expressed as a lost stop of DR. How many stops of DR that you can afford to lose before the primary subject and important shadow detail are starting to be buried in noise depends on the camera model (and or any cropping), the output size, and to some degree subjective and personal considerations.

-- hide signature --

Internet Interlocuter

Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow