Sunrise over Coquet Island
23rd February 2016
New Computer
12th March 2016

Another Coquet Sunrise

There’s nothing better than getting up early in the morning and going for a brisk walk looking for photo opportunities. It clears the mind, gets the heart beating and the early morning light is fantastic.

OLYMPUS DIGITAL CAMERA

Coquet Sunrise

That sunrise was yesterday. I got up early so before the sun came up I could take long exposure test shots. I was deliberately over-exposing in manual mode by keeping the shutter speed and aperture the same and increasing the ISO to reduce noise.  Yes, that sounds counter intuitive, but this is how it works.  Long exposures create more noise because the sensor heats up as the ratio of electromagnetic radiation, which can cause noise, to photons increases.

Usually, by increasing the ISO one reduces the shutter speed or aperture to compensate, letting less light onto the sensor, causing the amount of noise to increase in relation to the reduced number of photons hitting it.  By making the ISO higher and keeping the other settings the same one is not affecting that ratio. The ISO setting is not making the sensor more sensitive but an in-camera amplification of the signal sent from the sensor to the processor. In this way the information in the highlights is not lost from the raw file.

Reducing the exposure in Lightroom brought some nice test results and I was able to recover blown highlights that were apparently four stops over-exposed. The result was much cleaner than a correctly exposed image taken at the native ISO for my camera.

OLYMPUS DIGITAL CAMERA

Test shot before Dawn

 

1 Comment

  1. Julie says:

    That second shot is a real stunner, Ivor. I love the blue mood. 🙂

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