Luminous Landscape Forum

The Art of Photography => Landscape Showcase => Topic started by: shadowblade on December 13, 2020, 11:16:34 pm

Title: Melbourne skyline at sunset
Post by: shadowblade on December 13, 2020, 11:16:34 pm
Sunset over Melbourne from Point Ormond.

Sony A7r3 with Sony 100-400mm f/4.5-5.6 GM. 16 averaged shots at 135mm, f/9, 1/640s, ISO 640.

A technically challenging shot - due to the wind, a single shot at less than 1/400s or so was impossible, even with a sturdy tripod, with or without IS. But shots taken at 1/640 were each individually sharp, and could then be stacked and averaged to produce the equivalent of a longer exposure at a lower ISO. 16 shots at 1/640, ISO 640 gave the equivalent of a single 1/40 exposure at ISO 40, without the camera shake issue.
Title: Re: Melbourne skyline at sunset
Post by: Paulo Bizarro on December 14, 2020, 03:57:50 am
Excellent work.
Title: Re: Melbourne skyline at sunset
Post by: Slobodan Blagojevic on December 14, 2020, 09:05:23 am
... 16 shots at 1/640, ISO 640 gave the equivalent of a single 1/40 exposure at ISO 40, without the camera shake issue.

Can you dumb it down for me, please?

Is that technique the same/similar as this one:

https://blog.kasson.com/the-last-word/averaging-images-in-photoshop/
Title: Re: Melbourne skyline at sunset
Post by: shadowblade on December 14, 2020, 07:09:41 pm
Can you dumb it down for me, please?

Is that technique the same/similar as this one:

https://blog.kasson.com/the-last-word/averaging-images-in-photoshop/

A single image taken at 1/640, in this lighting, doesn't capture a huge number of pixels, and required ISO 640 for proper exposure (some shadow detail and intact highlights). For a landscape image, this is quite noisy

Add a second image and average it and you now have 2/640 of exposure (i.e. 1/320), while averaging the random noise out, equating to an effective ISO 320.

Repeat it up to 16 shots and you end up with 16/640 (i.e. 1/40s) of total exposure, with an effective ISO 40.

It's the same stacking technique used in astrophotography to separate faint stars from background noise.