Using a polarizer versus changing the sky with selective AI - Can you tell which is which?

Which photo is shot without a polarizer, altered in post , or shot with a polarizer?

Three photos.  One was taken without a polarizer filter.  That same image was then altered in Photoshop by selecting the sky using AI.  The third was a different photo shot with a polarizer.  Can you tell which one is which?

The first one (left) was photographed without a polarizer and the second one was a separate photo using a polarizer filter.  The last image (right) used the original and adjusted it by selecting the sky (AI select) and altering the image using Levels.

You can see the differences made using the polarizer.  The bench is a slightly different colour as some of the polarized blue light from the sky was removed.  The tree in the background is he same; the greens are a little truer.  The most glaring change is the reflection off the water as there is less reflection.

However, if you don't have a polarizer and want to simulate its affect on the image, you can do this using the technique I followed.  The trick here though is to use AI in the selection process as selecting the sky from the tree would take a very long and arduous time.  With AI it took me all of a minute to make the change.

A polarizer makes far more changes to the scene than you can simulate.  The white balance is truer, reflections are curtailed, and skies are noticeably altered (under the right circumstances).  Plus there is the reduced work in post and no need for a pixel editor with an AI interface.

Polarizer filters reduce the light by between 1.3 to 2 stops.  This is not usually a problem when shooting scenics as that can be overcome with adjustments in exposure.  However, if that light loss is critical and you need the polarizer effect, simulating it may be the best solution.

Thanks for reading.

Eric Svendsen     www.ericspix.com

Comments

Post a Comment

Popular posts from this blog

Harjit Bahia - Science teacher and colleague from Garibaldi died August 2, 2024

Image
You will be missed Mr. Bahia.  You made a difference and we are sad you are gone. I keep in loose contact with my fellow retired teachers from Garibaldi Secondary School.  I talked with my long-time friend, Mike Lynch, today, and discovered that Hargit died over the summer.  Unbeknownst to him, he had an underlying heart condition and passed away after working out on his treadmill.  The date was August 2, 2024. I was shocked to hear this.  He was only 49 years old, turning 50 some 3 months later.  It was a shock to everyone, for he was loved by all who knew him.  As a teacher, Mr. Bahia was kind and fun.  He contributed to students in many ways and was always available to help those in need.   For myself, I knew him as a fellow science teacher and taught in the adjoining room to him.  He was always available to help, share ideas, and work together.  Easy to approach, I found that I could talk to him about anything and appreciat...
Read more

I found a black widow spider in a plant pot today

Image
The spider I found is a western black widow spider, one of three species of black widow that occur in North America.  The fact that this one has another red patch on the back of its abdomen above the spinnerettes tells us that it is an immature individual. The one thing that people know about black widow spiders is that they are extremely poisonous.  Their venom is something like 15x more toxic than that of a rattlesnake.  The saving grace is that there is very little venom injected from a black widow bite than what a rattlesnake can deliver.   The good news is that black widow bites seldom lead to death.  You are more likely to suffer nausea, muscle pain, and swelling around the bite.  Symptoms usually last only 12 hours or so.  Death may be a result in people with compromised immune systems or in the very young or the elderly.   In 2018, it was reported that there were 1015 cases of people bitten by black widows.  Of those, there ...
Read more

The passing of a generation

Image
Kathryn's mom and dad with our children, Josh and Leanne. A generation, for North America, tends to be between 20 and 30 years.  During that time a couple will give birth and raise children to see them repeat the pattern as they themselves have done.  Each generation has its own set of standards, values, and ideals based upon their experiences and culture, and some of that is passed down to their offspring.  What changes are the life experiences of the following generation and the new customs and ideals that are blended together as a couple becomes a family. Kathryn's mom passed away a few days ago, she was predeceased by her husband several years ago.  Both of them were the grandparents of my children, the mother and father of my wife, Kathryn.  It was my pleasure to know them and to love them as my own, for to me they were Mom and Dad.  And they were there to welcome my children into the world just as my children were with them in spirit when they left it...
Read more