Tag Archives: explanation

Composition – Creating many photographs with different crops of an original

Composition – Creating many photographs with different crops of an original

Some of your photographs have the potential to look interesting with many different crops. Of course cropping reduces the resolution of your image, makes the noise more visible and reduce sharpness so you have to judge for yourself how much your are willing to crop.

For this article, I made an experiment with a photograph that I took of the singer songwriter Doctor Robert. There you can see how many variations are possible from a single image, and I invite you to experiment the same with your images.

http://www.damienfournier.co. Example of creating many photographs with different crops of an original

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damienfournierco

August 3, 2014

The simplified Formula of Depth of Field

The common photographer knows that the Depth of Field varies with the aperture, focal length and subject distance. But which one is the dominant parameter ? And how much is the influence of each parameter ? This article uses the equation of the DoF, and demonstrates that when the DoF is short, it varies proportionally with the aperture, and with the square of the focal length and distance to subject.

So here comes the only formula you need to know when you deal with short DoF but not macro photography :

dof_formula_3
- A is the aperture number
- c is the circle of confusion
- f is the focal length
- s is the subject distance
- H is the hyperfocal distance
- DoF is the depth of field

In the rest of the article you can read where this simplified formula comes from, what it means in practice, and how accurate it is compared to the exact formula of DoF.

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damienfournierco

March 15, 2014

Depth of Field and Subject Magnification

The focal length and the distance to subject have an influence on the Depth of Field, and this influence is simple to understand if it is explained with the notion of subject magnification. The subject magnification is a function of the focal length and the distance to subject. It is the parameter that influences the most the DoF, much more than the aperture. This articles explains what is the subject magnification and in which way it impacts the DoF.

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damienfournierco

February 25, 2014

Composition – Why do parallel lines converge ?

Parallel lines can be projected either as parallel or as converging lines on a 2 dimensional photograph. As converging lines they are considered a distortion of the reality, nevertheless they can be useful to give the illusion of depth. It is your choice as a photographer to represent those lines parallel or not, and this article explains how to control it.

composition_parallel_lines_tower12

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damienfournierco

February 14, 2014

Depth of Field and Aperture – A simple relationship ?

It is common knowledge among photographers that the Depth of Field increases when the aperture decreases, but by how much ? Unfortunately there is no simple relationship between the DoF and the aperture, but this article provides a accurate and simple answer to the question.

dof_aperture_7guitars

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damienfournierco

February 7, 2014

Flash Technique – The 1st and 2nd curtain explained

A DSLR camera provides the option to fire the flash on the 1st or 2nd/rear curtain, which can produces different photographs in the same conditions.  This article explains what it means, and how to use it.

The series of pictures below shows a tennis ball falling down, captured with different settings of flash and ambient light. It put in evidence the influence of setting the flash on the 1st or 2nd curtain.

flash_technic_curtain_drawing_2The rest of the article also explains what are 1st and 2nd curtains, and provides recommendation on which setting is better.

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damienfournierco

February 1, 2014

Depth of Field and Hyperfocal Distance

The Depth of Field (DoF) increases with the distance to the subject, and even becomes infinite beyond a certain distance, which is called the hyperfocal distance. This article tells you everything you need to know about it…

dof_near_and_far_limits

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