Photo Notes

July 16, 2018

Large Format Photography Class

I am teaching Large Format Photography at the Art Institute of Indianapolis this quarter. I will be posting a lot of information from this class, and edited audio versions of the lectures here, on my blog. If you would like to help edit the lectures please let me know! This is my first attempt at a pod cast, and it has some glitches. The information is good, and the presenter is enthusiastic

Here is the link to the first podcast:

I mentioned the quiz that I gave my students in a Facebook post. I was very disappointed by the outcome of the quiz I presented. So the first thing I want to do is go over the questions and answers, and how to get the right answers.

Question 1: You are shooting a waterfall. Your camera is on a tripod. The exposure is ISO 400 f8 and 1/125th of a second. You decide to use a 1/15 of a second to blur the water. You change your ISO to 100, what is your aperture?

The number of stops between 1/125 and 1/15 is 3. The change in the ISO, from 400 to 100 is 1 stop. So you need to change your aperture by 1 stop, that is from f8 to f11. The answer is f11.

Question 2. What stop is 3 stops less light that f5.6

1 stop less light is f8, 2 stops is f11 and three stops is f16. The answer is f16

Your exposure is 1/125th of a second and f4 and ISO 200. You want to use f8 and keep your shutter speed at 1/125 what would you change your ISO setting to?

The difference between f 4 and f8 is 2 stops. So you need to change your ISO by 2 stops. ISO 400 is one stop, 2 Stops is ISO 800. The answer is ISO 800

The standard shutter speeds are

1, ½, ¼, 1/8, 1/15, 1/30, 1/60, 1/125, 1,250, 1/500, 1/1000.

Each change lets in less light

The standard apertures are

1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22

Each change lets in less light

The standard ISO numbers are

100, 200, 400, 800, 1600, 3200

Each change INCREASES sensitivity

The difference between any two of these numbers, say f8 and f11 or 1/125 and 1/250 or ISO 100 and ISO 200 is one stop. That is the same amount of light. A one stop aperture change changes the exposure in the same way a one stop change in shutter speed or a one stop change in ISO would. You make decisions primarily based on how you want to affect depth of field or stop action.

There are intermediate numbers, like f1.8 or 1/100 or ISO 125. These are between the full stop numbers. They are generally a ½ or 1/3 stop change from a full aperture number or shutter speed. The eye can recognize a 1/3 stop change.

You should KNOW THESE NUMBERS.

This is a photomicrograph of an Autochrome. Autochromes were the first easy, well sort of easy, way to make color photographs. It shows how red green and blue particles of potato starch are used to record color with a monochrome emulsion. Some of you may be aware that this is how your digital camera records color. Red green and blue are recorded by specific pixels. Digital cameras use a Bayer Filter to record this information rather than the random potato starch grains of an Autochrome, but your digital camera uses a solution from 1907 to take color pictures!

These articles have some bearing on the subject of this and the next few posts.

Hand Assembling Lenses for the View Camera

Microphotography

Camera Building

And, just a reminder, here is the link to my DIY Page.

I hope you’ll also check out my books, use the links below:

One more thing, there are almost 8500 people registered on this blog. Wow! Thanks everyone.

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