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Learn to Use It!
The following post is from Australian photographer Neil Creek who is part of the recently launched Fine Art Photoblog, and is participating in Project 365 – a photo a day for a year – on his blog.
Welcome to the first lesson in Photography 101 – A Basic Course on the Camera. In this series, we cover all the basics of camera design and use. We talk about the ‘exposure triangle’: shutter speed, aperture and ISO. We talk about focus, depth of field and sharpness, as well as how lenses work, what focal lengths mean and how they put light on the sensor. We also look at the camera itself, how it works, what all the options mean and how they affect your photos.
This week’s lesson is Light and the Pinhole Camera
About Light
Light is everywhere, even where you can’t see it. Without delving too deeply into the mysterious physics of light, there are some basics that are helpful to know as a photographer:
- We only see light when it reflects from something, or we look directly at the source
- Light can be bounced (reflected) or bent (refracted) and always does so in predictable ways
- Reflected light scatters depending on the “smoothness” of the surface
- White light is made up of all of the visible colours
- Different coloured light has different energy levels or “wavelengths”
- Shadows occur when something comes between a light source and another surface
- Light varies hugely in brightness, and our eyes very cleverly adapt to see clearly in a wide variety of brightnesses
- Cameras are far less capable of “seeing” clearly in as wide a variety of lighting conditions
Fig 1.1.1 Light hitting a textured surface scatters in all directions, like water splashing from a thrown water balloon. Click for clearer version.These observations are pretty basic, and most of them are either obvious or should have been taught in the science classroom. As straightforward as they are, these basic points are at the heart of photography, and understanding them is very important. Throughout this course, and through your adventures with the camera, you will be working with some or all of these essential principles of light. If you are unclear about any of the above points, it would be helpful to do a little bit of independent research. You’ll find some good links for further reading at the end of today’s lesson, and I encourage you to explore further by searching the ‘net.
The central point of photography is turning light into an image. An image is actually just an illusion. Anything that is a representation in light of a real thing is an image. So how do we turn light, which scatters randomly around the universe into an image that we can recognise?
The Camera Obscura
Fig 1.1.2 – Imagine a typical outdoor scene with the sun shining brightly on a tree. The light from the sun travels in parallel rays, shown here in black. When they hit the tree, the light is scattered in all directions, shown in grey. This is known as “diffuse” light. Because of diffuse light you can see the pretty tree, as some of this scattered light hits your eyes.
Fig 1.1.3 – Now lets imagine we pitch a tent with perfect light blocking material and a tiny hole in one wall. To keep it simple, a single ray hitting the tree will diffuse in all directions, but only a very tiny sliver of that light will go through the small hole. If you were sitting in this tent in the middle of the floor and you closed one eye and looked through the hole from there, you would only see a very tiny part of the tree at once. If you move to the right a bit, you will see the left of the tree. If you move up, you will see further down the tree. Your view of the tree is opposite to the direction of your movement.
Fig 1.1.4 – Of course there is more than one ray of light hitting the tree. These rays reflect diffusely in all directions. This is why you can see more of the tree by moving around inside the tent. If we were to set up a screen in the tent opposite the hole, which is made of nice bright white material, we would actually be able to see an image of the tree, projected onto it! For the reason that we saw parts of the tree in the opposite direction when we moved, the projected image of the tree appears upside down.
Fig 1.1.5 A camera obscura made by blocking a window. Photo by brighterorange, used under creative commons.The room we just made in our imagination is called a “camera obscura” and you can make one just as I have described. Instead of a tent, you could find a room in your house with one window, and cover the whole window with thick card or foil. Then make a tiny hole (1-5mm) in the cover and look at the opposite wall. You should see a very dim, upside down image of the world outside.
The image will be dim because only a small amount of light can pass through the hole. If you make the hole bigger, the image will be brighter, but less sharp. Why is this? A small hole is very good at restricting the direction from which rays of light can enter the room. If the hole is bigger, then more light can get in, but that extra light comes from a bigger range of angles, and it overlaps nearby parts of the projected image.
 Fig 1.1.6 – A small hole through which the light passes, restricts the possible angles of light reflecting from a certain part of the tree. The overlap of light rays on the projection is very small and the result is a sharp image. The trade-off is that the image is dim. |
 Fig 1.1.7 – A large hole allows a greater variety of angles of reflected light from a particular part of the tree to pass through onto the projection. This means that much light from neighbouring parts of the tree overlap each other. This results in lower contrast and a blurry image. The benefit however, is that more light can get through and the projected image is brighter. |
How is it relevant?The trade-off between sharpness and brightness should be a familiar one to many photographers. The “hole” of the camera obscura is the aperture of a modern camera. When you open up the aperture you let more light into the camera, but the depth of field narrows, and more of the image drops out of focus. We’ll talk more about this in a future lesson.
The Pinhole Camera
The camera obscura is a very old idea, first built around 1000AD in what is now Iraq. A variation on the concept is the pinhole camera. This shrinks the room of the camera obscura into a handheld box, and is the simplest possible camera. Pinhole cameras can easily be made of almost anything. All it needs is a light-proof box, something to project the image onto, and a tiny hole. There are countless projects online to make your own pinhole camera, or make a pinhole “lens” for your DSLR. Due to the tiny hole used in these cameras, one advantage is that they have is an enormous depth of field.
Homework
To help you get a feel for the issues discussed in each lesson, I’m going to be assigning some homework. Naturally it’s completely voluntary, but you learn by doing, and practical exercises will certainly help you improve your photography. I list a few assignments below, and you are welcome to do any or all of them. Please post links to your completed homework assignments in the comments on this post.
- Make a camera obscura – Whether it be a tent or a room of your house, build and photograph a camera obscura in action.
- Visit a camera obscura – There are a handful of publicly accessible camera obscuras around the world as tourist attractions. Visit one and take photographs.
- Make a pinhole camera – There are many projects online to build pinhole cameras from matchboxes, sardine tins, or various other materials. Make one yourself and share photos you take with it.
- Make a pinhole attachment for your DSLR – By drilling hole in a body cap for your DSLR camera, putting some foil over the hole and making a tiny hole in the foil, you can turn any DSLR into a pinhole camera. Show us your modification and photos you took with it. Have a look at my attempt at this.
- Project the sun – This technique for viewing a solar eclipse can work all year round. Put a pin hole in a piece of card, and project the sun onto another piece of card. You will be able to see clouds pass in front of the sun, and maybe even observe sunspots. Share photos of your experiments.
Resources
- Specular vs Diffuse Reflection
- Camera obscura on wikipedia
- Pinhole photography on photo.net
- How to make a pinhole Polaroid camera on Make Magazine
- Making a pinhole “lens” for your DSLR
- Pinhole photography group on Flickr
Next Week
Photography 101 – Lenses and Focus.
In addition to posting his Project 365 photos to his blog, Neil also runs a monthly photography project. This month’s topic is Iron Chef Photography – The Fork.
Hi Neil,
Thank you very much for your lessons.
Here some of my "homeworks" or experimentations.
http://www.josephinedeclerck.com/#/blog/4559493082
Thanks again !
Hi from Spain! We are making a Camera Obscura Course several times during 2012, a good pretext to have a long weekend holiday. Cheers!
camera obscura course Andalucia: http://www.lei4sure.es/camera-obscura-weekend-in-seville/
great article, thank you very much!
Will give it a go some day, looks very interesting
This site has been more informing than most of the books I've read. Thank You.
Will be helping my young son create a pin hole camera for his upcoming school project. We'll both benefit for this project! Thanks.
Hi, I just wanted to thank all of you for putting your time in this. This really is helpful for a beginner liker myself. Thank you so much!
Hi. I am about to start my studies on phtotgraphy and found these quick lessons very helpful and my understanding is already much better, I especially love the pinhole camera and am going to make my own one to experinment with.
Thank You
Thank you!!!
I am just beginning to venture into the photo world beyond "auto" settings but there is so much confusing stuff for a novice out there! (novice with really big dreams :)
Your tutorials are fantastic and the best I have found at making everything "simple for dummies". Great work and excellent website!!! Thanks again.
great tutorial, thanks a lot!
Great tutoials,nice and easy to follow! Thanks.
I've been searching for a long time such of this site where professional photographers shares their techniques and ideas. it helps a lot. God Bless those generous soul who share their ideas for free...
This really helped to understand the concrpt of a pinhole camera! The pictures really really helprd me, too. Thanks!
Thanks for the great class!
Here's my effort for lesson 1 homework, a little late but better late than never!
I wrote a post about it on my blog: How to make a camera obscura
Excellent article - very well written, amusing and informative. Thanks! :-)
This is excellent, I can save myself thousands of dollars going to a course by learning from you guys. Thank you so much, you guys are so inspirational.
When I took photography my freshman year in high school, um..many years ago, we made cameras out of shoe boxes, using photo paper as film, it was a great learning experience. Also we made cameras out of card board and attched them to 110 film and took pictures that way. Another great learning experience!
Neil, my congratulations on your new undertaking! Illustrations are very professional, do you have some graphic background? BTW, here's a nice URL to go with this article: http://pro.corbis.com/creative/readycam/ - it has great DIY pinhole camera you can print and make out of photo paper and some film. They come in different designs with crazy patterns on them!
This is great. I really think I'll learn a lot from this site. I also can't wait to try out a pinhole lens on my next shoot. I'm sure I heard of them a long time ago, but never had any use for them so they were in the back dustbin of the brain, and you were able to bring out to the front. Thanks.
Thank you so much for the information! I'm a beginner in the DSLR world, for all intents and purposes, and this will definitely help with developing a base of knowledge that I can build upon and use to become a more serious photographer.
Did the DSLR body-cap-to-pinhole modification during a Photo class last semester for interesting results. To those trying this out: Do not be discouraged if your pinhole is too "big" and you are getting very fuzzy images! You can always make a new hole, but the fun of the pinhole is to focus more on light, color, and form rather than "Kodak moments"--although a friend of mine got a darling photo of her aunt and baby cousin with this technique.
For the experimenters: Light-block tape is the best to use, but since I didn't have any at the time, I didn't think GREEN DUCT TAPE would make a difference... But it definitely did, especially in the sun. Everything took on a green cast which I liked over the landscapes I'd shot.
If you decide to leave this on your camera for a long period of time, put tape over the hole on the opposite side of the cover from pinhole-tape. Don't want dust getting in. :D
This is great. I've told all my blog readers to check this out and I'll be intently awaiting your next entries!
fantastic post - can't wait to see your camera and lenses tutorial next! thanks
I love this first lesson. I understand!
Very informative tutorial. It is good to get a basic understanding of photography as todays high tech stuff for beginners can be very daunting. It is important the user controls the camera, it should not be just a matter of settings and buttons and let the technology do the rest.
Thanks
You're off to an excellent start! I'm already waiting for the next "chapter". Thank you!! :)
This is a great first lesson!
I've heard of a camera obscura before but never looked into them. And I've never made a pinhole camera.
So I love the homework and can't wait to give them a go...
Thanks
For those of you with DSLR the camera lens cover makes a great device for making a pin hole camera.
Do buy a spare cover as you need to drill a tiny hole in cap.
This hole will be too big as it is best to find metal coated mylar or plastic type film. Use a tiny pin and with paper backing make a tiny hole. glue this on the back of the camera and Vola a pin hole camera. Due keep in mind that the F-stop is about 264.
Therfore if a normal shot at f8 was 1/100 sec then the new setting will be about 8 stops more or about 2 sec.
This is only an approximation to get you in the right ball park. Use the histogram to fine tune exposure.
Niels Henriksen
of to a good start thanks.
By pure coincidence, I actually did this over the weekend with my Canon 30D and it's lens body cap, with a hole drilled in the middle and aluminum foil taped to the front with a pin hole it.
You can see the results here http://www.emmett-photography.com/gallery/4480148_H4oE3/1/263516714_E4JmJ
It's not a brilliant photo, but it's got me excited about trying this out more, with finer holes, etc. It was a great reminder to me about the basics of photography.
Thanks/Peter
Well done for picking that up! Yeah I proofread the thing five times, I got my wife to read it too, and I'm sure Darren had a look over. But we all missed it. And as soon as the story had gone live, I noticed *slaps forehead*. I've sent a couple of repaired images to Darren. So I'm sure he'll swap them soon.
Guys! Very nice post!
Only one thing: in fig. 1.1.6 and 1.1.7 the image formed by the light that comes through the hole should be upside-down
Good luck on your assignments everyone, I'm looking forward to seeing what you come up with!
A great tutorial, thanks!
One small thing - figures 1.1.6 and 1.1.7 need to have the image of the tree inverted.
I love you guys.. I am new to all this and these lessons are great.. My fav website so far.. thanks guys for all the hard work..
Thanks!
Keep them coming! :-)