The Joy of Hack » Photography

Don’t Submit Photos To Frommer’s Contests

Aijaz Ansari — Sat, 13 Mar 2010 05:01:04 +0000

I’m not a professional photographer. I’m merely an student of the art and science of photography. Sometimes I think of submitting my pictures to contests or for use by others – not for the money, but for the personal satisfaction. Now after reading this post by Bob Krist, I’ll make sure to pay attention to photographers’ rights when I submit my pictures anywhere. I will also refuse to buy any product from Frommer’s Travel Guides, and urge you to do the same.

As Bob points out, when you submit a photograph to Frommer’s not only do they want the rights to use it for the stated purpose, they also want all rights to do anything with your picture, even license it out to others for perpetuity. In other words, they are asking for the rights of the photographer, without paying for what those rights are worth. This is regardless of whether a photo is accepted for publication or wins a contest or not. It appears that they’re counting on the fact that most people who submit photos will not read the fine print, or will be amateurs who are just happy that they have a picture good enough to send to a competition. As Bob correctly points out, this kind of action will end up ‘kill[ing] the freelancers’ who make their livelihoods selling the rights to use their pictures, not all the rights to their pictures.

I went to their website and entered the following on their ‘Contact Us’ page:

This is is regard to the issues brought up at Bob Krist’s blog, found at http://www.bobkrist.com/blog/frommers-now-fing-freelancers-and-photo-enthusiasts/

I’m not a professional photographer but I am a frequent traveler. I just want you to know that I find your company’s take on photographers’ rights reprehensible, and that I intend to boycott you and your products, and urge all my friends and family to do the same – until you change your policy on seeking perpetual rights for submitted photographs.

Please reconsider your position.

Sincerely,

Aijaz Ansari.

Keeping true to my word, I urge you, readers of this blog, to boycott Frommer’s products in protest of their licensing policies.

A Stop Sign in Sharjah, U.A.E.

David duChemin On Being A Professional Photographer

Aijaz Ansari — Wed, 10 Mar 2010 13:44:48 +0000

I recently discovered David duChemin’s blog. I’d like to share a couple of his posts with you. In ‘Just?’ he offers advice to people who consider themselves ‘just an amateur photographer.’ In his follow-up piece ‘Confessions of a So-Called PRO’ he serves up an ‘anti-pep-talk’ that demonstrates that professional photographers aren’t necessarily that different from amateurs like you and me.

Camera Clock Correction After The Fact

Aijaz Ansari — Sun, 07 Feb 2010 05:40:25 +0000

I had this dilemma a few days ago: I had taken almost 4,000 pictures during a vacation 12 months ago. The vacation was in Asia (two continents over), and the time on my camera was wrong. I was importing the pictures into Adobe’s Lightroom, and wanted them to have the correct time just in case I wanted to know when in the day certain pictures were taken. I thought of looking for pictures taken during sunset, and then using solar calendars to figure out when sunset was at a certain landmark on a certain day of the year. But then I had a better idea:

Surely in those 4,000 pictures there must be at least one picture with a wall clock or a watch in the picture. After scanning through thumbnails of the pictures, I finally found one photo where a person seating across from me at a restaurant had his left hand by his face and there, prominently displayed, was the face of his wristwatch. After zooming in on the wristwatch I was able to make out the local time (8:49 p.m). The camera thought the time was 10:28 a.m. That made it really easy: I was able to switch all pictures 10 hours and 21 minutes ahead, and just like that all my pictures now had the correct time.

When I travel I usually forget to reset my camera clock. Now I know a surefire way to set the correct time on pictures: Take a snapshot of a wall clock at least once during the trip. This way I tell the difference between the real time (the one on the wall clock) and the one in the camera. I’m sure others have found out this trick before me, but I’m very happy that I came up with this quick and dirty hack all by myself.

Here’s one of the pictures from that trip:

A Stone Window - Taken during a recent trip to Asia

What Is An F-Stop?

Aijaz Ansari — Fri, 05 Feb 2010 04:20:37 +0000

In a previous article we looked at how lenses work. We learned about the focal length. Today we’ll focus on camera lenses and what the term f-stop means.

The term f-stop is a ratio. It has no dimensions. You don’t measure an f-stop in meters, inches, kilograms or even degrees Fahrenheit. An f-stop is the ratio of two distances. It’s the ratio of the focal length of a lens to its diameter. In figure 1, the f-stop is f/d where f is the focal length and d is the diameter.

The f-stop of this lens is f/d

Why do we care about a lens’s f-stop?

Before we answer this, let’s review how cameras work. A camera uses a lens to focus light on one side of the lens (the outside) onto a film or sensor on the other side of the lens (the inside of the camera). The more light that falls on the film or sensor, the brighter the image will be. Most films or sensors need a certain minimum amount of light in order to take a good picture (one that’s not too dark). If there’s too much light, though, the picture will be too bright.

Now, in photography terminology, the size of the hole that light passes through is known as the aperture. As a simplification, you can think of this as the effective diameter of the lens. In other words, d is the diameter of the aperture. The bigger the aperture, the more light will pass through, and the brighter the picture will be. So you can see why d is important. The bigger the aperture, the less time you need to pass a sufficient amount of light for a good picture.

You can use the bucket analogy: think of the lens as a hole in the bottom of a bucket. If you want to drain the bucketful of water through that hole, the bigger the hole, the less time you need for the bucket to drain.

Another measurement of a lens that’s important is f, the focal length. Lenses with a small focal length are called wide angle lenses — they allow light from a wider angle to pass through the lens and onto the film (or sensor). Lenses with a large focal length are called telephoto lenses — they allow a smaller cone of light into the lens, but the benefit is that picture is bigger (you can see things far away clearly).

So now we can revisit why we should care about a lens’s f-stop. The f-stop is defined as f/d, so if you have two lenses with the same focal length, the one with the smaller f-stop will have a larger aperture – it’s diameter will be larger and it will allow more light through.

Why are advertised f-stops numbered so strangely?

Lenses are circular. The apertures through which light travels are circular. The amount of light that can pass though the lens depends on the area of the circle that defines the aperture. The area of a circle is πr² where r is the radius, or half of the diameter.

F-stops are defined so that every consecutive f-stop either doubles or halves the amount of light entering the lens. To get area to double or halve at every adjacent f-stop, the ratio of adjacent f-stops need to be the square root of 2 (1.414). A more detailed explanation can be found here.

Why don’t we just use the diameter?

The definition of the f-stop is a way to have different lens manufacturers agree on a standard. Two lenses with an f-stop of 1.4 means the same amount of light can enter the lens, regardless of the focal length of the lens. This also allows for lightmeters to display their results without having to know what lens you’re using to take a picture.

References

Licenses

Figure 1was adapted from
http://en.wikipedia.org/wiki/File:Focal-length.svg and is licensed under
the Creative Commons Attribution ShareAlike 3.0 License.

Digitally Blending Photos With Adobe Photoshop

Aijaz Ansari — Tue, 26 Jan 2010 02:41:48 +0000

I’m interested in tinkering with High Dynamic Range photography, but before I get Photomatix, the software that’s recommended most often, I thought I’d try out a technique that’s a very crude approximation of HDR. It involves taking one image that’s underexposed, and one that’s overexposed, and merging them in Photoshop. The technique is described in this article at luminous-landscape.com. Essentially, you put the underexposed image in a layer above the overexposed one. Create a layer mask on the darker layer, and copy the brighter image to the layer mask. Apply a Gaussian blur to the layer mask, and you have your blended image.

I took 3 shots, one underexposed, one overexposed and one correctly exposed (the Programed Auto setting on the camera). Then I blended the first two images and compared the resulting image with the correctly exposed one. I like how the blending brought out the dark areas, and lessened the washed out highlights. I can’t wait to try this outdoors, when the weather gets a little warmer. It’s a very quick and simple technique, and might work out well for some kinds of landscape photography.

What do you think? Is the blended image decent?

The Underexposed Image

The Overexposed Image

The Blended Image

The Correctly Exposed Image

How Camera Lenses Work

Aijaz Ansari — Sat, 23 Jan 2010 17:27:46 +0000

This is the first in a series of blog entries on photography. Today we look at one of the most critical parts of any camera – the lens.

Have you ever noticed that people can run faster on flat ground than on sand or water? It’s the same way with light. Light travels faster in air than in glass.

When light travels through air it moves at roughly the ‘speed of light.’ When light hits a glass surface, it can’t move as fast, and slows down. If the light hits the glass at an angle, something very strange happens. It bends a bit.

Imagine a car driving off an asphalt surface onto a sandy pit at an angle. As shown in Figure 1 below, the right wheel gets onto the sand first, and slows down a little bit. Meanwhile, the left wheel is still moving at the original speed. This causes the car to turn slightly towards the right.

Figure 1

Light behaves the same way – depending on the angle at which it hits the glass, it bends a little bit or a lot when it starts moving in the glass. Similarly, light also bends when it comes out of glass into the air.

Figure 2

Now, a lens is just a specially shaped piece of glass. A convex lens is one that bulges outward. When a beam of light hits a convex lens ‘head on’ (parallel to the principal axis), the shape of the lens will cause the light to bend so that it passes through a point known as the focal point. For every lens there is only one focal point, and the distance between the focal point and the lens is known as the focal length. This is shown in Figure 2.

Objects reflect rays of light in all directions. When rays of light reflected off a nearby object hit a convex lens the features of the lens cause the rays of light to converge on the other side of the lens in such a way that the object appears upside down, as in Figure 3. The image will appear sharp (focused) at a distance that depends on the focal length of the lens and how far away the object is from the lens. This is essentially how cameras work. They bend the light so that it appears focused on a film or, in the case of digital cameras, a sensor.

Figure 3

Now that we know the basics of how lenses work, we can look at commercial camera lenses and see what f-stops are.

References

Licenses

Figure 2 was adapted from
http://en.wikipedia.org/wiki/File:Focal-length.svg and is licensed under
the Creative Commons Attribution ShareAlike 3.0 License.
Figure 3 was taken from
http://upload.wikimedia.org/wikipedia/en/thumb/7/71/Lens3.svg/550px-Lens3.svg.png and is licensed under
the Creative Commons Attribution ShareAlike 3.0 License.