Posts Tagged ‘exposure’

A Year-Long Exposure of the Toronto Skyline

On January 1st of last year, photographer Michael Chrisman began shooting a solargraph by placing a pinhole camera in the Port Lands of Toronto and aiming it at the city’s skyline. Over the next 365, the rising and setting sun slowly exposed the photo paper inside. The total exposure time? 31,536,000 seconds. Instead of developing the image using traditional darkroom chemicals, he instead used a scanner to capture the extremely overexposed image — destroying the original image in the process — and ended up with the photo you see above. Those yellow lines you see in the sky shows the gradual shifting of the sun’s path over the course of 2011.

(via Toronto Star)


Image credit: Photograph by Michael Chrisman and used with permission

Photo of a Nuclear Explosion Less than 1 Millisecond After Detonation

This might look like some kind of microscopic organism, but it’s actually a high-speed photograph of a nuclear explosion. It was captured less than 1 millisecond after the detonation using a rapatronic camera, which is capable of exposure times as brief as 10 nanoseconds (one nanosecond is one billionth of a second). The photograph was shot from roughly 7 miles away during the Tumbler-Snapper tests in Nevada (1952). The fireball is roughly 20 meters in diameter, and three times hotter than the surface of the sun.

(via Wikipedia via Damn Interesting)

Kaufmann’s Posographe: An Amazing Exposure Calculator from the 1920s

Kaufmann’s Posographe is an intricate pocket-sized mechanical calculator invented back in the 1920s. Measuring 13x8cm and filled with tiny scribblings, the device allowed photographers to approximate the exposure values they needed by simply sliding around six small pointers.
Read more…

Exposing to the Right May Not Be as Right as Sensors Improve

Exposing to the right” is a well-known rule of thumb for maximizing image quality by pushing exposure to avoid noise, but the equation is changing as the quality of image sensors continues to improve. Ctein over at The Online Photographer writes,

In theory, you can still use the dubious right-hand rule. Just be careful to never blow out any pixels.

[...] Unless you’re sure you’re dealing with a low contrast subject, pushing your exposure to the high side makes it likely you’ll blow highlights. If you’re trying to improve your odds of getting a good exposure, pulling away from the right is a much smarter thing to do. If you know your subject is really high in contrast, pull far, far away from the right. Keep those highlights under control and let the shadows go where they may.

[...] Just, whatever you do, don’t expose to the right unless you’re absolutely positive there are no highlights to get blown. It was a questionable rule to begin with; these days I call it downright dangerous.

‘Expose to the Right’ is a Bunch of Bull [The Online Photographer]


Image credit: Out and about again by c@rljones

Old School Rotary Exposure Calculator

Want to challenge yourself by shooting manually without a light meter? Head on over to eBay and pick up a Johnson “Standard Exposure” Calculator for less than $10. Released in the late 1940s, it’s a simple rotary device that lets you calculate the proper exposure by choosing the current scene, weather, exposure time, and film speed. Find more about these exposure calculators over on photomemorabilia. You can also check out the Exposure-Mat for a printable card that helps calculate exposure too.

(via swissmiss)

Future Cameras May Be Equipped with Invisible Flashes

Future generations of photographers may one day look back and wonder why we often blinded each other with painfully bright flashes of light for the sake of proper exposure.

NYU researchers Dilip Krishnan and Rob Fergus are working on a dark flash that eliminates the “dazzle” effect of regular flashes in a low-light room. They’ve created this camera rig that combines common infrared photography techniques with an ultraviolet flash that produces a dim purple glow instead.

The team placed an infrared filter on the lens of the Fujifilm S5 Pro, which is has a modified CCD sensor that specializes in IR and UV photography. To supplement existing UV light, the team created a modified filter on an external flash to emit only UV and IR wavelengths. Read more…

Photojournalist Develops Last Produced Roll of Kodachrome

It’s the end of an era. Photojournalist Steve McCurry has developed the last roll of Kodachrome film produced by Kodak.

National Geographic has been following the final journey of the last Kodachrome roll ever since Kodak’s announcement last year that it would retire Kodachrome. Kodak has been manufacturing Kodachrome since 1935.

McCurry developed 36 slides on Monday at Dwayne’s Photo Service in Parsons, Kansas, which is the last labs to process the film type. The final images were shot in New York City, but the last three frames were taken in Parsons.

If you’ve got undeveloped canisters of Kodachrome of your own, Dwayne’s will develop them only through December of this year.

(via Associated Press)


Image Credit: Old Kodachrome canisters by Ryan Sahb

A Long Exposure Desk Portrait

On the same day I was experimenting with the light painting I described in a post yesterday, I also fiddled around with long exposure portraiture. I had my buddy Aaron pose for me at his desk in near darkness. The only sources of light in the room were his laptop screen, a few LED flashlights that I placed on his desk in various directions, and a lighter that Aaron held in his hand.

Here’s the original, unedited photograph that resulted:

aaron2

It was taken with a 10 second exposure at ISO 100. It was probably a mistake to use such a low ISO, since I could have gotten the same exposure with less time if I had used a higher number. Every time the ISO number doubles, the shutter speed is cut in half for the same exposure (assuming aperture is kept constant). This is pretty intuitive, since if you double the sensitivity of your film, you’ll only need half as much time to expose it with the same amount of light.

Keeping the aperture at a constant f/8, here’s what the difference would have been.

ISO 100 – 10 second exposure
ISO 200 – 5 second exposure
ISO 400 – 2.5 second exposure
ISO 800 – ~1.25 second exposure
ISO 1600 – ~.75 second exposure

Luckily, Aaron was able to hold still enough to not appear too blurry in the photograph, making it acceptable when viewed at a normal web resolution. If it were to be blown up or printed, the faster shutter speed would have helped a lot.

Here’s a crop showing the different small sources of light that I used to illuminate the scene:

aaron3

What I found interesting about lighting up the scene this way was that each of the sources of light were a slightly different color temperature, giving the scene an interesting look in terms of colors and lighting.

During post processing, I increased exposure a little, did a little recovery, added a splash of fill light, and pushed contrast up a little. Here’s the final image (hover over it to compare it to the original):

aaron1

If you’re looking for something new to learn and photograph, try your hand at taking longer exposure portraits with unconventional sources of light. Just find a friend that can hold still!

Painting With Light and Long Exposures

I love experimenting with photography, and trying out interesting new techniques, angles, and styles. One of the things I’ve really enjoyed playing around with over the years is drawing pictures with light using long exposures.

These photographs definitely aren’t hard to do. All you need is a stationary camera (i.e. tripod?), and some mobile source of light, like an LED light or a flashlight. Simply set your camera to an extremely slow shutter speed (enough time for your to paint in), make sure the focus is set to where you will be standing, and paint away!

Here are some basic examples of simple shapes I painted:

lpbasic

These four photographs were all taken at ISO 1600 at shutter speeds between 13 and 15 seconds. In retrospect, I probably should have used a wider aperture setting to blur the background. These were between f/6.3 and f/11.

Another thing I did was use the timer to give myself 10 seconds to get into position in front of the camera. For long exposures, you could actually omit this and still get pretty much identical results, since the second or two you’ll take to get into position won’t amount to much of the exposure.

Writing is interesting, but a little tricky:

lpname

Since you can’t see what you’re doing, you’ll have to remember where in the air you drew each letter. It might take a little practice to get right. Also, keep in mind that whatever you draw will appear backwards in the photograph. In these photos, I decided to write backwards, but you can also write normally and then flip the photograph horizontally to correct it.

Once you get bored with simple shapes and writing messages, try experimenting further and coming up with stranger ways to use the combination of light and longer exposures.

Here are a couple shots I took where I made myself appear multiple times in the photo by turning the light on and off while moving to different areas of the frame.

lpmultiple

I had to keep in mind where I was at each point to keep from overlapping with prior faces.

A couple more examples of weird experimentation:

lpthrow

Hmmm… Not sure what to say about that one. How about an angel?

lpangel

Get a little boy or girl to pose for that one and it might look pretty neat. With me it just looks creepy.

Now, onto some more complicated drawings. First, some scribbles and an example of drawing gone wrong:

lpscrilbbles

These are a little better, but strange nonetheless:

lpbetter

Notice how you can make certain lines or areas glow brighter by allowing your light to stay at that point for a little longer. Finally, a very generic drawing:

lptree

Hopefully this brief walkthrough of light painting was interesting, informative, and inspiring. Though it’s not really useful for improving your general photography, I’ve found that experimenting and doing random things with my camera has helped me grow a lot more familiar with it and the technical side of photography in general.

If you have any interesting results or examples of light painting, feel free to link to them in a comment! If there’s good ones I might update this post with links.

Underexposing vs. Overexposing

One of the things I became very aware of during a recent road trip to Oregon is how much easier it is to salvage an underexposed photograph versus an overexposed one. When you overexpose a photograph and “blow out” the highlights in the image, those areas that were blown out to white are unsalvageable, whereas much more detail could have been preserved in areas of the photograph that appear to be pure black but are not (though noise results from salvaging these areas). An implication of this is that when taking portraits of people in strong sunlight outdoors, it’s much safer to underexpose and leave with a muddy looking photograph, than to overexpose and blow out detail in faces.

Of course, ideally you’d like to correctly expose a photograph, but if you need to guess, you should be conservative by underexposing. Here are a series of photographs that examines under and over exposure. The scene is half brightly lit, and half in the shadows. They were shot in RAW with a Canon 40D and a 24mm f/1.8 using evaluative metering and ISO 100. Aperture was set on f/5.6.

Properly exposed

As determined by the camera’s evaluative metering (shutter speed 1/160). The half in the shadows is not completely black, while the half under direct sunlight isn’t completely blown out either.

img_1402

First, we look at how the salvageable the image is when you underexpose it to various degrees.

1-stop under-exposed

Each of these photographs is corrected in Adobe camera raw by compensating for the under or over exposure. Hover over each one to view the uncorrected and incorrectly exposed photographs:

img_14031

2-stops under-exposed

img_1404

3-stops under-exposed

img_1405

4-stops under-exposed

img_1406

Notice how we were still able to recover a good amount of the underexposed brighter half of the scene, even though virtually all of the shadow area was lost to black. Also, notice how we’ve managed to preserve the colors of the leaves.

Now lets compare the results above with attempts to recover overexposed photographs:

1-stop over-exposed

img_1407

2-stops over-exposed

img_1408

3-stops over-exposed

img_1409

4-stops over-exposed

img_1410

Conclusion

From this experiment, we’ve found that we were able to salvage a somewhat acceptable photograph from an image that was under-exposed by four stops. On the other hand, a photo that was over-exposed by four stops was pretty much unsalvageable, as both detail and color were lost in the blown out areas.

The moral of the story is: when in doubt, under-expose.