No Tripod, No Flash, No Problem
Not all that long ago, shooting under low-lighting conditions without benefit of a flash or tripod meant pushing your film 1,2, or 3 stops beyond its native ISO rating. When shooting black & white this usually meant rating Tri-X at 800, 1200, or 1600 instead of its usual 400 speed rating, which in practice meant underexposing the film and developing it longer to 'make up' for the loss of exposure time. Pushing film usually did the trick at the cost of additional contrast and graininess. If you were really desperate you could also shoot Kodak 2475 Recording Film, which had a native ISO of 3200, but the grain was so bad you could see it on the contact sheets with your naked eye. And because the film curled up tighter than a Slinky it was a challenge to just keep it flat in the enlarger's negative carrier.
When shooting color things weren't much rosier. Color slide films were available in 400, 800, and 1600, but the grain, color, and contrast levels left much to be desired. Color negative film was equally on par, but instead of grain, you had to deal with multi-colored mush. (Think Froot Loops soaking in a bowl of milk for a few hours and you'll get the picture).
But in the last year or 2 things radically changed in the digital world as camera manufacturers introduced extended range ISO ratings. And while the highest optimized ratings for the new DSLRs topped out at 6400, 'Hi' settings of 12,800 started appearing and while they weren't perfect, they also weren't half-bad.
Nikon D3S, 85/1.4, ISO 102400 (f1.4@1/8000th)
Since then the guys in the white lab coats have been tweaking whatever they tweak when wearing white lab coats and the results of their efforts appear in Nikon's D3S and Canon's EOS 1D Mark IV. Each of these amazing machines now include ISO 12,800 as standard ISO rating, which is high enough to enable sharp, nighttime hand-held imaging. And for those requiring even higher ISO ratings, the Nikon D3S and Canon EOS 1D Mark IV can be set to an ISO equivalent of 102400. Are the results noisy at these nosebleed ISO levels? Yes they are, but when was the last time you hand-held an 85mm lens on a rainy night at f1.4 at 1/8000th?
But perhaps more important are the 'slower', 5-digit, optimized ISO ratings these cameras deliver. In a word, they're stunning. The highest optimized rating found in the newest DSLRs from Nikon, Canon, and Sony is currently ISO 12800, which is ample speed for capturing sharp hand-held images under night-time lighting conditions. As for noise, at ISO 12,800 it's barely perceptible. As a reference point, the image quality is better than most point-and-shoot digicams at ISO 800 (and even ISO 400 if your pocket-cam is over a year old!)
Nikon D3S, 21mm/f2.8 Zeiss Distagon ZF.2, ISO 12800, f3.5@1/400
As you climb through the Hi1 (ISO 25600 equivalent), Hi2 (ISO 51200 equivalent), and Hi3 (ISO 102400 equivalent) settings, the noise levels become increasingly pronounced, yet even at Hi3, the results are quite usable. At the highest ratings banding patterns sometimes appear, but when you think about the fact you're shooting hand-held under miserable lighting conditions as if it were daylight, you can't help but chuckle as you watch sharp pictures appear on the camera's LCD.
So now the big question is "How do they do it?" In the case of Canon's EOS-1D Mark IV, the ability to achieve 6-digit ISO levels is attributable to a combination of ever-improving CMOS technologies and image processors. According to Chuck Westfall, manager of Canon U.S.A's Camera Division Technical Information Department, these technical advancements include larger microlenses that are placed closer to the sensor than previous generation microlenses for improved light-gathering efficiency, and a new material for the RGB color filters, which enables quicker light transmittance to the photodiodes.
Other ISO-boosting factors include improved semiconductor fabrication technology that accumulates more light than earlier designs, improved photoelectric conversion efficiency in which incoming light is converted to an electrical signal within the sensor itself, new high-output pre-amplifier circuitry for improved signal-to-noise ratios at all ISO speeds, and better suppression of noise from external sources.
The EOS 1D Mark IV's DIGIC 4 image processor, which is 6-times more powerful than its predecessor, also plays a part in improving ISO sensitivity levels. These improvements include more powerful, High ISO noise reduction (Low, Standard, or Strong) and more powerful Auto Lighting optimization, both of which are user-adjustable.
|Nikon D3S||Canon EOS 1D Mark IV|
Now here's the kicker - Shooting sharp, hand-held imagery at night doesn't necessitate cashing in your 401K plan. It seems while one group of techies in white lab coats were tweaking the sensors and image processors on the big guns, another group of techies in similar white lab coats were diddling around trying to figure out other ways of taking back the night, and the results of their efforts can be found in a trio of cameras each costing well under $500. This very cool technology is called Hand-held Twilight Mode and it can be found in Sony's Cyber-shot DSC-HX1, Cyber-shot DSC-WX1, and Cyber-shot DSC-TX1, which for the fashion-conscious amongst you is available in Blue, Silver, Gray, and Pink. (The HX1 and WX1 are available in black only)
|Sony Cyber-shot DSC-HX1|
|Sony Cyber-shot DSC-WX1||Sony Cyber-shot DSC-TX1|
Hand-held Twilight Mode is pure digital Voodoo and the way it works is really cool. When set to Hand-held Twilight Mode the camera bumps the ISO up to about 500 and captures a bracket of exposures faster than you can say 'click, click, click, click, click, click'. The camera then samples each of these images and searches out the sharpest, most detailed portions of each shot and melds them into a single optimized image, in seconds, and in-camera.
The following shots were taken with a Sony Cyber-shot DSC-WX1 in Hand-held Twilight mode. The exposure times for each of these shots averaged 1/8th to 1/15th-second, with the lens maxed out at f/2.4. Considering the Sony WX-1 is a point-and-shoot camera, the image quality is quite impressive.
Curious to see how far I could push the Sony WX1, I ventured onto an empty ball field that was devoid of ambient street lighting, aimed the camera up towards the heavens, and fired off a few hand-held exposures by moonlight. How did the Sony perform? You be the judge. (The white dot below and right of the moon is Venus.)
Now before we wrap things up I want to make it quite clear the images captured by Sony Cyber-shot digicams - as amazingly good as they are – fall short of the images produced by the flagship DSLRs in terms of image sharpness, speed, or durability. And even though the Sony Cyber-shots can capture up to 10 full-resolution images per-second in standard mode, not so in Hand-held Twilight mode. You can capture a hundred full-size JPEGs with the D3S in the same time it takes the Cyber-shots to capture and process a single image. The 6-image capture process also means fast-moving subjects under low-light conditions can be difficult to capture without ghosting and/or strobing. (For capturing fast motion, Sony recommends using the Cyber-shot's Anti-blur mode, which like other digicams stops low-light action at the cost of higher noise levels caused by higher ISO ratings.)
But regardless of whether your budget is a few hundred dollars or a few thousand dollars, what you get for your money is pretty darn amazing.