Low Light and Existing Light Photography: Lenses, ISO, Aperture, and SLRs

Morgan asked: “Just wondering how you are able to capture motion with so little light and not have the picture come out a blurry mess?”

Low light photography is an area where most dSLRs triumph easily over point and shoot cameras. I won’t go into much detail but the sensor size of a dSLR is larger than a P&S, allowing a much cleaner image when in low light. This holds especially true as manufacturers cram more and more pixels into a sensor in the megapixel race. This is why many people will say, for example, that a 6mp dSLR from a couple years ago will still outshine the latest 8-10mp P&S in regards to noise.

If we’re talking strictly about how to capture motion with low light while only using a dSLR (vs a P&S), then it’s primarily due to four factors: the lens, the ISO, the shutter speed, and the aperture chosen. (all affecting the amount of light captured in the time the shutter is open)

Morgan was referring to my Kecak photos posted earlier. (the night shots with the fire dancing) They were all taken with a Canon 350D handheld (didn’t have a tripod or my 5D), ISO 800-1600, and an 85mm f/1.8 lens. The problem I had to deal with was that this dance is intense, high energy, with constantly moving performers. That sets you up for a much different situation than, say, a still scene in low light (where you’d be better off using a low ISO and longer shutter speed).

The movement here required me to do a tough balancing act of stopping motion while allowing enough light into the camera for proper exposure. In a situation like this it’s best to experiment a bit; see what works, and take lots of shots. If your shutter speed is set too low, you’ll see camera shake (when your hands shake while holding the camera), and most likely the subject will be blurry. If you set the speed too high, your image will be sharp but most likely too dark.

Ideally, you should have some sort of support for the camera when doing any night shots, but I’ve always been reluctant to haul one around – in a place like Indonesia it can become a definite intrusion, making some of the subjects feel more ‘on the spot’, breaking some of the mood that may have caught my eye in the first place. This is a case of ‘do as I say, not as I do’.

ISO is one critical tool that I see many people misunderstand and misuse. Most P&S cameras have lots of noise above anything over ISO400. At that level, it still might only be equal to a dSLR’s ISO1600. Often a camera set to ‘auto’ will pump up the ISO to the highest setting; people become frustrated when they see abundant noise in their images. In this case, I’d prefer to set the ISO myself and either use a tripod or some alternative way to steady the camera.

Many people will say “use a flash” – however a flash is not always allowed, nor are flash lit photos always desirable – certainly not the ones built into cameras. Not one of the photos I took on my latest trip to Bali were with a flash – I didn’t even bring my flash. So everything you’ll see is handheld using existing light.

When talking about dSLRs, lenses become even more important than the camera body. Generally the more light the lens allows in for a given focal length, the more you’ll pay for that lens. There’s a little secret to this rule – prime lenses. For those who can deal with changing lenses (or using your legs as a zoom), you’ll be rewarded with sharp, crisp, beautiful images while using equipment that doesn’t weigh a ton.

Case in point: I have a 24-105mm f/4 IS L-series lens – cost? Around $1150. It’s an amazing overall lens and the IS (image stability) is phenomenal for allowing up to 3 (or 4) additional stops of light. I can handhold it down to around 1/8 second before camera shake is evident – but if it’s not capturing a stationary subject, you’d have motion blur regardless. It’s quite heavy, but on the Canon 5D it’s a fantastic combination. However, there’s no way that maximum aperture of f/4 would have let enough light in to capture that Kecak dance – the performers would have been a blurry mess. In this case, my 85mm f/1.8 allowed much more light in – therefore allowing for a faster shutter speed, offered sharper images, and coincidentally threw out background (full of tourists) in a nice blur. Cost of the lens? $280. Additionally, Canon makes a ‘nifty fifty’ – a 50mm f/1.8 lens for about $75. I highly recommend it for those starting out. I don’t mean to sound like a Canon fanboy, but that’s what I use and what I’m experienced with. Other manufacturers make similar equipment.

There are many variables to consider when taking photos in low or existing light. The more experienced you become, the more confident you become in making those decisions quickly for each given case. However, it can be quite confusing to someone just starting out; this is a time when more practice will pay vital dividends.

99% of my photos are taken with existing light. I find it to be much less intrusive in a place like Indonesia, and often I come across scenes that would be ruined with the use of a flash – either by way of startling the subject, breaking the mood, or misrepresenting the vision. It’s certainly not for everyone, but those who are patient and make the right choices when buying gear and setting up their camera, will be rewarded with very natural reflections of what was initially seen with their own eyes.

Here are some examples of what these particular lenses are capable of:

50mm f/1.8 and more here.
85mm f/1.8 and more here.
24-105mm f/4 IS L and more here.