The need for (high ISO) speed…

Angela Nations

Angela Nations performing with Raqs Helwa
Canon 40D - 1/60sec @ f/2.8, ISO 1600

Usually when I’m shooting belly dance, I’m working in very low light. Apparently people who light stages think the absence of light creates ambiance.  Or perhaps they just have better eyes than me. 😉   Also I generally am not allowed to use flash – which is fine with me.

So how do I maximize the possibility of capturing the moment when there’s barely enough light on the moving subject to even permit autofocus to work?

I’m generally shooting in Aperture priority (‘Av’ on a Canon mode dial) because the stage is usually not evenly lit front to back and side to side.  There are three factors at play here:

  • the camera’s aperture
  • the “speed of the film” – ISO setting on your digital camera
  • the shutter speed.

In Aperture priority mode I can control the aperture and the ISO and the camera will calculate the third factor (the shutter speed) based on the settings I dial in for the first two.

The aperture (f-stop) controls the depth of field (how much of the subject is in focus) in front/back of your focus point.  Want lots in focus?  Then dial your aperture up numerically, e.g. f/8 or f/16 (this is also called “stopping down”).

What’s the tradeoff?   The more that’s in focus (where the ISO remains the same) the more time the camera needs to get the picture imaged on the sensor/film.  So if you want more speed – dial your aperture to a lower number (open up your aperture), e.g f/2.8, f/2, or whatever is the fastest (widest) aperture the lens you are using will permit.

“OK, so I’ve dialed down (opened up) my aperture and my shutter speed is still 1/4 second and I’m only getting blurry smears!  I need real stopping speed! You lied you dog!”

WHOA!!! Hold up there!


Amara performing with Sabaya Bellydance
Canon 40D - 1/50 sec @ f/2.8, ISO 1600

That’s were the ISO setting on the camera (film speed or ASA) comes into play.  For example all of the settings below give you the same exposure:

Aperture ISO Shutter Speed
f/2.8 100 1/4 sec
f/2.8 200 1/8 sec
f/2.8 400 1/15 sec
f/2.8 800 1/30 sec
f/2.8 1600 1/60 sec

“So all I have to do is crank my ISO as high as it will go and I’m done – yes?”

Yes… and no… As with everything in photography there are trade-offs, what you gain in one arena, you lose in another. In this case – digital noise.

But we’ll talk about that another time. Stay tuned…

About vstrick

I’m a photographer who loves photographing renaissance festivals and dance. They are great communities and I enjoy capturing some of those moments and being able to share them with the community. My day job is in IT at The University of Texas at Austin, wrangling the virtual infrastructure – working with VMware vSphere, vCenter Operations, SRM, Cisco Nexus 1000v, and consuming as many SAN resources as I can get. :-)
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3 Responses to The need for (high ISO) speed…

  1. Vance, were you shooting the Belly Dancers with something like a 70-200mm f/2.8 zoom lens?

    The zooms I’ve got for my Nikon cameras both have a maximum aperture of f/3.5. So I bought one of the ~$200 Nikon 35mm f/1.8 DX lenses to use in low light conditions. That lens on my new D7000 (with a normal max ISO of 6,400, and a “Hi-2” ISO of 25,600), should allow me to shoot with fairly fast shutter speeds without a flash.

  2. vstrick says:

    Hey David,
    Generallly for this type of work I’m shooting Canon EF-S 17-55 f/2.8 IS zoom and prime lenses, e.g. 100mm f/2. Basically the faster the better because it’ scores a bit more shutter speed. Also, I can’t hold a 70-200 f/2.8 for a 3-4 hour gig (with breaks), my hand/arm would get waaayyyy to shaky.

  3. ron mailloux says:

    Beauty is in the eye of the beholder. The above image is excellent artistically, but some would not appreciate the blurring of Angela’s hands. But some don’t apprciate Monet and others… If the task at hand is to get photos with good lightng that freezes action, then many of the low light environments are intimidating, and without question, investment in your equipment pays off. The D7000 is amazing at 6400 and with a 2.8 zoom you will get photos that most others cannot. I shoot on manual mode keeping my speeds at 1/250 or faster to significantly reduce blur. I am often at 2.8 which is usually good for solos (pick the lead ladies for groups) and I shoot at 3200-6400 depending on light. I shoot manual because darker outfits are very different to shoot than nice bright ones so I am constantly balancing speed with aperature. And I alway shoot in RAW format (NEF for me). By shooting in RAW you can ‘push’ the photo lightling a lot more than you can push a Jpeg and get another full stop or more in the processing. For Internet photos you can push almost 2 full stops. And for those interested, I shoot a D700 with either a 24-70mm f2.8 or a 70-200mm f2.8. And yes the 70-200 gets really heavy when I shoot 1,000+ photos a day at the youth competitions!

    Back to reality though, a little bur is not always devastating. Blur shows movement which can be part of what says something in a photo. A beautiful blured veil around a well captured face can be an awsome photo. I really like the photo of Angela above. Just recognize the limitations of your kit and have a fantastic time making art within the capabilities of your equipment. Get a decent set of photo processing software and lern how it can help you as it is essentually part of your kit. If you can push light a full stop with your software, take advantage of this when you set up to capture the moment!

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