Embracing automatic ISO.

Recently, I find myself in more and more situations where I know what I'd like my shutter speed and aperture to be, but realising that the light situation is changing around me. In a recent round of street photography, for example, I wanted to shoot wide open (f/2.8, using my 70-200mm lens), and I knew that I wanted reasonably fast shutter speeds (I spent the day shooting at 1/800 second)... But given that I was walking down Southbank in London, where there's a lot of trees, overhangs, and rapidly changing light situations, what's a guy to do? The solution, more and more often, is automatic ISO: Select the things you care about, and let your camera adapt to the changing lighting situations by varying the ISO.

It isn't that long ago since this would have been completely impossible - Most of the camera bodies I've had so far, have had rubbish quality photos beyond ISO 3200 or so. With my most recent camera bodies, however (Canon EOS 5D mark 3, which I ended up selling because I found it too heavy for everyday street photography, and replacing with a Canon EOS 6D instead), the full breadth of the ISO range is perfectly usable.

The above photo, for example, I captured by setting my camera to f/2.8 and 1/800. The camera selected ISO 320 for this shot. Perfectly fine; there's no discernable noise in the image at all.

Going Macro

More extreme, however, was the example I experienced recently. I've done a fair bit of macro photography (I did write the book on it, after all), but I found myself in a situation that was nearly impossible: Taking photos of insects on the move, without my usual flashguns. What to do? I was shooting with my 100mm f/2.8 Macro attached to my Canon EOS 6D, and no light sources or light shapers. All natural meant that I needed a relatively high shutter speed (because I was shooting hand-held), and a relatively small aperture (to deal with the extremely limited depth of field). Even in bright sunlight, that doesn't leave an awful lot of light left... But it turns out that automatic ISO still does the trick:

So I guess the lesson here is that on modern cameras, you can in many situations leave the camera to get things right, whether you're willing to let shutter speed, aperture, or ISO to be variable. Nifty stuff.

Darkening a room by adding light

I was doing a photo shoot a few days ago, where I was photographing a lemon suspended from a piece of thread. I wanted to make it look as if it was hovering in pitch darkness.

Upon seeing the results, someone asked me an interesting question: Isn’t it difficult to focus your camera in the dark? Well, no, because the photo was taken in the daytime, with my lights on. So, how come does it look like it was taken at night?

That, my friends, is the power of contrast in lighting. You have to remember that you don’t need a dark room in order to make a background completely dark – you just need to ensure that your foreground is significantly brighter than the ambient light. Here’s how and why… 

It’s all about relative brightness

To take the lemon photograph, I used a pretty simple set-up: A couple of flashguns aimed at the lemon, from a very close distance. Because the flashes were so close to the subject (they are just out of frame, in fact), it adds a lot of light. If you’re curious why that is, check out the inverse-square law on Wikipedia.

Say 'bonjour' to the magical space-lemon. It's citrus powered, awesome, and magical. Oh, and it hovers in space, clearly. That's what makes it awesome. If you want to take a closer look, click on the photo!

The reason why the photo came out as it did, is because of the camera settings: The camera was set to ISO 100, with f/9.0 aperture and 1/200 second shutter time. If you can’t visualise what those settings would do in the circumstances described, I welcome you to try that right now. Don’t worry, we’ll wait. Set your camera to precisely those settings, and take a photo indoors, without using a flash.

If you can’t be bothered to do the experiment: Even in a relatively well-lit room, that will result in a very dark photo indeed.

So, as far as the camera is concerned, it is taking a horribly underexposed photo. Which is perfectly fine, because I want a dark background. It’s the foreground that is important, and that is where my flashes come in.

Let me get this straight, you’re taking photos that look like darkness in a well-lit room?

This portrait was also taken in a relatively well-lit room - but again, because of the high flash output and the fast shutter time (in this case, f/8.0 and 1/500 second at ISO 100), it looks like it's taken in pitch darkness. Groovy. Clicky for bigger.

Short answer: Yup.

Slightly longer answer: Yup. You can do this by settin your camera to manual, and use an exposure which results in a dark room (by choosing a fast shutter time). The next step is to use your flashes to light the subject.

Of course, this doesn’t work if the light from your flashguns spill onto the background (you’re trying to keep that as dark as possible, remember?) so it is a good idea to use a snoot or a honeycomb grid to ensure that the flash light isn’t accidentally re-lighting your background, because then you’re back to square one.

Can this be used for anything else?

Well of course. Always remember that it’s all about the contrast in lighting: If your flashes are more powerful than the light you are photographing in, then you can ‘darken the room’ with your camera settings, and use the flashes to light your scene.

Hell, if you’ve got enough flashes, you can turn even broad daylight into night. Don’t believe me? Check out this article on ganging flashes, and scroll down to “Turning Noon Into Night With High-Speed Sync”. Pretty impressive stuff, but there’s a pretty ridiculous amount of money in flash equipment being used right there.

You don’t have to go to those extremes, though – using flash outdoors on a shady day can give great effects, because when done well, your subjects look as if they are brighter than the surroundings. When done subtly, it can look bloody fantastic – your eyes are automatically and subconsciously drawn to the main subject – always a good sign in a photograph.

Found: Cheap strobist flash review

If you’re an aspiring strobist, you might be shocked by the amount of cash you have to plonk down for a few Canon EX-580s. To get a decent set-up, you’ll need 3 of them, at least. And at $450 a pop, you’re not going to be much richer for it, really.

Luckily, there is a way out: The Chinese company Yongnuo makes some absolutely bargainous flashguns: the YN-560s are nearly as powerful as the 580s, and have a few clever tricks up their sleeve.

At $85 per flashgun, they’re also a fifth of the price of the Canon equivalent – but does it stack up?

It looks a bit cheap, and the LED interface can be tricky to wrap your head around, but who cares: it's all about the light you get out of the flashgun.

The legendary flasher David Hobby, of Strobist fame, got his paws on a production model YN-560 speedlight.

He found that the production quality was solid, but the Quality Assurance left quite a bit to be desired:

I so wanted to love you, YN-560. Now you hit me with a second, non-working feature. The absence of which essentially makes the flash unusable for me, necessitating a round-trip return to China.

On the one hand, this is why I strongly suggest buying direct. On the other hand, I would also suggest that Yongnuo join LumoPro in hand-checking each unit before it goes out. It is only a wasted effort if your quality control is hitting 100%. And you are not there yet, Yongnuo.

Then again, for $85, you can afford to buy a few extra ones, and keep sending the defective ones back to China for replacement under their 1-year warrantee, can’t you?

You can read the Strobist’s full test drive over on the Strobist blog.