Saturday, March 22, 2008

#2 - The Flash

A few tips on flash in general.

The technology of taking photographs in low light advances all the time. However, until someone comes up with a camera that can take a perfect exposure in pitch darkness, we will continue to need the flash.

Flashes come in three basic flavors:
- Built-in on our cameras
- A separate flash that we slide into the hotshoe slot on top of our cameras
- Off camera flash

Knowing the limitations and advantages of each help us to know how and when to use each one of these tools.

Let's take a look at these one at a time

The flash thats built into most of our cameras.

The advantages:
- Convenient
- Easy to use (usually controlled automatically)
- No additional costs (comes with the camera)
- Can be used to light up the scene to some extent

The Disadvantages:
- Limited range
- Limited width
- Quality of the results is not often very pleasing (often flat, lifeless)
- Becuase of it's location, causes the infamous red-eye in your subjects
- If using the macro fuction, often cannot light your subject due to lens or camera interfereance
- Consumes camera batteries reducing number of pictures on can take on a single charge

The external flash that we place on top of our cameras.
The advantages:
- Convenient
- Easy to use (usually controlled automatically)
- Increased range over the built-in flash
- Increased width over the built-in flash
- Can be used during the day for increased photo quality
- Quality of the results is superior to the built-in flash
- In some cases it is possible to control manually

The Disadvantages:
- Adds a little weight to the camera
- There are additional purchase costs
- Becuase of it's location, it can cause the infamous red-eye in your subjects
- If using the macro fuction, can potentially not light your subject due to lens or camera interfereance, but less chance of this happening than in the case of the built-in flash.
- If not used properly, the results can often be flat and lifeless

Off camera flash
The advantages:
- Increased range
- Increased width
- Increased Dynamics
- Can be used during the day for increased photo quality (fill flash)
- Quality of the results is superior to the built-in flash
- In many cases it is possible to control manually
- Most versatile
- No additional weight on the camera
- Easy to eliminate red-eye
- Offers the best results
- Offers near limitless creative freedom

The Disadvantages:
- Ease of portability becomes a consideration
- There are additional purchase costs higher than the above two options
- There is some additional learning needed to acheive good results

Ok, now we know the pluses and minuses... lets take a look at using these technologies!

The built-in camera flash:
Not much to do here, it really is point and shoot. They are not adjustable in any way and the camera controls the flash strength and duration. Sometimes they are prone to over-exposing but this is easily fixed by using the exposure compensation in the camera.  For heaven's sake, don't try to use something like a diffuser even if it is by taping a small tissue or other translucent paper over the front of the light. All you are doing is making the flash work harder, without making it more diffused.  There really is not much more than can be said about this technology. It really is the most limiting and unflattering light source possible.

The external flash that we place on top of our cameras:
Now we have moved into a solution that can potentially offer some very nice advantages over the small built-in solution. We have a flash that can offer us a longer and wider range. But, wait, we have that red-eye to contend with right? Yes we do, but there is a relatively simple solution, if your flash supports it... and that is to bounce it.

When one talks about bouncing flash, they mean that they tilt the head of the flash upwards and bounce the light off the ceiling. Some of the better flashes on the market not only swivel up and down, but can swivel from side to side. That means that we can not only bounce off the ceiling, but off the walls in any of the directions we may need to at the moment. The result is that we now have a picture that looks more naturally lit and since we did not fire directly forward, we stopped annoying your subjects. We've also now totally eliminated red-eye.

Great, we now know how to take a photo thats much better than blasting the subject with a directly aimed flash by bouncing. We get to where the subject is, look up and... uh-oh, we're outside, what now? If I raise the flash now, it just goes off into space, and if I lower the flash, I blast them with that direct beam of light that will give me red-eye and a flat lifeless picture. What do I do now?

We need to do something that will diffuse the flash, thats what. For that, we have a couple of options. We can use a diffuser (they often come with the flash), or use an aftermarket diffuser. The aftermarket carries many solutions for us. A fast google of items like a "lightsphere" or a "Gary Fong diffuser" or just "diffuser" will net you all kinds of results. Typically, though, I find diffusers expensive for what they do and there are cheaper and possibly more effective alternatives.

On some flashes like Nikon's SB-800, already come with a diffuser *and* a bounce card built right into it and do a wonderful job of diffusing and spreading the light across a scene beautifully. I prefer to use a bounce card instead of a diffuser for better results (IMHO). If you do not have an integrated bounce card, why not make your own? It can be no harder than having access to a rubber band and a piece of white paper cut to a particular shape and use the rubber band to hold said paper in place on your flash. I bet if you went and visited that you would get all kinds of ideas. Problem solved!

Ok, so now we have a beautifully lit subject... but the background is still not where we want or need for it to be lit. This is where I tell you to take that camera OFF of "P" or "Program" or "Auto" mode and start thinking more intelligently than any camera ever can for you!

When a camera sees or detects that there is a flash on it, the first thing it wants to do is use the fastest flash sync speed, and usually 1/200th or 1/250th of a second. While great for freezing action or aiding in lighting up your subject, we can set our camera to manual or shutter priority mode and lower shutter speeds to something like 1/125th or 1/60th or maybe as low as 1/30th. The result will be that the camera uses and captures some of the ambient light in the room and uses it to it's advantage. This comes in especially handy if we are using apertures with deeper depth of fields and we want people or objects well lit and we don't want them to fade away into the bokeh.

First thing you may ask yourself is, if I am letting more light in overall, won't the foreground overexpose? No. If you are still taking advantage of and using TTL, it will automatically compensate. The result, a properly exposed foreground and a background that is now better visible. Oh, but what I set the flash to manual? Easy. Drop it down manually so that your subject is properly metered.

Surprise, we've just discovered something rarely touched on in photography... light has a depth of field too! We've also discovered that it is more often than not, controlled by aperture and flash intensity. Nowhere is this more easily visible than in our next section... but that is the topic of my next article, off camera flash.

A few examples:

Built-in flash:
Note the lightly blown out surrounding area and overall loss of contrast and flat look of this picture. You can see it, but tell its not a very good pic.

External on camera flash - straight on:
There is a slight improvement, but that is more because of the flash's superior quality in responding to the TTL commands. It's still washed out and contrast is poor. The bear is properly metered, but nothing else.

External on camera flash - bounced:
In this picture, what I want you to pay attention to is the contrast. It's much better and also note that the bear and the couch beside it are properly metered and exposed. Clarity is better. We can see that this is a better picture than the two above it.

In our next article, we will look at a very basic article about the next step in our series, and that is off-camera flash.