Dem Purty Pictorz: Light/Exposure Control

Picking up from that hack job that was my intro, we’ll be jumping into the first talking point of the series: Exposure management. This little bit pretty much covers the basis of photography in general: the act of capturing light onto film. Unlike using traditional film, digital photography involves sensors, which simplifies our post-processing work, reducing the need for as many skills before we can achieve usable results from our amateur attempts. Breaking down the exposure, there are a list of items that we could consider separately: shutter speed, ISO, aperture.

Shutter Speed:

With shutter speed, the longer the exposure, the more light you’re allowing to flow into the sensor. As such, the longer you allow light to flow onto the sensor, the brighter that exposure becomes (and the same in reverse, the shorter the exposure, the darker your image). This also determines how long of a “moment” you are attempting to capture into a single image. As you can imagine, the more you time in a single image of something moving, the blurrier that image will become. 

Unsteady hands... Image used without permission

Since our toys are inanimate and will (or should, ‘cause if your toys are moving, then this would be some whole new kind of awesome…) not be moving, there should not be any blurring. When we do eventually get that blurry exposure, it usually boils down to our hands shaking while you are capturing this image. While this trait is ultimately unavoidable (you may feel your hands to be steady, but our every heartbeat causes micro-tremors that becomes captured on the camera’s sensor), there are various remedies to combat this effect. Most of the time, the simple solution would be to stabilize the camera using a tripod and thus allowing the removal of biology in the equation, though this can add another layer costs to your rig*. The other solution would be to reduce your shutter speed to capture a shorter moment/reducing the effect of your shaky hands, or to boost your ISO to make the sensor process the exposure at a higher sensitivity level. 
*There are also mono-pods, or straight up stacking boxes/books/etc and so on, but lets not get too far into that for now…

Budget Tripod... Image used without permission

ISO

When you’ve reached that limit where your shutter speed is causing the image to blur due to the shakes, there is also the ISO setting(light sensitivity). With traditional film cameras, you were limited to whatever ISO film you had loaded at the time. This trait is fortunately eliminated with the digital systems we have now, thus allowing us yet another option whenever we desire it. The higher the ISO setting, the higher the sensitivity of light: allowing either a shorter exposure or a brighter image at the same speed.

Unfortunately, this solution is also not without drawbacks. Increasing ISO settings will also introduce noise into our images (this is usually observed in the form of graining). While upping it a few levels will not dramatically affect the exposure, going beyond what your sensor’s sweet spot WILL result in extra noise, so use this function in moderation. 

Example:

To show you roughly what I mean, I've got 2 photograph of the same area, using the same aperture setting(I had the camera set to aperture priority), where the only difference is shutter speed/ISO. Keep in mind I've adjusted the first shot(darkened it), to emphasize the difference in noise at a similar brightness level. In reality, the first shot is 2 stops brighter, (Shown inside the red box is the image at it's normal brightness level) though that is more of a result of the shutter speed being about 23 times longer...

f/2 0.7 Exposure at ISO1000: not much noise(image is still fairly smooth), but longer exposure due to a lack of light, causing a very blurry exposure. Or BOOO HISSS No moar TRON!!!

f/2 1/30 Exposure at ISO3200: photo is a good deal sharper due to a much faster shutter, but notice the artifacts(noise) in the shot. Or BOOO HISSS NOISE BAD!!!

Aperture:

With the aperture settings, you are controlling the physical size of the hole your let light through to your sensor. This little bit tends to throw beginners for a bit of a loop, as the aperture number actually counts backwards to the aperture size... With f/1 being absolutely huge (imagine a large blast template), whereas f/22 being a rather tiny (imagine a bolter round having a template). Naturally, this will affect how much light your sensor is exposed to, again affecting how bright or dark your pictures turn out. There is in fact a further affect that aperture has on your images, but without stepping on the toes of my next entry, I will stop here for now.

Bigger Hole = More Light. If you have trouble with that, I recommend you get checked...

Next time: Focus control!! Or how to get the most out of your warcas... I mean lenses!!