In the previous article, “The Three Most Basics A Beginner Photographer Should Know”, there are graphics and explanations on Aperture, Shutter Speed, and Film Speed/ISO scale. I’d like to share more depth about them.
All three are represented by numbers. In the photography world, the interval from one number to another is called a “stop.” You can stop up (increase) or stop down (decrease)—for example, an aperture of f/5.6 to f/4 is one stop up, and f/5.6 to f/8 is one stop down. The same applies to shutter speed and film speed/ISO.
Shutter speed from 1/125 to 1/250 is one stop up, and from 1/125 to 1/60 is one stop down. For film speed/ISO, 200 to 100 is one stop down, and 200 to 400 is one stop up.
Just to avoid confusion, “up” and “down” refer to the amount, duration, and sensitivity of the light reaching the film plane (in film photography) or the digital sensor (in digital photography), not the numbers themselves.
There are terms in film photography: push and pull. “Push” is used when shooting with ISO 400, but the camera is set to ISO 800—known as “pushing one stop.” The reverse situation is when ISO 400 is set to ISO 200, aka “pulling one stop.”
Why did old-school photographers push or pull the film speed? A couple of reasons, from my experience: sometimes photographers, during an important moment, ran out of their preferred film stock. The only film stock available was ISO 400, but the shoot took place at a music concert where the light was low and inconsistent. The ideal ISO for that situation might have been ISO 1600, so the photographer set (pushed) the ISO to 1600 in the camera while using ISO 400.
During development, the photographer—or the lab—developed the film for ISO 1600. The result is that film developed for ISO 1600 produces more noise, maybe a bit more than true ISO 1600. However, the result gave an artistic feel—that’s another reason photographers sometimes pushed film.
Although in all three (aperture, shutter speed, and film speed/ISO), if we look closely, each number is exactly a double (a factor of 2) from one step to the next.
In the most common lenses, the largest aperture is f/1.4, which sits next to f/2. The following number is f/2.8, which is exactly f/1.4 × 2. Similarly, f/2.8 sits next to f/4, and the next after f/4 is f/5.6, which is exactly f/2.8 × 2. Do you get the idea?
In digital photography, aperture has more increments and decrements than in film photography. Thanks to technological advancements, digital cameras (DSLRs) have increments up to 1/4 stop. Not only does aperture have more increments in stops, but shutter speed and film speed/ISO do as well. All of these offer more creative freedom for photographers to explore how to make stunning photos. Not all DSLRs are created equal; some have more capabilities than others. However, the basic principles are the same across the platform.
CALIBRATING THE EXPOSURE READINGS
As I mentioned earlier, the three basics (aperture, shutter speed, and film speed/ISO) must work together to achieve proper exposure. Before setting shutter speed or aperture, film speed/ISO must be preset, and white balance must be set for a DSLR.
For example, when taking pictures outdoors in daylight, ISO 100 is advisable. White balance can be set to either Auto White Balance (AWB) or Daylight. When using the Daylight setting, always remember to check it if the location changes—such as moving from indoors to outdoors, or shooting under cloudy or nighttime conditions. Occasionally, I forget to change the white balance when changing locations. Although I can correct it later when shooting in RAW using software such as Adobe Camera Raw or Adobe Lightroom, I usually set my white balance to AWB. From my experience, auto white balance is not entirely accurate, but it is still preferable to setting it to Tungsten while shooting in daylight.
Note: RAW file acronyms include CRW or CR2 for Canon, NEF for Nikon, ARW for Sony, RAF for Fuji, etc.
White balance settings in nearly all DSLR cameras are virtually similar, with minor variations: AWB (Auto White Balance), Daylight (5600K), Shade/Shadow (7000K), Cloudy (6000K), Tungsten (3200K), Fluorescent (4000K), Flash (5500K), and Custom White Balance (where you set your own reference point). By convention, Kelvin (K) is used to measure color temperature in photography. Daylight is typically between 5000K and 5600K, where white appears truly white.
In the article “The Three Most Basics A Beginner Photographer Should Know” it explains that film cameras do not have a white balance feature. In film photography, white balance is determined by the type of film used. Digital cameras, on the other hand, use image sensors similar to video cameras, and the white balance feature helps balance colors and gray tones more accurately.
While some may argue that white balance settings are less critical today—since modern photo software allows adjustments in post-processing—it remains a helpful tool. It’s also worth noting that auto white balance (AWB) can vary between camera brands, because each manufacturer uses slightly different algorithms to compensate for ambient light.
SHUTTER SPEED PRIORITY
Once ISO and white balance are set, I move on to choosing between aperture and shutter speed, depending on what I want to shoot. For example, when photographing my kids outdoors and I want to ensure they stay in focus during their activities, I select shutter speed priority (“Tv” on Canon cameras, “S” on Nikon, Sony, and others). Choosing shutter speed priority helps ensure that my shots maintain focus.
What shutter speed should I set? For most outdoor action, 1/125s usually suffices, but I increase the speed if my kids suddenly move like “Flash” or “Superman.”
It’s important to note that lens focal length affects the required shutter speed. The longer the focal length, the faster the shutter speed needs to be to prevent camera shake when shooting handheld. Unless you’re using a tripod, the shutter speed should generally be no slower than the lens focal length. For example, with a 105mm lens, the minimum shutter speed should be 1/105s or faster. This guideline—known as the reciprocity rule between shutter speed and focal length—is widely used to keep handheld images sharp.
After selecting shutter speed priority, the aperture automatically adjusts to achieve correct exposure. Conversely, in aperture priority, the shutter speed adjusts to maintain proper exposure (exposure meter at “0”).
Let’s explore a hypothetical practice scenario using the tables below to demonstrate how these settings interact:
When using shutter speed priority (Tv), any change in shutter speed automatically adjusts the aperture to maintain proper exposure. For example:
- Tv 1/125s → Aperture f/8
- Tv 1/60s → Aperture f/11
- Tv 1/250s → Aperture f/5.6
The same principle applies when using aperture priority (Av or A): changing the aperture will automatically adjust the shutter speed to achieve the correct exposure.
Understanding this relationship is essential when learning full manual mode, where both shutter speed and aperture are set manually. In manual mode, always keep an eye on the exposure meter (EXP) at “0” to ensure the image is correctly exposed.
APERTURE PRIORITY
In aperture priority (Av or A), the shutter speed automatically adjusts to achieve proper exposure based on the chosen aperture and the set ISO (film speed). The main reason for using aperture priority is to control depth of field and regulate how much light enters the camera to properly expose the image.
- A larger aperture (smaller f-number) produces a shallow depth of field, making the subject stand out sharply against a blurred foreground and background.
- A smaller aperture (larger f-number) increases the depth of field, keeping more of the scene in focus.
Prime lenses generally achieve wider maximum apertures than zoom lenses, giving photographers greater flexibility for shallow depth of field effects and low-light shooting.
Setting aperture priority means switching the camera dial to “A” (or “Av” on some brands). When you adjust the aperture to achieve your desired depth of field, the camera automatically changes the shutter speed to maintain proper exposure.
For example:
If you open the aperture by 2 stops to f/2.8, the shutter speed will automatically increase by 2 stops to1/250 sec, keeping the exposure balanced.
If the aperture is set to f/5.6, the shutter speed might adjust to 1/60 sec.
FULLY MANUAL MODE
There was a time when I questioned why I should use full manual mode when I could just prioritize one setting. It’s true that full manual mode can slow you down compared to aperture or shutter speed priority, since you must control both settings yourself. For time-sensitive situations, like documenting an important event, priority modes are often more practical.
However, full manual mode gives you complete creative control. It prevents the camera from misreading subjects with unusual contrast or exposure, and it allows techniques like time-lapse photography. Some images simply can’t be captured properly without full manual control—especially when dealing with a drastic range of contrast or exposure.
Full manual mode allows a photographer to manage aperture, shutter speed, exposure value, depth of field, focal point, focus, and more. These advantages are not fully achievable with priority or auto modes. Using priority modes is like taking the first steps toward mastery, while full manual mode is where true creative freedom begins—but it requires practice and experience.
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