What's on this page
This is a lookup page, not a tutorial. It collects the numbers photographers reach for again and again, the aperture scale, the exposure stops, sensor sizes, and focal lengths, into one reference you can bookmark. If you want the reasoning rather than the numbers, the exposure triangle explainer and the full-frame versus crop guide work through the why, and the deep field notes on what aperture is, what shutter speed is, and what ISO settings on a camera do walk each dial stop by stop. These are standard industry figures; individual bodies and lenses vary, so treat them as reference points, not absolutes.
The stop: the unit that ties everything together
Every exposure control is measured in stops, and one stop is a doubling or halving of light. That shared unit is what lets you trade one control against another. Open the aperture a stop and the frame gets twice as bright; shorten the shutter a stop and it gets half as bright; together they cancel, and the exposure holds while the look changes. Keep that in mind and the three tables below stop being lists to memorize and become one connected system.
Aperture: the full-stop scale
Aperture f-numbers look irregular because they track area, not diameter. Each full stop changes the light by a factor of two, and the f-number steps by the square root of two, about 1.4.
| Full-stop f-number | Relative light | Typical use |
|---|---|---|
| f/1.4 | most light | low light, strong background blur |
| f/2 | half of f/1.4 | portraits, available light |
| f/2.8 | fast zoom standard, events | |
| f/4 | general, some depth of field | |
| f/5.6 | groups, daylight | |
| f/8 | landscapes, sharp across the frame | |
| f/11 | deep depth of field | |
| f/16 | least light | maximum depth, risk of diffraction softening |
A lower f-number means a wider opening and a shallower zone of focus. Most cameras also click in third stops between these, such as f/3.2 and f/3.5, but the numbers above are the reference points.
Shutter and ISO: the other two stops
Both scales are simple doublings, which makes them easier to hold in your head than the aperture scale.
| Shutter speed (full stops) | ISO (full stops) |
|---|---|
| 1/1000 s | 100 |
| 1/500 s | 200 |
| 1/250 s | 400 |
| 1/125 s | 800 |
| 1/60 s | 1600 |
| 1/30 s | 3200 |
Faster shutter speeds freeze motion but pass less light; higher ISO brightens the image but adds noise. A rough guide for handholding is to keep the shutter at least as fast as one over the equivalent focal length, so a 100mm-equivalent lens wants about 1/100 second or faster unless you have stabilization.
Sensor sizes and crop factor
Crop factor compares a sensor to full-frame 35mm and gives you the effective field of view. Multiply the lens focal length by the crop factor for the full-frame-equivalent framing.
| Sensor format | Approx. dimensions | Crop factor | 50mm lens frames like |
|---|---|---|---|
| Medium format (common) | about 44 x 33 mm | about 0.79x | about 40mm |
| Full frame | 36 x 24 mm | 1.0x | 50mm |
| APS-C (Nikon, Sony, Fuji) | about 23.5 x 15.6 mm | about 1.5x | about 75mm |
| APS-C (Canon) | about 22.3 x 14.9 mm | about 1.6x | about 80mm |
| Micro Four Thirds | 17.3 x 13 mm | 2.0x | 100mm |
| 1 inch | about 13.2 x 8.8 mm | about 2.7x | about 135mm |
The lens does not change when you move it between bodies; only the angle of view the sensor records changes. The full crop versus full-frame tradeoff, including depth of field and low-light differences, is worked through in the guide.
Focal length: what each range is for
These are full-frame-equivalent numbers. On a crop body, multiply by your crop factor to find the lens that frames the same way.
| Focal length (equiv.) | Angle | Best for |
|---|---|---|
| 16 to 24 mm | ultra wide to wide | landscapes, interiors, astro |
| 35 mm | wide standard | street, documentary, environmental portraits |
| 50 mm | standard | everyday, close to natural eye view |
| 85 mm | short telephoto | portraits, flattering compression |
| 100 mm macro | telephoto | close-up detail, product, nature |
| 70 to 200 mm | telephoto zoom | sports, events, wildlife at moderate range |
| 300 mm and up | super telephoto | distant wildlife and action |
If you are deciding between two primes, the 35mm versus 50mm comparison and the best lens for low light guide go deeper on how these lengths behave in real scenes.
How to use this page
Set the look you want with one control, then balance the exposure with the others in equal and opposite stops. Want a blurred background? Open the aperture, then shorten the shutter or lower the ISO by the same number of stops. Need to freeze a bird in flight? Shorten the shutter, then open up or raise ISO to match. The tables are reference points drawn from standard camera and lens conventions; your specific gear may differ slightly, so confirm against your camera’s manual, and let the exposure triangle explainer fill in the reasoning behind the numbers. If these tables reveal that your camera cannot reach the settings your scenes keep demanding, that is a named limit, exactly the kind our field note on how to upgrade your camera is built around.
Frequently asked questions
What are the full f-stops in order?
The standard full-stop aperture scale is f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, and f/22, often starting from f/1 on fast lenses. Each full stop changes the aperture area by a factor of two, so it either doubles or halves the light, and the f-numbers step by a factor of about 1.4, which is the square root of two. Modern cameras also offer third-stop clicks in between, such as f/3.2 and f/3.5 between f/2.8 and f/4, but the full stops above are the reference points.
What is a stop in photography?
A stop is a doubling or halving of light. Opening the aperture one stop, lengthening the shutter one stop, or raising ISO one stop each doubles the exposure, and closing, shortening, or lowering does the opposite. Because all three controls are measured in the same unit, you can trade them evenly: if you open the aperture one stop to blur a background, you can shorten the shutter one stop to keep the exposure the same. That equal trade is the whole idea behind the exposure triangle.
What is crop factor and how do I use it?
Crop factor is how much smaller a sensor is than a full-frame 35mm sensor, and it tells you the effective field of view of a lens. Multiply the lens focal length by the crop factor to get the full-frame-equivalent focal length. On a 1.5x APS-C body, a 35mm lens frames like a 52mm lens does on full frame; on a 2x Micro Four Thirds body, it frames like 70mm. The lens itself does not change, only the angle of view the smaller sensor records.
What focal length should I use?
As a starting guide: 16mm to 35mm is wide, for landscapes and interiors; about 35mm is a natural street and documentary length; 50mm is a standard, close to what the eye sees; 85mm is a classic portrait length that flatters faces; and 70mm to 200mm is telephoto, for sports, wildlife, and compression. These are full-frame-equivalent numbers, so multiply by your crop factor if you shoot a smaller sensor. The right choice depends on your subject and how close you can stand.
How are shutter speeds and ISO measured in stops?
Both double and halve just like aperture. The full-stop shutter scale runs 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, and so on, each step doubling the time light hits the sensor. The full-stop ISO scale runs 100, 200, 400, 800, 1600, 3200, and up, each step doubling the sensor's sensitivity. Because all three exposure controls share the stop as a unit, a change in one can always be balanced by an equal and opposite change in another.
Is a bigger sensor always better?
Bigger sensors gather more light and generally give cleaner high-ISO images and more control over background blur, but they are not automatically better for every use. Smaller sensors make lenses and bodies lighter and cheaper and give more apparent depth of field, which helps for travel, wildlife reach, and video. The best sensor size is the one that fits your subjects, your budget, and how much weight you want to carry. The full-frame versus crop tradeoff is worked through in the guide linked below.