Are there general rules for selecting the correct shutter speed and ISO in manual mode?

Question

I have purchased my first DSLR (a Canon 500D) and have been playing around quite a lot within the aperture priority mode, with auto shutter speed and ISO.

Anyways as I would like to become a better photographer I would like to start taking all my photos in Full Manual mode.

Are there any general rules that I should use to help me select a shutter speed and ISO combination? Currently I am using trial and error and while I get there in the end, it often takes a while. I understand that I will learn this with experience, but anything to get me started will help.

Further to this, do most 'Professional' photographers set these manually? The auto settings work so well for an average shot, and it seems too time consuming to adjust these for every angle and light variation.

Answer 1

Shooting manual mode doesn't make you a better photographer, understanding what all the settings effectively do will. Your camera has three basic settings:

• Aperture: Use this to control depth of field (DoF). This is usually the most important setting to most photographers, as it influences both subject matter and composition. You're not going to be taking pictures of things if they're too big to fit into focus.
• Shutter speed: Use this to control in-frame movement and blur. While very important, there's really not much of a difference in a typical print between a normal, semi-still image shot at 1/250 and 1/8000. As a general rule, if you're trying to keep motion frozen you want this above 1/125.
• ISO: This determines the "image quality" of an image. Keep this as low as possible.

The most common strategy is to first set the aperture, make sure that you have enough DoF to cover your entire subject (or whatever you're trying to achieve). Have your ISO set to the lowest possible value (without going into 'extended ISO' modes) and check your shutter speed. Is it at least 1/60 or 1/125? No? Bump the ISO up a stop.

Your 500D has a exposure level reading that you can see the bottom of its viewfinder. Use that to determine where your exposure needs to be. For example, if you're dialed in at f/5.6 and 1/500 @ 100 ISO, but the meter reads -2, you know you're going to underexpose with those settings. You can change your shutter speed to 1/125 or increase your ISO to 400 to get to the 'correct' exposure. If it reads +1, increase your shutter speed or lower your ISO to compensate.

All that said... experiment. Play around with it. You're shooting digital, who cares if some of your shots are blurry?

You can also try using the Sunny 16 rule, it might help you 'get' exposure. The Sunny 16 rule says: on a bright, sunny day, you can set your aperture to f/16 and your shutter to the same speed as your ISO value (so 1/100 for ISO 100, 1/400 for ISO 400). On a sunny, but slightly less so day, try f/11 or f/5.6 on cloudy day.

Manual mode's number 1 use is for consistency. When you take a series of photos in non-changing light conditions, you want your known color values to stay as close to each other as possible. With constant metering, especially in-camera metering, you can't hope for that kind of consistency. Point your camera at a white wall, look at the readings, then put a piece of black paper on that wall and see how wildly the meter reading changes.

There are also situations where in-camera metering doesn't do you any good, mainly in the studio. I don't know of any camera that meters for strobe/flash light effectively. 4

Answer 2

First, stay away from the "icons" on your 500D. These are the automated settings, and offer no freedom to choose your aperture and shutter speed.

Once you do that, here are four simple rules I follow:

Rule #1: stay above 1/60.

If you are using a tripod, you can go below this speed, but when hand holding the camera, always stay above this speed. If you do not, you will tend to get blurring from camera movement. Yes IS can help....but just remember the rule, its easy.

Rule #2: Keep your shutter speed 'above' your lens focal length.

This also helps ensure reduction of blur from camera shake. If you are shooting at 200mm, be sure your shutter speed is above 1/200th a second. If you are shooting 75mm, stay above 1/75th. If you are shooting 35mm, stay above...careful...1/60th.

Rule #3. Remember to choose bigger aperture numbers when you are shooting things farther away.

When shooting landscapes or other scenes, or when you want your background in focus, choose a "bigger number" for aperture. This actually selects a smaller aperture, but the result is that you get more distant objects in focus, even if you are focusing on a subject fairly close by. Basically, the camera is 'squinting its eyes" , just like you do, trying to bring distant objects in focus. This suggests that you can use aperture to manage the 'look' of your image, which indeed is what you do: pick an appropriate shutter speed (rules 1 and 2) and then adjust aperture until you get the look you want, within rules 1 and 2.

Rule #4: if you can not take your shot within any of the above 3 rules, adjust your ISO up, until you get a rule to apply.

So if you shoot at ISO 100 or 200 (and you should basically all the time), move up to ISO 400, then 800, etc until you can follow the rules.

Finally,

Rule #0: Check your ISO DAILY!

Always check your ISO before you use your camera, as you will be very upset when you shoot a critical event at ISO 3200 and have awful grainy shots when you didn't need ISO 3200.

Answer 3

In general you want to use as low an ISO setting as you can to avoid noise. If the lowest ISO means shooting at a low shutter speed, say 1/15th then you may bump up the ISO a bit so that you can shoot at a faster shutter speed.

If the light isn't changing, setting everything manually means that you get consistent exposures. Think of a sports or events photographer. If you leave in Aperture priority, then as your background changes (more sky in the photo for example) the camera may adjust the exposure and you end up with under or overexposed images.

Nothing wrong with using Aperture or Shutter priority if it suits you. Full manual yields more consistent results when you have time (and remember you're in manual!) and especially when you'll do a lot of shots in the same light.

Answer 4

Taking all photos in full manual mode seems a bit extreme to me.

To get proper exposure in manual mode just use the small light meter in the viewfinder or on the back screen and adjust the settings until the little arrow is in the middle - or - half press the shutter button on Auto, P, Av or Tv mode (this will show you the settings both in the viewfinder and on the screen) and copy the settings.

Than, after you used the light meter to get the baseline adjust the setting to your taste (I assume you want to adjust them because if the light meter gave you the results you are looking for just use P/Av/Tv and save the time it takes to "dial in" the settings)

If you take ISO off auto mode you get most of the control also in Av and Tv mode (learn to use exposure compensation), here are my rules for choosing modes (I'm an amateur learning photography, I expect people with years of experience will have completely different rules - especially the first one):

1. For once in a lifetime photos take at least one photo on Auto - that way you at least have a picture, losing a once in a lifetime chance to incorrect camera settings hurts.

2. If you care more about movement (you either want to freeze motion or create motion blur) use Tv mode (example: children playing, sports)

3. If you care more about depth of field use Av (example: portraits, landscape)

4. If you want consistent settings between photos (or controlled changes) use M (example: panorama, HDR, multiple pictures that will be printed together on the same page)

5. If you do anything that confuses the camera, obviously use M (example: lightnings, fireworks, external manual flashes that don't use the camera's flash metering system)

In Av and Tv modes always look at the automatically chosen values (Shutter speed in Av mode and Aperture in Tv mode) before taking the picture - just the make sure the camera didn't choose something ridicules like 30 seconds (Av mode, too dark for the value you set - happens to me all the time) or f/36 (Tv mode, way too much light for your settings)

Answer 5

Exposure

There are several technical factors that will affect your images directly which you have control over. Depending on each situation that you want to shoot, you may want to have the others adjusted automatically by your camera, or adjust all of them manually yourself. Shooting moving subjects generally means shooting in Shutter priority mode and shooting portraits usually means shooting in aperture priority mode or manual mode. Doing serious flash photography, you will almost always use manual mode to be able to expose freely.

Focal Length

This is a property of your lens. Focal lengths are normally given as 35mm equivalent focal lengths, that is to say, the length given on the lens indicates the focal length when used with 35mm film, or a full frame sensor. Focal length along with aperture, affects depth of field, longer focal lengths generally having a larger effect on the amount of blurring than just a wide aperture.

Aperture

This determines just how wide your lens will be opened once the shutter is triggered. It directly restricts the total amount of light that is going to hit your film or sensor, and as a result, controls all lights in your image, whether they are there for the entire duration of the exposure, or only appear for part of your exposure, like a flash, or a car entering your image at night in the middle of your exposure.

Depth of Field

The depth of field of an image is the distance in front of and behind the subject you focus on which is in focus. Wide apertures give you a shallow depth of field, allowing you to blur your backgrounds to draw attention to your subject while closing down your aperture allows you to get a wider shot while keeping several subjects at different distance in focus.

Flash control

The light of a flash is instantaneous, as such, if you are using flash with constant power (Manual flash settings), you can adjust the effect that the flash is having on your exposure precisely by changing your aperture.

Shutter speed

Exposure length is the length of time that the shutter will remain open once triggered. This controls just how long your sensor will be exposed to light. Exposure length controls whether you can shoot a photo hand-held without camera-shake affecting sharpness as well as how subjects appear in the image.

Short exposures

Short exposures allow for shooting still images of subjects in motion, things that the naked eye cannot perceive as anything but a blur. For really high-speed photography, additional light sources are a necessity.

Long exposures

Long exposures can be used to get a bright enough exposure under low light conditions, or, combined with a circular polarizer filter / ND filter used to capture motion in a still image. Moving lights will appear as streaks in an otherwise unmoving frame.

Long exposures with flash

Flash used at the beginning of a long exposure will cause the subject to appear to be frozen at the beginning of their motion while the rest of their motion appears trail off of this first image. The backlights of a moving car would actually become a streak of light over the car in a photo shot this way.

Flash used at the end of exposure is generally called rear curtain flash and allows for motion trails to lead to the sharp, well exposed image in a long exposure. The backlights of a moving car shot with rear curtain flash would become a streak of light behind the car.

Camera Shake

Combined with the focal length, shutter speed also determines if an exposure can be made hand-held, a rule of the thumb on this is to match focal length to shutter speed - so if you're using a 50mm lens, shooting at 1/50 or faster, or 1/200 with a 200mm lens is supposed to give you about 100% blur free images if you have relatively steady hands. However, image stabilization on a lens affects this, and it is possible to shoot at high-speed burst modes and get completely sharp photos with an unstabilized lens at speeds approaching even 1/4 of the speed the above rule would suggest as the rule only really applies to probabilities - the human nervous system has completely normal, random muscle shakes several times a second, so if there's a 25% chance that a given shutter speed is long enough to include a shake, there is still a possibility that this won't happen and the image will come out sharp at that speed if you simply shoot 4 times - this is why it's a good idea to use high-speed burst mode at low light conditions.

ISO

The ISO value is a property of the film or the sensor in your camera. Basically, it is the speed at which the film or sensor absorbs light. The faster this speed, that is to say, the larger the ISO, the grainier an image will become, especially in the darker parts. However, the slower (smaller) ISO numbers will not only result in a much cleaner image, but will also require more light to properly expose. Unless you wish to achieve a certain grainy look, try to shoot at the lowest ISO level that your other considerations for your image will allow you.

Answer 6

I'll provide some answers for some specific situations where I find manual mode useful, with or without auto-ISO:

• Astrophotography. For moon, I use f/8 (the sharpest aperture of the lens @ 250mm), ISO 100, 1/200 s. This provides exposure equivalent to the Looney f/11 rule, but with a sharper aperture. For milky way photography, I have planned to use something like f/2.8 (the largest aperture of the lens), ISO 3200, 20 s, but haven't had a chance to shoot outside of streetlight areas when the moon is not up. For astrophotography, there is really no other option than manual mode.

• Nighttime outdoors photography or Christmas light photography. I choose f/2.8 or f/1.8 depending on the lens (the largest aperture of the lens), ISO 6400, 1/40 s or 1/80 s (depending on focal length to avoid camera shake). The images will be dark, but then again in these conditions the dark look is what you're looking for. Auto-ISO goes on my camera only up to ISO 3200 (although there may be a setting somewhere to allow using ISO 6400), and for the shutter speed I find it preferable to set it manually to avoid shaken shots.

• Wildlife photography. The automatic settings of the camera choose too slow shutter speed for flying birds. Thus, I shoot it manual mode, f/5.6 (the largest aperture of the lens @ 250mm), 1/1000 s and let the exposure be handled by using auto-ISO that can when photographing shadowy areas be as high as ISO 1000 and according to the sunny f/16 rule shouldn't be below ISO 120. So, these settings use an acceptable ISO for any conditions during the daytime. Far over ISO 1000, my camera would produce noisy shots.

• Photography with a flash. The flash is your source of exposure for the lit subject, but for the background, flash can't expose it. Thus, the manual mode ensures you can adjust the amount of exposure for the subject and for the background separately. You can either use manual flash settings if you have the time, or if you want to be quick, use TTL metering for the flash to set its power automatically. This covers the foreground. The background exposure will be set by experimenting with various exposure times. You should use manual ISO, since you have the possibility to set the ISO low for a low noise. In practice, ISO 100 is what you want to use (it's the base ISO on most cameras). Set the aperture for correct depth of field, and choose the exposure time depending on experiments that reveal how much background exposure you have. ND filter may be necessary if the background is very bright, such as in sunlight.

I haven't shot fireworks yet (I only bought my first DLSR this year), but I'll probably use the manual mode for fireworks too. I don't do sports photography, but for that situation manual mode could be useful as well.

I would categorize astrophotography, nighttime outdoors photography, Christmas light photography and fireworks photography into low-light photography. I would also categorize wildlife photography and sports photography into action photography.

So, as summary:

• For action photography, you probably want to use manual mode with auto-ISO
• For low-light photography, you probably want to use manual mode without auto-ISO
• For flash photography, you probably want to use manual mode without auto-ISO, and depending on whether you have the time, either manual or TTL mode for the flash

For the rest of the situations, I typically use aperture priority, with auto-ISO. The aperture is what controls the depth of field, and I want to have that critical parameter under my control. Sometimes, when looking for a motion blur effect, I use shutter priority and let the camera choose the aperture and use auto-ISO.

By the way, if you want to become a good photographer, exposure is not the only parameter what you're concerned about. You should master your camera's focusing and burst settings. For action photography, you probably want to use servo autofocus with burst mode, for astrophotography and fireworks photography you probably want to use manual focus, for other situations you probably want to use one-shot autofocus without burst mode.

So, to answer the question: you shouldn't use the manual mode to be professional. You shouldn't use the automatic mode either. You should use something in between. There is plenty of middle ground between these (Do you use auto-ISO or not? Do you use shutter or aperture priority? If using flash, do you use TTL?)