Friday, January 20, 2012

CAMERA EXPOSURE

A photograph’s exposure determines how light or dark an image will appear when it’s been captured by your camera. Believe it or not, this is determined by just three camera settings: aperture, ISO and shutter speed (the "exposure triangle"). Mastering their use is an essential part of developing an intuition for photography.


UNDERSTANDING EXPOSURE

Achieving the correct exposure is a lot like collecting rain in a bucket. While the rate of rainfall is uncontrollable, three factors remain under your control: the bucket’s width, the duration you leave it in the rain, and the quantity of rain you want to collect. You just need to ensure you don’t collect too little ("underexposed"), but that you also don’t collect too much ("overexposed"). The key is that there are many different combinations of width, time and quantity that will achieve this. For example, for the same quantity of water, you can get away with less time in the rain if you pick a bucket that’s really wide. Alternatively, for the same duration left in the rain, a really narrow bucket can be used as long as you plan on getting by with less water.

In photography, the exposure settings of aperture, shutter speed and ISO speed are analogous to the width, time and quantity discussed above. Furthermore, just as the rate of rainfall was beyond your control above, so too is natural light for a photographer.


EXPOSURE TRIANGLE: APERTURE, ISO, & SHUTTER SPEED


Imagine a triangle with equal sides and angles. The top angle would be aperture (depth of field), the lower right angle would be ISO speed (image noise), and the left angle would be shutter speed (motion blur)


Each setting controls exposure differently:

Aperture: controls the area over which light can enter your camera

Shutter speed: controls the duration of the exposure


ISO speed: controls the sensitivity of your camera’s sensor to a given amount of light


One can therefore use many combinations of the above three settings to achieve the same exposure. The key, however, is knowing which trade-offs to make, since each setting also influences other image properties. For example, aperture affects depth of field, shutter speed affects motion blur and ISO speed affects image noise.

The next few sections will describe how each setting is specified, what it looks like, and how a given camera exposure mode affects their combination.

SHUTTER SPEED
A camera’s shutter determines when the camera sensor will be open or closed to incoming light from the camera lens. The shutter speed specifically refers to how long this light is permitted to enter the camera. "Shutter speed" and "exposure time" refer to the same concept, where a faster shutter speed means a shorter exposure time.

By the Numbers. Shutter speed’s influence on exposure is perhaps the simplest of the three camera settings: it correlates exactly 1:1 with the amount of light entering the camera. For example, when the exposure time doubles the amount of light entering the camera doubles. It’s also the setting that has the widest range of possibilities:

Shutter Speed
Typical Examples
1 – 30+ seconds
Specialty night and low-light photos on a tripod


2 – 1/2 second


To add a silky look to flowing water
Landscape photos on a tripod for enhanced depth of field


1/2 to 1/30 second



To add motion blur to the background of a moving subject
Carefully taken hand-held photos with stabilization


1/50 – 1/100 second


Typical hand-held photos without substantial zoom
1/250 – 1/500 second


To freeze everyday sports/action subject movement
Hand-held photos with substantial zoom (telephoto lens)
1/1000 – 1/4000 second


To freeze extremely fast, up-close subject motion

How it Appears. Shutter speed is a powerful tool for freezing or exaggerating the appearance of motion:


With waterfalls and other creative shots, motion blur is sometimes desirable, but for most other shots this is avoided. Therefore all one usually cares about with shutter speed is whether it results in a sharp photo — either by freezing movement or because the shot can be taken hand-held without camera shake.


How do you know which shutter speed will provide a sharp hand-held shot? With digital cameras, the best way to find out is to just experiment and look at the results on your camera’s rear LCD screen (at full zoom). If a properly focused photo comes out blurred, then you’ll usually need to either increase the shutter speed, keep your hands steadier or use a camera tripod.


APERTURE SETTING
A camera’s aperture setting controls the area over which light can pass through your camera lens. It is specified in terms an f-stop value, which can at times be counterintuitive, because the area of the opening increases as the f-stop decreases. In photographer slang, the when someone says they are "stopping down" or "opening up" their lens, they are referring to increasing and decreasing the f-stop value, respectively.

By the Numbers. Every time the f-stop value halves, the light-collecting area quadruples. There’s a formula for this, but most photographers just memorize the f-stop numbers that correspond to each doubling/halving of light:



Aperture Setting
Relative Light
Example Shutter Speed
f/22
    1X 
        16 seconds
f/16
    2X
          8 seconds
f/11
   4X
          4 seconds
f/8.0
   8X
          2 seconds
f/5.6
 16X
          1 second
f/4.0
 32X
       1/2 second
f/2.8
 64X
       1/4 second
f/2.0
 128X
       1/8 second
f/1.4
 256X
     1/15 second


The above aperture and shutter speed combinations all result in the same exposure.

Note: Shutter speed values are not always possible in increments of exactly double or half another shutter speed, but they’re always close enough that the difference is negligible.

The above f-stop numbers are all standard options in any camera, although most also allow finer adjustments, such as f/3.2 and f/6.3. The range of values may also vary from camera to camera (or lens to lens). For example, a compact camera might have an available range of f/2.8 to f/8.0, whereas a digital SLR camera might have a range of f/1.4 to f/32 with a portrait lens. A narrow aperture range usually isn’t a big problem, but a greater range does provide for more creative flexibility.

Technical Note: With many lenses, their light-gathering ability is also affected by their transmission efficiency, although this is almost always much less of a factor than aperture. It’s also beyond the photographer’s control. Differences in transmision efficiency are typically more pronounced with extreme zoom ranges. For example, Canon’s 24-105 mm f/4L IS lens gathers perhaps ~10-40% less light at f/4 than Canon’s similar 24-70 mm f/2.8L lens at f/4 (depending on the focal length).

How it Appears. A camera’s aperture setting is what determines a photo’s depth of field (the range of distance over which objects appear in sharp focus). Lower f-stop values correlate with a shallower depth of field:

ISO SPEED
The ISO speed determines how sensitive the camera is to incoming light. Similar to shutter speed, it also correlates 1:1 with how much the exposure increases or decreases. However, unlike aperture and shutter speed, a lower ISO speed is almost always desirable, since higher ISO speeds dramatically increase image noise. As a result, ISO speed is usually only increased from its minimum value if the desired aperture and shutter speed aren’t otherwise obtainable.

note: image noise is also known as "film grain" in traditional film photography


Common ISO speeds include 100, 200, 400 and 800, although many cameras also permit lower or higher values. With compact cameras, an ISO speed in the range of 50-200 generally produces acceptably low image noise, whereas with digital SLR cameras, a range of 50-800 (or higher) is often acceptable.


CAMERA EXPOSURE MODES

Most digital cameras have one of the following standardized exposure modes: Auto (green rectangle), Program (P), Aperture Priority (Av), Shutter Priority (Tv), Manual (M) and Bulb (B) mode. Av, Tv, and M are often called "creative modes" or "auto exposure (AE) modes."

Each of these modes influences how aperture, ISO and shutter speed are chosen for a given exposure. Some modes attempt to pick all three values for you, whereas others let you specify one setting and the camera picks the other two (if possible). The following charts describe how each mode pertains to exposure:

Exposure Mode
How It Works
Auto (green rectangle)




Camera automatically selects all exposure settings.

Program (P)
Camera automatically selects aperture & shutter speed; you can choose a corresponding ISO speed & exposure compensation. With some cameras, P can also act as a hybrid of the Av & Tv modes.

Aperture Priority (Av or A)

You specify the aperture & ISO; the camera’s metering determines the corresponding shutter speed.
Shutter Priority (Tv or S)

You specify the shutter speed & ISO; the camera’s metering determines the corresponding aperture.

Manual (M)

You specify the aperture, ISO and shutter speed — regardless of whether these values lead to a correct exposure.

Bulb (B)
Useful for exposures longer than 30 seconds. You specify the aperture and ISO; the shutter speed is determined by a remote release switch, or by the duration until you press the shutter button a second time.

In addition, the camera may also have several pre-set modes; the most common include landscape, portrait, sports and night mode. The symbols used for each mode vary slightly from camera to camera, but will likely appear similar to those below:

Exposure Mode


How It Works




Portrait
portrait mode
Camera tries to pick the lowest f-stop value possible for a given exposure. This ensures the shallowest possible depth of field.



Landscape
landscape mode


Camera tries to pick a high f-stop to ensure a large depth of field. Compact cameras also often set their focus distance to distant objects or infinity.


Sports/Action
sports/action mode
Camera tries to achieve as fast a shutter speed as possible for a given exposure — ideally 1/250 seconds or faster. In addition to using a low f-stop, the fast shutter speed is usually achieved by increasing the ISO speed more than would otherwise be acceptable in portrait mode.

Night/Low-light
Camera permits shutter speeds which are longer than ordinarily allowed for hand-held shots, and increases the ISO speed to near its maximum available value. However, for some cameras this setting means that a flash is used for the foreground, and a long shutter speed and high ISO are used expose the background. 
Check your camera’s instruction manual for any unique characteristics.


However, keep in mind that most of the above settings rely on the camera’s metering system in order to know what’s a proper exposure. For tricky subject matter, metering can often be fooled, so it’s a good idea to also be aware of when it might go awry, and what you can do to compensate for such exposure errors.

Finally, some of the above modes may also control camera settings which are unrelated to exposure, although this varies from camera to camera. Such additional settings might include the autofocus points, metering mode and autofocus modes, amongst others.

Saturday, July 23, 2011

Crop Sensor (APS-C) Cameras and Lens Confusion

Despite the fact that so called "crop sensor" digital SLRs have been with us for over 5 years, there's still a huge amount of confusion out there about exactly what a crop sensor camera is and what effect is of using a lens with a crop sensor camera rather than a full frame camera. The photography forums are full of confused newcomers asking about focal length, field of view etc.

First, what is a crop sensor camera? Well, it's simple. A full frame 35mm camera ( whether it uses film or a digital sensor) records an image that is approximately 36mm x 24mm in size. In the early days of digital sensors it was not possible to make digital sensors that big in any sort of quantity, and the ones you could make were so expensive that hardly anyone would have been able to buy a camera which used one. So camera makers decided to use a smaller sensor, around 15mm x 22.5mm. This just happens to be close to the image size which was used with the short-lived APS film format, specifically the APS-C image size of 25.1 × 16.7 mm (there was also APS-H and APS-Panoramic format).


The "crop" name comes from the fact that if you take a full frame image (24x36mm) and crop the center 15x22.5mm out of it, you get an image the size of "crop" sensor cameras.


So why does the format size matter and what effect does it have on focal length? Well the answer to the second part of the question is "none". The focal length of a lens is the focal length of the lens. Whether you mount that lens on a 35mm camera, a medium format camera of a large format camera doesn't change its focal length. All 35mm lenses and lenses designed for use on APS-C DSLRs are marked with their true, actual, focal length.


The problem is that most of us have been trained to think in terms of focal length rather than field of view when comparing lenses. We've been trained to think that a 50mm lens is "normal", a 35mm lens is "wide normal", a 28mm lens is "wide", a 24mm lens is "very wide", a 20mm lens is "super wide", a 16mm lens is "ultrawide" and so on. In fact this is true ONLY if that lens is making a 36mm x 24mm image. The field of view (which is what "wide" is all about) is actually determined just as much by format size as by focal length. The diagram below shows why.




As you can easily see from the diagram, the larger the format, the wider the angle of view for a lens of a given focal length (shown by the red lines for the larger format and the blue lines for the smaller format). That's why a 28mm lens on a full frame 36x24mm gives a wide view (red lines), but on a smaller format camera such as one using and APS-C crop sensor, it's not so wide (blue lines). In fact if you put that same 28mm lens on a Canon EOS crop sensor camera, the angle of view decreases as you can see from the figure above. The angle of view decreases to the extent that it's now the same as that of a 44.8mm lens mounted on a full frame camera. It means that if you look through the viewfinder of an APS-C crop sensor camera with a 28mm lens mounted on it, you'll see exactly the same angle of view as if you looked through the viewfinder of a full frame camera with a 44.8mm lens mounted on it.
To get the same field of view as a 28mm lens on the full frame camera, you'd need a shorter focal length lens when used with the APS-C crop sensor. That's illustrated by the green lines in the image above. In the case of EOS DSLRs, the focal length would need to be 17.5mm. The relationship of these numbers will be explained next.

Wideangle Lenses


 Angle of View (degrees, Hoizontal)35mm
"full frame"
APS-C "crop"
Normal lens39.650mm31.3mm
Normal-wide54.435mm21.8mm
Wide65.528mm17.5 mm
Very wide73.724mm15mm
Super wide8420mm12.5 mm
Ultra wide96.716mm10mm

The factor relating the 50mm focal length of the normal full frame lens and the 31.3mm of the equivalent normal APS-C lens is often called the "crop factor", sometimes the "digital multiplier". It's 1.6x for Canon EOS DSLRs and 1.5x for Nikon, Pentax and Sony (who have very slighly larger APS-C sensors). It doesn't actually multiply the focal length. It's just a factor which you can use to judge the field of view a lens will give you. That's what you want to know of course. You don't care if the lens is 10mm, 20mm, 30mm or 40mm. You want to know if it gives you a wide, normal or telephoto view. "normal" lenses have a horizontal field of view of around 40 degrees, wideangle a field of view of 65 degrees or more (these are somewhat arbitrary numbers, but they are representative of commonly accepted values).


So when you want a wideangle lens for your APS-C crop sensor camera, you really want a lens with a field of view of 65 degrees or more. In this case that would correspond to a lens with a focal length of about 17.5mm (for EOS APS-C bodies). Now you may be used to thinking in full frame terms, where you'd need a 28mm focal length lens, but you have to forget that! For example the 28-135 lens was a "wide to telephoto" zoom on a fill frame film SLR, but on an APS-C DSLR it's more like a "normal to longer telephoto" zoom.


Telephoto Lenses


We can apply the same reasoning to telephoto lenses. When we think of a telephoto lens we normally think of a long focal length, but again, focal length doesn't define a telephoto lens, angle of view does. So, for example, while a 300mm lens is considered to be a telephoto lens for 35mm cameras, for 8x10 cameras a 300mm lens is a "normal" lens, i.e. it gives you about the same view as a 50mm lens would on a 35mm camera. What we want when we want a telephoto lens is a small angle of view, so that a small and distant subject fills the frame. The focal length that gives us that desired angle of view depends on the format we are using, as shown on the table below:

 Angle of View (degrees, Hoizontal)35mm
"full frame"
APS-C "crop"
Telephoto9.5135 mm84.3 mm
Long telephoto4.3300 mm187.5 mm
Super Telephoto2.1600 mm375 mm
Extreme Telephoto1.5840 mm600mm

As you can see, for the same angle of view (which we could call "telephoto power"), we need a shorter focal length lens for the APS-C format than we do for the full frame 35mm format. This is actually often good, because shorter focal length lenses are cheaper! Alternatively if you have a lens of a given focal length, such as 600mm, it gives you a 2.1 degree of view when mounted on a full frame camera, but a narrower 1.5 degree angle of view when mounted on an APS-C camera. So on an APS-C crop camera, the lens has more "reach", i.e. you can fill the frame with a smaller or more distant subject. Again the "crop factor" or "digital multiplier" can be used to calculate what lens on a 35mm full frame camera would be needed to give the same field of view as a 600mm lens on an APS-C crop sensor camera 35mm camera. For Canon EOS APS-C cameras the "crop factor" is 1.6x, so a you'd need an 840mm (600 x 1.6) on the full frame camera.


Of course we could get EXACTLY the same result by simply cropping the full frame image as by using the "crop" sensor (again, that's why they are sometimes called "crop" sensors), but you'd usually end up with a picture comprised of fewer pixels that way, so the quality would not be so high. If we took a full frame sensor with 16MP and we cropped it to Canon EOS APS-C size, we'd have an image containing 6.25MP, and that is a fairly low number by today's standards for APS-C cameras. If we used an EOS 40D we'd have 10MP and if we used an EOS 50D we'd have 15MP.


Conversion Factors - Digital Multipliers


If you want to know what focal length you need to give you the same field of view (FOV) on a crop sensor camera as a lens of "X" mm does on a full frame camera, you DIVIDE the focal length by the "digital multiplier", which is 1.6x for Canon EOS cameras and 1.5x for Nikon, Sony and Pentax. So, for example, to find what lens on an EOS 40D (crop sensor) gives you the same view as a 100mm lens on and EOS 5D (full frame sensor), you divide 100 by 1.6 and the answer is that you'd need a 62.5mm lens. So the EF-S 60/2.8 macro will give you approximately the same field of view on an EOS 40D as a 100mm macro does on an EOS 5D.


The go the other way, to find what focal length lens you'd need on a full frame camera to give you the same field of view (FOV) as a "Y" mm lens on a crop camera, you MULTIPLY the focal length by the "digital multiplier". So if you have a 300mm lens on your 40D, you'd need a (300 x 1.6) = 480mm lens on your EOS 5D to give you the same field of view.


So to summarize for Canon EOS cameras and lenses:
• APS-C crop sensor focal length to EQUIVALENT FOV full frame focal length - MULTIPLY by 1.6
• Full Frame focal length to EQUIVALENT FOV for APS-C crop sensor - DIVIDE by 1.6
Note that the aperture stays constant. An f2.8 lens always acts like an f2.8 lens. There is no "digital multiplier" for lens speed.


Image Circle - Canon "EF" and "EF-S" lenses


There's one more thing to understand about lenses for full frame and APS-C sensors and that's the concept of the image circle. Basically all lenses produce a circular image field and the diameter of that circle has to be larger than the diagonal of the frame, otherwise the corners of the image will be dark. For full frame 35mm a lens must have an image circle larger than 43.27mm, and for a 15 x 22.5 mm APS-C frame, an image circle of at least 27.04mm. This is shown schematically below:


As you can see, if you use a lens intended only for APS-C sensors on a full frame camera, the image circle would not cover the sides and corners of the frame. However if you use a lens with an image circle designed for 35mm use, it will be just fine on an APS-C camera. In the Canon lens line, "EF" series lenses have full coverage of the 35mm frame, but "EF-S" lenses have a smaller image circle and are only intended for use on APS-C crop sensor cameras. Nikon designate their APS-C image circle lenses as "DX", Tamron designate theirs "DiII" and so on. While some systems allow the smaller image circle lenses to by physically mounted on full frame bodies, Canon do not. EF-S series lenses will not physically mount on any full frame EOS camera body.


Note that image circle has nothing to do with focal length. It's part of the lens design. For a larger image circle you usually need a larger lens barrel and larger lens elements. This often leads to higher cost and higher weight as well as a larger diameter lens.


Depth of Field


The subject of differences in depth of field between full frame and crop sensor images is somewhat complex since it depends on if you use the same lens or diffferent lenses on the two cameras and if you shoot from the same position with both cameras. However you can basically state that for images with the same angle of view (i.e. the same magnification), crop sensor images have a larger depth of field. This may be good for landscapes, but not so good for portraits where you often want a shallow depth of field to blus out distracting background details. For a full discussion of all the factors involved, please take a look at this article:



Aperture


If Gertrude Stein had been a photographer she might have said "f2 is f2 is f2". The maximum aperture of a lens is constant. The f-stop is given by the focal length divided by the aperture size. If you have a lens with a focal length of 100mm and a physical aperture of 50mm, it's an f2 lens and will produce an image with a brightness determined by the fact that it's an f2 lens. Since neither the actual physical focal length nor the actual physical aperture change the when the lens is mounted on a camera, it's always an f2 lens. It doesn't matter if you use it on a full frame camera, an APS-C camera or and 8x10 camera. If it's f2, it's f2. Of course the angle of view that is recorded will be different for different formats and unless the lens was designed for 8x10, if you use it with an 8x10 camera you'll get a tiny image in the middle of a field of black, but the actual image brightness won't change because the lens will always be f2.


For an equivalent field of view, the physical aperture of an EF-S lens designed for an APS-C camera will be smaller than that for a full frame lens, but that's because the focal lengths will be different. It's not actually related to the format of the camera attached to the lens. Thus a 50mm lens on an APS-C camera gives the same field of view as an 80mm lens on a full frame camera and so you can consider them to be "equivalent", though obviously they are in fact different since they have different focal lengths. If they were both f2, then the physical aperture of the 50mm lens would be 25mmm and that of the 80mm lens would be 40mm, so the crop sensor lens would be smaller and have a physically smaller aperture even though they were both f2. This is a point which causes some confusion, but the bottom line is that if you mount a lens marked "50mm f2" on an APS-C crop camera or a full frame camera, it's f2 on both of them and it's 50mm on both of them. The so called "1.6x digital multiplier" is really a factor which affects the field of view which is recorded and which does depend on format size. It does not affect the aperture and it does not affect the true focal length of the lens.


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Sling Your Camera With A DIY C-Loop For Under $5



The C-loop, R-Strap and Sun Sniper are three systems designed to change the way you carry your camera around.
They all share a similar idea - the strap goes inside the tripod screw. Of course, this probably makes the camera designers pull their hairs as they invested so much time in making those little two 'ears' that the normal strap goes on.
Anyhow, using a system like the C-Loop really changes the way you carry your camera around - something we have discussed before - it is way more comfortable that any "regular" strap.
In this tutorial Cameron Texter will show you how to make a DIY C-Loop for your camera. (warning, this is for a point and shoot, not sure I would trust this DIY with my Nikon D300 + the 24-70 2.8)
Parts
1 x ¼-20 bolt (You might want a 1.25 inch bolt, because with the part on the U Bolt (below) that sticks out takes space away from the screw so you won't have enough to get the screw to be stable in the tripod slot. I got the 1 inch bolt and had to sand off the part on the U bolt that sticks out to give it more room. Make your calculations before you purchase the items.)
1/4-20 Extruded U Nut and another Extruded U Nut with a bigger thread size than the bolt, so it will glide right through it, but not have moving room.
Optional, but is really good to have: Washer that fits the size of the 1/4-20 bolt
The Build
The build is actually quite simple. All you have to do it take the two U Nuts and slide one onto the other one, with the hole that sticks out on the outside, on both sides. Make sure the holes are aligned.
Next, put your screw through the 1/4-20 screw hole and it should come out the other end since the thread size is larger than the screw.
[I made the mistake of buying the same size (1/4-20) U nut, and I didn't realize my mistake that it wouldn't go through the other end because the threads were backwards on the other end, so I had to remove the threads by drilling through the hole.]
Once you get the two U bolts aligned together with the bolt going through one end and out the other end, it's finished, all you have to do is have a washer and then put your camera strap through the slots.
If you want that extra bit of safety, dub a bit of silicon on the screw so it won't scratch anything.
The last step is to thread your "regular" strap ends into the places on the U nut.
Now you have your DIY C-Loop for under $5!

* C-Loop is a DIYP sponsor and we really love their stuff.

Thursday, June 9, 2011

How to Photograph a Rainbow


A Rainbow is something that has the power to stop you in your tracks when it unexpectedly appears when you’re least expecting to see one. They’re beautiful – but how do you photograph a rainbow?
Following are a few Rainbow Photography Tips that come to mind – feel free to add your own to comments below:

Find a Rainbow

This is the most obvious but also perhaps the hardest part of the process. Their appearance will depend upon the conditions and they are something that will often happen completely out of the blue. Having said this – you should especially be on the look out for rainbows when you have two elements present – falling/spraying water droplets and bright sunlight. As a result they’re common when a storm is approaching and around waterfalls/sprinklers/fountains.

Backgrounds

As rainbows are not solid objects one of the keys to photographing them is to capture them in front of a background that allows them to stand out as much as possible. Ideally you’ll want to get a background that is uncluttered and if possible one that has darker colors (think dark clouds, mountains etc). While it’s not always possible to change the background – you might find that you’re able to change the angle that you’re shooting from or to focus just upon part of the rainbow that is in front of a good background.

Composition

While rainbows are a beautiful thing – it’s the surrounds that they appear in that make one rainbow photograph really stand out from others. As a result it’s important to carefully think about how you compose your shot when photographing them. Particularly pay attention to the following:
  • Positioning – how you position the rainbow (and the rest of the landscape) in your shot is important. Rules like the rule of thirds could be useful when thinking about focal points and leading the eye into your shot.
  • End Points of the Rainbow – the point where a rainbow hits the ground/horizon is an important point in any rainbow photograph. This is a natural point of interest so think about where you’ll put it in the frame. You might want to zoom in on this spot or even quickly change your own position so that it lines up with some other object in the scene.
  • Zoom/Wide Angle Perspectives - quickly experiment with different focal lengths (if you have different lenses or a zoom). A wide angle lens that captures a full rainbow can give you some wonderful wide vista shots – but don’t forget that zooming right in on a part of the rainbow can also lead to spectacular results. Particularly focus in on any point where the rainbow intersects with any object – or where it begins and ends.

Foregrounds

Consider not only the background of your rainbow shots – but the foregrounds. These can add interest to the shot but also lead the eye towards focal points. Also scan the foreground for distractions that you could remove.

Multiple Rainbows

Keep in mind that where there is one rainbow there can often be a second one – or at least another layer of one that arches over the first. Including both can lead to an extra layer of interest in the shot

Polarizing Filter

If you have a polarizing filter experiment with rotating it to see what different effects it will have. You’ll find that in doing so you’ll get different saturations of colors, reflections and levels of contrast in your shot which can drastically impact the shot and help the rainbow to stand out more.

Aperture

Choosing different apertures will have less impact upon the rainbow itself and more effect upon the overall shot. Choose a small aperture and you’ll get as much of the scene in focus as possible (ie it’ll have a large depth of field).

Tripods

Keeping your camera as still as possible is important in all landscape shots – but it’s particularly important for rainbow shots as they often appear in darker conditions (like before a storm) and if you use a polarizing filter and a small aperture you’ll probably need to use a longer shutter speed. Of course rainbow shots are not something that you can always plan for – so you might need to find some alternative ways to secure your camera.