Tag Archives: Under Exposure

Correct snow scenes using exposure compensation

Bright snow scenes create a problem with the auto-settings for exposure

Bright snow scenes create a problem with the auto-settings for exposure
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Green shoots through the snow By Netkonnexion on Flickr External link - opens new tab/page

Snow reveals a problem with auto-modes.

The brightness of a snow scene throws off exposure. Cameras in auto-modes work to a “normal” type of scene. When unusually bright scenes are encountered the camera cannot compensate. It leaves the scene grey. This is because the camera is calibrated to work with a mix of colours, light and darks that represent the sort of scene we encounter every day. It senses the luminance levels in the scene and sets exposure to the middle of the range between light and dark.

If the camera senses an unusually bright scene, like the snow scene above, it is unable to compensate properly. The brightness is outside its normal range of compensation. The camera responds by underexposing the shot, and the snow turns grey. The photograph above shows the scene as shot in the right hand panel. It is grey. The left hand panel shows the correct exposure after the underexposure is compensated by an exposure compensation of 1.66 stops (one and two thirds stops). (See: Definition: f-stops)

Photographers are more accurate than camera auto settings

In these bright (or dark situations) we can dial in exposure compensation to manually set the scene to be brighter. Using the exposure compensation we can increase the exposure to brighten the scene (+ settings) or even darken the scene (- settings) as appropriate. Then, we take another picture. By looking at the screen on the camera (“Chimping”) we can get the exposure correct by adjusting the exposure compensation to correctly whiten the scene.

This exposure compensation principle applies to the camera modes which are automatic or semi-automatic. In full auto, the camera calculates the exposure by balancing the ISO, shutter speed and aperture settings. However, in the semi-automatic modes the photographer changes one of the settings while the camera changes the other. In these modes, as in full-auto, the camera can still make the mistake of under-exposing (or over-exposing). Only the photographer can judge the exposure correctly.

When using aperture priority mode, you the photographer, makes the decision on the aperture size (f-stop setting). The camera calculates the appropriate shutter speed. If your camera cannot correctly interpret the scene, as with snow for example, then you will need to dial the exposure compensation to correct for the under-exposure. If you are using shutter priority, same again, the camera calculates the aperture (f-stop) setting. If the camera makes a wrong exposure decision, you can manually set the exposure compensation to over-ride the f-stop setting the camera would set.

Full manual mode, where the photographer sets all the settings directly, cannot use exposure compensation. In this mode the photographer makes all the decisions. The camera does not interfere with the exposure settings. In this case the photographer is free to make decisions to fix the exposure setting for all three factors of exposure – ISO, aperture and shutter speed. There can be no element of compensation for a failed camera decision. The photographer stands by their own settings and has full discretion to control the exposure as they wish. Deliberate over or under-exposure as well as accurate exposure are all possible. It is for this reason that I urge you to work in full manual where you can. You have far more control over the outcome of the shot. You also as a consequence have more artistic control over your image.

If you are working in RAW, the native data mode of image files in camera, it is possible to correct for camera exposure errors in post-processing. As I have argued elsewhere it is better to try and get all the settings correct in camera than to spend time processing afterwards for a number of reasons. So, no matter what file type you are using, try to set the shot up correctly from the start.

There you have it. Exposure compensation is a camera setting which is wholly dedicated to compensating for the mess-ups that the camera makes with its exposure calculations in auto or semi-auto modes. But when using auto-modes, and/or using *.jpg files, it is essential to be able to compensate for the cameras’ failings by using exposure compensation – otherwise your snow will be grey!

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By Damon Guy (author and Photokonnexion editor)

Damon Guy - Netkonnexion

Damon Guy (Netkonnexion)

Damon is a writer-photog and editor of this site. He has run some major websites, a computing department and a digital image library. He started out as a trained teacher and now runs training for digital photographers.
See also: Editors ‘Bio’.
See also: Profile on Google+.

Five tips to create a winning image with ‘mystery’

"Mysterious Landscape". Creating an air of mystery draws your viewer into the picture

“Mysterious Landscape”. Creating an air of mystery draws your viewer into the picture.

Keep the viewer looking and you have a winning image

Sometimes it’s what the viewer cannot see that makes the image powerful. The ultimate aim of your picture is to draw the viewer into the image and keep them there thinking about what they see. One way to do that is to create a mystery…

Something unseen

In a previous article I discussed the way a title is part of your overall communication. You can capture the imagination of the viewer by hinting with your title. Something that cannot be seen, but could be there, draws the attention. The viewer wants to find what is behind the hint. Give them something to look for but don’t show it. Mist is a great device for this. The very thought of a misty forest is primeval and mysterious.

Darkness

Darkness creates a sense of menace if it is done right. Anything with lurking shadows and moody lights creates the sense that something may be there – but not quite seen. This is a situation ripe for the use of under-exposure and low lights. It does not have to be a night scene. However, use of low lights, threatening colours and impenetrable shadows brings on the mystery. Mood and threat make a great combination. Both urban scenes and moonlight landscapes are ideal. I am sure you can let your imagination run wild!

Around the corner

I used to manage parks. When we were designing new landscapes we often tried to give an air of mystery. People enjoy going to parks much more if there is a sense of the unknown around the next corner. Walks and views were designed to give people somewhere to go where they could not initially see the destination. So it is with photographs. Create a path, steps, road – anything – that leads somewhere you cannot see. Make the viewer look down the line expecting to see something, which at the end, is not there. An implied destination is a great way to draw in the viewer.

Hidden faces

One thing humans love to see is a face. We train ourselves from birth to take in peoples faces, understand them, communicate with them. Deprive the viewer of a face and the mystery is on. Masks are great fun. A deliberately hidden face is an immediate mystery. Wide-brim hats in dark places are powerfully mysterious. We have a compulsion to find out who the mystery person is – and it immediately captures our attention.

Illusion

Perhaps the most timeless way of creating mystery is to fool the eye. You know something is wrong and you cannot see what. Your eyes tell you one thing, you feel there is something else. A good illusion has you visually chasing around the image to find the issue. If you create a good illusion you will have a great image based on mystery. There are lots of places on the web to find out about photographic illusions.

 
There are other ways to create a sense of mystery. We would love to hear about mysterious images you have created. Please leave a comment below with a link if you have an image online.

By Damon Guy (author and Photokonnexion editor)

Damon Guy - Netkonnexion

Damon Guy (Netkonnexion)

Damon is a writer-photog and editor of this site. He has run some major websites, a computing department and a digital image library. He started out as a trained teacher and now runs training for digital photographers.
See also: Editors ‘Bio’.
See also: Profile on Google+.

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