How to solve problems encountered when taking photos

All photographers will occasionally encounter some problems when taking photos, sometimes due to equipment failure, sometimes due to human error. If the photos you take do not match your expectations, please refer to the following. You will find that there are several problems listed in the illustrations, some are caused by the exposure process, and some are caused by digital printing. How should we solve these problems?

1、 Camera/lens problems

Part of the picture is blocked by lens mask or filter.Use the appropriate type of hood for your lens. Lens hood is designed according to lens focal length. If the hood is too long for your lens, it may extend too far to block the picture. When multiple filters or filters are used together with the hood, it may cause halo, especially when using a short focus lens. If necessary, you can remove the light shield and shield the lens by hand. Just make sure your hands are out of the picture.

There is dust on the sensor during exposure.A little dust on the photosensitive surface will affect the arrival of light during the exposure process. When changing the lens, keep the camera body clean by blowing the ball or dust cover. Small black spots can be erased during image editing, or removed by silver plate or bleaching technology.

Dust on scanner glass during scanning. (Film)Dust on the negative or scanner glass will prevent light from passing through the negative, thus showing white spots on the positive image. The opaque objects in the scanner or the dust on the image will show dark spots. In digital images, these defects can be modified later, but it is more convenient to keep the objects clean.

2、 Exposure problems

The light meter is affected by the background.When shooting an object with a bright background (such as a bright sky), if you use the overall metering reading, the subject is likely to be underexposed and too dark. If your subject is small and bright, and the background is large and dim, you will encounter similar problems. The subject is overexposed and therefore too bright. Move the light meter to the subject, and manually set the aperture and shutter data according to the light metering results. Light meters of some new cameras can avoid this kind of situation. They use a variety of light sensitive modes to compare the light conditions of different parts of the scene and automatically adjust the exposure.

3、 Sharpness problem

The camera does not focus on the subject.For example, the subject moves, but the camera does not refocus. When using an autofocus camera, it is likely that the camera has not been given enough time to adjust the focus before exposure.

The camera focus is completely wrong.For example, when taking a close-up shot, the lens inexplicably focuses at a distance. It may be that the camera system is not allowed enough focusing time before exposure when taking pictures with the auto focus camera.

In many cases, it is caused by camera shake.If the hand-held camera uses too slow shutter speed when shooting, the picture will be blurred as a whole. As a rule of thumb, when shooting with a hand-held camera, at least use the lens focal length value as the slowest acceptable shutter speed – 1/100 second for a 100mm lens, 1/250 second for a 200mm lens, etc. Try to use a tripod when shooting with a slow shutter speed.

The lens is too dirty.This will generally reduce the sharpness of the picture, especially when it appears at the same time as the lens glow.

Insufficient depth of field.Excessive aperture will result in deep small scenes, and some of the camera focused scenes are sharp, but the foreground and background are blurred.Motion blur.Other parts of the picture are sharp, but the moving objects are not solid.

4、 Color problems

The shooting scene is a fluorescent environment.The fluorescent device emits a lot of green light, which makes the whole scene look green. Assembling FL fluorescent lamp filter on lens can solve this problem.

The white balance is not adjusted correctly (digital camera), or the color film does not match the light type.Raw format (RAW) files can adjust white balance without losing image quality, but JPEG and TIFF formats cannot.Film type:When shooting with tungsten filament lamp balance film under daylight or flash light conditions, the scene will turn blue, so daylight balance film should be used. When shooting with daylight balance film under the condition of tungsten filament lamp, the scene will turn red, so you should shoot with tungsten filament lamp balance film under the condition of indoor tungsten filament lamp.

The reflected light from nearby colored objects will cause the scene to be biased.Taking a portrait in the shade of a tree will make the skin color appear green unexpectedly, because the light is filtered by the green leaves. Similarly, the images taken through the obvious color wall reflection will show the color of the wall. This effect is remarkable on skin tones such as white and gray or neutral colors.

The shooting scene is a fluorescent environment.The fluorescent device emits a lot of green light, which makes the whole scene look green. Assembling FL fluorescent lamp filter on lens can solve this problem.

5、 Flash problem

The light reflected back from a reflecting surface.When shooting directly against the glass window, mirror, scripture surface or shiny wall, if the flash is on the camera or close to the camera, the light will be reflected back to the camera lens. When shooting in a scene with reflective surface, move the camera or flash to one side, so that the shooting axis or light path is at a certain angle with the reflective surface. Glasses have the same problem. You need to let the line of sight of the subject slightly deviate from the camera, or take the flash off the camera.

Red light reflected from the vascular rich retina.Let the person’s eyes move away from the camera, or remove the flash from the camera. Some cameras have a red eye reduction mode: the flash is turned on before the main exposure process starts to avoid the iris of the subject and reduce the amount of visible red light.

The flash is at an angle that creates unnecessary shadows.”Delineating” a virtual line between the flash and the subject helps to predict the location of the shadow. A low-power tungsten filament lamp can also be placed near the flash lamp, which is also the function of this modeling light in the flash lamp device of large studio. Or keep the subject away from the wall, so that the shadow falls on the ground outside the film frame, rather than appearing prominently on the wall.

Use flash in strong field light.This phenomenon is easy to occur when the scene light is very bright and the camera shutter speed is slow. When the shutter is open, two images are recorded when the film is exposed – a clear image in a short flash and a blurred ghost in bright field light. Make sure the shutter is set to the maximum flash adaptation speed. Depending on the situation, you can also dim the spot light and shoot when the subject is in low motion, or shoot with only the spot light under the high-speed shutter.

Each part of the original scene is not at the same distance from the flash. The part away from the flash is darker than the part near the flash, because the longer the light from the flash travels, the weaker the intensity becomes. Try to gather important parts of the subject so that they are close to the flash.

The shutter speed of a camera with a focal plane shutter, such as a single lens reflex camera, is too fast.The shutter is not fully open when the flash is triggered. If you manually set the shutter speed, check the manufacturer’s guide to find out how to set the camera when using flash. For most cameras, 1/60 second is safe enough, and some cameras can set a higher shutter speed when using the flash. The flash shutter synchronization speed may be marked with different colors, which are different from other values. Or it may be marked with an X or flashing sign. If the camera automatically sets the shutter speed when using flash, your camera needs to be repaired.

If the subject is too dark, it means that the scene is underexposed — the light shining on the subject is too weak.If you manually set the exposure when using the flash, the camera lens aperture may be set incorrectly or the shutter may be started before the flash is fully charged. In manual mode, you can add one exposure when shooting in outdoor night or indoor large space (such as gym). In other cases, dark scenes that absorb ambient light may increase exposure.

If the subject is too bright, it means that the scene is overexposed — the light shining on the subject is too strong.In some cases, overexposure in manual mode is caused by the camera lens aperture setting error. In manual mode, when shooting in a small room or a room with colored lighting, you can turn down the aperture by one stop to balance the excess light reflected from the wall and ceiling.

6、 Digital Photography Problems

The image resolution is too low for the intended use.For display, 72~100ppi is appropriate, while using inkjet printer or thermal printer requires 200~300dpi. If you scan an image, you need to set a resolution higher than that for the above purposes. If the picture comes from a digital camera, try to increase the resolution in the “Image – Image Size” column of Photoshop. Select the so-called cubic smoothing difference method. The next time you shoot, use a higher resolution.

The picture quality is too low for digital cameras.In the low picture quality setting (basic or good picture quality), the camera sets the picture with low resolution or compresses the picture. When the compressed image is reopened, the details will be lost. When printing small photos, the results may be insignificant. However, when printing large photos, the loss of image quality will be very obvious. Plan the final size and production method of the photo. Photos used only for the network can use low quality storage. If you want to print 8 x 10 or larger photos, set the camera to the highest quality.

This often occurs in the shadow area of a photograph taken at night, or in a long exposure under low light conditions.Try shooting with a lower ISO setting. Try ISO 100 or ISO 200 instead of ISO 800 or ISO 1600. In Photoshop, try the “Filter – Heather – Spot Removal” function. This method can reduce noise, but it also makes the picture soft. Some software and Photoshop plug-ins may have better noise removal effects.

When shooting with a digital camera, it may be because the ISO is too high.Try shooting this scene with a lower ISO. You may need a tripod, or a slower shutter speed, or flash and extra room light. Sometimes, when some stripes appear, the shooting effect with existing light is better than that with additional light and flash. At this time, the ISO sensitivity must be increased.

Digital images are too sharp in image editing software.If the sharpness of the original file has not been artificially improved, return to the original file for operation. If you need to increase the sharpness, you can reduce the sharpness.