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DSLR – Taking Photographs with Aperture Priority (A/Av Mode)

Aperture priority is a practical alternative to automatic or program mode, with which you can specifically control the depth of field. By automatically adjusting only one or two parameters of the manual aperture setting, this mode offers a lot of creative scope for the photographer.

Depending on the camera, the Aperture Priority or Aperture Value mode is marked A or Av on the mode dial, which stands for Aperture Priority or Aperture Value mode. As the symbols are similar, Av mode is sometimes confused with fully automatic mode. To avoid confusion, many cameras display a short help text explaining the program’s core function when it is selected. Automatic mode is labeled “AUTO” or displays as a green box labeled “A”. Furthermore, P stands for programmed auto, S (Tv) for shutter priority, and M for manual mode.

In Av mode, the photographer sets the aperture value and the camera automatically adjusts the exposure time and, depending on the camera, the ISO value accordingly. By specifying the aperture value, the photographer can control the depth of field without having to select or evaluate the appropriate shutter speed. Aperture priority is often used specifically in portrait photography or for subjects with an unsteady background, because when a low aperture value is set, the subject in the foreground is sharp while the background is slightly blurred.

Hilfstexte bei der Auswahl des Modus und der Blendenwerten

How do I set the Aperture Priority and what do I need to keep in mind?

To shoot in Av mode, first set the mode dial to A or Av. Once you have set the aperture priority, the display will show the current aperture value, which you can then open or close depending on the desired depth of field. The larger the f-number, the greater the depth of field. With a small aperture value you can blur the background and sharpen the foreground.

When the shutter release button is pressed halfway, the camera starts metering and displays the calculated shutter speed and the appropriate ISO value, if applicable.

To determine the ideal depth of field for your subject, try different aperture values. When checking shots, be aware that the preview on the display shows a smaller version of the captured photo, which may cause the sharpness and image quality in the preview to differ from the actual image. The actual result can usually only be judged on the computer or after the photos have been developed.

Vergleichsbild mit 2 verschiedenen Blendenwerten

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What are possible errors and how can they be fixed?

Frequent errors associated with aperture priority are overexposure or underexposure due to an aperture that is too wide open or closed. When looking through the viewfinder of the camera, the image effect achieved by the settings is usually not visible. Unfortunately, the viewfinder does not allow you to estimate the depth of field or possible exposure errors that will occur later, and the subject usually appears brighter than it should be with the aperture value set. Some SLR cameras have a Depth Preview button that serves to control the depth of field at the set aperture value. By pressing the button while looking through the viewfinder, the camera fades down to the set value and makes it easier to control the depth of field and creatively design the image.

Since A/Av mode automatically calculates the exposure time, warnings are displayed when the required adjustment exceeds the technical capabilities of the camera. If the shutter speed starts blinking red next to the set aperture, change the aperture or if possible the ISO value, otherwise the photo may be overexposed or underexposed. If the aperture is too wide open, the fastest shutter speed blinks and warns of overexposure. If the longest shutter speed blinks, the aperture value is too low and the image is underexposed. If possible, you can compensate for this by increasing the ISO value or by opening the aperture further.

Also note that Aperture Priority refers only to the aperture value, shutter speed, and ISO depending on the camera type. Before shooting in A/Av mode, you should also check other settings such as exposure compensation and image quality and adjust them to the shooting conditions if necessary.

Conclusion

Aperture Priority is a creative mode in which the aperture is used as the main design element. By selectively influencing the depth of field of the photo, the photographer can achieve a specific image effect. For example, a portrait can be sharply highlighted against a restless background such as a busy street. The A/Av mode is also ideal for beautiful macro shots, for example of plants, insects or small objects with a blurred background. The automatic adjustment of the exposure time makes it possible to achieve the desired depth of field even under changing shooting conditions, while still leaving enough room for various adjustment options.

Photoshop: Photo stacking for continuously sharp images

The term ‘focus stacking’ describes an image processing technique in which several images of the same motif merge with each other. Differently selected focus points enable a sharp representation over large parts of the picture, which would normally not be possible.

We will show you what you should consider for the correct preparation and execution and how the subsequent image processing succeeds.

Preparation – photography

Good preparation is indispensable and increases the quality of the results that can be achieved in image processing. Focus stacking requires as many identical image series as possible. The only exception is the differently selected focus.

That is why the DSLR camera should always be mounted on a tripod. It is also recommended to use a remote shutter release so that the camera does not have to be touched more often than absolutely necessary. In order to be able to edit the images well later, you should photograph in the file format RAW.

In poor lighting conditions and the resulting long exposure times, even the slightest shocks can lead to blurred images. To avoid this, activate mirror lock up in the camera settings. The mirror will now fold up a short time before shooting and will no longer cause any shocks.

Another factor that should not be underestimated is the lighting on site. Fluctuating lighting has a negative effect on the series of pictures and makes it more difficult to merge them afterwards. Therefore, make sure that the lighting is as consistent as possible, regardless of whether you are taking pictures outdoors or indoors.

Furthermore, you should select a suitable motif for your photo shoot. The general opinion is that the technique of focus stacking is particularly suitable for macro photography. Without post-processing, the often very detailed motifs, such as small animals or flowers, can usually not be reproduced in full focus.

However, even in landscape photography, entire image areas can shine in new splendour thanks to focus stacking. Choose your subject keeping in mind that it must remain motionless for the duration of the shot. Some photographers use specially prepared insects in macro photography.

Tips for a successful execution

Practice makes perfect

For the best possible result, take plenty of pictures with different focus ranges. It is important to focus as evenly as possible. So feel your way forward slowly. In principle, there are two ways of taking pictures.

  • Automatic focusing
  • Manual focusing

If you want to take pictures using autofocus, you should use the Live View function of the camera if possible. This allows you to see the composition of the image on the display and to move the focus point easily.

Alternatively, you can do the focusing yourself. To do this, simply switch from autofocus to manual focus on the lens. The focused area can be shifted with the focus ring of the lens.

Regardless of which method of focusing you choose, be careful when handling the camera. Any touch, however small, could cause your camera’s viewing angle to change, resulting in different shots. Therefore, make sure that the tripod is stable and the camera is firmly locked in place. Focus on the point closest to the subject and slowly work your way back over several focusing planes.

Post-processing and merging with focus stacking software

Once the entire subject has been photographed, the computer can make changes to exposure, contrast, and similar parameters if necessary. Image editing can be done with most common photo editing software. However, it is important that each image receives the same correction and that there are no differences between them.

Image editing with Lightroom

In Lightroom, value corrections can first be made for one image and then applied to the other photos in the series. To do this, make the desired changes to any image. Then select all images and press Sync. A dialog window opens, which you confirm with OK.

Bildwertkorrekturen in Lightroom und das Dialogfenster Synchronisieren in Lightroom

Adjust exposure, contrast and colour values and transfer to all images (“synchronize”)

 

If you are satisfied with the result of the image processing, open all images in Photoshop or an image processing software with similar functionality. As a free alternative to Photoshop, we recommend the focus stacking program CombineZp, with which individual images can be automatically merged together.

Das Dialogfenster Synchronisieren in Lightroom

Stacking in Photoshop

Next, select all layers and press Edit – Auto-Blend Layers.

For further processing, all images must now be superimposed as layers.

 

Inserting multiple images into Photoshop and stacking them

Insert individual images as layers into a document

 

Selecting and merging multiple layers in Photoshop

Select images and edit – Auto-Blend Layers

Then an additional window opens with the title Automatically blend layers. Here you select the option Stack images and confirm your selection with OK.

 

Dialogfenster Ebenen automatisch überblenden in Photoshop

Joining the layers may take some time, depending on the performance of your computer. Photoshop analyses the existing layers for similarities and compares them with each other. The focused areas of the individual layers are then highlighted and connected. At the end of the process you have a photo motif which is focused over the entire area.

Ergebnis des Focus Stackings

Bottom line

Focus stacking offers the possibility to combine several differently focused photos into a single sharp image. This procedure is particularly popular in macro photography, where it is sometimes impossible to focus on all desired areas of the subject despite a small aperture and high depth of field. However, focus stacking can also be used for other things, such as landscape photography. The decisive success factors are, as so often, the right preparation and a lot of patience. With the help of the most modern image processing software, image series can ultimately be combined to form one perfectly sharp image in just a few simple steps.