a20 October 2012

Tutorial: Getting extreme depth of field in landscape photos

I wanted to have focus both on the rocks in the foreground, rocks staying in water and on the islands in the background. This required taking photos at 4 different focal points (I took for 5 but one turned out to be not necessary).


Today I would like to share a short tip with you - how to get an extreme depth of field in your landscape photos.

Unless you're using a tilt-shift lens sooner or later you will be faced with a following problem. You want to take a landscape shot with some objects in the foreground (like rocks in the photo above, or leaves, or fallen tree trunk) but you want to have an extreme depth of field across your frame - you want both the foreground and the background to be sharp, to stay in focus. So what do you do to achieve this? Of course you do use a wide-angle lens as they are known for the fact it's easy to get huge depth of field, of course you set aperture to a value like f/16 or even more (like f/22 - note however that for some very small apertures image becomes blurred so it's not really a good idea to use apertures that small) and you take the shot. Then you discover that your photo isn't sharp enough. If you focused on the foreground it is very sharp but the background is blurry. If you focused on the background the foreground is a bit soft. If you focused somewhere between the foreground and the background neither of them is sharp enough. Not good...

The solution is simple although it requires an additional step. Instead of taking a single shot, you will need to take a few shots. First focus on the foreground, then on something a little further and finally on the background. Although it's best to do with manual focusing, you can also try using various auto focus points to achieve something similar. Also note that this technique is very popular amongst macro photographers who work with very shallow depth of field.

When back in front of your computer:
  1. You will need to open all your photos in Photoshop CS.
  2. Once you have files opened in Photoshop, select File -> Scripts -> Load Files into Stack...
  3. In the dialog box that appears, click on the Add Open Files button and then on the OK button.
  4. Select all layers of the new image.
  5. Select Edit -> Auto-Blend Layers. If you think that your images might be misaligned you might also need to use Edit -> Auto-Align command to align them.
  6. In the new dialog box, select Stack Images blending method and click on the OK button.
Photoshop then processes your images, trying to achieve as huge depth of field as possible. Most of the time it does that just great :) (provided source photos cover enough depth of field of course).

Now a few words about the photo from this post. When taking it I set my focus to 0.7 meters, 1.5 meters, 3 meters and infinity (in fact I took one more photo but it wasn't really needed). As it is an HDR photo at each focal point I took a sequence of 5 photos. So I ended up with 4 bracketed sequences. For each of them I used the same settings in Photomatix Pro. After processing them in Photomatix Pro, I loaded them into a Photoshop and focus stacked them using a procedure described above. It did quite well apart from the clouds. As they were moving between the images I decided to copy them from one of the source images.

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