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Photography techniques – focus stacking

Depth of Field

This articles looks at a lengthy and complicated procedure to render every part of a scene with perfect focus. the aim is to achieve a high depth of field (DOF) whilst maintaining the high quality of your lens’ sweet-spot. The main challenge is, maybe, deciding what situations exactly would require this sort of treatment. This technique is popular for macro work, where the DOF is usually too shallow to capture all the sharp detail in a subject. Landscape could benefit as there is a requirement for sharpness throughout the scene. Usually an f/16 and careful hyper-focal calculations will achieve this. For my first attempt, I chose a landscape scene with a huge focal challenge. In this scene the immediate foreground is just a few inches from the front of the lens.

Even at f/22, I would not have been able to capture full sharpness in every part of the scene. Without Focus stacking, I would have attempted to get the whole of the foreground in focus and left the sky and horizon out of focus. This was also an HDR image, so we can look at a few of the original frames for analysis.

Aperture sweet spot

This was the first shot using f/14. Choosing your aperture carefully is important. You don’t normally need to close down to f/16 or f/22 because the technique allows you to layer the different focal plains. The choice should be around the middle aperture of your lens to get the sharpest image possible. Lens have their best quality in the middle somewhere around f/8. I had to choose f/14 for this sequence because the immediate foreground was closer than the nearest point of focus. Therefore, a smaller aperture was required to include a bit more of the immediate foreground focus. As you can see, the very bottom of the rock is still not in focus. The part of the rock which is line with the edge of the puddle has the best focus – everything else is a blur.

The next shot has the focus on the rocks at the back. The aim was to include the rest of the foreground rock. As you can see the immediate foreground and sky are a blur.

Short of infinity

For the last shot, I focused just short of infinity. This captured the sea, horizon and sky nicely.

Ok, all shots taken and I mentioned that this was HDR so I had nine separate exposures to play with in photoshop. First I need to prepare them in my RAW processor to make sure they all have the same white-balance. then I made separate HDR images and used the same settings for each tonemapped image.

The following procedure was done on Photoshop CS3, it is possible that if you have an earlier version this might not work…
Go to FILE > SCRIPTS > LOAD FILES INTO STACK

File= data-lazy-src=Scripts=>Load files into stack" height="845" width="582" srcset="https://www.icelandaurora.com/phototutorials/wp-content/uploads/sites/5/2009/08/scripts.jpg 582w, https://www.icelandaurora.com/phototutorials/wp-content/uploads/sites/5/2009/08/scripts-207x300.jpg 207w" sizes="(max-width: 582px) 100vw, 582px">

File=>Scripts=>Load files into stack

When the dialogoue box appears make sure you check the ‘Attempt to automatically Align Source Images’ box… and then continue.

Remember - Attempt to automatically Align Source Images

Remember - Attempt to automatically Align Source Images

Photoshop CS4

Go to the layers palette and select all the layers (Press Ctrl and click each layer or Select=>All layers) then go to Edit=>Auto-Blend Layers. Select ‘Blend Layers with Seamless Tones and Colours’ and CS4 will automatically find the sharpest parts of each layer an create a super sharp image.

Photoshop CS3

Go to the layers palette and select all the layers (Press Ctrl and click each layer or Select=>All layers) then go to Edit=>Auto-Blend Layers.

Auto blend layers

Auto blend layers

Now we need to do some manual masking to bring out the sharpest parts of each layer.

Use a white paintbrush to paint over the sharp parts.

Use a white paintbrush to paint over the sharp parts.

Use plenty of trial and error and keep zooming to 100% to check your work.

The result

Stacked focus technique

Stacked focus technique

Nacreous Dawn

Nacreous Dawn

Nacreous clouds are difficult to expose. The trick here was under-exposure to make sure I didn’t loose any of the details and colours in the glowing cloud.

January Star

January Star

It was horrible conditions that brought about this beauty. We were sand blasted and windswept on the black sand beach, day 2 of a 3 day tour.

ColourRipples

ColourRipples

We caught the tail end of the overnight storm. The wind & sand created incredible scalloped textures in the fresh glacier ice.

5 Comments

  1. John Dunne

    Hi Tony,

    A great read thanks for sharing. Focus Stacking for Landscapes has been something I’ve been considering for a while now as I become more critical of the sharpness of my images, particularly when enlarged for 24″ or 30″ prints.

    I was just wondering if you have any advise/direction on focus stacking for long exposures, and how PS manages the blending?

    Thanks in advance.

    Cheers
    John

    Reply
    • Tony

      Hi John, thanks for your comment. I am going to look into the possibility of altering the focus for different parts of the image during the exposure using something similar to the magic cloth technique. I think the results will be interesting.

      Here is a long exposure image with focus stacking (done the traditional way):

      http://icelandaurora.com/blog/wp-content/uploads/2011/01/Stacked.jpg

      Reply
  2. John Dunne

    Thanks for replying so quickly Tony and my apologies for the delay in coming back.

    I have yet to try the focus stacking but will be trying it during a sunrise shoot on Saturday. I’ll report back then 🙂

    I’d be very interested to see how the magic cloth approach would work and will be watching for your updates.

    Thanks again
    John

    Reply
  3. NW

    Hi,

    Did you actually use the three images to compose nine? Then using photomatix or a similar tool to produce three HDR-images with different focus points, before finally stacking them on top of each other in photoshop and masking out the blurry parts?

    Kind of unusual process in my head, as I’m only used to “regular” hdr. I’m asking because I’m really fascinated by this technique using HDR and focus stacking combined 🙂

    Reply
  4. Tony

    yes, I think I did 3 separate HDRs for this one, but you could easily acheive it with 3 shots:
    1) Expose and focus on the foreground
    2) Expose and focus on the Middle ground
    3) Expose and focus on the background

    Reply

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