Macro Photography - An Introduction to Focus Stacking

An Introduction to Focus Stacking

Macro photography is a great field to have fun and experiment with.  It allows you to slow down the capture process and fine tune your settings to realise your creative vision.  One aspect of macro photography you may wish you had more control over is depth of field.  When we think of depth of field it's usually associated with a portrait where we might want a very narrow focus to separate our subject, or in the case of a landscape it could be everything in focus.  Despite the tiny size of the subject, macro photography can often result in extremely shallow depth of field which may look creative but doesn't reveal all the intricate details throughout the image as below.

Stopping the aperture way down on a macro lens isn't always a solution to this problem.  Most lenses will show their peak sharpness at around f/8, using a smaller aperture will increase your depth of field but may also begin to soften your image due to an effect called diffraction.  In a basic sense, diffraction is the scattering of light as it is forced to pass through a small opening.  This light now reaches your camera sensor in not quite the right spot and as a result the image looks slightly out of focus.  Selecting an aperture of f/32 for example may get your entire macro subject "in focus" but will almost certainly lack the biting sharpness desired.

So what if there was a way to combine the sharpest aperture of our macro lens and achieve a depth of focus throughout the image?  Thankfully there is, it's called Focus Stacking and it's easier than you might think.  To get started with focus stacking you'll need a couple of things:

• Your camera, macro lens, a suitably small and stationary subject
• A sturdy tripod and cable release trigger is very helpful
• Fixed position lighting: can be either natural or artificial
• Manual focus and manual exposure settings (or your images won't match!)
• Software for stacking such as Photoshop/Photoshop Elements or Helicon Focus

The setup is just like any other macro photo but instead of taking just one image we'll be taking several and shifting our focus point between each image.  How many photos you require to complete the stack will depend on the size of the subject and a bit of trial and error.  Aim for around 8-12 images to begin with.  If your camera has a "Live View" function and/or Depth of Field preview this will greatly help you visualise how the plane of focus moves through your image.  Below is a series of images I took at f/8 in preparation for stacking.

Open your stack in Photoshop making each image its own layer.  If you imported your images into Lightroom first you can select the set there, right click and choose "Edit In -> Open as layers in Photoshop".  With your images neatly arranged as layers, select all the layers and choose "Edit -> Auto-Align Layers".  We're aligning the layers because most lenses actually change their view slightly when shifting focus, this is called Focus Breathing.  In regular photography it's barely noticeable and has no impact on a single image, however a macro stack with multiple images of varying focus can show a lot of breathing.  After the alignment is completed you can crop away the outer edges.

We're almost done!  Select "Edit -> Auto-Blend Layers" and check the seamless blend box.  It may take up to a few minutes for Photoshop to process the stack but when it's done you should have an image with focus throughout.  Merge the layers together to preserve the blend and finally save your file.

Final image of the fork using the focus stacking technique

Final image of the flower using the focus stacking technique

Picture of a leaf using the focus stacking technique

This blog has been prepared by Ryan from our Brisbane store. Ryan is a wealth of technical and practical photographic knowledge. He is always willing to share his know how at a level everyone will understand. The next time you are in our Brisbane store say hi.

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Macro Month

February is Macro Month at Digital Camera Warehouse. If you want more information regarding macro photography techniques and you live near one of our stores, we are running a number of macro photography photo walks at some locations. We will also have a macro photography setup in each store so that you can get hands on and learn more about the gear you might require. Finally make sure to check out some of the macro shots taken by some of our staff on Instagram during the month of February.

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Basic Portrait Retouching with Adobe Photoshop

Post-processing of your photos is a vital element in the photography workflow. Luckily in this information and technology age this process is made fairly straightforward with powerful applications like Adobe Photoshop providing an in-depth myriad of options and capabilities to help you get your images looking the best they can be. 

In this short, but hopefully helpful article we would like to give you some pointers on adding a touch of magic to your portrait shots.

The tool names in the article are representative of those in Adobe Photoshop; however the techniques can be applied in many software suites. Consult your manual for the appropriate similar tools in your preferred software.

Find a recent portrait shot you’d like to improve; if possible use a RAW format file so you have the most data available for editing and let’s get started!

1. Check Your White Balance. Do the skin tones present in the photograph look natural? While you may have adjusted your settings in-camera, sometimes indoor lighting can be difficult to balance correctly. If your white balance needs adjusting, a simple way of doing this is as follows:

Click “Add level adjustment layer” by going to Layer – New Adjustment Layer - Levels and select “Auto”. Did this work? Sometimes it won’t do much of anything to improve your image. If that is the case we need to go deeper (and this will likely yield a better result anyway!).

Use the three “eyedropper” icons to pick the black, grey and white samples from your photo. Typically you can get away with simply using the black and white tonal value selectors, but if you find your images still requires further adjustment try picking grey as well. For these finer adjustments, hit up Image – Adjust – Hue/Saturation and make your finer adjustments to the colour there, paying attention to the overall tones in the image – if it starts looking a little too cool or warm bring the levels back slightly until you find a natural look.

2. Spot healing and skin softening. Everyone, even the big stars have skin marks and imperfections. Take a high-resolution photo of a face and they will often show up quite prominently. If you’d like to mask these a little, there are a couple of things you can do.

Spot healing tool (In the expandable Band-Aid icon on the tool panel) – This is a handy tool for removing blemishes, acne scars and other marks on the face. Don’t go completely nuts with it – just dab it over the real imperfections, don’t go removing every line and freckle as not only will the overuse give the image a plasticky look, it will remove the unique features of the face and the natural structure.

If you simply want to improve the appearance of something, such as a hairline with deep follicles or a mole, the clone tool can be a better option. Adjust the opacity for a more translucent effect that works well for natural blending of skin areas.

Skin softening – Everyone loves to look smooth and young, but overdoing this in the editing process will alter the natural look of the model – refining and softening the skin will give the face a lovely glow, but do keep it realistic or the person will look like a wax dummy. Less is more. Here’s a quick way:

First, duplicate the layer (Command+J on Mac, Control+J on PC).

Then invert that layer (Command+I/Control+I).

Add a “high pass” filter to the layer. You can do this by hitting Filter – Other – High pass. Use around setting 5. Hit “OK” and set the blending for the layer to “overlay”. Right now it may look quite scary, but we are not done yet.

Add “Gaussian Blur” by hitting Filter – Blur – Gaussian Blur and set this to half of the High pass filter setting, so 2.5 for the sake of this example. This should have it looking better.

If you like, you can now add a layer mask and work the face detail like lips and eyes back into the image if you have already worked on them.

3. Clean up the eyes. Perhaps the model still has glassy morning eyes, and some people simply have a redder look to their eyeballs in general. If you’d like to make them stand out by making the whites a little whiter, do the following:

Add a new blank layer (Perhaps change the name to something like “eyeball clean up”).
Change the blend mode to “Color”.

Pick the brush tool and ensure the opacity setting is around 50%.

Hold the ALT key down and pick some “good” white from the eye as a sample. 

(ALT+click on the good sample).

Paint the vessels and blotches with the brush tool.

Adjust the opacity of the layer if you find it looks a little overcooked.

And there you have it! Three tips for improving your portraits.

Check out our Adobe software products!

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