Focus stacking is a technique which makes use of your cameras sharpest aperture to capture various images which are later combined together using editing software.
Im certainly no expert and this technique is something I’ve only recently got to grips with but its definitely something that seems to make a massive difference to the right kind of shot. When it comes to picking up little tips and tricks like this YouTube is always your friend, but I’ll try to explain what Ive learnt on the technique so far.
Me waffling on probably makes it sound more complicated then it is but once you’ve got your head around it, its really simple. Your only really going to need:
Detail from main panoramic of Derwentwater.
– Trigger Release
Now whats different about the focus stacking technique for lansdcapes is that usually we would use an f/stop of around 11-14 as usually this is the most adept at capturing them. At this size there is no depth of field – the whole image is sharp, and we havn’t begun to loose quality as you get towards the higher end of the aperture such as f20-24 – so it seems to be the perfect balance.
This is all true and works perfectly, BUT…. it isnt going to be utilising the sharpest sweet spot of your camera.
So how can we capture the image by using this alternative f/stop (which is usually lower) and maximise the clarity of our shot. This is where focus stacking comes in…..
Every lens has a sweet spot in terms of sharpness. At one particular aperture your lens will give the sharpest images compared with all others and this is something you can take advantage of to increase clarity and detail through your frame. Obviously this is different from lens to lens and there is always a never ending discussion over which brand gives the greatest results but for your setup you can easily find out the general consensus for your lens with a quick google search.
I use a Canon 5D with a 24-105 lens and it seems f/8 is where your gonna maximise its sharpness. Once you’ve found out your cameras sharp point your ready to go find your subject matter..
Get setup on the tripod wth your trigger release as you normally would and compose your shot. Now assuming your sharp point is f/8 use this as starting point for your exposure – set this as your aperture. Your camera should be setup on the tripod so we can afford to have the lowest possible ISO for quality purposes (50 in the case of the Canon 6D) without worrying about shake. Now that just leaves the shutter speed to complete the exposure, again were set up on the tripod and have got the trigger release ready so longer shutter speeds are northing to worry about.
This is where things get alittle weird and change alittle, switch your focus to manual (if you don’t already do so) and manually change your focus ring to the closest guide point, on my 5D this is labelled as ‘Macro’.
Think of your view from the tip of your lens towards the horizon as being split into silces, the view is sliced up into plains which move further and further away from you. The closest ‘slice’ or ‘plain’ is called ‘macro’, so when we take this first photo only things that are within this first slice will be in focus, the rest of the shot will be blurry. This is OK, this is what we want. Then we adjust the focus ring to its next guide point (on my 5D this is 0.7) and repeat the process. We do this all the way through to the furthest slice (labeled with an infinity sign on my lens). This gives us roughly 7-8 photos where only thin strips within the image are in focus, but the important thing to remember is they are using the optimum aperture of f/8 so the level of sharpness will be top notch. So how do we combine these strips together? This is where technology comes in.
Im sure there are various ways to do this but this is how my workflow goes, I import the 7-8 images i’ve just taken into Lightroom, and ‘Stack’ (select all images using Shift, then right click them and select Stacking > Group into Stack), this groups them together and lets me know all the images are related. I then right click the stack of images now labelled with a number (corresponding to the number of images in the stack) and click:
Edit In > Open As Layers In Photoshop.
Through the realms of magic these 7-8 images will then be loaded up into 1 file in Photoshop, layered one above the other. Now select each layer in Photoshop and go to:
Edit > Auto Align Layers.
This will make sure the layers are all exactly aligned, because we used the tripod it should be 99% there anyways. Then once aligned, Right click all images again, and go to:
Edit > Auto Blend Layers.
Within the dialogue box click ‘Stack images’
And thats it, after a minute or two of blending you should now have a loaded image with completely pin sharp….sharpness. If you save this 32Bit Tiff it should now appear in Lightroom and be ready for Editing as you would any other image.
I hope that helps, sometime it takes a few goes to get your head around but it can really give some impressive results, and when combined with bracketing & panoramic’s opens up a whole different angle to your technique.