What is Focus Stacking?
Before digging into the Photoshop vs Zerene Stacker challenge, I’d like to give a brief introduction to what focus stacking is. Focus stacking is the process of combining multiple images during post processing in order to create sharp detail throughout the entire field of view. This technique can be very useful for landscape and macro photographers who do not want to settle for a shallow depth of field.
In order for the technique to work properly, you should have your camera on a tripod and must take at lest two photos that have different focal points. For example, shoot one image focused on your foreground and the second shot focused on your background. Using manual exposure mode will yield the best results because you want both exposures to be as close to the same as possible.
The number of shots that you need will be determined by your aperture and the depth of field in the scene. In many landscape scenes, two images are plenty when your aperture is set to f/16. If you’d like a slightly sharper image you can set your aperture to f/8 and take a few extra shots making sure to focus throughout the entire scene. If you choose to shoot with a larger aperture than f/14 you may want to take anywhere from three to ten shots depending on how close you are to your subject.
Macro photographers will have to take many more photos due to the incredibly narrow depth of field that is intrinsic to shooting objects close up. Many macro scenes will require 25 shots or more to achieve a sharp image throughout the entire scene.
Photoshop vs Zerene Stacker
Photoshop is an incredible all around editor but it does have some drawbacks. Focus stacking happens to be one of Photoshop’s weaknesses. In a pinch, it does a pretty decent job but the software is inconsistent and often introduces artifacts with the masks that it generates.
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Zerene is a standalone application that can process Tiff and JPEG images into focus stacks. Since Zerene is dedicated focus stacking software, it does the job really well. It has two different focus stacking algorithms to choose from. The Pmax (Pyramid) method is good at preserving detail and handling overlapping objects such as grasses, hairs, and bristles at the cost of potentially increasing noise and causing a slight color shift. The PMax method works great on deep macro focus stacks that consist of many images. The DMap (Depth Map) Method does a great job of retaining the original color and smoothness of an image at the cost of loosing a little bit of detail. The best of both worlds can be achieved by using Zerene’s built in retouching tool which allows users to blend the Dmap and Pmax images together.
Real World Examples
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Throughout my testing, Zerene did a much better job of preserving the details on the edge of the frame. Both programs required a little bit of cropping which is to be expected when moving a lens element or lens. In most cases, the Zerene images required less cropping than the Photoshop images and Zerene removes a post processing step by automatically performing the crop for the user.
Ease of Use
Focus stacking is relatively straight forward in Photoshop and Zerene. With just a few clicks you can combine your images in both programs. Zerene automates the process a little more than photoshop by allowing users to align and stack images at the same time, whereas Photoshop requires users to align and stack in two separate steps. To simplify the stacking process, Zerene offers a Lightroom plugin for users who purchase their prosumer and professional licenses. The plugin speeds up the stacking process by eliminating the need to export out of Lightroom and import into Zerene manually. If you’re going to be using the software regularly, I recommend purchasing a license that includes the Lightroom plugin.
What program processes focus stacks the fastest? When processing just a few images there is little noticeable difference in speed between Photoshop and Zerene. Once the load gets heavy though, the story changes. Using a 3.6 GHz 8-Core Intel Core i9 i mac with 128 Gigs of Ram Zerene was three times as fast as Photoshop when tasked with processing identical 94 image focus stacks. Using the Pmax method I was able to export from Lightroom and process the stack in 6 minutes and 21 seconds. Photoshop took three times as long at 19 minutes and 2 seconds.
Perhaps even more impressive was Zerene’s ability align and stack a DMap and PMax version of the image in nearly half the time that Photoshop took to process a single stack. Using the align and stack both method, Zerene created both stacks in 10 minutes and 37 seconds.
Final Thoughts – Photoshop vs Zerene Stacker
Focus Stacking is a fantastic way to achieve incredibly sharp photos. If you’re new to the technique, I suggest trying out a few trial runs with Photoshop. Once you get the hang of the concept you’ll probably want to purchase a dedicated focus stacking program because it will most defiantly provide better results. I’ve been very happy with Zerene Stacker and highly recommend it to anyone who is going to be processing focus stacks more than just a few times.
Zerene’s customer service is fantastic and they’re more than happy to answer any questions that you have about their software. The personal license goes for $89, but I recommend purchasing the $189 prosumer version which comes with the Lightroom Plugin which will greatly speed up your workflow.