I've been running into the limitations of Photoshop when processing focus-stacked images for my greenhouse blog. After some internet research I found five ways to do focus stacking with my particular camera, which is a Canon R5 Mark II.
- Photoshop (my current method)
- In-camera Depth Composite
- Canon Digital Photo Professional Depth Compositing
- Zereme Stacker program
- Helicon Focus program
To start the testing, I shot three new sequences of my succulents that I thought would provide a good workout for each of the methods. If anyone happens to read this and they are wondering "What about...?" then you can do your own testing. This is real world testing for me. Zerene and Helicon both have 31-day trial programs. All of the images were shot in AV mode at f/8, ISO 100, exposure time set by the camera. I didn't use any supplemental light in our kitchen, so exposures were more than a second and a tripod was mandatory. Once again, these are real-world conditions for me. The subjects are:
- A little Powder Puff cactus with a flower. Photoshop chokes on the flower, I think because the background has higher contract. I shot 18 exposures with focus steps of 3.
- An Echeveria Purpusorum with a flower stalk. The overlapping leaves give Photoshop problems. I shot 24 exposures with focus steps of 3.
- An Echeveria Neon Breakers. I figured the overlapping leaves and crinkly edges would provide a real challenge. I shot 48 exposures with focus steps of 2.
The in-camera method is quickest because it produces an image immediately. But the output is only JPG. Also, there is no opportunity to select which images to use. All of the images in the stack are included. It did OK, not great, as there was extensive haloing around the Neon Breakers leaves. I usually use steps of 3 or 4, so I wasn't sure how many images to take using steps of only 2. It turns out that 48 was way too many. Fourteen was the right number, omitting the first image and the last 33.
DPP took 21 minutes to process the 48 images of Neon Breakers. It's a hands-off process and there are few parameters to fiddle with. I would call the result identical to the in-camera processing, which makes sense since they are both Canon. Reducing the number of images to the 14 which were actually needed cut the processing time to six minutes, and eliminated much of the haloing. There is none around the back leaves with a distant background, but still some around front leaves where they are close to other leaves. I'm actually impressed.
Photoshop required a few more mouse clicks, but only took four minutes to process the 14 source images. Alas, in my opinion the image was inferior to the DPP version. There was stronger haloing around the front leaves.
Next up was Zerene Stacker. It can't handle RAW CR3 files so I loaded the JPG files. It took three minutes to stack and save two images using different algorithms, PMax and DMap. According to the documentation, "PMAX excels in preserving fine detail and sharpness, while DMAP is ideal for smooth transitions and natural results." In my opinion, PMax produced a better image, but has weird artifacts scattered around the image in the form of short lines. Except for these artifacts, this is the best image so far. Condescending interweb opinions claim these are dust spots that somehow become trails as the focus changes. This doesn't explain why these show up in Zerene and not in the other methods.
Finally, Helicon Focus took only three minutes to process and save the images using three different algorithms, Weighted Average, Depth Map and Pyramid. I loaded the CR3 images and the output was DNG, which would seem to give Helicon an advantage over Zerene. In my opinion, the Weighted Average was the best of the three, and in fact produced the best image of any of the methods. (And didn't have any streaks.)
I already have a winner in mind, but I want to see how the various programs handled the cactus flower. I determined that it was appropriate to use all 18 of the images so I just looked at the in-camera processing and did not use DPP. The flower is not in focus and that is all I will say about that. I downloaded the program Zerene Stacker yesterday to see if it really could handle this better. First, what is the problem? In this first image, Photoshop used the wrong part of the stack for some of the leaves, and the result is blurred leaves. (Look at the tips of the three leaves closest to the camera.) In the second image, Zerene Stacker handled it much better.
Zerene Stacker also introduced some weird artifacts into the image, about five randomly-placed short diagonal lines. (They aren't in frame in the above image.) I cleaned them up with the Photoshop Remove tool, but if that happens all the time it would be a problem. The result was clean enough to replace the Photoshop version in the previous post. I also did another test using a cactus images, and there were no artifacts. It's always fun trying to figure out intermittent problems.
One definite deficiency with Zerene Stacker is it cannot handle Canon RAW files. I have to feed it either JPG or TIFF. Since I routinely have the camera save images as both CR3 and JPG, I already had JPGs to use for the test. In theory this is bad, but in practice I really don't see any difference between the two above images in the parts that are in focus. I process JPG files in Photoshop RAW filter all the time, and that's what I did with this one from Zerene Stacker, using the exact same settings as with the PSD file Photoshop made from the RAW CR3 files. If I had to convert to TIFF to preserve some image quality, that would be an onerous extra step; in practice I don't think it would be necessary.
Today, I started testing Helicon Focus, the Beta 9 version. Although my desktop computer is less than two years old and I thought I got one with good specs, I have been running into resource issues if I have Photoshop running and I try to run another program that takes a lot of memory. This isn't limited to Helicon, but it happened during my initial testing. These are my initial impressions of Helicon:
- The user interface is much more polished than Zerene.
- It is very easy to use.
- It handles CR3 RAW files from Canon.
- It can output DNG RAW files.
- The first image I did was inferior to Zerene's and about the same as Photoshop. There are different settings to fiddle with, but Zerene has the lead right now.






















Visiting was a mediocre Yankee team, six years removed from winning the World Series and nine years away from winning their next one. Twins pitcher Jim Kaat got the first two Yanks to fly out, but the third connected for a home run. It was my first major league hit, so to speak. Referring to the scoring instructions, next to the name "Mantle" I drew four horizontal bars (four-base hit) and a "7" (to left field) then circled all of it (run scored). The scoreboard flashed the message that it was the 528th home run of Mickey Mantle's career.