My first step in becoming familiar with focus bracketing was watching YouTube videos. These were helpful, but it also became clear that numerous settings require experimenting and/or adjusting to particular circumstances to achieve the desired result.

For my specific experiment, the equipment and settings used were as follows:

• Canon R7 mirrorless APSC body on a tripod;
• Canon 24-105 f4.5-5 EF L IS USM lens, attached via a lens adaptor;
• Focal length set at 58 mm (= 93 mm on a full-frame sensor);
• Cable release;
• The exposure shooting mode dial was turned to Manual and set for f8.0, 0.8 sec, ISO 200;
• IS turned off, and
• Focus is set to Automatic and spot-focused on the nearest part of the subject-object.

Distance from the camera’s sensor plane:

• 18 ¼ inches to the nearest angel’s hands
• 24 ¼ inches to the rear of the scene
• Depth of field, therefore, 6 inches

For the individual, conventional aperture-priority shot (i.e. not focus-stacked), shown in Picture #1 on the next page, the focal distance was 20 1/2 inches (the distance from the camera’s sensor to the tip of the harp being held by the angel at the front close to the saltshaker).

On pressing the shutter, the camera simultaneously produced 30 JPG and 30 cRAW files, plus a single focus-bracketed/ focus-stacked JPG image. This in-camera process took about 8 seconds, and all 61 files (30+30+1) were stored in the camera’s SD card. The total size of the 61 files saved to my PC was approximately 656 MB.

I observed the lens rotating from the closeup macro distance, moving to the end at the Infinity position. This rotation results in a tighter and tighter zooming-in process. It is important to leave some room around the subject(s) in the frame to allow for the tightening zoomed shots.

I also took a conventional straight shot (Picture #1 below) with the Aperture Priority (Av) set at f22 to provide the most available depth of field available from the lens and applied manual focus (M) with the focal point set to about 1/3 into the frame's depth (the harp's tip of the angel musician on the front left). My DOF Calculator app shows that only 2.56 inches of DOF is available at these particular settings, even with f22 applied, while the depth of the scene required 6 inches of coverage.

For processing and editing, the 61 files were copied to Canon's DPP4 editing program, and two TIF files were created by merging the 30 JPGs and the 30 cRAWs with a processing time of about 2 1/2 minutes for the JPEGS and 37 minutes for the cRAWs. (I understand that, as yet, a program will not create a RAW output file from a focus-bracketed source.) The two TIF files and the individual JPG file were edited in the PSE20 (Photoshop Elements 20) program to compare the different outputs for sharpness of focus and depth of field range.

Results and Comparison of the Final Images

The three focus-bracketed images, Pictures #2 (merged in camera), #3 (30 JPGS composited in Canon’s DPP4) and #4 (30 cRAWs composited in Canon’s DPP4), were taken at the same settings and about the same moment and theoretically could produce three different image outputs. To my eyes, though, these three focused-stacked images are similarly successful, with the depth of focus covering the entire range and offering noticeably more depth of field than the conventional single shot.

But you be the judge!