Focus Stacking

Sometimes you need to take a picture with an extremely large depth of focus. A common technique for is to stop down lens aperture - however this leads to using a slower shutter speed, and may require using a tripod.

Focus Stacking is a technique that allows you to take multiple images of the same scene, focusing on different parts of it. These multiple images are later merged into a single image on a computer. The resulting image will have all objects in focus, creating an extremely large depth of field without sacrificing available light.

Promote Control provides an easy to use Focus Stacking mode. It is currently compatible with Canon and Nikon digital SLR cameras that have Live View mode, such as Canon 5D Mark II or 7D, or Nikon D7100. With Nikon cameras, the rear LCD Live View will not be available while tethered via USB, and therefore Focus Stacking will have to be set up using the distance scale on the attached lens. Focus Stacking support for Nikon cameras depends on your camera model (out of Live View enabled Nikon cameras, Nikon D3 is not supported due to camera limitations).

Usage

Use the following workflow to get the most out of Focus Stacking with the Promote Control:

1.Switch your Promote Control to the "Focus Stacking" mode.

2.Connect your camera to the Promote Control using a black USB cord as described in the Connections section. Shutter cable connection is not required.

3.Turn your camera on.

4.Enable automatic focus on your camera. This will allow Promote Control to drive lens focusing mechanism as required.

5.Make sure your camera lens focusing range covers the entire focus stacking range required by your subject. Some lenses may have a focus range limiting switch that may need to be set to the "Full" position.

6.Disable Mirror Lock-Up mode on your camera. Promote Control cannot ensure correct functionality in Focus Stacking mode with Mirror Lock-Up enabled.

7.If your Canon camera is set up to enable automatic image preview when images are being taken, please set the image preview duration to no longer than 2 seconds. You may also need to completely turn off image preview when using Focus Stacking mode. A long image preview may interfere with image acquisition in Focus Stacking mode. The Promote Control will warn you if this is the case, and prompt to set Image Preview to a shorter time. On Nikon cameras this should not be an issue.

8.IMPORTANT: If your camera has a Live View specific "AF Mode" setting (such as Canon 5D Mark III in its "SHOOT4" setting bank), make sure it is NOT set to "Face detection Live Mode". Either regular "Live Mode" or "Quick Mode" should work fine for Focus Stacking.

9.Change "Step" setting on Promote Control from "None/Reset" to "Small". You may use a different focusing step size if appropriate. You may want to experiment with the step size to pick the ideal step for the currently used lens.

10.Your camera will activate its Live View mode. A Canon EOS camera will display the currently framed image on its rear LCD, while a Nikon camera will not (this is a limitation of the Nikon camera firmware).

11.Use your camera lens focusing ring to pre-focus the camera where you want to begin focus stacking.

The Promote Control shows a focusing range in the following form:

+000...+000

The first number indicates beginning of the focus stacking range, while the second number indicates the end.

Scroll to the second number and use your "Up" and "Down" keys to pre-focus the camera where you want the focus stacking to end. On Canon cameras you may use the rear LCD Live View to verify the focus positions. With a Nikon camera, please use your lens' distance scale to do the same. You should end up with a display similar to this:

+000...+025

The "Frames" setting shows how many images will be taken as a result. You may reduce the number of frames if you feel that the resulting focus stacking sequence will be too gradual.

You can optionally change the "Exposure" setting from "<On Camera>" to "<HDR>". This will allow taking not one but multiple images per every focus stacking stop. Promote Control will use settings from the High Dynamic Range mode screen for the HDR. See High Dynamic Range Mode section for more information on HDR settings. To switch to the High Dynamic Range mode faster, hold "Left" button and press "Mode" until High Dynamic Range mode is shown.

When done, press "Start" button on the Promote Control. If you switched to High Dynamic Range mode in the above step, you will need to return to Focus Stacking mode before pressing "Start". Now Promote Control will drive your camera lens focus back to the start point, then start refocusing your lens and take pictures as it goes along. The resulting image set may be merged into a single, focus-stacked image in a software application of choice. See Focus Stacking Software Applications section for more information on picking a software package.

Important To Know

1.If you operate your camera lens focus ring after setting focusing range on the Promote Control, you need to change "Step" to "None/Reset" and repeat the set up process as described above. Failing to do so will result in incorrect focus range tracking.

2.If you change your "Step" size setting on the Promote Control after setting focusing range on the Promote Control, the focusing range settings will revert to 0, and the set up process will have to be repeated as described above.