diff --git a/README.md b/README.md
index d9e3b47..9904de3 100644
--- a/README.md
+++ b/README.md
@@ -145,10 +145,16 @@ for i in *.JPG; do convert $i -resize 50% $i.tif; done
 Then I was able to align all images:
 
 ```
-align_image_stack -ma aligned_ AJ9E94*.tif
+align_image_stack -ma aligned_ *.tif
 ```
 
-Once all images had been alignes, I created the final image from my stack of photos:
+This command not only aligns all the images, the -m options optimized the field
+of view. In a focus stacking setup, the camera gets moved towards or away from
+the object, so not only the focus plane is moved but the whole objects gets
+bigger or smaller. With this option, all images are resized, so the object
+stays in the same position and size throughout the full stack of images.
+
+Once this is done, I created the final image from my stack of photos:
 
 ```
 enfuse -o result.tif --exposure-weight=0 --saturation-weight=0 --contrast-weight=1 --hard-mask --contrast-edge-scale=0.5 aligned_00*