Darkroom Booth | Documentation
If your camera cannot achieve focus while using auto-focus Booth will make up to 3 total attempts per session displaying the message "Retaking" on screen before moving on. Any images not taken due to not being able to focus will be filled in with other images from that session so the strip doesn't have blank spots. If no images were able to be taken for that session the session will cancel and no strip will save or print
If your camera fails to auto focus randomly it may be cause by an improper setting in the camera. In this illustration we see what it looks like looking through an SLR viewfinder. Yours may have more or less of the little red squares and they may be arranged in a different pattern but most look something like this. The red squares represent the focus points or spots the camera will try to focus on. Most cameras are set to use all of these points to lock the focus but you can also select a single point too. In this image you can see that all of the points land on some area of the subject with the exception of the one on the far left that goes between his arm. If this camera were set to only use that point then it would not be able to focus on the subject but would try to focus on the plain background and may not be able to focus at all. Each camera varies so check your manual or the internet and make sure your are using all of the focus points for the most reliable auto focus. Also, make sure you have enough light on the subject so the camera can see to focus.