If you are expecting your photographer to take photos after dinner... cake cutting, dancing, throwing the bouquet and couple leaving, you need to include them for a meal. Weather it be at a table with your guests at the reception (usually with larger receptions) or at a separate restaurant on the property, it's always appropriate. My experience is that it's best to be with the rest of the group as he/she may have to get up and get a shot of toasting during the meal. Although, you can't ask them to just nibble on something on the run, especially if it's been a long day.