Question: when was the single lens reflex camera invented
[{'answer': '1861', 'provenance': [{'wikipedia_id': '3193137', 'title': 'History of the single-lens reflex camera', 'start_paragraph_id': 1, 'start_character': 237, 'end_paragraph_id': 1, 'end_character': 241, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '3193137', 'title': 'History of the single-lens reflex camera', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 1013, 'bleu_score': 0.988269287301458, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12394364499425598865}, 'section': 'Section::::Early large and medium format SLRs.\n'}]}]