A male 35 year old presents to the clinic with blackening and pain in upper anterior tooth. He also told that trauma to the tooth occurred 5 months ago. Intraoral findings reveal non-vital tooth #21. RCT was started and IOPA #21 taken for initial working length. After initial debridement of the canal was performed, another X-ray was captured with the initial root length measured and it appears that the file is approximately 4 mm from the apex. How could the doctor have obtained a more accurate initial length measurement?