Foreword
It is now universally acknowledged that photography in dentistry is an essential and irreplaceable clinical tool for documentation and communication. (1-3) One of the characteristics, but also one of the limits, of photography is that it is a totally static document, a specific scene fixed in its instantaneous form, but not in its development, while video recording is the narration of a scene as it develops within a given period, and therefore is totally and intrinsically dynamic. We believe it is necessary to explore and understand the potential and the limitations of video recording in dentistry, to use and if possible integrate the two disciplines with a view to obtaining increasingly modern and effective documentation. As a rule in dentistry, it is always necessary to adapt the tool to specific clinical needs, and so also for video recording suitable and specific protocols for clinical use must be developed. We believe that photography and video recording are not conflicting, but must necessarily be integrated with a view to obtaining modern, effective and complete documentation, and suggest that from now on scientific documentation in dentistry should be considered as one discipline implemented with two distinct and integrated methods: static and dynamic. In some disciplines the static nature of the photographic image suffices to describe the clinical objectivity, while in others the dynamism connatural to the procedure is best represented by a video recording. Due to its intrinsic dynamism, the implementation of a surgical procedure is best narrated and described through a video recording, while the pre-operative state, the final result and the follow-ups can be documented using photography. A prosthetic case can be sufficiently and effectively described through photography, although a video recording of the various phases of the operation greatly enhances and completes the documentation. There are disciplines, such as gnathology, in which the dynamics of masticatory movements can only be completely described through a video recording, playing an essential role in diagnostics as well as in documentation. Moreover, if the documentation is prevalently for didactic purposes, video recording is much more effective and efficient than still photography. In this paper we shall illustrate the protocols developed by us to allow the dentist to document clinical procedures through videos that, due to their characteristics, can be considered optimal.
Overview of shooting techniques: the documentation project
We believe that each video recording must be the accurate implementation of a precise programme established in advance, which we call “documentation project”. This means that the operator must have a precise idea of exactly what is to be narrated with the video, and the camera/camcorder merely represents the tool that allows this project to be fully implemented and, like any other tool, must be used following a precise logic. It has already been said that “to photograph things well you must know them well”, (1) and this is one of the fundamental principles of scientific documentation. Those who intend to document must have detailed knowledge of the subject to be narrated through the photographic or video medium, and must not improvise according to emotions of the moment. If the project is the initial idea to be materialised, then the shooting techniques represent the rules to be used to put this idea into practice. (1) The settings of the camcorder do not coincide with the shooting techniques but rather determine them; in other words, the settings must be chosen according to the needs and the characteristics of the documentation process. The characteristics and the quality of the shooting techniques classify a video or a photograph as scientific, artistic or simply pointless. In the same was as for photography in the past, the Author observes here how the rules and procedures for filming a video with scientific characteristics have not been sufficiently described in the literature. (1) A scientific video must comply with at least three requirements: it must be universal, repeatable and accurate; the presence of these characteristics in varying degrees directly defines the scientific level of the documentation. In detail, the concept of universality refers to the possibility of immediate and easy understanding by all users, while repeatability is the possibility of creating, at different times, visual documents that can be superimposed such as frame, magnification and general filming conditions. Accuracy is the adherence of the document to the reality, in other words its faithfulness, without distortions or manipulations. As movement makes total control of shooting conditions almost impossible, video documentation must necessarily be granted greater tolerance than photography. Therefore, while in photography the patient and the subject being documented can be positioned conveniently according to the precise rules established, in video recording this is only possible within certain, and unquestionably wider, limits.
Consequently, this condition must be acknowledged in advance, while attempting to adhere as strictly as possible to the rules of correct documentation, which by analogy with photography are magnification, depth of field and perspective. Nonetheless, it must be understood that, due to the particularities of the video, while these three rules of orthography of images are essential, they are not sufficient to obtain optimal documentation. To achieve excellence, further rules for filming videos must be applied, which take form and substance from the particular needs of video documentation in dentistry. The additional rules developed and proposed by us are stability and perimeter of the frame, which complete those described in the orthography of photographic images. The video is created to be offered to viewers and therefore it is from their perspective and visual and information needs that we must start to plan our documentation project. The scientific video must be composed of an orderly and rational sequence of significant moments and not simply contain interesting scenes alternated with others that are pointless, insignificant or without a common thread; this means that post-production is essential. The dynamic nature of video recording implies a substantial change compared to static documentation: the shooting techniques must be shared with and accurately implemented by a third person, the video director. We shall analyse the tasks and function of this figure in detail, but firstly we must accurately define the rules for filming scientific videos, starting from the specific rules for video recording and concluding by discussing how the rules used for photography can also be applied to dynamic documentation.
The rule of stability
The most important parameter in scientific video recording is the stability of the frame: fixed frames inside which the movement occurs should be preferred and the subject being filmed should always remain in the centre of the frame. The camcorder is designed to record movement and not to create it; therefore, continuous changes of focal length and of magnification by zooming must be avoided at all cost. The gesture of changing focal length and magnification is per se a movement that, especially if carried out rapidly, creates a disturbance for the viewer by generating a “seesaw” effect; it is more appropriate to stop shooting, reposition the camera to the magnification required and resume with a new frame. In particular, the use of digital zooming should be avoided, as, besides worsening the annoying “blur” effect, this also causes an irritating fuzziness of image. The correct technique is to use the zoom only before shooting to select the right focal length, i.e., the magnification required, naturally based on the documentation project; this also makes focusing easier to manage, as will be described in the dedicated paragraph. From the description of this first rule it can be understood how the quality of the shot and consequently of the final video depends on the clarity and on the quality of the documentation project, i.e., the extent to which its details have been fine-tuned before recording starts. The words of Stephen Covey, often quoted by the master Peter K.Thomas, “begin with the end in mind”, accurately define the importance of the therapeutic or, in our case, documentation project.
The rule of the perimeter
In order to establish the basic rules of shooting techniques it is necessary to reflect on the scientific criteria of dental documentation and on the visual needs of the users this documentation is destined for. The conventional rule of thirds that is applied both in photography and in general video recording cannot be transposed as such also to our area of interest. This is due to the fact that scientific documentation must meet different visual criteria and needs to those required in art: the subject of interest must effectively occupy the centre of the frame, which almost never occurs in general or artistic photography. Having established that the subject of interest must be viewed in the centre of the frame, two problems still remain: how to isolate and valorise the subject and how to remove unnecessary elements from view. Knowing that the eye of the viewer moves instinctively and inevitably inside the whole of the frame, also to the edges of the frame, it is very likely that the presence of visual elements positioned in this perimeter area will distract the viewer’s attention from the main subject. We define these secondary subjects as “parasitic” as they divert the viewer’s attention without offering any benefits and they are obviously located at the edges of the frame, i.e., on the perimeter of the frame. Unfortunately, during shooting it is very easy for the director, concentrating on the established main subject of interest, to lose sight of the peripheral elements of the frame, which however may be just as important. This is why it is necessary to constantly observe the perimeter around the main subject during shooting, to ensure it is always free of parasitic, or unnecessary, visual elements, and the solution to this problem is through correct magnification. The rule of the perimeter thus establishes that peripheral visual elements are just as important as those in the centre of the frame, and must be carefully monitored; in actual fact, the rule of the perimeter is not specific to video recording, but forms the basis for formulation of the first rule of scientific photography, namely magnification. In fact, it was created for the same principle of controlling parasitic visual elements in the static frame and it is therefore natural also to apply it to dynamic documentation by developing the concept of correct magnification in video recording. (1)
The concept of magnification
Just as in photography, correct magnification of the subject of the video recording is the first and most important criterion to be considered. Unfortunately, unlike still photography, the noteworthy problem that occurs in video recording is that the more the shooting angle is narrowed (and magnification is increased), the more shooting is affected both by movements of the operator and of the subject being shot, creating a very annoying “blur” effect. The blur effect is undoubtedly the major limitation of video recording and all the operator’s efforts must be concentrated on eliminating or, at least, minimising it. As the beauty of video recording in dentistry is directly linked to the richness of detail that only high magnification can offer, it is essential to find the right balance between these two parameters, magnification and stability of the frame, acting both with appropriate solutions while shooting and through hardware measures. Solutions while shooting include the correct initial selection of magnification, without continuous subsequent adjustments. If the blur effect becomes evident, it is essential to stop shooting and review the degree of magnification, decreasing it if the blur effect is too strong. The practitioner and assistant must focus on keeping the patient’s head, and consequently the field of view, still; to avoid disturbing viewing of the video, all movements must be, insofar as possible, controlled and not too fast. The operators are jointly responsible for the video recording and, in addition to their specific clinical role, they must, insofar as possible, also take the requirements of the director on board. Hardware measures include the choice of a suitable physical support system of the camcorder using well-balanced articulated arms, the choice of a high quality three-way pan/tilt head with fluid movements. Also the choice of camcorder with built-in optical stabilisation is important, but it must be mentioned that in this case stabilisation only relates to micro movements and not shake.
Depth of field and illumination
With regard to the essential parameter of depth of field, the depth of the area of sharpness must be extended as much as possible also in video recording, using the minimum aperture of the diaphragm, and similarly underexposure caused by diaphragm aperture must be solved with adequate lighting. (1) Naturally, the instantaneous flash is of no use in this case, but a continuous light, preferably with a suitable colour temperature (5000/5500 K), is required. LED lights with limited costs and energy consumptions that may prove suitable for the purpose are currently available. Just as for photography, the source of light must not come from only one direction to avoid the formation of shadows in the field of view. (3) Therefore, the choice preferably falls on an annular illuminator, to be positioned on the camcorder using dedicated fixing rings. The topic of lighting inevitably leads us to that white balance, i.e., the quality of light. This subject has been studied in depth in dental photography and therefore it is sufficient to follow the instructions indicated in the next paragraph of the camcorder settings without repeating the theoretical notions.
Perspective
Shooting perspective is the point of view from which the camcorder shoots, and this is a fundamental aspect for video quality. The rule is that the perspective must allow the viewer to perceive most of the detail of the scene framed while maintaining repeatability. It is essential for the viewing perspective to be natural, and to correspond as much as possible to the position the viewer would naturally take, to avoid the upside down effect. The director must therefore ensure that the subject of interest is positioned in the centre of the frame, eliminating parasite elements (rule of the perimeter) maintaining a pleasing and natural viewing perspective. We believe the frontal perspective, perfectly centred with the sagittal and horizontal occlusal plane, as expressed in the concepts of orthography of image (1), can be a fundamental reference point, as it is the most natural and instinctive perspective possible, that of “looking someone in the face”. Therefore, the director should shoot the scene without introducing or, at very least, minimising particular angles in relation to the two planes of reference identified. Especially in the surgical field, perspective is unavoidably influenced by the particularity of the situation, and it would be utopian to believe it possible to constantly maintain a given perspective or magnification for the entire duration of the procedure. In fact, if the shooting area is positioned on a hemi-mandible, the framing perspective will necessarily be asymmetrical. The solution is always to seek the smallest possible angle in relation to the vertical sagittal and the horizontal occlusal planes of reference. The consistency of the shots in relation to the horizontal occlusal plane is the condition to be sought most carefully, as it is easier to obtain than consistency with the vertical sagittal plane. The difficulty in obtaining perfect consistency in relation to the two planes cannot authorise or justify absolute freedom, but must instead encourage the whole team to collaborate better with a view to obtaining excellent quality shots. In video recording, the role of director must be covered by a suitably trained operator, who interacts constantly with the practitioner and assistant. Indeed, we can state that it is the director who must guide the operators to position themselves and position the field of view to obtain the best possible video. This problem cannot be circumvented: the practitioner is responsible for the clinical procedure, while the director is accountable for the video recording, and the requirements of one or other may prevail at different times and in different situations. The tools that assist the director in always finding the right shot are represented by the three-way pan/tilt head, preferably quick locking, and the articulated support arm.
Focusing technique
The issue of focus is key when shooting video, as it is here that all critical problems linked to focal length, magnification and closest focusing distance converge and materialise. It is advisable to use a long lens, preferably with macro characteristics, i.e., a low “closest focusing distance”, making it possible not to get too close to the practitioner and assistant while maintaining a suitable magnification. In this way, clinical work is not hampered and the light can expand correctly, although paying the price of a narrower depth of field. In fact, we must remember that this field decreases considerably as magnification increases, and therefore it is important always to consider that greater magnification means shallower depth of field. Consequently, the director must find a balance between these different needs, bearing in mind that the priorities of video recording are found in magnification and in stability of the frame. In practice, the right focal length should be chosen before starting to shoot based on the magnification desired, and focusing should be carried out manually on the shooting distance selected. By positioning the focus to this shooting distance and selecting manual focus mode, foreign objects such as surgical instruments and the like passing through the field of view will not cause defocusing due to the camcorder attempting to recompose, which translates into better video quality. At this point, it can be better understood how the director’s role is key, as he or she is responsible for the effective implementation of the filming techniques to realize the established documentation project.
The role of the director
The term “director” means a person with ability and expertise in the direction and coordination of a specific procedure, such as video recording. If we think of the film industry, the director is the person that, through knowledge and technical expertise, translates an emotion or a story otherwise narrated into visual language that everyone can understand. Put like that, it is natural to think that in the clinic the dental practitioner should take the role of director, but this poses the insurmountable problem of the practitioner not being able to manage two such important and different roles simultaneously. In still photography, it is the dental practitioner, aided by the assistant, who creates the documentation and decides the contents, magnification and all other parameters to obtain the expected and desired result. However, in video recording it is almost never possible for the dental practitioner to take the director’s role, especially in surgical disciplines, as naturally the surgeon must perform the actual operation and is unable to manage the video recording. This does not prevent the dentist from also taking an active role, but this role must be limited to facilitating the director in the video recording, insofar as possible complying with his or her requests. Here we come to the crucial point: video recording is a documentation technique that requires an extremely high level of collaboration between dentist, assistant and director; a collaboration that will be fine-tuned over time, dedicating energy to studying the videos to identify critical points and together find the appropriate corrective measures. The director must be aware of this and participate in the documentation project established by the dentist, and only in this way can satisfactory results be achieved.
Camcorder supports
To obtain videos of high quality, it is essential for the camcorder to be stable and at the same time easy to manoeuvre, and therefore a support must be used to sustain the weight of the camera for the whole of the procedure, leaving the director free to shoot. The physical support of the camcorder consists of two separate components: the pan/tilt head to which the camcorder is attached, and the head support, which can generically be a tripod or an arm of different type. As shooting should preferable take place from a frontal perspective, any support that does not allow the director to position the camcorder directly in front of the patient must be excluded in advance. It is necessary to consider that the patient may have to adopt different positions, even extreme: from sitting to lying horizontally, but also all intermediate positions, naturally without interfering with the practitioner and assistant. Consequently, the support must allow the director to position and maintain the camcorder in the space in front of the patient, which translates into the need for a three-way pan/tilt head positioned on an articulated arm connected rigidly to a wall or to the ceiling, or alternatively to the light pole of the dental unit. The arm should have a wide range of travel in the three directions without wobbling or causing other interference with the stability of the shot. The ideal solution seems to be an arm articulated in various segments to offer greater versatility. Arms without joints or with screw or rigid joints are not sufficiently easy to handle to fluidly follow the dynamism of the field of view, and should therefore be avoided. The arm secured to the light pole of the dental unit could cause problems of wobbling, especially if the patient moves.
Which camcorders?
As regards camcorders, in our opinion, the idea that the more it costs the better it is should be shunned, as the quality of the video depends essentially on correct shooting techniques and post-production skills. Naturally, this does not mean that the camcorder shouldn’t have certain specifications, but simply that a high-end camcorder for amateur use can easily satisfy all the operator’s needs, without resorting to costly equipment for professional use that, due to its complexity, would probably only be used to a minimum extent. There is also a practical problem: video recording should be within the reach of all operators and not reserved for a privileged few due to costs and expertise. For this reason, we have always thought that each procedure must be simplified as much as possible and made available to all in the interest of patients; in fact, let us not forget that documentation is a tool for growth and comparison, not only with colleagues but also with yourself, to improve your clinical activity and consequently the quality of life of your patients. To conclude on this topic, we can sum up by stating that a high-end camcorder for amateur use, combined with in-depth knowledge of video recording and post-production techniques, is a sufficient condition to create filmed documentation of great interest and quality. In particular, some essential specifications of the camcorder are the possibility to record in UHD format (also defined incorrectly as 4K), to facilitate post-production, and the possibility to manually adjust aperture and focus.
Camcorder settings and recording formats
The camcorder settings concern the shooting parameters most suited to the specific nature of the discipline. We have already mentioned the need to use minimum aperture of the diaphragm to optimize the depth of field. With regard to focusing, we recommend manual adjustment to prevent the camcorder from making continuous adjustments due to movement of instruments or the like inside the operating field (and consequently the field of view), as this would result in annoying temporary defocusing. As regards white balance, we recommend measuring the colour temperature using the neutral white card, and then, just as in photography, choosing the preset white balance settings. (7, 8) With regard to the recording format, it must be said that the modern UltraHD format (3840×2160 pixels, unlike cinema 4K which has 4096×2160), is ideal for our dental video recording, as the higher resolution compared to HD (1920×1080 pixels) allows a great richness of detail and greater sense of depth and consequently more realistic images. Moreover, this higher resolution also makes it possible to increase magnification of the video, or parts of it, during post-production by cropping. The drawbacks of UHD format are naturally linked to the size of the video files, which require particularly high performance memory cards with a high read/write bit-rate, and occupy a large amount of space on storage media.
Post-production in video recording
The essential difference between video recording and photography is that in the former post-production and video editing are absolutely essential. While in photography this phase should play a minor role, in video recording post-production (or editing) is just as important as the quality of the shot. Post-production is necessary even if the shots are “clean” and accurate, as parts of the video that are not satisfactory will in any case have to be eliminated or tools will have to be used to improve and customise the original video. We have already stated that the scientific video must be considered as an orderly and planned sequence of significant moments, and not simply contain scenes without a common thread, and this makes post-production necessary. Therefore, it must be taken into account that the final production of a high quality video will require an investment of time and energy that is not limited merely to the filming phase, but which continues subsequently with the necessary post-production phase. This phase requires the use of specific software applications that take some time to learn; in this sector the choice is varied and personal preferences must be taken into account, also in relation to the operating systems used.
Conclusions
In this paper we believe we have provided the basic information to start documenting through video recording. Naturally, we realise we have not covered all the topics or shed light on all the problems, but trust that we have provided some tips for starting on a journey that will bring great satisfaction.
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