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Pediatric Dental Journal

journal homepage: www.elsevier .com/locate /pdj

Original Article

Evaluation of the optimal exposure settings forocclusal photography with digital cameras

Yu Sugawara, Kan Saito*, Masaharu Futaki, Masahiro Naruse,Mariko Ono, Ryoko Hino, Yuta Chiba, Makiko Arakaki, Aya Yamada,Satoshi Fukumoto

Division of Pediatric Dentistry, Department of Oral Health and Development Sciences, Tohoku University Graduate

School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, 980-8575 Sendai, Japan

a r t i c l e i n f o

Article history:

Received 17 December 2013

Received in revised form

11 March 2014

Accepted 9 April 2014

Available online 21 June 2014

Keywords:

Intraoral photography

Digital imaging

Close-up photography

Mirrorless camera

SLR camera

* Corresponding author. Tel.: þ81 22 717 838E-mail address: kanta@dent.tohoku.ac.jp

http://dx.doi.org/10.1016/j.pdj.2014.04.0020917-2394/Copyright © 2014 The Japanese So

a b s t r a c t

Background and objective: Recently, therehavebeenproducedseveralkindsofcamerasystems,

lighting devices and image processing programs. The intraoral photographs are periodically

required in pediatric dentistry, since the oral environment of children changes rapidly and

dramatically because of disease, growth, and tooth eruption. However, the suitable settings

for intraoral digital imaging have not yet been reported. In this study, single-lens reflex and

mirrorless cameras were used with a ring flash, ring light emitting diode (LED), or standard

fluorescent lamp to determine the optimal exposure parameters for occlusal photography.

Materials and methods: Fifty-six dentists evaluated images of a discolored nonvital central

incisor and first molar with recurrent caries and stained fissures clipped from a low-

magnification photograph of the adult maxillary occlusal surface reflected in a mirror by

using various F-numbers (representing aperture), shutter speeds, and International Orga-

nization for Standardization (ISO) numbers (representing light sensitivity).

Results: The results showed that F-numbers between 5.6 and 10, shutter speeds faster than 1/

30s, and ISO 800 produce the best occlusal images when a 60 mm f/2.8 Macro lens is used.

Better images are obtained with ring LED than with ring flash. Furthermore, ISO 3200 is

required for low-magnification photography in natural light. Finally, intraoral digital images

should be captured under low magnification, because tilted or deflected images can be

adjusted by using imaging software.

Copyright © 2014 The Japanese Society of Pediatric Dentistry. Published by Elsevier Ltd. All

rights reserved.

1. Introduction

Intraoral photographs enable dentists to evaluate various

hard and soft tissues [1,2]. These images can be used to record

2; fax: þ81 22 717 8386.(K. Saito).

ciety of Pediatric Dentist

and identify pathological changes in normal tissues, such as

caries including recurrent caries, restorative material wear,

enamel hypocalcification or hypoplasia, fluorosis, tetracycline

staining, dentine exposure, defective restorations, gingivitis,

gingival clefts or scarring [1,2]. Intraoral photography is

ry. Published by Elsevier Ltd. All rights reserved.

Fig. 1 e Intraoral photographing and clipping. A 1:4

magnification was chosen to image the maxillary occlusal

aspect. The focus was the right premolars (a). An amalgam

restoration with recurrent caries and stained fissures (b) in

the left first molar and a discolored central incisor (c) are

noticeable. Images of these teeth were clipped from the

whole occlusal image. The first molar photograph was

converted to a 16-bit gray-scale image to assess focal

accuracy in terms of contrast (d).

p e d i a t r i c d e n t a l j o u r n a l 2 4 ( 2 0 1 4 ) 8 9e9 690

especially important in pediatric dentistry because children

cannot keep their mouth open for extended periods, but im-

ages can be thoroughly analyzed. Furthermore, they allow

periodic assessment of therapeutic effects, prognosis, and

growth- or disease-induced changes in children, who show

dramatic transformations in a short time. The photographic

requirement varies according to the situation, such as low-

magnification images of the whole dentition and high-

magnification images of problematic teeth.

Cameras include single-lens reflex (SLR) and rangefinder

cameras. Although rangefinder cameras are convenient for

everyday use because of their small size and automatic focus,

they have limited applicability in dentistry because parallax is

an unacceptable drawback in close-up photography. The

viewfinder of a rangefinder camera is inevitably offset from

the taking lens, given their different optical axes. Therefore,

the seen image will not be recorded correctly on film or a

digital sensor. In contrast, the viewfinder of an SLR camera

transmits the image directly “through the lens”.

The film SLR camera mainly used by dentists in the past

had a ring flash included in the macro lens (i.e., Medical Nik-

kor 120 mm F-number of 4). However, this camera was so

heavy that several assistants were needed to hold dental in-

struments such as themirror and lip retractor during intraoral

photographing. Furthermore, they often failed in taking pho-

tographs which could not be previewed. Therefore, balancing

of the aperture (F-number), shutter speed, and light sensitivity

(ISO number) was difficult. Low and high F-numbers result in

shallow depth of field and dark images, respectively. Fast

shutter speeds yield dark images and slow shutter speeds

cause blurred images, because of camera shake. Further, low

ISO numbers result in dark images and high ISO numbers

create noise. Therefore, dentists should know the appropriate

values of these parameters.

The introduction of digital SLR cameras has allowed

instantaneous assessment of photographic errors via the

preview function. Mirrorless cameras have also been devel-

oped, and the recent digital cameras are compact and light-

weight, and offer high definition [3]. Moreover, white light

emitting diode (LED) produces bright, power-saving illumi-

nation and thus reduces camera weight. Digital images can be

saved on a computer, reducing space requirements [4].

Furthermore, images can be compiled easily by using imaging

software [5]. Contrast and brightness can be regulated and

high-magnification images can be obtained by cropping wider

photographs, which may enable better examination by digital

zoom. In future, the imagemay be used for retrospective study

such as historical cohort study. Digital photography also helps

in treatment planning as the patient can instantaneously view

images on electronic visual displays and have a visual guide to

understand the disease, treatment, and outcomes.

However, digital zoom causes image deterioration. There-

fore, intraoral photography requirements should be investi-

gated while considering digital zoom. Intraoral digital

photography involves cutting-edge technologies. However,

only a few studies of such imaging have been performed

[1e8,10]. This studywas aimed at determining the appropriate

exposure parameters for occlusal photography in consider-

ation of digital zoom with digital cameras. In this reason,

zoomed image of the maxillary occlusal aspect reflected in a

mirror was examined for recurrent caries, stained fissures,

and nonvitality.

2. Methods

2.1. Cameras

EOS Kiss X5 (also known as EOS REBEL T3i or EOS 600D; Canon,

Tokyo, Japan) and EOS M (Canon) cameras were used for im-

aging in this study. The former is an 18.0 effective-megapixel

APS-C CMOS digital SLR camera weighing 560 g including the

battery and card. The available ISO numbers range between

100 and 6400, and the image processor is DIGIC4. The latter is

an 18.0 effective-megapixel APS-C CMOS sensor digital mir-

rorless camera weighing 262 g including the battery and card.

Its available ISO numbers range from 100 to 12,800, and the

image processor is DIGIC5.

2.2. Lens and light source

An EF-S 60 mm f/2.8 Macro USM lens (Canon), weighing 335 g,

was used in both the cameras. Its angle of view is equivalent to

a 96mm lensmounted on a 35mm format camera. F-numbers

between 2.8 and 32 can be selected and magnification varies

from 1:1 to 1:5.

p e d i a t r i c d e n t a l j o u r n a l 2 4 ( 2 0 1 4 ) 8 9e9 6 91

MR-14EX Macro Ring Lite (Canon) was used as a ring flash.

It weighs 430 g with 8 AA 1.5 V batteries and has a coverage

angle of 35�. HVL-RLAMMacro Ring Light (Sony, Tokyo, Japan)

was used as a ring LED; it weighs 180 gwith 4 AA 1.5 V batteries

and has an 80� coverage angle. Finally, illumination from a

standard fluorescent lamp was used without a dental chair

lamp as a natural light source. A private room (2.9 m � 3.9 m)

without sunlight was used for the experiments. Eight fluo-

rescent lamps (100 V, 32 W; Panasonic, Osaka, Japan) were

shone from a height of 2.5 m on the 65 cm-high dental chair.

2.3. Experimental condition

For this study, the image quality was set as high, size was 18

megapixels, magnification was 1:4, mode was Av (fixed ISO

and F-number, automatic shutter speed), and focus was

manual. The subject was a man having recurrent caries and

stained fissures in the upper left first molar and discoloration

of the nonvital upper left central incisor. The subject signed

written consent after explaining the purpose of this study. His

maxillary occlusal surface reflected by amirror (Fig. 1aec) was

photographed with the cameras focused on the upper right

premolars.

2.4. Evaluation

Images of the problematic teeth were cropped from the whole

occlusal image using different exposure settings. These pho-

tographs were evaluated by 56 dentists (31 men and 25

women, mean age ¼ 28.7 years) to identify the best images for

diagnosing the subject's dental problems.

2.5. Assessment of focal accuracy

The cropped first molar photograph was converted into a

16-bit gray-scale image by ImageJ software (http://imagej.

nih.gov/ij/). Brightness was graded from the interproximal

space between the first and the second molars (minimum

brightness) to the mesial marginal ridge of the first molar

(maximum brightness) by ImageJ (Fig. 1d). Contrast at the

stained fissures between the distal interproximal space and

the mesial marginal ridge was used to assess focal accu-

racy, because greater contrast (i.e., large difference be-

tween bright and dark parts) indicates better focus.

Fig. 2 e Occlusal photographs with the SLR camera and ring

flash. The F-number ranged from 5.6 to 14 and ISO number

ranged from 100 to 800 (ael). The shutter speed (seconds) is

indicated at the lower left corner of every image. The most

accurate image was evaluated by 56 dentists (m).

3. Results

3.1. SLR camera with ring flash

The SLR camera was used with the ring flash under ISO

numbers varying from 100 to 800 and F-numbers varying from

5.6 to 14 (Fig. 2). ISO 100-derived images showed no noise

(Fig. 2aec). However, camera shake was strong because of

slow shutter speeds (1/8 to 1 s). ISO 200 and 400-derived im-

ages also did not have noise (Fig. 2dei). The shutter speedwith

ISO 200 and 400 was faster than that with ISO 100. Images

captured with F-number of 5.6 and ISO 200 or 400 were fine

(Fig. 2d, g).

Weak noise was noted at high magnification of ISO 800-

derived images (Fig. 2jel). F-numbers of 5.6 and 10 produced

comparatively clear images (Fig. 2j, k). A slight blur in the

transverse palatine fold was caused by the depth of field in F-

number of 5.6-derived images. Blurred images were obtained

with F-number of 14 at slow shutter speeds.

Twenty-seven dentists (48.2%) evaluated that F-number of

5.6 yielded high-quality images, especially when used with

ISO 800 (Fig. 2m). The fastest shutter speed usedwas 1/80 s. As

a next evaluation setting, 13 (23.2%) and 12 (21.4%) dentists

chose F-number of 5.6 with the ISO 200, ISO400, respectively.

Other settings were hardly accepted.

3.2. SLR camera with the ring LED device

The SLR camera was also used with the ring LED under the

aforementioned ISO numbers and F-numbers (Fig. 3). The light

intensity appeared dark compared with those obtained under

the ring flash. The shutter speeds by using the ring LED were

slower than thosewith the ring flash. Therefore, under ISO 400

produced more blurred images (Fig. 3g, h) than the images

derived from F-number of 5.6 or 10 with ISO 800 (Fig. 3j, k).

However, the focus was not suitable because the depth of field

Fig. 4 e Occlusal photographs with the SLR camera and

natural light. Imaging was performed under the

illumination of a standard fluorescent lamp. The F-number

ranged from 5.6 to 14 and ISO number varied from 800 to

6400 (ael). The shutter speed (seconds) is indicated at the

lower left corner of every image. The most accurate image

was evaluated by 56 dentists (m).

Fig. 3 e Occlusal photographs with the SLR camera and ring

LED. The F-number ranged from 5.6 to 14 and ISO number

varied from 100 to 800 (ael). The shutter speed (seconds) is

indicated at the lower left corner of every image. The most

accurate image was evaluated by 56 dentists (m).

p e d i a t r i c d e n t a l j o u r n a l 2 4 ( 2 0 1 4 ) 8 9e9 692

was shallow in F-number of 5.6. The each 27 (48.2%) dentists

determined that ISO 800 with F-numbers of 5.6 and 10 yielded

the best images in this category (Fig. 3m). Other settings were

scarcely accepted.

3.3. SLR camera with natural light

Photographs captured by the SLR camera under natural light

with F-numbers of 5.6e14 and ISO 800e6400 were evaluated

(Fig. 4). Shutter speeds slower than 1/25 s resulted in blurred

images (Fig. 4aec, e, f). Good images were obtained with F-

numbers of 5.6 and 10, but slight noise was seen in images

derived from ISO 1600 (Fig. 4d, e). The noise increased and the

gingival shine decreased in ISO 3200-derived images

(Fig. 4gei). However, the discoloration of the central incisor

and recurrent caries and stained fissures in the first molar

were identifiable. The soft-tissue evaluation was difficult,

since gingival color reproduction also decreased and noise

increased in ISO 6400-derived images (Fig. 4jel). Twenty-seven

(48.2%) dentists judged as the best images which were ob-

tained with F-number of 10 and ISO 3200 (Fig. 4m). On the

other hand, 11 (19.6%) dentists chose F-number of 10 and ISO

6400. Thus, ISO 3200-derived images were considered better

than ISO 6400-derived images by the dentists.

3.4. Mirrorless camera vs. SLR camera

The mirrorless camera with the ring flash (Fig. 5) and ring LED

(Fig. 6) was evaluated under the same settings as for the SLR

camera. A major difference was not observed with the ring

flash compared with Fig. 2, probably because the same sensor

was used in both the cameras. Good images were obtained

with ISO 400 and 800 and F-numbers of 5.6 and 10 using the

ring flash (Fig. 5g, h, i, k); twenty-six (46.4%) of the partici-

pating dentists evaluated that the best images were obtained

with F-number of 5.6 and ISO 800 (Fig. 5m). As a next evalua-

tion setting, 15 (26.8%) dentists chose F-number 5.6 with the

ISO 400. Clear images were also obtained with ISO 800 and F-

numbers 5.6 and F10 by using the ring LED (Fig. 6j, k). In this

case, F-number 5.6 and ISO 800 yielded the best photographs

Fig. 6 e Occlusal photographs with the mirrorless camera

and ring LED. The F-number varied from 5.6 to 14 and ISO

number ranged from 100 to 800 (ael). The shutter speed

(seconds) is indicated at the lower left corner of every

image. The most accurate image was evaluated by 56

dentists (m).

Fig. 5 e Occlusal photographs with the mirrorless camera

and ring flash. The F-number increased from 5.6 to 14 and

ISO number ranged from 100 to 800 (ael). The shutter

speed (seconds) is indicated at the lower left corner of

every image. Themost accurate image was evaluated by 56

dentists (m).

p e d i a t r i c d e n t a l j o u r n a l 2 4 ( 2 0 1 4 ) 8 9e9 6 93

for 51 (91.1%) dentists (Fig. 6m). Under ISO 400 images were

not completely evaluated.

The photographs under natural light were derived by F-

numbers ranging from 5.6 to 14 and ISO numbers varying from

800 to 6400. Under ISO 800, noise was minimal, but blurring

occurred (Fig. 7aec). F-number of 5.6- and 10-derived images

were good in the ISO 1600 setting (Fig. 7d, e). In ISO 3200, no

blurring instead of increased noise was noted, but clear im-

ages were obtained with F-numbers of 5.6 and 10 (Fig. 7g, h).

Noise increased in ISO 6400-derived images, although it was

less than with the SLR camera (Fig. 4jel, Fig. 7jel). Images

taken under ISO 800 and F-number of 10 and 14 were selected

less often than those with F-number of 5.6 (Fig. 7m).

3.5. Equipment assessment

With regard to the suitable photographic equipment (Table 1),

17 (30.4%), 13 (23.2%), and 11 (19.6%) dentists selected “SLR

camerawith ring LED,” “mirrorless camerawith ring LED,” and

“SLR camera with ring flash,” respectively. Interestingly, 10

(17.9%) dentists judged “SLR camera with natural light” as the

most distinct. Individually, the mirrorless camera was

selected by 18 (32.1%) dentists and the SLR camera was chosen

by 38 (67.9%) dentists. As for the light source, 16 (28.5%), 30

(53.6%), and 10 (17.9%) dentists chose the ring flash, ring LED,

and natural light, respectively.

3.6. Focal accuracy

Focal accuracy was analyzed on the basis of contrast.

Preferred settings by dentists were extracted in each device

from results of Table 1. Fissure staining was not detected

under natural light (Fig. 8; green line in web version). The

natural light is not suitable to diagnose the staining of the

fissure. No differences between the SLR and the mirrorless

cameras were identified. Use of the ring flash or ring LED light

allowed identification (peak) of three fissure stains. However,

the image of the ring flash produced slightly darker images

than the ring LED light, as indicated by the relative location of

the red line in web version in Fig. 8.

Fig. 8 e Estimation of contrast in the 16-bit gray-scale first

molar image. Brightness was measured from the distal

interproximal space (IS) as a minimum to the mesial

marginal ridge (MR) as a maximum (a). Upper and (b) lower

panels depict the results obtained by using the SLR and

mirrorless cameras, respectively, with the best setting for

each light source.

Fig. 7 e Occlusal photographs with the mirrorless camera

and natural light. Imaging was performed under the

illumination of a standard fluorescent lamp. The F-number

ranged from 5.6 to 14 and ISO number varied from 800 to

6400 (ael). The shutter speed (seconds) is indicated at the

lower left corner of every image. The most accurate image

was evaluated by 56 dentists (m).

p e d i a t r i c d e n t a l j o u r n a l 2 4 ( 2 0 1 4 ) 8 9e9 694

4. Discussion

Various views can be captured for intraoral photography, such

as full face, occlusal view, frontal view, profile, and treatment

comparisons. Treatment comparisons are photographed with

high magnification, whereas the full face is photographed

Table 1 e Evaluation of the photographic equipment.Distribution of the images that were selected as the bestamong the Figs. 1e6 by each participating dentist. (SLR,single-lens reflex camera; ML, mirrorless camera).

Camera Light source n Preferred parameter

SLR Ring flash 11 ISO 800, F5.6

SLR Ring LED light 17 ISO 800, F5.6 and 10

SLR Natural light 10 ISO 3200, F10

ML Ring flash 5 ISO 800, F5.6

ML Ring LED light 13 ISO 800, F5.6

ML Natural light 0 ISO 1600, F5.6

with low magnification. For high-magnification photography,

F-number of 22, shutter speeds of 1/125e1/250 s, ISO 100, and

magnification of 1:1e1:2 are generally used [5,6]. In this study,

to investigate the ideal exposure parameters for intraoral

digital photography, a low-magnification image of the adult

maxillary occlusal aspect viewed in amirrorwas evaluated. At

high magnification, the F-number should be increased to

widen the depth of field.

Color shade such as white balance was not evaluated.

Although Figs. 1e6 were obtained from the same subject, the

color shade (in web version) differed completely. The quality

of light depends on its color temperature. For example,

daylight has a color temperature of 6500 K, while electronic

flash and LED have a 5500 K color temperature [7]. If color

adaptation were absent, a white card would appear bluish at

high color temperature and yellow at low color temperature.

All cameras have an automatic white balance setting, where

the internal electronics calculate the white balance according

to the color temperature of ambient light. For most situations,

this setting is adequate. However, thewhite balance should be

changed according to the color temperature, and using a color

chart is recommended. The white balance of a digital image

can be adjusted by imaging software, which is a useful feature

of digital cameras.

p e d i a t r i c d e n t a l j o u r n a l 2 4 ( 2 0 1 4 ) 8 9e9 6 95

Digital SLR cameras have two main sensor types. The full-

size sensor is the same size as a 35mm (36� 24mm; 864mm2)

film, whereas Advanced Photo System type-C (APS-C) is

considerably smaller. Canon's APS-Cmeasures 22.3� 14.9mm

(332.27 mm2). The full-size sensor resists darkness, and the

captured image is pure because it is 2.6 times bigger than APS-

C sensor, which makes the device heavy and expensive.

Therefore, APS-C is generally used for dental photography.

Because a smaller portion in the center of the focused object is

captured and then expanded to full size for viewing, the

effective magnification and focal distance of the lens increase

when using an APS-C camera. The true magnification and

focal distance created by Canon's APS-C is 1.6 times as large as

that of the full-size sensor, since each dimension of a sensor is

36 cm versus 22.3 cm. Amacro lens with amagnification of 1:2

while it ismounted on a full-size sensor camerawould have to

be set to a magnification of approximately 1:3 to capture the

same imagewhile it ismounted on an APS-C camera. A 60mm

f/2.8 macro lens was used in this study. If the full-size sensor

were used instead of APS-C, a 96 mm lens would be required.

This focal distance is suitable for imaging a part of the

dentition. However, an APS-C camera should have a magni-

fication lower than 1:3 for photographing the occlusal surface

of the dentition reflected by a mirror. Because rotation

correction is possible in digital cameras, the 1:4 magnification

is effective. With this magnification, the quantity of light is

weak because the focal distance is about 1000 cm. Several

teeth will not be imaged; moreover, if the image rotation

needs to be corrected and digital zoom used in the software, a

lens of 35e50 mm is recommended for wide-angle photog-

raphy, which is equivalent to a lens of 56e80 mmmounted on

a 36mm format camera. In the future, technological advances

will allow low-magnification images to be clipped as required

and used as high-magnification images. It may be helpful in

retrospective study in the future if the parameter of this study

was used for taking picture.

Pictures takenwith the SLR andmirrorless cameras did not

show a clear difference. Although mirrorless cameras have

slow automatic focus, they are suitable for intraoral photog-

raphy because they are small and lightweight. The problem of

slow automatic focus can be resolved if manual focus is used.

Dentists can even photograph by using one hand, leaving the

other hand free to hold a mirror or an air syringe and thus

increasing convenience.

In the dentists' evaluation, images derived from F-numbers

of 5.6 and 10 were considered good. As the depth of field is

shallow at F-number of 5.6, although the focus suits coronal

imaging, the palate appears blur. However, the shutter speed

is slower than that used at F-number of 10. Although F-

number of 22 was recommended earlier [7], an F-number be-

tween 5.6 and 10 is sufficient for occlusal photography. The F-

number should be changed depending on the enlargement

ratio.

ISO 100 and 800 did not result in a clear difference in image

quality. Noise increased from ISO 1600 and detail was lost in

ISO 6400-derived images. Blurring was pronounced at shutter

speeds slower than 1/10 s. High-magnification photography

requires a shutter speed of 1/250 s. Portrait images require a

shutter speed between 1/60 and 1/100 s [8]. The light quantity

and focal distance should be considered within these limits.

Although the ring LED produced darker than the ring flash,

it is easy to focus because of the continuous intraoral illumi-

nation; the ring flash cannot be used for serial photography

because it should be charged for 6 s. The ring LED also weighs

less than the ring flash (180 g vs. 430 g). The light intensitymay

have darkened because the ring LED scatters light extensively,

increasing the coverage angle. However, the image photo-

graph of the ring LED became bright because shutter speed

was slow. In this study, the dentists preferred the ring LED as a

light source, suggesting that bright images enable easier

identification (Table 1, Fig. 8). Therefore, A bright image at the

sacrifice of shutter speed may be favorable. If the quantity of

light is sufficient for close-up photography, the ring LED is a

more effective device.

Practical photographs were obtained under the natural

light with a high ISO number. The discolored central incisor

and first molar with recurrent caries were identified by these

images as well. If the teeth were illuminated by an artificial

light source such as a ring flash or LED, color tone would be

difficult to detect, because the light would be reflected by the

tooth plane. Moreover, the intensity of artificial light is

affected by the focal distance. Therefore, for shade selection

in dentistry, artificial light is extinguished and natural light is

used. Periodic photographing is recommended for diagnosis

because a traumatized tooth sometimes becomes discolored

in about 6 months [9]. Photography under natural light is

probably suitable in such cases.

EOS Kiss X5 and EOS M have the same sensor, but the

image processor of EOS M is DIGIC5 and that of EOS Kiss X5 is

DIGIC4. The noise reduction performance of DIGIC5 is four

times better than that of DIGIC4. Therefore, EOS Kiss X5 pro-

duced noisier images. However, the dentists preferred the SLR

camera irrespective of the light source. Probably, the stained

fissureswere difficult to identify in bright pictures due to high-

sensitivity resistance. Because the halation decreases and

shutter speed increases when EOS M is set for dark images,

clearer photographs may be captured. In another study, no

camera produced satisfactory results in the default mode [10],

and all the cameras had to be adjusted at least once for taking

satisfactory images. Some image manipulation may be

required because of the difference in image processors.

In this study, 10 dentists considered the SLR camera and

natural light to produce the best images. A major drawback of

ring flash and LED is the uniform light output, which creates

shadow-less, flat, bland, and lackluster images [7]. Electronic

flashes abolish fine detail, translucency, and subtle color

variations of individual teeth.

5. Conclusion

The most suitable exposure parameters for occlusal photog-

raphy with a 60 mm f/2.8 Macro lens, regardless of the type of

digital camera, are as follows: F-number between 5.6 and 10,

shutter speeds faster than 1/30 s, and ISO 800. For low-

magnification imaging of the whole occlusal surface under

natural light, the ISO number should be increased to 3200.

Finally, intraoral digital images should be captured under low

magnification, because tilted or deflected images can be

adjusted by using imaging software. Image may be available

p e d i a t r i c d e n t a l j o u r n a l 2 4 ( 2 0 1 4 ) 8 9e9 696

for retrospective study such as historical cohort study that

watched the specific region.

Conflict of interest

None of the authors has any conflicts of interest that should

be declared.

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