Konica Minolta SLR User Manual

Journal of Orthodontics, Vol. 33, 2006, 000–000

FEATURES

Comparison of 10 digital SLR cameras

SECTION

for orthodontic photography

D. Bister, Faranak Morderai and R. M. Aveling

Department of Orthodontics, Guy’s Hospital, London, UK

Digital photography is now widely used to document orthodontic patients. High quality intra-oral photography depends on a
satisfactory ‘depth of field’ focus and good illumination. Automatic ‘through the lens’ (TTL) metering is ideal to achieve both
the above aims. Ten current digital single lens reflex (SLR) cameras were tested for use in intra- and extra-oral photography as
used in orthodontics. The manufacturers’ recommended macro-lens and macro-flash were used with each camera. Handling
characteristics, color-reproducibility, quality of the viewfinder and flash recharge time were investigated. No camera took
acceptable images in factory default setting or ‘automatic’ mode: this mode was not present for some cameras (Nikon,
Fujifilm); led to overexposure (Olympus) or poor depth of field (Canon, Konica-Minolta, Pentax), particularly for intra-oral
views. Once adjusted, only Olympus cameras were able to take intra- and extra-oral photographs without the need to change
settings, and were therefore the easiest to use. All other cameras needed adjustments of aperture (Canon, Konica-Minolta,
Pentax), or aperture and flash (Fujifilm, Nikon), making the latter the most complex to use. However, all cameras produced
high quality intra- and extra-oral images, once appropriately adjusted. The resolution of the images is more than satisfactory
for all cameras. There were significant differences relating to the quality of color reproduction, size and brightness of the
viewfinders. The Nikon D100 and Fujifilm S 3 Pro consistently scored best for color fidelity. Pentax and Konica-Minolta had
the largest and brightest viewfinders.

Key words:

;

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Refereed paper

Introduction

Intra- and extra-oral photography are widely used to
document orthodontic patients at the start of treatment
and to monitor treatment progress. The ideal character­istics for intra- and extra-oral photography for dentistry
and orthodontics in particular, are reproducible magni­fication of the images, good depth of field and
consistent, homogenous illumination. Ideally, all the
above characteristics should be standardized within one
series of images, as well as consistent over long periods
of time.

sharpness, and extends in front of and behind the point
of focus. For good depth of field in intra-oral photo­graphy a small aperture (such as f522) should be used.
Consistent exposure at such settings can best be
achieved by automatic ‘through the lens’ (TTL) meter­ing.
should be easily programmable.

advertised for use in dental imaging, only Single Lens
Reflex (SLR) cameras consistently fulfill all the above

1,2

‘Depth of field’ is defined as the zone of acceptable

1

These settings should either be factory pre-set or

Although there are a large number of digital cameras

parameters. Additionally, SLR cameras allow for ‘best
preview’ of the proposed image as the viewfinder shows
the object, as it will appear in the eventual image.

In the pre-digital era the ‘Yashica Dental Eye’ was
produced for intra- and extra-oral photography. This
SLR camera had a 100 mm macro-lens, which was
permanently fixed to the body with a built-in ring-flash. A
macro-lens allows for distortion-free imaging at close
range with high depth of field. The aperture settings were
automatically adjusted when changing the focus from
intra- to extra-oral photography, and was thereby very
user friendly; no changes in camera settings are necessary
between intra- and extra-oral photography. It was also
reasonably priced. The ‘Dental Eye’, however, will not be
made available in the digital format. In this article, this
camera was used as reference, as it had all the above­mentioned ideal properties for dental photography.

1

Digital SLR cameras have only recently become more
affordable. SLR cameras are now subdivided into two
groups: professional and ‘prosumer’. The professional
group is more expensive, but usually has a range of
advantageous features over the ‘prosumer’ group such
as:

Address for correspondence: D. Bister, Department of
Orthodontics, 22nd Floor, Guy’s and St Thomas’ Foundation
Trust, Guy’s Hospital, London Bridge, London SE1 9RT, UK.
Email: [e-mail]

#

2006 British Orthodontic Society DOI 10.1179/146531205225021687

2 D. Bister et al. Features Section JO September 2006

higher pixel count (the higher the pixel count the

N

larger the image);
increased dynamic range (reproducing lighter and

N

darker areas better);
advanced color reproducibility (ability to reproduce

N

more colors);
tougher camera-bodies (which are better able to

N

withstand exposure to humidity and dust and are less
likely to break on impact);
longer battery life;

N

faster response time to turning the camera on and/

N

or shutter release delay (delay between turning
the camera on/pressing shutter release and actual
exposure);
cleaning the sensor on start-up (to remove dust

N

particles from the sensor).

However some of these features are also found in the
‘prosumer’ group; the Canon EOS 20 D is fast:

0.2 second response delay on turning the camera on
and the Olympus E1 has sensor clean.

Although other authors
digital cameras, no comprehensive review has recently
been undertaken. The professional group was not tested
as most of the above-mentioned features are not
necessary for dental photography.

For good illumination a macro-flash is ideal: it avoids
shadows from cheek retractors at close range and allows
for homogeneous illumination of the teeth. Ideally, these
macro-flash units should be strong enough for extra-oral
photography; thus, avoiding the need for a second flash
system. With regards to the macro-lens and macro-flash
the manufacturers’ respective devices were tested.

2,3

have previously tested

Aim

The aim was to assess 10 digital SLR cameras in the low
to medium price range (less than 2500 J for the body),
the so called ‘prosumer’ models (comparable to the
‘Yashica Dental Eye’) with manufacturers’ recom-

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mended macro-lens and flash in terms of:

Figure 1 Fully assembled unit with macro-lens and macro-flash

time needed to recharge the macro-flash (time taken

N

between two photographs);
weight of the unit (including batteries, flash-unit and

N

lens);
pricing (inclusive of macro-lens and flash, excluding

N

Value Added Tax).

Materials

COLOUR

FIGURE

ease of use (how many settings needed changing

N

between intra- and extra-oral photography, and how
easy these were to accomplish);
quality of photographs (color reproducibility and

N

pixel count);
quality of the viewfinder: size and brightness (brighter

N

and larger viewfinders allow easier focusing and
handling);
homogeneity of light on the object and strength of

N

macro-flash (ability to take intra- and extra-oral views
with the same flash unit);

The cameras tested (shown in Table 1) were single lens
reflex (SLR), with a macro-flash and a macro-lens, as
recommended by the manufacturer. The guide-number
for the flash-units represent their power: the higher the
number the more powerful the flash unit. One such
assembled unit is shown in Figure 1. The Fujifilm S 3
Pro was tested with a Nikon SB 29S Speed-light and
60 mm Nikkor macro-lens.

Standardization of focal length of the macro-lenses
was not possible. The choice of macro-lens was
determined by availability (Konica-Minolta and

JO September 2006 Features Section Comparison of digital SLR cameras 3

Pentax only produced the 100 mm macro-lens at the
time of testing,); Olympus only produces a 50 mm
macro-lens, which takes magnification differences

Pentax *ist

DS

between analogue and digital formats into account.
The lenses chosen for this study were kept as close as
possible to a 100 mm equivalent (for 36 mm analogue

Olympus

E300

film). Nikon and Fujifilm use a small sensor, which does
not fill the 36 mm film-area. A magnification factor of
approximately 1.5 applies. This magnification factor was
adjusted by choosing a 60 mm macro-lens for those
cameras.

Methods

Ease of use

All cameras were initially set on automatic mode
(factory preset); with the flash turned on. The intra-oral
exposures were taken at approximately 1:2 magnifica­tion. The aperture selected by the camera was recorded
and checked for suitability, particularly depth of field.
Homogeneity of illumination was checked for suitability
by assessing shadows on the image. There is a reverse
relationship between the f-setting and the aperture: the
larger the number of the f-setting the smaller the
aperture and the larger the depth of field. These settings
were found to be too small for all cameras (the aperture
was too large, giving poor depth of field) and were

Konica -

Canon EOS

Minolta 7D Nikon D100 Nikon D70s Nikon D50 Olympus E1

20D Fujifilm S3Pro

therefore changed to aperture priority mode; the
aperture was closed to at least f522, which gives good
depth of field (Figure 2). The camera was then used for
extra-oral photography and the settings changed again
until appropriate, in this case an aperture of at least f58.
The number of changes necessary between the settings
was recorded. The camera was only considered metering
‘through the lens’ (TTL) if the flash settings did not need
to be changed.

Quality of the photographs: Color-fidelity

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Table 1 Cameras tested and specifications

For consistency, intra-oral photographs (front, right

Canon EOS

350D

770 1243 2206 1409 1348 858 746 1226 919 858

490 490 466 490 466 466 466 662 662 515

588 588 539 919 539 539 539 453 453 551

1612 1874 1891 2329 1765 1660 1605 1768 1688 1324

and left lateral views) were simulated by taking pictures
of a demonstration-model (Ormco), against a green
background (Figure 3). A non-clinical method was
preferred to taking images of a patient: the 10 cameras
were not all available at the same time and changes in
oral hygiene may have influenced color consistency over
time. Even if all cameras had been tested on one patient
on one occasion the discomfort would have been
considerable. The white balance selection was auto for
all cameras. The images were subsequently downloaded

Body

Meagpixels (rounded figure) 8 8 12 6 6 6 6 5 8 6

Body (UK list price without

VAT in Euro)

Flash MR-14 EX MR-14 EX SB 29S R 1200 SB 29S SB 29S SB 29S SRF - 11 SRF - 11 AF 140 C

Guide number 14 14 11 12 11 11 11 11 11 14

Macro Speed-light (UK list price

without VAT in Euro)

Macro - Lens 100 mm 100 mm 60 mm Nikkor 100 mm 60 mm Nikkor 60 mm Nikkor 60 mm Nikkor ED 50 mm ED 50 mm 100 mm

Macro - Lens (UK list price

without VAT in Euro)

Unit - Weight (in grams inclusive

batteries)

on a ‘SONY VAIO’ (Sony Corporation, Japan)
computer. The computer screen was adjusted to project