A Photographer's Camera
After having been a hobby photographer for nearly 40 years, and living
through the evolution from entirely mechanical film cameras to present
day digital equipment, I have a pretty clear idea of what is desirable
in a camera, and what isn't, at least for the kind of photography I do.
In this article I will explain what features I think a good, modern
camera should have, to be liked by long standing photographers. Maybe
some manufacturer, established or new, reads this and considers
implementing it, or maybe we could even develop such a camera as an
This should be a digital camera, designed from the ground up
to have a logical and practical structure, doing away with things that
aren't really needed. It should have highest image quality, a simple
and logical user interface, and it should interface to the broadest
possible range of existing "accessories" - meaning lenses, flashes,
tripods, etc. All interfaces to the outside world should be
open-source, so that the camera can act as the core of a multi-brand,
universally compatible system.
Given that the 35mm film format was the most widely manufactured system
in photo history, the largest number of high quality lenses in
existence are for this format. It follows that to make best possible
use of existing lenses, this camera must have a sensor that is either
the same size as a conventional film frame, that is 36x24mm, or some
size compatible with it. The sensor must not be smaller, because that
would reduce the final image quality. A specially interesting
possibility would be a large, square sensor, such as 40x40mm. Standard
lenses intended for 36x24mm will vignette the corners of such a big
sensor, of course, but the camera electronics can give the user a wide
choice of interesting formats, such as square 31x31mm, panoramic
40x16mm, round 40mm diameter, various oval formats, while the
standard format would be 36x24mm. Of course each of the rectangular and
oval formats would be available in both horizontal and vertical
orientation. The format selection would simply
indicate the proper crop in the finder, while the photo would always be
taken using the full sensor, and the final cropping would be done in
software on the computer. That gives the photographer the chance to
second-guess his original choice of format for each photo. And if this
large 40x40mm sensor is too expensive or not practical, then a simple,
plain 36x24mm sensor should be used. These exist right now, and have
existed for several years.
This camera would have no separate finder, of course, nor would it be a
reflex camera. Instead it would use the main sensor to get a live
finder image, doing away with the mirror box, mirror mechanism, matte
screen, pentaprism and some other overhead of a conventional SLR
camera. A decision that must be made is whether to use only the LCD
screen on the back of the camera as a finder, or add a dedicated
"peep-hole" finder with a small LCD and an ocular. Many conventional
photographers will probably like the peep-hole finder, as it blocks out
stray light and allows to better concentrate on an optically enlarged
finder image, while many people who have to wear glasses, and are
permanently hampered by eyepoint problems with finders, will
be glad to use just the open LCD screen on the camera's back - as long
as it can be seen even in full sunlight!
Maybe a good compromise could be a peep-hole finder with a tiny color
LCD inside, and high eyepoint optics, combined with a
monochromatic, passive, always-on LCD on the back of the camera. All
image viewing, both during shooting and during review, would be done
through the finder, while all status indication, setting up and
configuration of the camera would use the external LCD.
Really this matter allows several points of view, and gives room to
creative solutions. Those could include fold-out LCDs, passive color
displays, and so on. It's probably the area most open to variation in
this camera concept.
The main sensor would also be used for exposure measuring and focus
sensing. This results in no mirrors, prisms nor other things needed
between the lens and the sensor, which allows putting the
lens mount quite close to the sensor. This lens mount would follow an
open standard, so that both the maker of the camera and third parties
can make and sell lens interfaces that allow mounting a very wide
variety of existing and new lenses on this camera. The generous space
available between the camera's lens mount, and the seating plane of
conventional SLR lenses (typically around 45mm from the focal plane),
allows the inclusion of any required interface mechanics and
electronics in those lens interfaces. For a start, the camera
should be designed, and lens interfaces made available, for all of the
more common existing lenses, such as M42, Pentax-K in all its
variations, Canon FD and EF, Nikon in all its flavors, and additional
interfaces should show up soon. But also lenses can be developed
specifically for this camera, to mount directly on it, without using
any interface. Such lenses can take advantage of the short distance
between the lens seating plane and the sensor, which is a significant
advantage in the design of wide and ultra wide angle lenses.
To take advantage of even the better conventional 35mm lenses, the
sensor should have a pixel pitch of roughly 200 pixels per millimeter.
Even more than that is desirable, up to about 300 px/mm, but depending
on available technology this could be left for future models. At 200
px/mm, a 40x40mm square sensor would have 64 megapixels, while a
36x24mm crop would have nearly 35 megapixels. That's in line with what
currently available sensors (2014) in the best DSLR cameras provide.
More than 300 px/mm would be overkill even for pretty good lenses of
Dynamic range should be pushed as high as absolutely possible. At the
current state of technology, a full 16 bits of resolution per pixel,
with correspondingly very low sensor noise, would be really nice to
The camera would follow the principle of one dedicated knob per
function. All often used main controls, such as focus,
zoom, aperture, shutter speed and mode, sensitivity, format (if
provided), would have their dedicated switch or knob or lever or
button. Buttons are acceptable only for functions that toggle between
just two or maximally three states, and whose state is obvious.
Everything else should have levers or knobs that allow to see in what
position they are. Instead the less often used functions could be
buried in menus, because it would be highly impractical to provide
separate controls for all of them. Still these menus should be well
structured and use enough on-screen explanations, to allow using the
camera without constantly referring to the manual. It should be
possible to learn to use the camera with the help of the manual, and
then put that booklet to rest.
The manual focus, aperture and zoom controls would be those of
the lenses, when using lenses that have them. Lens mount
interfaces for any lenses that don't have an aperture ring, would
include such a ring in the interface. Lenses specifically designed for
this camera would have these control rings built in, of course.
The shutter speed control should be located where it's easy to get at,
like on top, near or around the shutter release button. Other controls
can be placed wherever convenient. Given the lack of a pentaprism box,
the top of the camera should have plenty room for several of
the main controls - maybe even all of them!
The camera must provide at least fully manual exposure, and aperture
priority automatic exposure. The exposure system should use the main
sensor, reading all its surface, either by actually reading each pixel,
or by reading a sample pixel in each small area. The exposure
system must have a mode in which it uses the brightest pixel of the
whole image as reference, setting exposure so that there will be
absolutely no saturated pixels, with the brightest pixel set close to
saturation. The camera may also provide a second exposure mode that
allows a certain percentage of pixels to saturate, and this percentage
should be user-adjustable (via menu). These two modes replace all
center weighted, spot, overall, area-selective, and fancy
motive-specific weightings, because by recording an image with no
saturated pixels, or with a small defined amount of saturated pixels,
all further adjustments can be made later in software. But images with
too many saturated pixels are always unusable, and images exposed lower
than necessary to avoid saturating any pixel just lose image quality,
in terms of noise.
In the above paragraph, single-color pixels are meant. The exposure
check that no individual color is saturated anywhere.
The shutter control wheel could have detents for manual shutter speeds
covering the camera's whole range in full steps, plus a long exposure
setting in which the shutter remains open while the button is pressed,
another long exposure setting in which the shutter opens on one button
press and closes on the next press, plus two auto-exposure settings:
Aperture priority with no saturated pixels, and aperture priority with
some saturated pixels. The latter is useful for example when the scene
contains some tiny spots reflecting sunlight, such as rippled water or
snow surfaces, and it is desired to avoid strongly darkening the whole
image just to keep those tiny spots from saturating.
Metering should be done with the lens stopped down to the value used
for shooting, to avoid errors arising from imprecise stopping down
after fully-open measurement. The most logical system would be keeping
the lens at shooting aperture most of the time, opening it fully only
when specifically desired for more precise focusing. This also makes
the camera highly compatible with old lenses that didn't have automatic
stop-down, and might even eliminate the need for the camera to have any
control at all over the lens aperture, simplifying the lens interface!
Given that an electronic viewfinder is used, there is no need to keep
the lens aperture wide open.
With my current cameras I find that I need exposure compensation
exclusively to correct for the incorrect exposure the cameras do. Most
of the time, if the lighting is such that a camera will do incorrect
exposures, I prefer switching into manual mode rather than using the
exposure compensation control. Consequently I think that an exposure
compensation control isn't really necessary, in this camera that would
have a no-saturation-based autoexposure system.
Any desired lightening or darkening of images can be done much
better during processing in the computer, by gamma changes.
Given the wide differences between legacy lenses in their autofocus
systems, and the large stock of high quality manual focus lenses still
around, the camera should be aimed mostly at camera-aided manual
focusing. In this mode, the user moves the lens focus ring by hand,
while watching both the finder image and some sort of focus
bar, meter, tool, whatever, displayed along with the image, that shows
the quality of focusing as detected by the camera's sensor. The main
focusing help might even be simply a strongly magnified spot of
the sensor displayed on the finder screen, to let the user
judge proper focus. This spot might be movable over the sensor area, or
several such spots could be displayed at the same time, covering all
zones of the image. For example, there could be a grid of 9 such
magnified focusing spots, each of them having a diameter of around one
sixth the image height or width, superimposed at regular intervals on
the background finder image. By pressing a dedicated button, the camera
would be switched between displaying all nine focus spots, or just one
in the center, or none.
Any further help the camera can provide to the user during manual
focusing is certainly welcome. For example, catch-in focus is very
useful for moving targets. Also, if the camera displays a focusing
indicator, it is MUCH more useful to have an indicator showing which
way one has to focus, and how out of focus the subject is, than one
that only shows whether or not the camera thinks the focus is correct.
The camera should also provide a simple electrical autofocus interface
on its lens mount, allowing dedicated lenses for this camera to contain
autofocus motors, and also allowing lens mount adapters for legacy
autofocus lenses to either relay the electrical signals, or include a
focus motor in the lens interface adapter, depending on the lens type
they are made for.
If technically feasible without image quality degradation, the camera
should not have a mechanical shutter, using electronic shuttering
instead. This would provide advantages in terms of cost, reliability,
noise, and vibration. If this proves unfeasible, a conventional
mechanical focal plane shutter would be used. Of course this shutter
would be open most of the time, closing only briefly before and after
each exposure, to allow setting up and reading out the sensor in
The camera should provide shake reduction, either by mechanically
moving the sensor, or by electronically shifting the image on
the sensor. Evaluation is required of the cost and quality of each
method. Input to the shake reduction system should come from both
accelerometers and the image itself. To avoid the need of entering the
lens focal length into the camera's software after every lens
change and after zooming, during pre-exposure the camera can compare
the image shift happening on the sensor, to the acceleration data, to
calculate the current compensation factor (and focal length, if
desired, to store it along with other image data), and then apply the
corrected acceleration data alone during exposure.
A flash built into the camera is not required. The camera should have
both a hot shoe, and an industry-standard connector for an
external flash. Both flash interfaces should include openly documented
functionality for proper camera-flash integration.
Specifically there should be plain simple on/off signals for flash
trigger, flash termination (both of them camera-to-flash) and flash
charged (flash-to-camera). Additional signals for more advanced flash
functions with dedicated flash units might be added, without deleting
the basic signals.
In manual exposure mode, the camera shouldn't send a flash termination
signal, so that operation remains fully manual. In auto-exposure mode,
the camera should measure received light during the exposure, to
terminate the flash at the proper moment. I don't know whether this can
be done via the image sensor. If not, a workable solution (better than
nothing) would be a photocell measuring overall light reflected off the
sensor. This wouldn't prevent the risk of saturating some pixels, but
would at least give a reasonable overall exposure.
The camera should have a plain simple industry standard connector for
an external shutter release switch connected by a cable.
The camera should provide some flexibility regarding the batteries
used. It must be able to function using some type of standard
batteries, such as AA rechargeables, or perhaps 18650-size lithium
cells. The batteries might be housed in a holder attached to the
camera, so that different holders can be made for different batteries.
The camera should accept a sufficiently wide range of input voltages to
accomodate several different battery types. For example, a range of 4.0
to 8.0V would allow the use of 4 to 5 NiMH cells, or two lithium cells.
The voltage at which it shuts down to protect the batteries should be
user-configurable, and instead of a battery charge indicator reading
percentual charge, which is always imprecise, it should simply display
the actual battery voltage, to let the photographer judge remaining
All battery charging should be done outside the camera.
Image data should be stored and downloaded in raw form, with no
processing altogether. The raw files should include the full data read
from the sensor, and any information the camera has, such as the format
selected, date and time, camera settings, etc.
In-camera image processing should be limited to the minimum required to
feed the viewfinder image, focusing, exposure control, etc.
The lack of internal processing into finished JPG images does away with
all need to configure things like contrast, gamma, color rendering,
etc. Even white balance doesn't need to be set, and the camera could do
completely without it. The user can later select the proper white
balance in the external processing software. If photos are shot under
special lighting, the user can shoot a photo of a white or gray sheet
under that light, and later use it for precise white balancing of the
other shots during processing outside the camera.
Given the fast development in memory cards and chips, it would be
desirable that the camera had an openly specified memory interface
protocol and connector, supporting very high memory capacity and speed,
and plug-in adapters for the currently available types of memory cards.
When standards change and new cards appear, it would then be easy to
bring out interface modules to take advantage of them.
This being essentially a photo camera, video support is not required.
If it is found easy to include video support, at nearly no added cost,
it could be done, but under no circumstances should the photo
performance of the camera be compromised to support video.
What else is not wanted
Modern cameras tend to sport a long list of "features" that are
perfectly useless to most photographers. Among them are "picture
modes", lots of tools to alter the colors, and all sorts of
automatisms, including some as weird as trying to recognize human
faces, and optimizing their rendering. Such features might appeal to a
few of the most non-technical beginners in photography, and maybe also
to a few old photographers who have become tired of actively defining
how their photos will look. For everyone else, though, they
are an offense!
All processing features, such as highlight and lowlight protection,
cross-processing, digital filters, etc, of course have no place given
that the camera won't internally process the images. HDR capturing is
also probably better left out. Instead the sensor and A/D converter
should be good enough so the camera doesn't need dynamic range
extension through multiple exposure HDR techniques.
Mostly useless gadgets, such as WiFi, Bluetooth, infrared
interfaces, GPS, attitude sensor, etc, should be left out, and instead
either the price should be reduced accordingly, or the money should be
invested in further improving the image quality.
The camera should have no beeper, speaker, bell, gong, nor any other
pointless noise-making device. And certainly it shouldn't play
creaky pre-recorded shutter noises and the like!!! If at all possible,
it should be completely silent. Confirmation that a photo was
effectively taken can be given via the LCDs. Pushbuttons
should give clear tactile feedback.
The camera should be as small, lightweight and unobtrusive as possible.
It should have neck strap attachments in forward locations, so
that the camera balances reasonable well when fitted with a typical
lens. As much as possible it should lie in the hands much like a
classical SLR camera did. It doesn't need to look fancy. It doesn't
need to look classical. It doesn't need to look modern. And certainly
it doesn't need to come in several colors! In
fact, how it looks is quite unimportant. Instead it should be
practical, compact, solid, and well made. Form should follow
function. The camera should sell for its capabilities and quality, not
for its looks.
A camera like this cannot be used to force a photographer to shelf all
of his existing equipment and buy everything anew. It cannot be used
either to firmly tie a photographer to a given company, brand, lens
mount, etc. So, it shouldn't be sold below production cost, as a lure,
to make people buy overpriced accessories. The camera would have to
sell on its own merits, for a fair price, that allows the manufacturer
to make a reasonable profit, while not preventing too many people from
buying it. My firm belief is that such a camera would find enough
friends and buyers to be a huge commercial success on its own, without
needing the sale of accessories to make it worthwhile to the
manufacturer! On the other hand, of course the manufacturer can and
should bring out optimized lenses and other accessories, to increase
his profits and give us photographers more nice toys, and third party
manufacturer can and should do the same!
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