where there’s smoke there’s fire

Nikon Rumors: continues to debate the ‘modular’ DSLR.

The first serious camera I used was a modular camera – my dad’s Nikon
F1 Photomic. But that was built in the days when cameras were
mechanical systems. Does a modular camera make any sense in the
digital age?

The question is not only relevant to cameras, Norman asked the same
question of mobile devices themselves in ‘The disappearing computer’.
So lets consider where modular makes sense.

Every professional DSLR is modular: lenses are interchangeable. Camera
bodies develop over time. Lenses represent a substantial fraction of
the cost of a complete camera and necessarily involve some form of
compromise with respect to performance, weight, cost and focal
length(s) supported. Even if cost were no object, a 14-400 mm f/1.4
constant aperture lens would be undesirably heavy and unwieldy.

Modular makes sense when:

1) Some parts of the system are likely to become obsolete over time
but a significant fraction of the value of the system is vested in
parts of the system that are likely to retain their value.

2) The suitability of the system for a particular purpose depends on a
component supporting a range of functionality that cannot be
adequately supported in a single instance using generally available
technology.

Both criteria apply to cameras and lenses. Bodies become obsolete
every 2 years or so but a lens design generally remains acceptably
close to the state of the art decades after it is introduced.
Professional photographers queue up to buy new bodies the day they are
announced but few would consider it essential to trade in their lenses
as aggressively.

So does a modular body make sense with respect to the first criteria?
Well lets consider where the majority of the cost goes. In rough order
of decreasing cost I would guess the breakdown would be something
like: sensor, cpu, calibration, body, display.

The sensor and the CPU are both developing rapidly over time. There is
no point in putting a 20MP sensor in a camera with a CPU designed to
support a 10MP sensor. Bigger sensors will demand bigger CPUs. There
is no particular advantage to using a lower resolution sensor with a
higher capacity CPU. Modularity makes no sense on this criteria.

Neither the body nor the display vary markedly in ways that make
support for modularity desirable. The design constraint of modularity
would almost certainly negate any imaginable advantage here. Moreover
each body is designed around a particular CPU and sensor combination.
So modularity makes no sense on the second criteria either.

There is however one area where modularity might make sense and that
is to allow the CPU capabilities of the body to be supplemented by an
outboard CPU. This does not make a great deal of sense for taking
still photographs but makes very good sense if one is shooting very
high definition video.

I suspect that it is no coincidence that the Sony 12MP DSLR chip
supports slightly greater resolution than the ultra-high definition 4K
format used in movies. The 8Hz maximum frame rate is very close to the
24HZ minimum for persistence of vision.

Nikon has an unrivaled range of professional lenses. If it developed
an F-mount body for cinematography it would probably become the
industry standard in a very short period of time. Processing the raw
data rate off the chip in real time is probably beyond what current
generation processors could perform in real time but well within the
capabilities of a high end PC workstation with modern graphics
hardware.

If there is a ‘modular Nikon’ I would expect it to be a dedicated back
for shooting high definition video for cinema with the job of capture
delegated to a dedicated off-camera processor/storage module. The back
would not be a DSLR back at all, it would be a multi-sensor 3CCD back
designed to capture the video and perform lightweight compression to
allow the resulting RAW feed to be captured to disk over a wired 1Gb
Ethernet connection.

Such a device would cost upwards of $10K with $20K being the likely
starting point, lenses being extra.