some effort has been made to 
alleviate the problem [33,34], 
only one camera manufacturer, 
Zeiss Jena, has addressed the 
issue by implementing a narrow 
angle light sensor with their 
exposure system [35]. 
Image Motion Compensation 
The three major manufacturers 
of aerial cameras, Zeiss Jena, 
Carl Zeiss, and Wild, all 
produce camera models with 
forward image motion 
compensation [36-38]. This 
technological advance has 
improved the overall sharpness 
of aerial imagery, and in some 
instances in a dramatic fashion 
(Figure 12). However, in 
pushing the limits of the 
technology with the use of slow 
high resolution films at large 
scales, occasional lateral 
image motion associated with 
aircraft pitch and roll has 
been encountered (Figure 13). 
This situation has required 
discretionary use of the high 
resolution films at large 
scales. 
SUMMARY 
The new films and processing 
techniques introduced over the 
past decade have practically 
forced both user and production 
firm to be more conscious in 
proper film type specifications 
for aerial photographic needs. 
Combined with the 
exposure/processing 
requirements imposed by the 
ICAS densitometric 
specifications, the process and 
use of aerial photography has 
demanded more knowledge and 
precision to best depict the 
information required by the 
user. As both user and producer 
agencies become more conversant 
and comfortable with each 
emulsion's capabilities the 
confusion regarding where and 
how to use what film will 
dimi nish. 
Future direction. The trend 
in emulsion engineering to 
develop finer grain and higher 
resolving emulsions without 
lowering emulsion sensitivity 
identifies the ' state of the 
art' in photography [39]. The 
benefits of these developments 
in aerial photography are 
particularly critical due to 
the moving platform used. With 
improvements forthcoming in 
aerial cameras, especially in 
compensating lateral image 
movement (Carl Zeiss has 
already addressed this in their 
most recent model, the RMK TOP), 
large scale imaging will 
improve significantly. It will 
be interesting to see whether 
Kodak and Ilford will respond 
to Agfa's panchromatic-I. R. 
films with an emulsion of their 
own, infact, with Fuji 
tentatively entering the aerial 
market with their HS film, a 
more competitive environment 
with regard to product quality 
and price is inevitable. 
ACKNOWLEDGEMENTS 
The author appreciates the 
technical review of the 
manuscript by Messrs. 
J. M. Brouwer and A. K. Stade 
(Alberta Forestry, Lands and 
Wildlife), and the additional 
commentary provided by Mr. 
R. J. Hall (Forestry Canada). 
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