.FOCUSING
ON FOCUSING
By
Sid Tyes Clacton C.C.
(From
East Anglia Federation of Photographic Societies, Spring 1996
Newsletter)
Autofocusing is
an excellent idea,it enables anyone to take in-focus pictures, at the
press of the button, or so the advertisements would have us believe. -
I believed it, I should have known better.
Having put my
AF camera through its paces this year. I was disconcerted to find that
the focusing plane was either in front of the object I was taking, or
behind it, in most of my
best shots. I could not understand it, my pictures should have been in
focus. It was only after taking a number of shots of my grandson in a
Nativity play that I solved the puzzle. Autofocus only works if it is
given time to work. If you move from close up to an infinity shot,or
vice versa,and do not allow the autofocus time to work then you will
waste your film.
This condition
is made worse with telephoto lenses, say 70-210mm zooms at their long
focus ends.The depth of field is very narrow especially at the low F
numbers and the errors are seen more clearly. How does one overcome
this problem?
Most AF cameras
enable focussing to occur when the shutter button is depressed half
way down. If you depress it you may be focused first time,my advice is
to depress it half way at least twice, preferably three times,before
firing the shutter. Experiments I have done since have indicated a
much higher rate of in focus pictures than before, if I operate the
autofocus several times first and then take the pictures.
I wish someone
had told me this before I wasted all the film I have this year. Ignore
it at your artistic and financial peril!
============================================
Reflections
of Colour Cast
Control
By
George Sparkes
(Are 22 Co-ordinator)
While searching
for an article on colour adjustment I was looking through the past
copies of CRCN from No.1 and found it in issue 29, April 1983, and
article by Brian Wheatcroft called "Factors" which influence
the colour rendering of Colour Slide Film" (or How to get it
right the Second or Third Time!" Here is a brief extract:
A green cast
may result from First Development due to:
(a)
Over development
(b) Too much agitation
(c) pH too high
(d) Too little Potassium Bromide.