Re: Focusing/Best time of day

[George L Smyth <GLSmyth@xxxxxxx>]

Chris Hulme wrote:
> 
>  Focusing:
> 
>  I've read the FAQs and other articles about adjusting focus to the
>  red index mark.  On my gear (Minolta AF), the index appears at or
>  about f/4.0. If I use, say, an aperture of f/8.0 will I achieve sharp
>  focus without having to adjust the lens?

Sort of.  What will happen is that you will increase your depth of
field, which in turn will help mask any focusing errors.  I think that
you want to turn the focusing knob to the red dot (or whatever IR
indicator your camera uses), as opposed to moving the aperture ring to
that dot.

>  Time of day/year:
> 
>  Many articles I have read stress the point that B+W infra-red works
>  best when there is plenty of sunlight.  It looks like I've
>  mis-interpreted here because I read it to mean that the middle of the
>  day provides the best results and consequently have been blasting
>  away with my Dynax on the stroke of noon.  After reading one of the
>  other postings, it appears early/late in the day are the best times
>  as there is a higher proportion of IR at these times.

It depends upon what you're trying to do.  My experience has shown that
midday will give you more IR in your image than later in the day.  I'm
guessing that they're saying that early/late in the day is a "better"
time to shoot, which I won't argue with as it simply works better with
their style.

>  Would this be the reason why I've not been able to achieve very dark
>  skies (which is the effect I was after) with either Konica or HIE
>  even though I appear to have got the exposure right in one of my
>  bracketed shots?

Look up in the sky before shooting next time.  Is the sky a washed out
blue, or is it a deep blue color.  If it's the former, then forget it,
if the latter then shoot in that direction.  That's right, look around
and you'll see a difference in the sky's color.  Midday, it'll be
difficult to get that dark sky, but early/late is a different story.

george

-- 
 Handmade Photographic Images     
  http://www2.ari.net/glsmyth

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Topic No. 10