[NHCOLL-L:5058] Re: is the best method of preserving insect damage fruit

[sam]

Photographing specimens, especially small ones.

Perspective is a function of distance, and
relative dimensions appear to change  more
as the lens approaches the subject.  Placing
any scales in the scene the same distance away
from the lens as the relevant subject matter will
help mitigate this effect. This is also when long
"macro" lenses are nice. The longer focal length
means the subject will be farther from the lens,
(to get the same image size,) so the perspective
will be more normal, and the subject will look more
natural. You can do the same thing using normal
long lenses with the addition of extension tubes,
or bellows.  The closer you get to the subject,
expect to need more exposure than your light
meter indicates.  So, test if using digital, or bracket
exposures on film way to the upside. Additionally,
y'all might consider recording lens-to-subject
distance when doing photomacrography, it's data
that might be useful some day.

Here's an extreme example of how perspective
changes with relative distance:  I'm looking at my
thumb at arms distance. It's the same size as the
width of the front door of the house across the
street. Now looking at my thumb a few inches from
my eye.  It's the size of the whole house!
No camera lenses involved in the above example.
Perspective is not controlled with choice of lens
focal length, photographic image size is controlled
with choice of lens focal length.

Best,
Sam Sumida
Avinet
_______________________________________________________

At 09:03 AM 11/3/2010, you wrote:
>>Posting on behalf of a plant health consultant who would like to 
>>know how to best preserve whole fruit and cucurbits damaged by 
>>insect larval feeding. Any suggestions appreciated.
>
>I find it hard to imagine any way to preserve such tissues other 
>than the way one would *normally* preserve such things: basically, 
>by pickling them. Any method that involves drying, even 
>freeze-drying, is going to involve a loss of color, shape and 
>definition of the damaged portions. Even pickling may not leave 
>things exactly as they appeared originally. That being said, with 
>digital photography as cheap and easy as it is, I'd think you could 
>do almost just as well (better, in several respects) if one took 
>lots and lots of close-up photos with a scale bar in them. If 
>nothing else, having photos means there are no physical specimens to 
>process and find long-term storage for, and also means that there 
>are as many copies as one needs, instead of just the single original 
>object. Only taxonomists are absolutely forced to maintain type specimens. ;-)
>
>Peace,
>--
>
>Doug Yanega        Dept. of Entomology         Entomology Research Museum
>Univ. of California, Riverside, CA 92521-0314        skype: dyanega
>phone: (951) 827-4315 (standard disclaimer: opinions are mine, not UCR's)
>              http://cache.ucr.edu/~heraty/yanega.html
>   "There are some enterprises in which a careful disorderliness
>         is the true method" - Herman Melville, Moby Dick, Chap. 82