Re: Ground Glass

[P3D <GCCampos@xxxxxxx>]

The way I use ground glass: 
I use it to determine the range that a lens 
is in focus.  I don't use it determine how sharply a lens is focusing. 
But I can tell if a lens is not focussing at all.
 
1. The ground glass is placed so that the ground side is against the film
guide.  
This will ensure that the ground surface is in the same plane where 
the film would be.  You can use a rubber band or tape to hold it in place.

2. Open the lens f/stop to the widest aperature.   This will let the most
light 
in and make a brighter image.  

3. Try to find something with sharp edges to focus on.  I like to use the
white posts that hold up my front porch.   

4.  While looking at the ground surface of the ground glass (yes, the image
will
be on the ground side), adjust the focus of the camera untill the image is
its sharpest.  Use a magnifying glass or loop.

5. Compare the reading on the camera's distance scale to the actual distance.
 

6.  If you have attached a close-up lens, record the actual distance to the
object and the reading on the camera so you can make a table of "camera 
versus actual" for that lens.  And take notice of the difference between the
viewfinder and the actual image.



I hope this helps.

Grant Campos


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