If APS-C and similar crop-sensor digital cameras have a focal length multiplying effect such that a 50mm lens has an apparent focal length closer to the field of view of an 80mm on a full frame camera, and yet at the same time the depth of field for the smaller sensor camera is more like the depth of field a 50mm lens would produce on a full frame camera (using the same aperture), then this would seem to suggest the concept of an "aperture dividing effect."

In other words, a 50mm f/1.8 lens on an APS-C camera would act more like a 80mm f/2.8 (approx. 1.8 * 1.6x) lens in 35mm equivalent — for depth of field, not considering exposure.

Can someone with a better understanding of the physics involved clarify this for me.  I've never seen this concept explicitly mentioned anywhere, so I am a bit suspect of it.


Question: Reading XML in C#
Answer: I always prefer working with POCO objects instead of Xml documents. If I correctly understand, you just want to parse an xml file into a set of objects.

To do so you need to:


Define objects model - that's it, just create a set of classes you want to get after deserialization. There are should be a root class that stands for the root xml element.
Put correct attributes into the properties of the classes. That's how you will bind properties with xml elements/attributes
Use XmlSerializer to deserialize the file into a normal POCO classes.


See a good explanation here - http://www.agiledeveloper.com/articles/XMLSerialization.pdf