Problems with Canon EF 50mm f/1.8 Lens

In message bApIc.75875$WB5.68310@pd7tw2no, Dave
writes
The bizarre, off topic and biased comments notwithstanding, DOF is
related to focal length, film/digital format, subject distance, and apeture.
It is largely unrelated to manufacturer. You could do a google search for
online free calculators that will give you DOF after you put in the details
of your lens. For example,

For 35mm, the circle of confusion is 0.025mm.
Multiply the F number used by the circle of confusion. Multiply this by
the (magnification+1) and then divide the answer by the magnification
squared. The total depth of field is twice this number (in units of mm).

Or the practical way. Looking at the DoF scale on my 50mm f1.7 lens, it
doesn't even have markings below f4. Focused at 1.5m, the next distance
marking on the lens is 1.75m. This is way off the end of the DoF scale.
So yes, you will have a shallow DoF when close-up with a fast lens wide
open.
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Paul Friday