I would agree with that Brian, some scopes do have a depth of field they have no right to have based on the numbers, for example some of the 50mm objective Hawke scopes have such a short steeply angled scope body I don't think the whole dia of the lens is utilised so it has a depth of field greater than other 50mm objective scopes.
I don't know how to measure the actual magnification of the lenses but with a mildot ret, presuming the ret is true at 10x mag the dot spacing can be used to measure mag, with 1 dot = 1" at 27.7 yards being 10x mag, 25y is 9x mag etc, CG can give you these measurements. Lining 10 dots against 10" on a ruler gives good accuracy then measure the distance.
HFT, for people with only 2 buttucks!
VooDoo TwoTwo The next chapter.