[Wavytone]

Stephen,

Many beginners are struck with the "stick your head in a fishbowl" effect of the UWA eyepieces (Ethos etc) - I agree it is amusing at first and useful on large extended nebulae and a handful of the larger galaxies, but ultimately I regard it as a party-trick.

In some situations UWA eyepieces aren't ideal for getting the most out of your scope on small objects because flooding you eye with things to look at affects your eye's dark adaptation ( ie night vision).

Conversely the smaller field eyepieces (such as Plossls, Orthoscopic, Vixen LV, Edmund RKE) have a much smaller field stop, which simply blacks out a large chunk of the field in your eye. The dark adaptation of your eye responds accordingly and is improved when looking at faint smallish objects like planetary nebulae and small galaxies, as well as the planets at high power. The effect is easily demonstrated in light-polluted urban skies, and even in Bortle 2-3 skies (Blue Mountains) it is noticeable.

A similar technique some use is to cover the observing eye with a black eyepatch while not actively observing, and only uncover it at the eyepiece. This assumes you have two good eyes (I don't) so you won't stumble around tripping over stuff in the dark.

The second aspect to consider is maximising contrast vs scattered light and ghosts in an eyepiece; these are a function of the number of air-glass interfaces in the eyepiece (fewer is better). For this reason some have monocentric or even spherical ball eyepieces (2 air-glass surfaces) which offer the ultimate contrast at the expense of a small field of view.

Many years ago an experiment was conducted in which a group of experienced observers, scopes and eyepieces were tested to find out what magnification/eyepieces were optimal for faint objects - specifically galaxies, as the application was visual searches for supernovae. It concluded that for faint objects there was indeed an optimal magnification - that which gives an exit pupil of 1mm, or X1 per mm aperture of your scope. This is surprisingly high magnification - not low power at all.