So I'm still getting to know my brand new skywatcher 6" dobsonian, first relatively cloudless night in a while here. I have two Skywatcher "SUPER"
http://www.skywatcher.com/swtinc/product.php?id=264 achromat/kellner eyepieces (25mm/50° "wide angle long, eye relief" and 10 mm/52°) that came with the scope. My workmate has kindly lent me two more eyepieces to try for a short while so that I can get an idea of what to expect. The first one is an Agena ED 9.5mm
http://agenaastro.com/agena-9-5mm-ed-eyepiece.html
which has a 55° AFOV, and the second is a TMB 6mm Planetary II
https://www.astronomics.com/tmb-6mm-...ce_p16540.aspx which has a 58° AFOV.
I was able to view Jupiter and Saturn, the moon and what I think was the orion nebula (I saw a small question mark shape of 4 stars close together over a cloudy smear that did not move). I found that the Agena 9.5mm seemed to have a noticeably larger field of view than the sw super 10mm, and as expected both had similar quality views of the planets in terms of size/sharpness/contrast, perhaps the agena was marginally better. The TMB 6mm indeed gave more magnification, perhaps 1.5 times larger views of planets, but much harder to get in focus. I struggled for a while with the focuser before discovering I could slowly screw the EP itself out from the barrel for a finer adjustment, although this made the eyepiece quite loose. Even at best, while giving a slightly larger view, I saw no improvement in sharpness or contrast, perhaps slightly worse than the 10mm sw/9.5 mm agena. Of course this may depend on seeing conditions and the aperture of my 6" scope. Either way, even given ideal conditions, I wouldn't want a smaller focal length eyepiece with a dobsonian mount, I'd want an equatorial or fine control AZ mount to be able to more easily track my target as it quickly moves out of the field of view.
I found that for both the loaned eyepieces, the more complex lens configuration not only made the EP longer and wider, they also were less forgiving of the eye not being exactly exactly aligned to the focal point. Initially I almost got a headache trying to keep my head in the right position to look down the EP without getting a tunnel effect cutting out part of the field of view. I assume that I would see a similar effect If I used my eyepieces with a barlow lens?