The UHCS certainly increases the contrast and brightness of any nebula with O3, Hbeta and Halpha wavelengths.Blue reflection nebula are suppressed and so is some yellow. A very good filter is the Hutech LPR as it has extra peaks which allow some yellow and green plus a bit of blue beyond a nasty Hg blue line.
There is nothing wrong with unmodded cameras as we cant normally see Halpha visually anyway. But it nice to use it if it is there. The only unfortunate thing is that the worst inherent camera noise is red at about the same level as low Halpha emmision from some dim nebula.
In any measurement it is about the ratio of signal to noise and filters can enhance this depending on the wavelengths emitted by the object of interest.
Hope this helps.
