The Baader UHC-L is aimed primarily at imagers, though should work fine for visual use.
Here's the thing: it has a narrower bandwidth than the UHC-S (which is a broadband filter), so is less appropriate for blue emission (as in reflection nebulae).
The UHC-S is going to be better for that. The UHC-L is neither a narrowband not a broadband filter (fits into the medium band category).
It will outperform the UHC-S on emission nebulae, but true narrowband filters will outperform the UHC-L.
Baader doesn't make what I would refer to as a narrowband filter (22-26nm bandwidth in the blue green, but covering the H-ß and O-III lines in the spectrum).
The really good ones are:
Astronomik UHC visual. This has a narrow blue-green bandwidth and an extensive red. Current ones, with the narrower bandwidth, are from 2017 on. Stars appear blue-green with some red, intermittently. It is available.
TeleVue BandMate II Nebustar. This has a narrow blue green bandwidth and no red transmission. Current ones started in 2018. Stars appear blue green. It is available.
Lumicon Gen.3 UHC. This is like the Nebustar. Unfortunately, it is out of production. It has varied through the years. Current ones started in 2018. Stars appear blue-green.
DGM NPB. This is the narrowest blue-green bandwidth of the narrowband filters and has a fair amount of red transmission. Stars appear red, but the contrast is superb. It is now available.
Orion Ultrablock. This is a narrow filter with no red. Stars appear blue green. QC varies, but it is the lowest price of the good narrowbands. It is available.
There are some others, but they are more expensive, and not widely distributed as a result.
Personally, I have used 23 different narrowband filters. I kept the DGM, TeleVue, and Lumicon. They yielded slightly different images of nebulae. I may get rid of either the Lumicon or TeleVue because they are very very close.
The DGM is very different and gives the best view of *some* H-II emission nebulae. [some people cannot tolerate the red stars, but you use a nebula filter to see nebulae, right?]
Edited by Starman1, 02 April 2023 - 02:51 PM.