No surprise, the Epson tackles really dark scenes, really well. I figure you are going up $1000 to find a projector that can do as well, or better, and it mostly blows away anything that costs the same or less (in terms of handling blacks). Being a black level fanatic – looking for the projector that really shines when handling really dark scenes (not brightly lit city nightscapes) – I knew going in that the black level performance of the Home Cinema 5050UB is a cut above - any projectors that cost the same or less, would prove unmatched. The closest tries would be the older, just discontinued UBs. BenQ's new HT3550 (DLP) (which I like for folks that can't afford this Epson UB), also has a dynamic iris, and is a lot better than other under $3000 DLPs to date, but still no match for this Epson.
It’s true that when there’s more than very little ambient light present, that the differences when viewing two projectors with different contrast and black level performance, that the differences are noticeably diminished by the ambient light.
So, to simplify: If you are going for a living room, media room, family room type of setup with less than perfect lighting control, you will not get the same extra bang for the bucks on really dark scenes, if you choose the HC5050UB instead of the less expensive HC4010.
However, if you are putting together the classic home theater/man cave (ok, in this day and age, let me amend that to “person or people cave”), with dark surfaces and great lighting control, I’ll always recommend spending the extra for the better black level performer, in this case because prices are reasonably close, and you should get a number of years enjoyment out of your new projector! If your room is mixed - less than great control in the daytime, but really darken-able at night, then for that nighttime viewing you'll get the full extra benefit, even if you get a slighter benefit with some room ambient lighting.
The Epson HC5050UB, thanks to its dynamic iris do a rather good job, despite many of the 4K UHD DLPs having more native contrast. That’s because the native contrast differences aren’t really huge, and because the Epson has a dynamic iris to help lower black levels on those dark scenes. We need to see more DLP projectors use dynamic irises, to improve their black levels.
I have mentioned the Acer VL7860 in other reviews, as the only DLP that’s 4K capable of the more than a dozen we’ve reviewed, that offers a dynamic iris (or rather has their laser light engine emulate one, something Sony does on their $39,999.99 native 4K laser projector). That Acer, which sells for about $2000 more has the best black levels of any of the DLPs we’re talking about, because of that “dynamic iris.” Unfortunately, lamp based projectors can’t really dim their lamps like an iris (many have tried – Dynamic Black), because they can’t lower blacks significantly because lamps dim and brighten too slowly.
When one tries to get the same range of a mechanical dynamic iris, by using lamp dimming, you’ll normally see very visible pumping of the image – as he image slowly brightens or dims to match the scene, but is usually playing catch-up, and is therefore very noticeable and distracting. As a result, we typically don’t even recommend using the Dynamic Black feature found on most home DLP projectors be they 4K UHD or lower end.