The #50 is smaller, less dense, and a different shape than the #61. When you see it from the side, the #50 is tapered, so the bristles are an oval shape when you see it from the top. The #61 is completely round, quite a big brush, and is way more dense. I don't have the Real Techniques Multitasker, but I have tried a few of their other brushes. In comparison the the Sephora Pro, in my opinion, the Real Techniques are more densely packed, but are not as soft nor give the flawless finish. For smooth and sheer coverage I'd go with Sephora Pro. For a fast and seamless coverage go with the #61, for a slightly sheerer and more precise coverage, I'd go with the #50. The size you choose depends on your size preference, but both would work well. Hope this helps you a bit!
answered 2 months, 2 weeks ago