RF 45mm f1.2 vs EF 50mm f1.4

[maysobano]

I shoot mainly primes, with a Canon R8 as my primary and 5DIII and a second camera. I'm trying to slowly move toward RF lenses with the future in mind. I purchased the RF 50mm 1.8, and while I love the physical size, I find myself using the EF 50mm 1.4 with an adapter when it counts. Does anybody have any experience with the new 45mm vs. the EF 50mm 1.4? All comparisons I see are with the red ring lenses, and I don't really have the budget for that considering this is mostly a hobby for me.

In addition to the 50mm, I do typically shoot with the EF 85mm 1.8 and EF 135mm 2.0. I also own the Sigma 50mm 1.4 Art lens, but due to its size, I rarely use it. And while absolutely sharper, I find backgrounds a bit busier and less dreamy than the 50mm 1.4. What I'm seeing about the 45mm sounds closer to what I want, but is there enough of a difference to make that change?

Any real world experience would be welcome! Is it worth the change?

[ebiggs1]

"I find myself using the EF 50mm 1.4 with an adapter when it counts...."

Sounds like you already have your answer.

[shadowsports]

I agree with my colleague.  It sounds like weight is of considerable importance to you.  The RF 45 at under $500 is not prohibitively expensive.  You could dump the RF 50 f1.8 to further offset the expense.  

The Canon EF 50 f1.4 is a little lighter than the Canon RF 45mm, but at the expense of adaption which negates the weight difference.

I'd say the real consideration should be between the Sigma EF ART and the RF 45.  From an IQ perspective, I don't believe you'll notice a difference, but you will notice a lens that weights 57% less + adapter than the Sigma ART on the front of your R8.  The lens coating on the RF 45 is going to be better than the 9yr old Sigma and the EF 50 f1.4 that was introduced in 1993 and manufactured through late 2015.