Talk me into or out of the RF 50/1.8

bodeswell wrote:

Texchappy wrote:

FotogGuy wrote:

Texchappy wrote:

For a while, I planned to get the the RF 50/1.8 stm. lately however, I’m leaning away from it. Against it is some sub par reviews, mushiness away from center, and it not being a zoom*. For it are cost and aperture **. So talk me into or out of it…

You are overthinking this decision. I would say get the RF50mm f/1.8 for the following reasons:

1. The 50mm will have better image quality than your 24-105L. Optical limits measurements will show that:

The RF 50/1.8, using f/2.8 or higher apertures, has better line resolution than your RF 24-105/4 at ALL focal lengths and ALL apertures and ALL areas of the lens.

Line resolution of RF24-105/4 at 40mm

Line resolution of RF50/1.8

2. Image quality of the 50mm will be better in low light conditions than your 24-105mm as it will have 2.7 stops more light (or more as you will have to add another stop to use f/5.6 at 70mm or longer due to the softness of the 24-105).

3. You can learn to crop out the softness apertures of f/1.8-f/2.5 by framing slighter wider. I process in mostly 4x3 or 4x5 so most of the soft corners are natually cropped out and aren't visible.

4. Bokeh is great on the RF50/1.8 and weak on you L lens.

5. You didn't say what you are shooting, but softness can be an advantage is certain types of subjects. Portraiture of older subjects with wrinkled or blemished skin come to mind. The corner softness can also be thought of as a natural vignette.

Here are the resolution measurements for both lens. (for the resolution charges, higher resolution is better).

RF24-105L/4.0 line resolution data from OpticalLimits

RF50/1.8 line resolution data from OptimalLimits

*Been shooting primarily primes on Fuji for the last decade. Being in a wheel chair while shooting, I’ve found zooms much more convenient. I currently have the RF 24-105L & RF 100-400.

**It’s hard to beat $200 but if I never use it then it’s still a waste. However, having nothing less than f4 is new to me.

Provided you can work with a fixed focal length lens, the RF50/1.8 will provide great quality above f2.8 over your current L lens.

Guess I haven’t seen any direct comparisons but the 50/1.8 always have caveats for IQ and the zoom seems to have pretty glowing reviews.

*For the 50 it’s always good for the price with softness and IQ mentioned as downsides versus the L glass.

The RF 50 f/1.8 is only soft in the corners wide open. For many typical shots that will not matter because there won’t be anything important in the corners. If you stop down to f/4 it will be extremely sharp right across the frame. Outside in the daylight you probably will either not care about the corners or you will stop down. Either way you win. If you will never use it there is no point in buying it, but the business about softness and IQ should not deter you otherwise. Sure the RF 50 mm f/1.2 is better at wide apertures, but it is also ~15x the price and a lot heavier.

Agreed, and for portraits, the soft corners almost never matter.  And if the eye of the model is near one of the orders, and you focus there, that corner will be sharp while the middle soft but that soft middle is not a problem.

I think soft corners only matter if there are several models in the portrait and some of them are near one or more corners, but even then, such a group picture would necessitate F4  or f5.6 or f8 or even f11 which would mitigate soft corners to a convincing degree.