Talk me into or out of the RF 50/1.8

EOSSpeedLite wrote:

FotogGuy 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.

You should not be surprised that a prime has better quality than a zoom lens. Zoom lens are a compromise design and will not excel at most apertures and focal lengths.

That's why I usually shoot with a prime. The exception would be a long lens like the EF 70-200 2.8 (non-IS and III). I love the compression and rendering of that lens.

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

Comparisons of different lens and focal lengths are hard to do and it doesn't seem most people are interested.

What I dislike about the RF50/1.8 is:

1. AF motor is noisy;

2. AF hunts in low light (more so on RP then other Rx bodies)

3. Bokeh can look a little too crisp (or what is often called nervous) at times (but that's a personal bias). Have a look at @thunderstorm's post above as an example.

I prefer my bokeh creamier like the RF50/1.2. or the Sigma EF50/1.4 Art; but I find my M43 Leica 25/1.4 too creamy. See below for a comparison on Canon RF bokeh.

But it's an easy fix in LR or C1 by masking and lowering clarity. For now, I have $2k extra in my pocket waiting the Sigma RF lens release.

Nervous looking bokeh on RF50/1.8

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https://www.instagram.com/hqphoto1/

Your blanket statement that suggests that a prime will always provide a better IQ than a zoom is wrong. Yes, in most cases, but not all. I've used many primes that provided worse IQ than some zooms, and I think most of us have.

Yes, I stated that generally primes have better IQ than most zooms. But the point we should be focusing (pun intended) on the results rather than just the technology. I rather use my primes (50/85/100) most of the time and zooms (16-35/70-200/120-300) when necessary. My 24-70/2.8 stays in my pelican case as I'm not a big fan of the quality or weight.

The RF 50 f1.8 (which I like a lot) may show better sharpening than the RF 24-105L f4, but there are other qualities that go into a lens, like rendering...in my experience, the L renders more pleasing than the RF 50 f1.8.

That is what I meant when I said the images look more creamy on the RF50/1.2 and too creamy on the M43/25/1.4. The resolution numbers provide one aspect of image quality which can be judged selectively.

I'm not a big fan of the RF24-105L or EF24-70ii but prefer the latter over the former. I'll take my primes anyday and tweak in post. It's tough to go from soft to sharp but easy to tweak sharp images for the desired look.

It's not right to compare a picture's bokeh shot at f1.8 vs the same scene shot at f1.2. Of course, the f1.2 bokeh is going to be smoother. The proper test is to shoot both at f1.8.

Agreed but it's more appropriate for a true IQ comparison to compare the 2 lens stopped down (eg. f/2.2 but then why spend the money on wider apertures?). The 1.8 stm is at a significant disadvantage wide open compared to the 1.2 stopped down.

For me, the 1.8 is my outdoors lens and the 1.4Art is my studio lens. I'm not fully invested in the RF ecosystem yet and generally agree with your comments in another post about very good portraiture results from the RF-STM consumer lens (with certain caveats.)