I used the RF 45mm F1.2 STM with two different cameras. I took most of my sample images with the EOS R6 Mark III, and ran Imatest labs with the 45MP EOS R5 Mark II. The RF 45mm delivers good central detail at its maximum aperture (3,100 lines) and captures sharper detail at narrower apertures. At f/1.4 it ticks up slightly (3,400 lines), and takes a leap to excellent at f/2 (4,000 lines), f/2.8 (4,100 lines), and f/4-5.6 (4,900 lines). Edges aren’t as crisp as the center at any aperture, but are good enough for landscapes in the f/4-11 range (2,700-3,000 line). I don’t count the soft edges as a problem; at wide f-stops, edges are naturally blurred by bokeh, and the RF 45mm is sharp enough across the frame when stopped down.
EOS R6 Mark III, f/1.2, 1/640-second, ISO 100 (Credit: Jim Fisher)
As mentioned, the lens relies on digital corrections to remove distortion and compensate for a vignette. If you use your camera for JPGs, HEIFs, or video, the profile is applied automatically and transparently. If you opt for Raw capture instead, you’ll want to apply a lens correction profile, as photos show noticeable barrel distortion and darkened corners without one. The most recent releases of Adobe Lightroom and Lightroom Classic support the lens. However, if you use a different workflow app, it’s worth verifying that it also supports the RF 45mm.
EOS R6 Mark III, f/3.5, 1/8,000-second, ISO 100 (Credit: Jim Fisher)
I’m quite impressed with how well the RF 45mm F1.2 controls flare, which can be a real problem with extra-bright lenses. I made several images directly into the sun and see no noticeable drop in clarity. I am able to induce false color if the light hits the lens at the right angle—you can spot a purple orb in the preceding image—but a slight shift in angle is enough to minimize the effect. Reflections are more prominent at narrower apertures, so it’s also worthwhile to try opening the iris if you want to avoid the effect. On the other hand, you can use a narrow aperture to create a sunstar effect in bright points of light, but doing so will exacerbate any ghosting. Therefore, adjust the camera angle to minimize this effect. The following image represents a worst-case scenario for reflections.
EOS R6 Mark III, f/16, 1/640-second, ISO 100 (Credit: Jim Fisher)
The RF 45mm F1.2’s biggest strength is its bright, background-blurring aperture. The lens catches just a tiny sliver of the world in focus when used wide open. The blur itself has a busy character, a look that some photographers embrace but may turn off those who prefer smoother bokeh. I see purple and green false color (a type of longitudinal chromatic aberration) and double-edged highlights with a cat’s-eye shape, both of which add texture to the background. On a positive note, the PMo lens element avoids the onion-skin highlight texture that glass aspherical elements typically create.
EOS R6 Mark III, f/1.2, 1/100-second, ISO 100 (Credit: Jim Fisher)
Backgrounds take on more definition at narrower apertures, but the lens also shows less LoCA, and highlights take on a uniformly round shape in the f/2-4 range. If you’re looking to get cleaner bokeh from the lens, it’s not a bad idea to ratchet the aperture down to f/2; you’ll still get plenty of blur (especially when you’re focusing near the lens’s minimum working distance). This gives the RF 45mm F1.2 a leg up in flexibility versus the RF 50mm F1.8, which also shows some false color wide open, but requires you to stop down to f/2.8 to minimize the effect.
EOS R6 Mark III, f/2.8, 1/4,000-second, ISO 100 (Credit: Jim Fisher)
