Both lenses would be fine for "close ups" of flowers, insects, etc.
These lenses render 0.50X magnification (half life size) at their closest focus, which is considerably higher than non-macro lenses. However, it also is only half the magnification many other macro lenses provide. For example, the Canon EF 100mm macro lenses (all three versions) focus closer and render full 1.0X magnification (full life size). The Canon RF 100mm f/2.8L IS USM is somewhat unusual among macro lenses in that it renders even higher 1.4X magnification.
I don't know how much close-up and macro work you've done, you may or may not be aware..
Magnification, minimum focus distance (MFD) and working distance are among the most critical considerations when choosing a lens. Lens focal length and lens size determine the last two factors. Another is whether or not the lens extends or grows longer when focused closer.
Minimum Focus Distance (MFD) is measured from the sensor plane of the camera to the subject itself. "Working distance" is measured from the front of the lens to the subject, because a significant portion of MFD is occupied by the camera and the lens themselves. Any accessories on the front of the lens will also reduce working distance.
The RF 35mm has an MFD of approx. 7 inches.
The RF 85mm has an MFD of approx. 13.75 inches.
The RF 35mm is slightly under 2.5 inches long, while the RF 85mm is just slightly over 3.5 inches long. But both lenses increase in length when focused to their closest. The RF 35mm increases to 3.5" in length, while the RF 85mm increases to almost 5".
Out in the field, this means "working distance" of these lenses will be...
Around 2.75" for the 35mm lens.
About 8" for the 85mm lens.
This is without anything attached to the front of the lens, like filters, the lens hood, or the Canon NT-24EX Macro Twin Lite flash I often use.
If you want to push either lens to higher magnification it is possible to do so by adding macro extension rings between the lens and the camera. This reduces MFD at the same time it increases the length of the lens, further reducing working distance. When working distance is too short shy subjects like insects will fly away or hide or sting, while more cooperative subjects like flowers might often be shaded by you and the camera.
Either lens would be capable of shooting the following close-up (I used a 100mm)...
But a longer focal length with greater working distance is better for...
For the bee on the California poppy I used an old manual focus Tamron 90mm macro lens that was adapted for use on one of my Canon (an EOS 7D in this case).
Taking all the above in consideration... in my opinion, for macro and close-up photography the RF 85mm would be a much more versatile thanks mostly to it's significantly larger MFD and greater working distance. Especially if wanting to make higher magnification images by adding macro extension tubes. (But, to be honest, BOTH lenses are on my wish list! 😀)
Of course, this puts aside your other purposes for the lens.... landscapes. While an 85mm might be usable at times, a 35mm lens would likely be more useful for that purpose! HOWEVER, I would think you have landscape photography pretty well covered with your 24-105mm, don't you? A large aperture lens... the primary advantage of the RF 35mm... is rarely needed for landscape shots. I usually find myself stopping down instead.
FYI: "life size" macro shots.... also called "1:1" or "100%" magnification... means that on a full frame camera you're able to render an image of an area the same dimensions as your sensor, approx. 24x36mm or slightly less than 1x1.5 inches.
This is approximately the difference between half life size 0.50X (1:2)...
... and full life size 1.0X (1:!)
Both the above were shot with Canon EF 100mm f/2.8 USM Macro lens on an APS-C format EOS 30D, with a diffused Canon 550EX flash on an off-camera shoe cord.
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Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2), EOS M5, some other cameras, various lenses & accessories
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