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Improving Autofocus in Low Light Situations with Canon EOS R6 and RF 24-105mm f/4L IS USM Lens


Hello everyone,

I recently purchased a Canon EOS R6 and I'm having some trouble with autofocus. Specifically, I'm finding that the autofocus seems to struggle in low light situations, and I'm not sure how to improve it.

I'm using the camera with the RF 24-105mm f/4L IS USM lens, and I've tried a few different autofocus modes, including "One Shot," "AI Servo," and "Face Detection." However, in low light situations, the autofocus often seems slow or inaccurate, and I end up with a lot of out-of-focus shots.

I've read that using an external flash or adding more light to the scene can help with autofocus in low light, but I'm not always in a situation where that's possible or practical.

Are there any other tips or tricks for improving autofocus in low light situations? Are there specific settings or modes that I should be using? Any help would be greatly appreciated.

Here are some additional details about my setup and shooting conditions:

  • I'm shooting in RAW format
  • I'm using the camera in manual mode with auto ISO
  • The scenes I'm shooting are often dimly lit with no available light sources to add to the scene
  • I'm using a tripod when possible to minimize camera shake

Thank you for your help.🙏



The technical specifications document for the R6 lists the AF EV range. They base the specs on One Shot AF with center AF point. 

John Hoffman
Conway, NH

1D X Mark III, Many lenses, Pixma PRO-100, Pixma TR8620a, LR Classic


The minimum aperture of f/4 will be the limiting factor here.   Are you at least using the center focus point?  That would be the most sensitive one.  From the specs, the camera can operate at -6.5 EV under the following conditions:

"When using f/1.2 lens under the following conditions: center focus point, room temperature, One-shot AF, ISO 100. This does not apply to RF lenses with DS (Defocus Smoothing) coating."

Do you have access to any other lens with a wider aperture?  e.g. an f/1.4 aperture would allow eight times the light as f/4


EOS 5D IV, EF 50mm f/1.2L, EF 135mm f/2L, 600EX-RT (x6), ST-E3-RT
EOS C70, RF 24-70 f/2.8L IS, EF-EOS R 0.71x

Hi CarolJenkins,

We are not sure how much photography experience you have.  The R6 and 24~105 f4 is a capable combo.

What John and Ricky are pointing out is that a lens with a f4 aperture can limit the cameras AF ability in extreme low light situations.  Even with a slow shutter speed and increased ISO, the camera may experience difficulty locking on to something and achieving focus.  Using a tripod is a good idea, as the smallest of movement under these conditions can cause blur. 

If you cannot use a flash or lighting, the only solution is a faster lens.  The big brother to the 24~105 is the RF24~70 f2.8.  Depending on what you are shooting, other options may be available.  We hope this information helps with the issues you are experiencing.  

Bay Area - CA

~R5 C ( ~RF Trinity, ~RF 100 Macro, ~RF 100~400, ~RF 100~500, +RF 1.4x TC, +Canon Control Ring, BG-R10

~DxO PhotoLab Elite ~DaVinci Resolve ~Windows11 Pro ~ImageClass MF644Cdw ~Pixel 8 ~CarePaks Are Worth It


Have you looked into the RF 28-70mm F/2L USM lens. This lens will allow more light into to the camera to allow the camera to focus faster. Also you won't have to use a slow shutter speed. This also allows you to use a lower ISO resulting in cleaner pictures. The AF Assist Beam ONLY works when the camera is set to ONE SHOT. The AF Assist Beam will NOT be emitted when set to Servo AF. Does the camera body's AF Assist Beam fire when the camera can't lock focus. IF you can use an external speedlite the IR AF Assist Beam WILL NOT FIRE. The camera cannot "see" the IR AF Assist Beam. Instead a Canon speedlite will fire an Intermittent AF Assist Beam. Note depending on ambient lighting the AF Assist Beam may be projected by the cameraInstead of the speedlite depending on the ambient lighting.

EOS R Series AF Assist Beam Protocol 2.png

EOS R Series Intermittent Flash AF Assist Beam.png


Current Gear: EOS 5D Mark IV, EF 16-35mm F/2.8L III USM, EF 24-70mm F/2.8L II USM, EF 50 F/1.8 STM, EF 85mm F/1.8 USM, EF 70-200mm F/2.8L IS III USM, 470EX-AI & 600EX II-RT

Retired Gear: EOS 40D & Sigma 17-50mm F/2.8 EX DC OS HSM


Current Gear: EOS 5D Mark IV, EF F/2.8 Trinity, EF 50mm F/1.8 STM, EF 85mm F/1.8 USM, 470EX-AI & 600EX II-RT

Retired Gear: EOS 40D
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