EOS Rebel T7 Focus won’t lock indoors/in lower light

[Gregkdeal]

Equipment:

EOS Rebel T7; Sigma 70-200 mm f/2.8 lens; Sigma 17-50 mm f/2.8 lens

My issue:

I bought a T7 in August 2024 — to replace a another EOS Rebel that failed on me — and the focus just recently started having difficulty achieving focus lock (and thus the shutter won’t release and take a pic) when I’m using autofocus indoors or in other low-light situations and have the dial set to full auto, shutter priority mode or other modes. This happens with both lenses and with any other lens I attach. 

In addition, I shoot night sports (mostly football) under stadium lighting, and I also just recently started getting lots of out-of-focus images when following the action in AI Servo mode (I use the 70-200 lens for this) and when the dial is set to the sports mode. 

Focus lock is fine when I’m in M (manual) mode.

With the football pics, I’ve had very good success in getting mostly in-focus images at games while operating in sports mode, until recently, when I have maybe 1 of 8 or so in the same action sequence come back in focus, and even then, the images are nowhere near as sharp as the were in the past. 

I certainly can shoot everything in M mode, but I wonder if the focus-lock issue might be pointing to another issue that might suggest additional problems will arise, even while in M. I mean, I don’t want to just let this go. As I said, it was fine in achieving focus lock in even super-low-light situations until just recently.

Notes:

I’ve cleaned the lens connections on both the camera body and lenses. I also reset the camera to factory settings.

[Waddizzle]

AI Servo doesn’t work well.  Don’t use it. 

[Gregkdeal]

Use single shot for my action pics?

[Waddizzle]

I forgot how it is named in your camera model.  Only use One Shot and AF Servo.  The AI Focus mode is the one with problems shooting sports.   

Your camera gives you a choice of one active AF point or all AF points activated.  Enable all points for AF Servo mode. It’s difficult to keep one AF point on a fast moving subject. Keeping your subject inside a box is easier until you get more practice.  

[deebatman316]

What are the FULL NAMES of the lenses in question. Is your Sigma 17-50mm the Sigma 17-50mm F/2.8 EX DC OS HSM lens. These older lenses have issues on newer cameras such as focus pulsing or not being able to lock focus. Is this the lens in question below yours. I had the same issue when I tried using this lens on the EOS 90D.

 

[Gregkdeal]

Yes. That’s exactly what I have. But, I’ve tried several other lenses, and I have the same problem. 

[deebatman316]

Will it focus on a bright sunny day. On something like a tree or something with plenty contrast. Make sure the camera is set to One Shot AF. The camera needs contrast to lock focus. The AF system in your camera is very slow. My old EOS 40D (released in 2007) also cannot lock focus in low light. Though my Canon 70-200mm F/2.8 Mark III does focus better on it. I noticed that newer Sigma lenses don’t play nicely with it for some reason. 

[p4pictures]

When you select sports mode on the mode dial the camera is setup to use AI Servo AF (on recent models this is renamed to just Servo AF) and also use all of the AF points. The Rebel T7 has a 9-point AF system and while all AF points can work at f/5.6, the central AF point is both horizontal and vertical line sensitive. This means it is better for tracking subjects. It is possible that when you use manual mode (M) that you also choose the central AF point. You can still select any other AF point or all. 

One possibility to try would be to select Tv mode, select continuous drive, AI servo AF, ISO AUTO and a shutter speed that suits the action. These settings give you more control of the camera than the sports mode.