55-250mm lens won't focus on moving objects

[jaydensu7]

my 55-250mm focus on moving objects like planes and birds. I use a t7. Help🙏🏻

[deebatman316]

What is the Full Name of the lens in question Canon has released 3 versions of the lens. The most recent model is the STM variant. If you remove the lens cap the outer ring of the lens will say the entire model name. I have 2 example lenses below to help locate the full model name of your lens. The lenses below are just samples to help you identify the model name. Not if you have the lens below.

Full name on the outer ringFull name is visible when the lens cap is removed

[Tronhard]

Hi and welcome to the forum.

Hi Jay and welcome to the forum:
If your lens will focus on static objects, then the issue is not the lens.  It is how your camera's focusing system is set up.   The Rebel T7 does not have any face and eye tracking options like the R-series cameras, or the later higher end DSLRs such as the 5DIV and 90D.

I shot for years without tracking technology, and getting focus on moving subjects requires practice and you will be very unlikely to get a major hit rate if the subjects are moving erratically, extremely quickly, or against confusing backgrounds - such as foliage.

However there is a setup that may well be helpful.  It is called Back Button Focus (BBF) and involves taking the focusing function from the shutter button and having it function off a button at the back of the camera.  For this technique, you need to also set up SERVO focus as opposed to single or AI Servo focus. (BTW, if continuous focus is enacted, turn that OFF - it just wastes battery power).
see these videos on BBF and how useful it is:
From Canon: 

and for your model.
To set it up for your camera, see also the manual on P265 - here is a copy of the manual for your reference.
eos-rebelt7-1500d-im2-en.pdf

This works best when you have single point centre focus point selected, as it speeds up the focusing system's reaction time.  So, what you do is place the subject in the centre of the frame and TAP the BBF button for a static subject, or PRESS AND HOLD to let the focusing system (set to SERVO) will refocus to follow the subject.
See reference for photographing moving subjects on P70 and P98.  See also P97 and P99-100 for setting single point focus.

I personally have disabled touch screen functions as it is easy to distract the focusing system if your face touches the screen while shooting.  You can do everything via the Menu button or Q button and use the arrow keys around the SET button (which is the OK or ENTER key function in menus).

All of the photos below were shot using BBF with Servo spot autofocus.

60D, EF70-300@110mm, f/9, 1/1250sec, ISO-200 EOS 7DII, EF 70-300@286mm, f/8, 1/640sec, ISO-200
EOS 7DII, EF 100-400@189mm, f/8, 1/1000sec, ISO-200

[ebiggs1]

The model of lens you have isn't really a factor since all of them AF. But the question should be does your lens AF on normal stuff? You can waste your time fiddlling around and Youtubing but the solution is very simple.

Reset the camera to default. Now set it to P mode. Set ISO to 200 and set focus to One shot never set Ai-servo.. Daylight WB. Make sure the lens is set to AFand not MF Now on a nice sunny day go outside and shoot a couple dozen shots of various subjects like people, parks and trees, buildings, dogs just general stuff. Come back in and examine the photos if they are in fuce, there is nothing wrong with your lens and the problem lies with your technique most likely or an improper camera setting. If  that's is the case now you can Youtube how to use your camera with BIF and/or airplanes.

If the photos still come out OOF there is something wrong with your camera/lens.

[Waddizzle]

This is an entry level camera body, and yours is an entry level lens.  That means the gear isn’t on the same level as what professional photographers are using.  

You will get the best results shooting fast action by enabling all AF points and setting the AF mode as AF Servo.  Note, this doesn’t mean every photo will be a keeper.  No one has a 100% keeper rate. Anything over 50% is great with any gear.  

Never use AI Servo mode for action photography because it tracks too slowly, if at all.  

[deebatman316]

I think you mean AI Focus. In DSLRs Servo AF was called “AI” Servo. I don’t know why Canon dropped “AI” from the name and calls it Servo AF now.

[Waddizzle]

Thank you. You are correct.  Canon changes the name from one family of cameras to the next.  

It takes some practice and skill to keep a single AF point on a fast moving subject.  I had the best keeper rates with my T5 by enabling all AF points.  

There were only something like (9) AF points.  Enabling all of them causes them to disappear and be replaced by a fixed, diamond shaped box, which wasn’t very large.   

Keep the box on the subject and you should be good, provided the subject is the closest thing to the camera.  

The box was similar to the “ring of fire” that appeared in the 1D4. 

[deebatman316]

Yes my old EOS 40D had that same slow AF system.  All of the AF points were in the in the center and the AF system was slow. Especially in low light it wouldn’t focus at all. 

[stevet1]

jaydensu7,

I too use Servo and Back Button Focus. I mostly use single point, but with a moving subject, you might choose a Zone Af, and pick the group of focus points in the center of your screen.

Your subject should stay in focus as long as it's in that Zone and nothing comes between you and your subject. Hold the BBF button down and follow the subject.

Steve Thomas

[ebiggs1]

"No one has a 100% keeper rate. Anything over 50% is great with any gear."

I may not get 100% but if I only got and was satisfied with 50% I would find a different hobby as photography isn't working out for you.