EF lens compatibility on models beyond the EOS Rebel T5 & T6

[Tko2007]

I am a true amateur. I have a rebel t6 and t5. I mostly shoot hockey games, football, cheerleading and equestrian events. I’m going to be purchasing a 70-200 2.8 tamron lens for these events. My main question is this.

I would like to upgrade to a better canon body what is suggested? Will my existing lenses fit? 
Any information will be greatly appreciated 

thanks

[rs-eos]

What specific lenses do you already own?  And what is your budget?

Note that in terms of camera body recommendations these days, it will be the Canon R-series of cameras.  However, to use existing EF (or EF-S) lenses, you'd need an adapter.  And when it comes to third party lenses such as Tamron, there may be incompatibility issues.

[Tronhard]

As Ricky very correctly said, it's helpful if we have some idea of budget.  Also, it would be helpful to know what other lenses you have to get an idea of how invested you are in the crop-sensor DSLR platform of which the Rebel line is an example.
Given you have decided on a lens, the Tamron is designed for both full-frame and crop-sensor DSLRs - of which you have one of the latter.  If you were looking to stay in that platform - i.e. a crop-sensor DSLR, then I would recommend the EOS 90D.
However, the movement and development is towards the Mirrorless Interchangeable Lens Cameras (MILCs) that offer more features and will allow you to develop further in the future.  The DSLR platform is not going to be developed further - the Canon EOS R range of MILCs is now where the market is moving.

If you decided to work with a MILC body, then I would reconsider the whole issue of lenses as the R platform uses a new lens mount that offers benefits over the old DSLR one.  In particular, it offers face and eye detection and tracking, and when using some bodies and lenses will give both Optical Image stabilization that is built into the lens, along with In Body Image Stabilization which, as the name suggests, has a very efficient stabilization system built into the body.  The benefit of these is that you can take images without camera shake being apparent in low light or with slow shutter speeds.  Also, the sensors on these cameras are now much more developed than your current units.

If you decided to go that way, you have a choice of APS-C or Full-Frame.  If you are referring to ICE hockey games, the likelihood is that you are shooting in relatively dim light, so a lens with a smaller f/stop value is advantageous - I assume that is why you chose the Tamron lens you mention.  You could still actually continue to get that lens, and it will be able to adapt to the R-series bodies via an EF-RF adapter, although you will be unlikely to get both the IBIS and OIS to work together.

In the Full-Frame range, I would suggest the Canon EOS R8 or an R6.  The latter is a slightly older unit but has the IBIS, while the R8 has a newer sensor and no IBIS, both may be likely to be about the same price.  There is an R6 unit on the Canon Refurbished site as an example: Canon Refurbished EOS R6 Camera Body | Canon U.S.A., Inc.

If you have some good lenses for your existing cameras and want to use them, I would continue with the APS-C R-series bodies.  In that case the R7 is the current top of the line camera.  Again, it will take your current EF and EF-S lenses via the EF-RF adapter.  So you could use them on all your bodies.

Ultimately getting lenses designed for the R mounts is best, but before delving into that, I will wait for feedback on your current situation as regards lenses and budget.

[Tko2007]

As of now I’m using a Sigma 18-300mm 3.5 - 6.3 

and

Tamron so 150-600mm f/5-6.3

[Tronhard]

Thanks for that information.
While the Tamron 150-600 is directly able to work with FF sensors, the Sigma 18-300 is designed for APS-C.
If you stay with APS-C bodies, then you can use the lenses you have on the R7 (for example) with just the EF-RF adapter.  If you go to a FF sensor - which has some advantages in low light, but does not give you the Field of View boost for telephoto lenses, you can use the 150-600, but would have issues with the Sigma.
If you went full frame R-bodies, you could consider the RF 24-240, which is an excellent lens and will cover a lot of general photography, it will combine its OIS with the R6's IBIS, for example.  Again, we don't know your budget.

[ebiggs1]

" I’m going to be purchasing a 70-200 2.8 tamron lens for these events."

Unless you intend to stick with your Rebels this lens is a bad idea. If you are going R series in the near future go with RF lenses, too.

[ebiggs1]

"As of now I’m using a Sigma 18-300mm 3.5 - 6.3"

For whatever it s worth the Tamron 70-200mm f2.8 G2 is a huge improvement over that Siggy.

[normadel]

How about a simple answer?

Any EF or EF-S mount lenses will work with Rebels and other crop-sensor DSLR bodies (xxD models, 7D). A full-frame body will only take EF-mount lenses.

EF and EF-S lenses can be used on R mirrorless bodies, with an EF/EF-S-to R mount adapter.

"A better camera" opens the biggest can of worms you can imagine. You need to think about why you need "better", what that means to YOU, etc. Where are the T5 and T6 lacking for your use? How much money do you have? Etc. etc.

[Tko2007]

Thank you absolutely best advise I’ve gotten 

[Tronhard]

I agree with Normandale's point about assessing your needs.  I would suggest checking out this article on advice for buying gear and consider the questions it poses.Questions to consider when buying camera gear .

That said, you might want to consider this, which was not posed by the 'Keep it simple' element.
One thing that might be worth considering is the benefit, if any, of improved performance in lower light situations - I am thinking of your comment about photographing hockey - by which I assumed you meant Ice hockey, which I also assume is played indoors and thus may be challenged for light intensity.
Full-frame sensors generally perform better in low-light situations, especially those with a lower pixel count.  I tested the R6 and R6II, which sit at 20Mp and 24MP against the R7 (APS-C crop sensor) at 32MP, but the pixel density of which is like using a 83MP Full Frame sensor - which no camera maker has successfully achieved.  As a consequence the images tend to be noisier on the R7 than the FF cameras, which can also work well at higher ISO values.   So, if you are seeking to improve low light performance, then a FF sensor in the 20-24MP range (i.e. either version of the R6) is going to help you.
If you do that, your Tamron150-600 will work fine, however your Sigma 18-300, while it will physically attach to a FF R body, will have a significantly reduced resolution - being cut down by a factor of 2.56 and reducing your sensor performance to single digit MP.   For that reason, I suggested the RF 24-240 lens to replace the Sigma one.

Yes, a simple answer is nice, but life isn't always that simple and you can get caught on what might appear to be details.