DeanS Loc: Capital City area of North Carolina

May have to compromise in ways that lead to lower output in favor of the physical demands on an old body. Thanks for your response.

TriX Loc: Raleigh, NC

👍👍 I’m sure there are some applications I haven’t considered, but so far, I have found that night sports are the most demanding genre’ in terms of equipment performance of anything I have tried.

Think about it this way. If a 300 f2.8 requires ISO 6400 for a proper exposure (and 12,800 is more likely), then a 100-400 at 400mm and f5.6 will require between ISO 25,600 - 51,200. will your body produce usable images at that ISO? End of story.

Pistnbroke Loc: UK

I have two tam 100-400 and am very pleased but you need the tap in console or set the FFA at 400mm.

Only cost $500 grey.

ggab Loc: ?

Do you want the best or the cheapest.
This is the only question that needs to be answered.
The fact that you ask the question indicates, to me, that you want to be convinced that the cheapest is as good as the best.
It is NOT.
In fact in my testing, the Sigma was better than the Tamron.

ggab Loc: ?

Have you shot @ f/5.6 to f/8 during a night HS game with your camera's yet? If not, before you buy anything perhaps rent one of the len's and give it a go.

As was pointed out, the ISO will need to be high. It would be a shame to shell out money for a lens and not be satisfied with the results.

DeanS Loc: Capital City area of North Carolina

I din’t need to be convinced of snything, just seeking opinion based on experience. Tks

OllieFCR

Of course, the OP will not get results anywhere near the quality your 1DX delivers if he shoots at ISO 20,000.

OllieFCR

Unless you have a physical disability I would suggest you get over the weight issue and learn to use a monopod. You will not be carrying this rig that far shooting a football game and will have lots of rest between times you move. As with other types of photography, if you are not willing to do what is necessary to get the shot you probably shouldn't bother doing that type of photography. Personally, I would always go with the superior lens and it is hard to beat the Canon lenses, either the 300 or 100-400 for build quality and sharpness. Buy used or refurbished to save some money. You may like the results so much that you end up shooting a lot more sports than you thought you would.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

IMHO, I believe you have already made up your mind. I will quote you here, "I’m not crazy abt spending Canon money for a lens that would see so little shooting. I have read a couple comparos, and other than build quality and focus dist, the diff is not that great."

Just so you know ahead of time, the Canon lens is built to better tolerances than the Tammy, the Canon will be worth at least twice the Tammy about 4 years from now, (if that matters to you).
The Canon was designed to be used with your camera, the Tammy was designed to be used on several different camera platforms.
Yes, those who have bought the Tammy are pleased with the results.
Again, bottom line, I believe you have already made up your mind, your just looking for validation from those here. You will not get it from me.

DeanS Loc: Capital City area of North Carolina

Possessed by several devils of reduced mobility, etc, plus just simply being old and worn. Mobility has been an issue for a number of yrs, some every little bit more creates a bigger impediment.

DeanS Loc: Capital City area of North Carolina

Appreciate your response, and all others as well, but my question was and is, “How much diff is there in IQ between the two lens?” Tks.

georgeretired Loc: Manitoba Canada

ISO 20,000 and your pictures look like what was posted.....OMG would not have guessed

Gampa

All I can tell you about the Canon EF 100 - 400L IS II is that it’s an AMAZING lens ... both in terms of autofocus speed and accuracy and clarity.

TriX Loc: Raleigh, NC

Just to clarify, i don’t have the 1DX - the shots in the link I posted at ISO 20,000 we’re not mine, but the OP of the thread. There are other less expensive cameras that will perform as well at the same ISO, but they won’t do it at 12 FPS. It’s that combination of high ISO performance, fast frame rate and excellent AF performance that makes cameras like the 1DX/MK2 and Nikon D5 the choice of pro sports photographers.

amfoto1 Loc: San Jose, Calif. USA

See for yourself....

Test shots done with the two lenses, side-by-side (on 5DS-R, other cameras can be selected): https://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=1178&Camera=979&FLI=0&API=0&LensComp=972&Sample=0&SampleComp=0&CameraComp=979&FLIComp=0&APIComp=0

The Canon lens is noticeably sharper throughout the zoom range (5DS-R with 50MP is very "demanding"). The difference is most dramatic at the 100mm end. The Tamron has more chromatic aberration, too. (The Canon uses fluorite in it's optical formula, which reduces CA.)

The Tamron doesn't come with a tripod mounting ring. One is optionally available, at an additional $129.

Just looking at the numbers, the Tamron appears to be 1/3 stop slower at 400mm. But if you dig into the details of where the variable apertures change in each zoom's focal length range, you'll find that the Tamron is actually 1/3 stop slower all the time and even 2/3 stop slower at some of the longer focal lengths. Both lenses drop from f/4.5 to f/5 fairly quickly, around 135mm. The Tamron further drops to f/5.6 at 180mm and f/6.3 at 280mm. The Canon is f/5 through 311mm and then f/5.6 the rest of the zoom range. (Note: The Sigma 100-400mm is even slower than the Tamron. The Sigma also doesn't offer option of a tripod mounting ring. There are a couple third party rings, but they don't have the functionality of the Tamron and Canon rings. I mention this because I wouldn't want a lens that reaches 400mm without a good means of mounting it on a tripod.)

The lenses' max apertures might be really critical, trying to use either of these lenses to shoot night football games. You will be shooting wide open with them a lot. Hopefully the stadium has good lighting, because these lenses need it. When I need to shoot in lower lighting conditions I put away my Canon 100-400 II and get out my f/4 and f/2.8 lenses.

More complete review of the Tamron can be seen here: https://www.the-digital-picture.com/Reviews/Tamron-100-400mm-f-4.5-6.3-Di-VC-USD-Lens.aspx

Canon 100-400mm II detailed review: https://www.the-digital-picture.com/Reviews/Canon-EF-100-400mm-f-4.5-5.6-L-IS-II-USM-Lens.aspx

Sigma 100-400mm detailed review: https://www.the-digital-picture.com/Reviews/Sigma-100-400mm-f-5-6.3-DG-OS-HSM-Contemporary-Lens.aspx

What type of lighting does the football stadium have? I ask because some use lights that fluctuate rapidly, the way fluorescent do. Many recent Canon cameras have Anti-Flicker feature that works very well to counter-act this and prevent a lot of underexposed images. AFAIK, the 5Ds-R doesn't have Anti-Flicker, but I think the RP does. The RP also has much higher selectable and usable ISO.

Personally I wouldn't use a full frame camera for sports photography. (Plus I'd be reluctant to use a 50MP camera to shoot sports!) A 100-400mm on an APS-C camera can cover an entire football field, no matter where you need to stand to shoot. The 7D Mark II is ideal with it's high performance AF system. The 80D is a close second, with slightly higher usable ISO and a little more resolution (24MP versus 20MP), but not quite as advanced AF and a little slower maximum frame rate. The new 90D should be excellent, too, though I don't know that 32.5MP is needed for sports photography. It's AF system appears to be very similar to the 80D's, so I'd still give the edge to the 7DII for sports.