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Canon RF 100-500 or Tamron SP 150-600?

I'm new here and I did some research before I opened this new thread. I didn't find a topic related to the question I have, hence this new topic.

Last year I upgraded to the RF Holy Trinity of Canon at f/2.8. I traded in my equivalent Tamron f/2.8 G2 lenses. I was happy to see that I got very good trading in deals from my local photo shop, although I still had to cough up a lot of money. But the RF's are brilliant!

Now I'm in doubt whether to trade in my (fourth and last) Tamron, the SP 150-600mm Di VC USD Canon for the Canon RF 100-500mm f/4.5-7.1 IS USM or not.

The Tamron has 100mm more focal length and at 600mm it still has f/6.3 whereas the Canon has "only" f/7.1 at 500mm. It would feel like it would be a downgrade. But is it a downgrade, apart from the 100mm less foacal length?

Maybe it's a stupid question but before coughing up another substantial amount of money, I would like to be well-informed. Thanks so much in advance!
 
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I'm new here and I did some research before I opened this new thread. I didn't find a topic related to the question I have, hence this new topic.

Last year I upgraded to the RF Holy Trinity of Canon at f/2.8. I traded in my equivalent Tamron f/2.8 G2 lenses. I was happy to see that I got very good trading in deals from my local photo shop, although I still had to cough up a lot of money. But the RF's are brilliant!

Now I'm in doubt whether to trade in my (fourth and last) Tamron, the SP 150-600mm Di VC USD Canon for the Canon RF 100-500mm f/4.5-7.1 IS USM or not.

The Tamron has 100mm more focal length and at 600mm it still has f/6.3 whereas the Canon has "only" f/7.1 at 500mm. It would feel like it would be a downgrade. But is it a downgrade, apart from the 100mm less foacal length?

Maybe it's a stupid question but before coughing up another substantial amount of money, I would like to be well-informed. Thanks so much in advance!
No, it is not a downgrade. I had the SP 150-600mm when it first came out and then the Sigma 150-600mm C, which was sharper. The RF 100-500mm is significantly lighter, sharper and superb AF, and better IS and weather sealing. Whether you trade it in depends perhaps on what you are shooting. I personally would take the RF 100-500mm every time over the Tamron for sharpness, speed of AF and weight. But, you might consider keeping it and buying in addition the RF 100-400mm, which is very light, cheap, sufficiently sharp, very good AF and excellent close up.
 
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Thanks Alan!! Now I am used to my current three Canon RF's, I can easily relate to what you say about AF and sharpness of the RF 100-500. But what about the fact the Tamron is faster at an even more large focal length of 600mm? That is my "concern".
Try it out. I remember that my EF 100-400mm II + 1.4xTC at 560mm was sharper than my Tamron 150-600mm at 600mm and outresolved it. My RF 100-500mm at 500mm outresolved my EF 100-400mm II + 1.4xTC at 560mm. So, if my experience is anything to go by, an RF 100-500mm at 500mm will outresolve the Tamron at 600mm and be better in every other respect and be only 0.3 stops slower. The RF 100-500mm is a superb, expensive lens, and the 150-600mm was a breakthrough at the time it was introduced at a very reasonable price.
 
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I don't have much to add to what Alan said, but I wanted to confirm what he says. I've had the same Tamron and Sigma lenses and I experienced the same results. EF 100-400mm II with 1.4x TC at 560mm was sharper than the original Tamron 150-600 at 600mm. I found the Sigma 150-600mm C was sharper than the original Tamron 150-600mm. I haven't found myself wishing the Canon 100-500mm was faster than f/7.1. And Alan's comments in various threads are the reason I bought the RF 100-400mm a while back. I've enjoyed using it. Good image quality and AF, and a nice size/weight.
 
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I've always shot with Canon body's, but have owned lots of 3rd party glass, which I really liked. Plenty of Canon glass too. Agree with everything that was said above. I prefer Sigma over Tamron, more for design and function over IQ which I fully acknowledge the G2's have. After moving to MILC, I thought I would transition slowly to RF. For still photography I think adapted EF glass works well, but I determined quickly that my Sigma lenses worked well, but not as good as native RF glass did. I also found out that AF on Tamron's 24~70 G2 didn't work at all in Cinema mode on the R5 C. Today I have fully embraced and am completely satisfied with my accelerated switch to RF.

Adapted glass can work, but in the end, RF glass with R body's is the way to go. I have the 150~600 C, but the 100~500 even at f7.1 is so hard to beat. Add a 1.4x TC (even if you can only use 300mm and above) is still worth it over the weight alone of the Sigma. On my wish list is a RF 100~500 mkII or introduction of the recently patented 200~500 with built in TC. We will see, but I would not hesitate going Canon RF over adapted Sigma. I think you will be more satisfied in the long term with this decision if your budget allows.
 
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