RF 100-400 vs Sigma 100-400

[kehanopni]

Hi. I'm planning on substituting my EF-S 55-250 II, since i recently upgraded my old camera to an RP, and it's not that nice shooting on crop only. I've narrowed the options to both the RF 100 400 (which i don't like for the low aperture) and the Tamron 100-400 (which i'm not sure if it will work out properly due to being 3rd party and EF). Reviews don't help me pick either. I use it for "general" long range photograpy and some action (dogs running lol, and planespotting. If anyone can give me some clarity on this? Other options are welcome on that price range. Thanks!

[SignifDigits]

I am assuming that you're comparting the Sigma 100-400 f/5-6.3 DG OS HSM Contemporary lens for EF vs the Canon RF 100-400mm f/5.8-8 IS USM

f5-6.3 vs f5.6-8 is not a huge night and day (pardon the pun) difference since Sigma claims up to 3 to 4 stops of stabilization and Canon claims up to 5.5.   It would also depend upon how much you shoot at 400mm vs 100mm.

I used a 2x extender on mine and it was fine for solar shots in the center, but I wasn't terribly happy with the overall sharpness of that solution, and wouldn't personally recommend the 2x extender. I hear people have more success with the 1.4x extender, and I know that DPP has lens profiles for both.  I'm super happy with the RF 200-800 f6.3-9 IS USM that I got refurbished, but it's definitely in a bit  higher price range.

I've heard of few issues using the EF adapter and EF lenses in general. The balance of the camera will be more weight forward with the adapter, if that bothers you.   Sorry that I cannot comment on the Sigma/Tamron more extensively. 

If it were me and the weight and size were not an issue, I would consider a good used Canon EF 100-400 f/4.5-5.6 L IS ii USM lens.  Used in good condition for $1,200 and in about the same price range I expect that would be significantly better image quality than either of your options, though it would also be significantly larger and heavier.    Again, that's just me.  You seems to have other priorities than me, which, is, of course great!

Thanks for dropping in and asking.  Let us know what you decide upon.

[March411]

This one is fairly easy for me, I owned the Sigma 100-400mm (EF) and loved the lens, it was great on my 90D and the 5D Mark IV. I did have to update the firmware when I went to R series bodies due to having challenges with the focus locking, it racked quite a bit. Once the firmware update was completed it was a solid lens. 

I rented the RF100-400mm just to see what I was missing. It was much lighter, the focus was much faster and it was every bit as sharp. I also liked the color I got out of the RF but they say that is subjective. I traded the Sigma for the Canon and haven't looked back and since I bought new I had the one year limited factory warranty (but I buy and extend CarePaks on all my Canon Gear).

Between the three only the Tamron will give you the stop you mentioned, Sigma and Canon are the same.Only you know if that one stop going to make that big of a difference.

I would probably buy a new RF with a warranty and as much as possible keep the lenses bodies you purchase in the same system.

In this instance you'll end up with less weight and warranty. Buying used at the same cost and getting heavier lenses with a 3rd party warranty (maybe) may not be a good option if you plan on continuing to stay with Canon as your primary gear.

Just some thoughts I had when I looked at the 100-400mm lens.

• RF100-400mm F5.6-8 IS USM New $750  635g  or 1.4 lbs - Warranty
• Sigma 100-400mm f/5-6.3 DG OS HSM Contemporary Used $750 1,135g or 2.499 lbs
• Tamron 100-400mm f/4.5-6.3 Di VC Used $775 - 1,135g or 2.499 lbs