Canon RF 100-400mm f/5.6-8 IS USM Lens vs EF-S 55-250mm f/4-5.6 IS STM Lens

[mglotspeich]

Hello,

I have had the Canon APSC T2i camera for years. I purchased the EF-S 55-250mm f/4-5.6 IS STM Lens when I received the camera (10 years ago). I now have a full frame r6 Mark ii camera and I am looking at purchasing the RF 100-400mm f/5.6-8 IS USM Lens ($699.00). With the cropped sensor I was getting 400mm out of the EF lens. If I purchase the RF lens for my R6 mark ii will it be an upgrade? Or should I get the adapter and use the old lens on my full frame camera? Or should I purchase the 600mm f11 lens instead?

Thank you! Mike, St. Louis, MO

 

[kvbarkley]

You probably do not want to use the 55-250 on the R6. Putting the -S lens on a full frame R camera will make the camera use only an APS-C chunk of the sensor. Get the R lens, which *will* be an upgrade.

[p4pictures]

I would go for the RF 100-400mm F5.6-8 IS USM lens for your EOS R6 Mark II, and then you can add an RF 1.4x extender to get you to a 140-640mm F8-11 zoom should you need the reach of a 600mm lens. You have the most versatility with the zoom lens.

[March411]

The RF 100-400mm and the R6 MkII are a great combination and adding the 1.4x if you can swing the expense would be a great play. I own this setup and it has provided many excellent captures.

[ebiggs1]

I am sure you really already knew the answer and should buy the RF 100-400mm f/5.6-8 IS USM. The EF-S 55-250mm f/4-5.6 IS STM Lens was never 400mm, you do know that? 

[mglotspeich]

Thank you for your advice!

[mglotspeich]

Thank you! With the RF 1.4x extender, wouldn't the RF 100-400 become a 140-560 mm?

Thanks again!

Mike

[mglotspeich]

Thank you, Marc for confirming your experience with the exact camera and lens with extender. Also, thanks for posting this beautiful photo! I will mainly be using the setup for bird photography.

Mike

[mglotspeich]

Hello.  I do not understand why you are sure that I knew the answer. If I knew the answer, I would not waste anyone's time asking a question. And yes, I did know that the EF 55-250 was never 400mm. But I ALSO knew that when attached to my T2i APS-C cropped sensor it is an equivalent to a full frame (35mm) 88-400mm lens. If I use the EF 55-250 on my full frame camera (using the RF to EF adapter) I will be getting 400mm out of the lens. I was asking if I should just keep the EF lens instead of purchasing an additional RF 400mm lens. 

Thanks.

Mike

[kvbarkley]

"If I use the EF 55-250 on my full frame camera (using the RF to EF adapter) I will be getting 400mm out of the lens."

At much less resolution.