Telephoto Lens For A R10

[Cantrell]

Buying a R10 with a RF-s 18-150mm lens. Is there a RF-s telephoto lens such as 100-400mm. Thank you in advance.

[Tronhard · Accepted solution]

Yes there is.  The  RF 100-400 USM and you can get a good-as-new one (with a warranty) from the Canon Refub store if you are in the US: Shop Canon Refurbished RF100-400mm F5.6-8 IS USM | Canon U.S.A., Inc.
You can see a review of it here: 

If this resolves your issue, please mark as resolved! 😊

[Cantrell]

Trevor,

Thank you for your response. Very helpful. Since Canon's crop sensor is 1.6X. Does that mean at 400mm it is actually at 640mm for a full frame?

Thanks again

[Tronhard]

The crop factor for an APS-C sensor actually applies to all and any lenses attached to it, whether they are marked as RF or RF-S, for example.  Thus the Equivalent Focal lengths of your lenses would be:
18-150 would render a Field of View equivalent on a FF camera to 29-240mm, and 
100-400  generate a FoV of 160-640mm equivalent.
Essentially, the focal lengths marked on lenses are a physical characteristic of the lens, and cannot be altered by the sensor.  What is different is what the sensor captures of that image projected onto it by the lens- thus generating a Field of View.
If you want the gory details on that read this article:
Equivalence: relating focal length and sensor size to field of view 

[ebiggs1]

"Does that mean at 400mm it is actually at 640mm for a full frame?"

What Trevor explained, very clearly, is spot on. It is important to know that a 400mm lens is a 400mm lens no matter what camera it is used on. The difference happens with the angle of view, AOV. It is a confusing topic and is not made any easier by the ole inner web. Lots of folks have no clue what they are talking about even some high up hot shots.

BTW, the AOV of a 400mm lens is 6 degrees. However, this debate goes way farther than just FL equivalent.  Is it better to use a cropper or a FF and crop in post editing? And, that answer is, yes and no!

[Cantrell]

EBiggs1,

Thank you for your response. This information from you and Trevor is very helpful. Hope, someday I will have a tenth of the knowledge that you and Trevor have.