Has anyone tried out R7 with RF 200-800mm and a 2x teleconverter?

[raj0640]

I've recently purchased the RF 200-800mm lens for my R7. What an incredible reach!

I haven't gone out with it yet because its just been a couple of days since i got this lens.

There are a lot of videos on this combo of R7 with 200-800mm lens. But I think none with a 2x teleconverter added to this combo. Even though this is more than enough reach for wildlife purposes.

Does adding a 2x teleconverter impact the image quality a lot? What would be the purpose to add a 2x teleconverter to this combo? Is it even supported?

[kvbarkley]

This isn't an R7, or the new RF 200-800, but this works:

The purpose is to get a 400 to 1600mm lens, It really depends on your combination as to whether it is worth it. It might be fun to try, but a 1600 mm lens is hard to handle.

[shadowsports]

My advice.  Lose the TC and get closer

  🤣🤣🤣

[p4pictures]

Many years ago I had the chance to try the EF 1200mm f/5.6L lens on a crop sensor EOS 350D body. I can tell you that a good tripod was essential just to be able to find the subject as the angle of view is so narrow, you think you are aiming at one thing and are actually missing it to the left or right by a 50 feet or more. 

The 200-800mm lens is f/6.3-9, with a 2x that makes f/11 to f/18 as the maximum aperture, meaning that you will need a lot of light to use fast shutter speeds as high ISO performance is not the best with EOS R7. 

The instruction sheet for the RF 200-800mm says that RF extenders 1.4x and 2x can be used, but also that AF speed will be slower with an extender. 

[johnrmoyer]

I do not have that lens, or that extender, or that camera. I have, however, stacked EF extenders. I hope some of this might be helpful. 

As a guess, I might expect the 1.4x extender to be more useful than the 2x. https://www.rsok.com/~jrm/2021Sep08_birds_and_cats/2021sep02_bumblebee_IMG_3837c.html

As Brian mentioned, one gets a large F number and one needs bright sunlight.

There will less contrast for small features. There will be small aperture diffraction blur. At a long distance there will be distortion from varying densities of atmosphere.

For small aperture diffraction blur, a Richardson/Lucy deconvolution can remove some of the blur to the extent that the central peak of the Airy disk is nearly gaussian and the aperture is nearly circular (or, if one has a mathematical model for Airy disk and aperture shape). In the Canon DPP software or in the camera, "digital lens optimizer" does this. In Rawtherapee, "capture sharpening" does this. In Gimp with the GMIC plugin, there is a menu item for Richardson/Lucy. Canon DPP knows about the Canon extenders and does well with the digital lens optimizer. If there is high ISO noise, the digital lens optimizer will also sharpen the noise.

For the loss of contrast of small features, unsharp mask can increase the apparent contrast at edges.

A Bumble Bee (Bombus pensylvanicus) was on a Zinnia in Norman, Oklahoma, United States on September 2, 2021. I made this photo with a very old lens as an experiment. I purchased the lens in 2011 and nearly wore it out. For this photo, it was attached to a newer camera body with an adapter with two telephoto extenders. ; Canon EF-S 55-250mm f/4-5.6 IS ; Kenko TELEPLUS HD C-AF 2X DGX ; Vivitar SERIES 1 1.4X AF ; F/16

If the purpose of the photo is to document the sighting of a small bird far away, then the extender will put more pixels on a far away bird. For example, one is allowed to stand in a blind at Salt Plains National Wildlife Refuge, but not allowed to get closer. https://www.rsok.com/~jrm/2023Sep06_SaltPlainsNWR/2023sep06_birds_IMG_6195c.html

Least Sandpiper, Western Sandpiper, American Avocet, and Killdeer at Salt Plains National Wildlife Refuge in Oklahoma, United States on September 6, 2023 ; EF100-400mm f/4.5-5.6L IS II USM +1.4x III ; Kenko TELEPLUS HD C-AF 2X DGX ; 1120mm ; F/18 ; ISO 200 ; 1/256 second ; distance about 400 or 500 meters

For close subjects, the 2x extender will double the magnification without increasing the minimum focus distance. The depth of field will be very shallow and because the aperture is already very small it is not practical to increase the depth of field by increasing the F number. The low shutter speed can be challenging. https://www.rsok.com/~jrm/2022Oct07_birds_and_cats/2022oct05_monarch_IMG_0664c.html 

Monarch Butterfly (Danaus plexippus) on Zinnia in Norman, Oklahoma, October 5, 2022 ; EF100-400mm f/4.5-5.6L IS II USM +1.4x III ; Kenko TELEPLUS HD C-AF 2X DGX ; 1120mm ; distance about 2 meters ; F/18 ; ISO 2500 ; 1/166 second