EOS RP pics taken with RF Extender 2.0 come out blurry

[Tims32ford]

In trying to take photos of a bald eagle in the top of a pine tree…about 100 yds away, every single image was out of focus.  Absolutely nothing is in focus…the eagle, NONE of the pine branches/needles.  I’m using a Canon RP with the RF 100-400 coupled to my just acquired refurbished (by Canon…purchased direct from Canon) RF Extender 2.0.  I removed the Extender and shot the same eagle/same location with probably just a 1 minute delay to remove and cap the extender.  Using just the RF 100-400…every image is SHARP…can be blown up to see just the eagle’s head…image is still SHARP. The RF body recognizes the lens and the extender.

Yes, AF switch is on.

Is there a chance the refurbished extender is faulty?

[jrhoffman75 · Accepted solution]

Can you post the two original images to One Drive or Dropbox so we can examine them? 
Based on what you just posted it sounds like you are enlarging the image too much. I don’t know about the RF 2X extender, but the EF 2X extender image quality isn’t great; additional “enlargement “ by cropping really degrades the image. 

[jrhoffman75]

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@Tims32ford wrote:

Ok…just tried another test…everything at equivalent 800mm…photo of dry tree branches about 30 ft away…using in camera magnify set on 4x…branches are in focus…using everything the same…image of pine tree branches about 300 feet away…using in camera magnify at 4x…image is clearly out of focus.  Still stumped.

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Did you refocus on the 300 ft trees or just change where you were viewing the captured image?

If you were in focus at 30 feet the depth of field would not have you in focus at 300 feet

[Tims32ford]

Watched through the viewfinder, while the lens refocused at 300 feet…did not trip the shutter until the lens had stopped focusing…absolutely NO breeze, so tree branches were stationary.  Confusing for me..I know the extender has absolutely nothing to do with the focus….all things being equal…if it’s in focus at 30 feet…it should be able to focus at 300 feet

[Tims32ford]

Hey, went on to gallery, tried to see how to upload images…can’t seem to see how to upload them….of course trying to do this from my iPhone…images were transferred from my RP to my iPhone gallery.

[p4pictures · Accepted solution]

There are a couple of key points here.

1. The lens manual mentions that you should attach the extender to the lens first, then put the lens + extender combination on the camera.
2. The size of the active focus area - where you can position the AF point, or where the camera can focus is reduced when an extender is used. Often you will see a smaller rectangular or square frame in the centre of the LCD/EVF to show this usable area. 
3. The lens will focus slower with an extender.
4. Make sure you do not have Continuous AF enabled.
5. Remember that the EOS RP cannot intelligently detect animals and birds. So you will need to use 1-point AF or AF point with expansion and position that on the bird's head to get the camera to focus on it.
6. Adding an extender to any lens reduces the optical quality of the lens. A 2x more so than a 1.4x. 
7. If you are still needing to crop in so that only 5MP remain, then you are looking at just 20% of the image area. 

[Tims32ford]

Brian,

THANK YOU for the detailed info…to confirm…I do connect the extender to the lens first…reverse order to remove…had noticed the lens seemed to focus a tiny bit slower with the extender…I was NOT using single point or expanded AF, will change to that for next attempt…HOWEVER, shouldn’t the branches the eagle was sitting on that the camera did focus on…be in focus? They aren’t in focus either.  Continuous AF is disabled.

Glad to know the info about the smaller focus area with the extender.

I did crop to the 5mp, mainly to see how sharp the image was with the extender.  Seems weird to me that I can crop the image taken without the extender…same lens at 400mm…and crop that down to 2mp, and the image is still sharp.  I’m betting the is some physics involved here that I don’t know yet.

Thanks again!

[p4pictures]

Make sure you have enough shutter speed. For a lens at 800mm you will need 1/1800 minimum though to test the lens it is best to go for 1/1000 or more to rule out shake causing the problem. Image Stabilizer in the lens does help, but if the subject is moving then it cannot overcome that. 

[Tims32ford]

Thank you for this info…is there some kind of formula for shutter speed/mm length?

[p4pictures]

Simplest one is to use the reciprocal of the focal length, so 800mm means 1/800, 400mm is 1/400. It's a fair starting point, but worth going a bit faster for sharper results.

[Tims32ford]

Perfect!  Exactly the starting point I need!  Thanks!

[Tims32ford]

Brian,

Thank you, thank you!!  I had the AF set on ‘L’+ tracking.  Changed to 1-point AF…retook image of pine tree top 300ft away, at 400mm WITH the extender…transferred image to my iPhone, cropped it down to 3mp just to look…hooray! You can see individual pine needles…even at 3mp!

I guess the camera AF, was trying to find a happy medium between the eagle, branches, and the background sky!

Goes to show you really need to know your settings, for the image you want to take.

Thank you again!