# Extenders on RF 100-500mm, RF 800mm and EF 400mm DO II



## AlanF (Jun 19, 2021)

The-Digital-Picture does nice IQ tests with charts but they are all at different distances so that the image fills the frame. I want to know how different telephotos perform and resolve details on a chart at a fixed distance away. Here is a collection of tests I have done for various lenses on the R5. The chart, courtesy of Bob Atkins, is only 13.6cm across, about the size of a small bird. The numbers on it are line pairs per mm. The distance was 20m, which means tests were performed outside in natural light that varied over time. I also used a standard laser printer for the chart and so the lines are not at high resolution - irregularities can be detected at pixel level peeping. Even so, you can get a good idea of how the lenses and extenders perform.

John has done an analysis with some high resolution charts. 
https://www.canonrumors.com/forum/t...out-rf-1-4x-tc-for-super-telephoto-use.40240/And I have done some earlier comparisons.





RF 100-500mm vs EF 100-400mm II + EF-ER adapter


It looks like I will be getting next week an R5. I do have two very good copies of the 100-400mm II + 1.4 and 2xTCIIIs and was intending to use one of those. I do have the opportunity of buying an RF 100-500mm, which is a serious outlay, especially with the high cost of RF extenders. I'd love to...




www.canonrumors.com


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## AlanF (Jun 19, 2021)

First, the RF 100-500mm on the R5. The bare lens at 500mm cannot resolve the 2.8 lp/mm rings. Adding the RF 1.4x TCs increases the resolution to resolve those rings, and the RF 2x at 1000mm even better resolution, an increase of 40% over the bare lens.


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## AlanF (Jun 19, 2021)

The RF 800mm has a nice jump in resolution on adding the RF 1.4x and an incremental increase with the 2x. At 800mm, it is better than the 100-500mm at 700mm, and close to to the 100-500mm at 1000mm.


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## AlanF (Jun 19, 2021)

For comparison is the EF 400mm DO II. The bare lens is outresolved by the 100-500mm. Adding the EF 1.4xTCIII to give 560mm leads to it outresolving the bare 100-500mm but is behind the lens at 700mm with the RF 1.4xT. The EF 2xTCIII at 800mm and f/8 is very similar to the RF 800mm f/11 in resolution. Stopping the lens down to f/11 (not shown) increases resolution a bit and draws slightly ahead of the RF 800mm f/11.


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## AlanF (Jun 19, 2021)

My bird photos in the field bear out these results, both at far and close distances. Even though I'll never use it much, I am keeping for the time being the RF 800mm for occasional us at 1120mm as it really extracts a lot of detail. I hope these charts are of so use.


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## AlanF (Jun 19, 2021)

A parent Peregrine Falcon keeping guard over her nest and chicks gave me the opportunity of comparisons in the field as she perched for so long. She was about 90m away, the light was overcast and I hand held the camera with a shutter speed of 1/1250s. In increasing focal length: 500mm, 800mm, 1000mm, 1120mm and 1600mm with the 100-500mm and 800mm f/11 with extenders, all 100% crops.


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## koenkooi (Jun 19, 2021)

In the dragonfly thread you have shots done with the 100-500mm and 2x at 3m, how would you rate the performance in that scenario? It’s my dragon and damsels lens and I’m considering adding a TC to get more pixels on the subjects when they are over water.

1000mm at F/14 is already in diffraction territory on the R5, can it still get the facial hair on a drafonfly nice and sharp?


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## AlanF (Jun 19, 2021)

koenkooi said:


> In the dragonfly thread you have shots done with the 100-500mm and 2x at 3m, how would you rate the performance in that scenario? It’s my dragon and damsels lens and I’m considering adding a TC to get more pixels on the subjects when they are over water.
> 
> 1000mm at F/14 is already in diffraction territory on the R5, can it still get the facial hair on a drafonfly nice and sharp?


The RF 800 with its 6m mfd has its limitations here. The RF 2x on the 100-500mm + RF 2x is very sharp close up, and the increase in focal length more than compensates for the diffraction. Here's a Common Blue Damselfy at 1000mm and 3.3m distance.


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## Click (Jun 19, 2021)

Very interesting information. Thanks for sharing, Alan.


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## Bdbtoys (Jun 20, 2021)

@AlanF I assume you are still happy w/ the RF extenders  .

Glad I helped you cross over that threshold.


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## AlanF (Jun 20, 2021)

Bdbtoys said:


> @AlanF I assume you are still happy w/ the RF extenders  .
> 
> Glad I helped you cross over that threshold.


Yes, you and @bhf3737 were most helpful. Thanks again!


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## Jack Douglas (Jun 20, 2021)

Alan, I assume I have little justification for dumping the 400 DO II for the 100-500 other than zoom and possibly close up shots (I was not happy with that item, switching from the 300 2.8). Funny, a benefit for me with the 400 - I leave it standing on end with the camera attached, ready to shoot, on the kitchen table.  What about the zoom range limitations?

Jack


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## AlanF (Jun 20, 2021)

Jack Douglas said:


> Alan, I assume I have little justification for dumping the 400 DO II for the 100-500 other than zoom and possibly close up shots (I was not happy with that item, switching from the 300 2.8). Funny, a benefit for me with the 400 - I leave it standing on end with the camera attached, ready to shoot, on the kitchen table.  What about the zoom range limitations?
> 
> Jack


Use what's best for you - we all have different priorities. Weight is an important consideration for me because I carry a camera and telephoto on walks every day and I find the 2.5 kg of the 400mm DO II too heavy as also would be the Sony 200-600mm and the Nikon 200-500 or Sigma 60-600. And, importantly, I can hold the 100-500mm and the 100-400mm II rock steady level or pointing upwards at a bird wheres those heavier lens both strain me and drift down. Also close focussing is important as well. I can live with a 3m mfd. If Canon comes out with an ultra light RF 400 DO f4 or maybe even a 500, then I might go for one. What I would have liked is a 500/5.6 as light and sharp as the Nikon 500PF. However, the 100-500mm is almost as sharp and is of similar weight and is only 2/3rd of a stop slower.


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## FrenchFry (Jun 22, 2021)

AlanF said:


> If Canon comes out with an ultra light RF 400 DO f4 or maybe even a 500, then I might go for one. What I would have liked is a 500/5.6 as light and sharp as the Nikon 500PF.



I am hoping for announcements of these lenses soon! That would be such great hiking wildlife photography lenses.
Thank you very much for putting together this information!


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## Jack Douglas (Jun 22, 2021)

FrenchFry said:


> I am hoping for announcements of these lenses soon! That would be such great hiking wildlife photography lenses.
> Thank you very much for putting together this information!


I often find myself reflecting on the criticisms that accompany virtually any Canon product. In this case it's the 100-500 and its F7.1. Then in due course the rubber hits the road and guess what, Canon wasn't so clueless.

Jack


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## bhf3737 (Jun 22, 2021)

AlanF said:


> Yes, you and @bhf3737 were most helpful. Thanks again!


Thanks Alan for this thread. My personal take is that regardless of what RF lens I use (100-500, 800, 600, combined with extenders) the final picture quality will be between good and very good. Perhaps close level of quality can be obtained by zooms and relatively cheap primes from other brands. The rest depends on personal preference, environment and budget. For me 100-500, 800 and an extender are more than enough. If one wants absolutely excellent picture quality, well RF version of great whites will be there to explore.


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## AlanF (Mar 11, 2022)

I have been doing various comparisons of the RF 1.4x and RF 2x on the RF 100-500mm and RF 800mm f/11 on the R5 and R6. I rarely use the RF 1.4x on the 100-500 on the R5 as I like the RF 2x so much. I have now found that the 2x zoomed out to 700mm has at f/11 is at least as good as the 1.4x at 700mm and f/10, which is only a 1/4 stop brighter. Zoomed out to the minimum of 600mm, it gives very good resolution. So, as far as I am concerned, the 1.4x TC is redundant with the 100-500 if you have the 2x. The RF 800mm on the R6 is really good. Although it has theoretically the same reach as 500mm on the R5, the 800 gives better resolution on the R6. And the 1.4x on it at 1120mm is very nice, very similar to the 100-500mm + 2x at 1000mm on the R5.


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