# Canon RF 2x Extender - anyone used one?



## AlanF (May 3, 2021)

The RF 1.4xTC works well on my 100-500mm and R5 with excellent AF and after some sharpening at 700mm it's pretty close to the RF 800mm in resolution and IQ. I am intrigued as to how well the RF 2x performs in terms of AF and IQ on the 100-500mm in particular. It's so expensive, that it would cost not much more to buy an 800mm RF. But, if the IQ etc are good, it would be tempting to have one in my kit for the occasional 1000mm f/14 shot. I'd be grateful for any first hand experience or for pointers to any reviews (TDP has image quality with it only on the 800mm).


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## bhf3737 (May 3, 2021)

I will have RF 2.0xTC this coming weekend on loan and will try it with RF 100-500mm and will post some results here if weather allows. Based on my own experience so far, RF 800 has better IQ that 100-500 + 1.x TC but is less flexible. So I don't expect 100-500 + 2.0xTC to pull a rabbit out of hat, but let's see.


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## AlanF (May 3, 2021)

bhf3737 said:


> I will have RF 2.0xTC this coming weekend on loan and will try it with RF 100-500mm and will post some results here if weather allows. Based on my own experience so far, RF 800 has better IQ that 100-500 + 1.x TC but is less flexible. So I don't expect 100-500 + 2.0xTC to pull a rabbit out of hat, but let's see.


Thanks and looking forward to your findings. I have done testing of the 800mm vs 100-500mm + 1.4xTC and usern4cr more so. The RF 800 does have the edge but as you say the zoom has the flexibility. I am very tempted by the 800 but having the 100-500 and my style of nature photography being opportunistic I am suppressing the GAS. Judging by my results of the EF 2xTC with the 100-400mm II, I am not hopeful. But as you write, let's see.


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## Bdbtoys (May 3, 2021)

@AlanF Is there something you want to see or have me check in particular?

I have the 100-500, 1.4x, & 2x. I can't directly check against the 600 or 800 because I went with the combo I did for flexibility. Also, I recently used the 100-500+2x (600-1000 effective) while I was at a Blue Angel's practice... which I was fairly happy w/ the results.


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## AlanF (May 3, 2021)

Bdbtoys said:


> @AlanF Is there something you want to see or have me check in particular?
> 
> I have the 100-500, 1.4x, & 2x. I can't directly check against the 600 or 800 because I went with the combo I did for flexibility. Also, I recently used the 100-500+2x (600-1000 effective) while I was at a Blue Angel's practice... which I was fairly happy w/ the results.


I am interested in seeing the quality at 1000mm - I'm with you for flexibility, and want to see if it's worthwhile getting the 2x.


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## Bdbtoys (May 3, 2021)

AlanF said:


> I am interested in seeing the quality at 1000mm - I'm with you for flexibility, and want to see if it's worthwhile getting the 2x.


long end, short end, or both?


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## AlanF (May 3, 2021)

Bdbtoys said:


> long end, short end, or both?


Long - at 700mm and below, the 1.4xTC will be better.


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## Bdbtoys (May 3, 2021)

AlanF said:


> Long - at 700mm and below, the 1.4xTC will be better.



Yes, but's it's nice to know how much IQ you would lose if you dip in the 600-700 range.

Here's the situation I was in... I wanted the variable range, but knew I was mostly going to need the long end, but every once and a while was also going to need the 600.

I semi-decided to do a few at both ends of the range with each configuration to get an overlap. I'll shoot for getting something tomorrow.


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## AlanF (May 3, 2021)

Bdbtoys said:


> Yes, but's it's nice to know how much IQ you would lose if you dip in the 600-700 range.
> 
> Here's the situation I was in... I wanted the variable range, but knew I was mostly going to need the long end, but every once and a while was also going to need the 600.
> 
> I semi-decided to do a few at both ends of the range with each configuration to get an overlap. I'll shoot for getting something tomorrow.


Thanks, much appreciate.


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## Bdbtoys (May 5, 2021)

TLDR: The TC's are better than cropping.

So did a quick little test w/ no TC, 1.4, & 2.0. I really want to do a better one (not in a semi dark hallway) and with a better test subject (what I thought was a nice piece of paper with black text) ended up being gray-scale text with pixel shading (which I didn't realize until I reviewed the pictures as it was not noticeable looking at it with first glance).

However, I can give a quick summary of what I noticed.

The TC was *always* better than a crop w/o the TC or a crop on a smaller TC. The detail gained was pretty dramatic.

I would have no issues grabbing the 2.0x over the 1.4x even if I was going to be in the 600-700 range (the overlap of the 1.4 & 2.0) if the 1 stop loss wasn't a factor... the IQ loss at equivalent focal lengths between the 1.4 & 2.0 were negligible.

I'm not happy with this shot, but it was a quick succession of 'something quick' so I could make a reasonable comparison. The ISO was higher than I would have liked (can notice the noise when at 1:1), but it didn't really hinder confirming what I suspected.

What you are seeing is a very small portion of a screen capture of the RAW image w/o any retouching at 100% and 25% scale (I did it this way to show the details and keep the file size super small). It was shot at 1000mm (500+2x), 1/250th, ISO 6400, F14, handheld (and not steady at that). The subject was a cheap paper ruler to measure IPD (text was backwards due to it is meant to be read in a mirror). The large vertical black lines are 1cm apart (so the 100% scale is approx a real life 1cm square). This was shot at a distance of approximately 9 feet. The fact that I could clearly see each printed dot of the grayscale was pretty impressive.


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## AlanF (May 7, 2021)

Bdbtoys said:


> TLDR: The TC's are better than cropping.
> 
> So did a quick little test w/ no TC, 1.4, & 2.0. I really want to do a better one (not in a semi dark hallway) and with a better test subject (what I thought was a nice piece of paper with black text) ended up being gray-scale text with pixel shading (which I didn't realize until I reviewed the pictures as it was not noticeable looking at it with first glance).
> 
> ...


Thanks for this, I have now ordered one. My old EF 2xTC III and one of my 1.4xTC II are being sold.


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## bhf3737 (May 11, 2021)

Here we had snow during Weekend! But today was good weather and I could take a few shots with R5, RF 100-500mm and 2.0x extender. My impression was that for stationary or slow moving objects, the combo works fine, image quality is good, if using some noise removal, but AF was quite sluggish for BIF. With 1.4x extender, the AF has been much better. The advantage of 2.0x was that it could still focus on close subjects. much closer that RF 800mm. The other advantage is that the whole frame can be filled so I ended up with more pixels to work with.
Some sample photos are attached below. I used Topaz Denoise AI for higher ISO files.

A mother goose and her goslings (about 15m away)



An American white pelican (about 30m away)



and a porcupine from about 3 meters away.


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## AlanF (May 11, 2021)

bhf3737 said:


> Here we had snow during Weekend! But today was good weather and I could take a few shots with R5, RF 100-500mm and 2.0x extender. My impression was that for stationary or slow moving objects, the combo works fine, image quality is good, if using some noise removal, but AF was quite sluggish for BIF. With 1.4x extender, the AF has been much better. The advantage of 2.0x was that it could still focus on close subjects. much closer that RF 800mm. The other advantage is that the whole frame can be filled so I ended up with more pixels to work with.
> Some sample photos are attached below. I used Topaz Denoise AI for higher ISO files.
> 
> A mother goose and her goslings (about 15m away)
> ...


Thanks so much for posting these.


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## Bdbtoys (May 11, 2021)

I have to agree the AF is a bit sluggish (or can miss) more than the 1.4.... however it does make for some very nice pictures (where @bhf3737 stated you have more detail/pixels in the finer points).

I may post the plane pictures from the vacation I mentioned.


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## AlanF (May 12, 2021)

My RF 2x Extender arrived lunchtime on a 14-day return basis and I put it through preliminary testing vs the bare RF 100-500mm and with the RF 1.4x extender, and also compared it with previous tests on the 100-400mm II and 400mm DO II. I was pleasantly surprised. At 19m distance from the charts, the RF 2x performs far better on the 100-500mm than does the EF 2xTC on the 100-400mm II. The 100-500mm at 1000mm produced crisp lines, and gave 40% more resolution than the bare lens and about 20% more than the 100-500mm at 700mm. It was just slightly better than the 400mm DO II at 800mm and f/8 and distinctly better than the RF 800mm, and even out resolved the 800mm at 1120mm with a 1.4x extender. At 12m from the charts, where I found the EF 2xTC on the 100-400mm II to be weak, the RF system at 1000mm is excellent. After those tests, I took some shots at the local lake and of a Greenfinch on my feeder. Here are some typical shots, cropped to fit on the site without compression and where 1 px on the crop = 1 px on the original. It focussed fast enough for some BIF. I'm keeping the RF 2x as it will be useful on those occasions where I am really pushed for reach - it won't be on my lens as a matter of routine although it does produce really sharp and contrasty images.


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## Bdbtoys (May 12, 2021)

Nice! Glad to hear you like it.


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## snappy604 (May 12, 2021)

nice to see some real world shots.. I'm tempted by the 100-500 vs my 150-600 sigma.. . but the extra range has always been a concern. so wondered about the TC and if would be worthwhile... seems like the answer is... yes.


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## Bdbtoys (May 12, 2021)

Alright... here they are. One at the 600mm, another at the 1000mm pretty much un-retouched (outside of resize/compression to fit in forum).


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## Click (May 13, 2021)

Cool shots!


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## AlanF (May 13, 2021)

I checked out the IS. My criteria are off scale compared with the usual as I count shots as being perfect only when no shake is detected at the pixel level when hand held at 20m from a high resolution target. At this distance, shake is magnified and at closer distances, shake becomes less and less observable. At 1000m, from 1/800 to 1/1600s, 70% were absolutely shake free, and 30% pretty minimal. At 1/500s, 50% perfect, 33% nearly there and 17% bad. At 1/250s, 30% perfect, 30% nearly there and 40% bad. At 1/125s, 17% perfect, 17% nearly there and 66% bad.
These figures are pretty good. In general, I try to keep shutter speeds faster than 1/500s for optimal sharpness. From experience, a setting of 1/1250s, iso 1000 at 1000mm f/14 would be fine for me on a bright day.


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## Bdbtoys (May 13, 2021)

AlanF said:


> I checked out the IS. My criteria are off scale compared with the usual as I count shots as being perfect only when no shake is detected at the pixel level when hand held at 20m from a high resolution target. At this distance, shake is magnified and at closer distances, shake becomes less and less observable. At 1000m, from 1/800 to 1/1600s, 70% were absolutely shake free, and 30% pretty minimal. At 1/500s, 50% perfect, 33% nearly there and 17% bad. At 1/250s, 30% perfect, 30% nearly there and 40% bad. At 1/125s, 17% perfect, 17% nearly there and 66% bad.
> These figures are pretty good. In general, I try to keep shutter speeds faster than 1/500s for optimal sharpness. From experience, a setting of 1/1250s, iso 1000 at 1000mm f/14 would be fine for me on a bright day.



I believe my AF/IS issues from that day watching the jets was more user error than anything else. I found that I had inadvertently had the IS switch in mode 1 when I started to take panning shots (so +1 on user error). The other was that I was missing focus occasionally probably because of IS, but also because I was struggling to keep still (handheld).

Of the shots I did like, I was impressed. For example, zoom in on the 1 plane shot and look at the face of the pilot.


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## bhf3737 (May 13, 2021)

In my experiment, I was more concerned about the time required to AF on a subject compared to the bare RF 100-500mm. The bare lens was fast and snappy. But with the 2.x, on the other hand, it was quite sluggish, specially on scene with less contrast. Needless to say that when it could AF, the result was always good.


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## Bdbtoys (May 13, 2021)

bhf3737 said:


> In my experiment, I was more concerned about the time required to AF on a subject compared to the bare RF 100-500mm. The bare lens was fast and snappy. But with the 2.x, on the other hand, it was quite sluggish, specially on scene with less contrast. Needless to say that when it could AF, the result was always good.


My biggest issue is that it sometimes overshot focus (blowing the image out). Then good luck getting it to refocus on anything since you can't recompose on the object (plane/bird in sky example).

However, those misses weren't so bad after dealing with it for a bit. And I would not trade it for anything else atm (that I can afford).


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## bhf3737 (May 14, 2021)

Bdbtoys said:


> My biggest issue is that it sometimes overshot focus (blowing the image out). Then good luck getting it to refocus on anything since you can't recompose on the object (plane/bird in sky example).
> 
> However, those misses weren't so bad after dealing with it for a bit. And I would not trade it for anything else atm (that I can afford).


Yes, that also happened to me a few times when there was little contrast in the scene, e.g. a grey seagull against cloudy sky.


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