# should you buy the RF 2.x extender ? wish I hadn't !



## Dpickup (Oct 9, 2020)

hi All, 
just got my RF 2.x and have to say I am massively disappointed, and just posted my first negative review on Canons web site :

_maybe i should have checked the specs more thoroughly, but this does NOT turn your RF100-500 into a 200-1,000 as it has a massive extension tube that protrudes into the lens barrel so the lens only retracts to 300 (ie 600) so you can't easily walk around with this when its attached as it makes the lens too big. Guess sits fine if its attached to a tripod and you are not going anywhere, but if you are shooting wildlife and they / you start coming closer you going to be wanting to take this off. this is a VERY weird deign choice - could they not just have made the tube itself bigger ?
like i say it does show this in the specs, so maybe my fault :
A mechanism which limits the zooming of the RF 100-500mm F4.5-7.1L IS USM zoom range (300 to 500 mm) prevents the lens elements hitting those of the extender.

but it has kind of limited the usefulness of this lens as its robbed me of both portability and zoom length._

am I being harsh ? 
for me its made a much less workable design.
will be great for taking pictures of teh moon, but not sure I would take it with me to shoot birds / safari - bring back my EF100-400 where i used to have a 2.x and a 1.4x and an extension tube meaning i could get var combinations of anything from 140 - 560 or if i plugged out all together 280 - 1,120mm


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## Joules (Oct 9, 2020)

I personally don't think leaving a negative review on the extender is reasonable, given that this limitation is caused by the lens design.

As for the lens, that of course is worth being critised for this property, if it is something that impacts your experience with the product.


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## Dpickup (Oct 9, 2020)

yeah i did consider if it was lens or extender that was a fault, and i THINK the design issue is the extender. Essentially if you put an extension tube between the lens an date extender (ie stopping the lens extension going in to the lens barrel) you would avoid this ?

i'm am far from an optical engineer here, so maybe my logic flawed, but this is how i got the EF100-400 to work with the 1.4x and 2x extenders....


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## BeenThere (Oct 9, 2020)

Dpickup said:


> yeah i did consider if it was lens or extender that was a fault, and i THINK the design issue is the extender. Essentially if you put an extension tube between the lens an date extender (ie stopping the lens extension going in to the lens barrel) you would avoid this ?
> 
> i'm am far from an optical engineer here, so maybe my logic flawed, but this is how i got the EF100-400 to work with the 1.4x and 2x extenders....


If I understand what you are saying, if Canon had put an extension on the TC it would have prevented infinity focus ability. The optical design of the lens is where the issue lies. If Canon had made the lens so that you could use the full zoom capability with the TC, then you would probably have lost something else (perhaps MF would have had to increase for instance).


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## Nelu (Oct 9, 2020)

Dpickup said:


> hi All,
> just got my RF 2.x and have to say I am massively disappointed, and just posted my first negative review on Canons web site :
> 
> _maybe i should have checked the specs more thoroughly, but this does NOT turn your RF100-500 into a 200-1,000 as it has a massive extension tube that protrudes into the lens barrel so the lens only retracts to 300 (ie 600) so you can't easily walk around with this when its attached as it makes the lens too big. Guess sits fine if its attached to a tripod and you are not going anywhere, but if you are shooting wildlife and they / you start coming closer you going to be wanting to take this off. this is a VERY weird deign choice - could they not just have made the tube itself bigger ?
> ...


Yeah, I agree it's an annoying limitation but it's no longer a surprise at this time; at least it shouldn't be.
Hell, I don't even own the R5 or the lens and I knew about it!


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## AlanF (Oct 9, 2020)

You haven't been following CR - it's been mentioned repeatedly in related threads. In my opinion, there is a design flaw and is one reason I am sticking with the 100-400mm II plus the two EF TCIIIs I have.


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## bhf3737 (Oct 9, 2020)

To be fair, the extender starts working from 300mm on but it does not change the minimum focus distance that much. So you can still take shot of close objects if they fit into the sensor. Leaving the extender on the lens (semi-) permanently and transporting them attached to the camera may damage the lens, though.


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## zim (Oct 9, 2020)

AlanF said:


> You haven't been following CR - it's been mentioned repeatedly in related threads. In my opinion, there is a design flaw and is one reason I am sticking with the 100-400mm II plus the two EF TCIIIs I have.


I agree but I wouldn't call it a flaw it was a choice. Not to stir up a hornet's nest but to me it's a constant theme that every lens has to be seen as superior to EF in some way or another when it's just not necessary


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## AlanF (Oct 9, 2020)

bhf3737 said:


> To be fair, the extender starts working from 300mm on but it does not change the minimum focus distance that much. So you can still take shot of close objects if they fit into the sensor. Leaving the extender on the lens (semi-) permanently and transporting them attached to the camera may damage the lens, though.


Your caveat "if they fit into the sensor" is spot on. In practice, the 2x extender gives a focal length range upwards from 2x300mm, that is 600mm - 1000mm. At short distances, OK for insects, flowers and small birds. With the 100-400mm, the range with the 2xTC is 200-800mm, which is a far more flexible range. I was out shooting with the 2xTC on the 100-400mm II last week and had to throttle back quickly to short focal length for some shots. If I get the 100-500mm, I'll probably use it without a TC - it's a great lens.


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## Dpickup (Oct 9, 2020)

I must have had my head in the sand then (or just didnt do my research ) as it was a shock to me.

ill try and live with it for a while before i do anything radical as i’m getting better pics with the 100-500 (for whatever / many reasons) than i ever got with the 100-400.

but i agree with Zim, i didnt need it to be “better” than my 100-400 and would have sacrificed the extra 100 to be able to use the extender

Ah well i live and learn


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## Dpickup (Oct 9, 2020)

AlanF said:


> Your caveat "if they fit into the sensor" is spot on. In practice, the 2x extender gives a focal length range upwards from 2x300mm, that is 600mm - 1000mm. At short distances, OK for insects, flowers and small birds. With the 100-400mm, the range with the 2xTC is 200-800mm, which is a far more flexible range. I was out shooting with the 2xTC on the 100-400mm II last week and had to throttle back quickly to short focal length for some shots. If I get the 100-500mm, I'll probably use it without a TC - it's a great lens.


Completely agree with the flexibility range comment
i’m torn 
not too bad a dilema to have in the grand scheme of things


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## zim (Oct 9, 2020)

I have to say though that if i had an R5 the 100-500 would be a must have with it. So Canon ain't doing too much wrong with mirrorless in my book!


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## Bdbtoys (Oct 10, 2020)

As I mentioned in another thread... the TC usage makes it hard to deal with your lens when attached. Going from 100-300 is 3" of extension on the lens... but going from 300-500 is only 1/2" more. So when using a TC, you are almost always at full lens extension.

However the 300 start was not a surprise. It was clearly communicated from what I seen. Doesn't mean I like it, but knew what I was getting into (well except I got the lens and TS's at same time... so wasn't aware how far out the lens would be extended at min focal length).


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## Bennymiata (Oct 10, 2020)

Personally, I don't understand why the new Canon extenders have such long tubes either as other brands' extenders hardly protrude at all.
It must really limit sales too as most of the R lenses won't work with them at all. Having your exteders designed to work with all of your lenses, would certainly increase the sales.
I've seen people using extenders with 24-70mm zooms.
I bet in a year or two that they come up with a new version(s) without that protruding tube.


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## Joules (Oct 10, 2020)

Bennymiata said:


> Personally, I don't understand why the new Canon extenders have such long tubes either as other brands' extenders hardly protrude at all.
> It must really limit sales too as most of the R lenses won't work with them at all. Having your exteders designed to work with all of your lenses, would certainly increase the sales.
> I've seen people using extenders with 24-70mm zooms.
> I bet in a year or two that they come up with a new version(s) without that protruding tube.


If Canon could have delivered the same performance in terms of optics, size and weight while increasing the compatibility of the TCs, they would have done so, I believe. So, while we don't know the exact compromise we avoided, I think we got what Canon thinks the majority of the market wants most: Less size and weight with options for greater reach at the long end.

Also, with resolutions climbing and the high MP R likely coming in at over 80 MP, they may see the need for TCs simply diminish as bodies progress.


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## AlanF (Oct 10, 2020)

Joules said:


> If Canon could have delivered the same performance in terms of optics, size and weight while increasing the compatibility of the TCs, they would have done so, I believe. So, while we don't know the exact compromise we avoided, I think we got what Canon thinks the majority of the market wants most: Less size and weight with options for greater reach at the long end.
> 
> Also, with resolutions climbing and the high MP R likely coming in at over 80 MP, they may see the need for TCs simply diminish as bodies progress.


Maybe you are right. I am not a lens designer but I have noticed that the rear elements of EF telephotos are well recessed inside the barrel and the EF flange to sensor distance is 24mm longer than the R. Attached is the collage I posted previously of Canon's own diffraction corrected MTFs of the EF and RF zooms they had calculated from their designs. The RF and its extenders' values are no better than those of the EF, indeed a tad worse, and so the RF lenses could have been made with longer barrels with the rear elements more recessed without compromising IQ. It looks like either the TC and lens design teams didn't speak to each other or the marketing team insisted on minimising the lengths of the bare lenses. In either case, it was, in my opinion, an unfortunate decision. Sony's 200-600mm works over the whole focal range with itsTCs, which are reported to be excellent. The 200-600mm has now been reviewed by the ever reliable Optical limits and is frankly spectacular see https://www.opticallimits.com/sonyalphaff/1097-sony200600f5663oss The Sony is the better lens for birding, but too heavy and long for me and I far prefer the size of the Canon 100-500mm, but the stronger and keener birders may think otherwise.


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## Mt Spokane Photography (Oct 10, 2020)

I have a older 2X II TC for my EF lenses. It seldom gets used. I did not upgrade it to the version III on purpose, it stacks with my 1.4X TC III while the newer version will not stack. I've only used them stacked to play with the AF capabilities of my R. I might see what happens with AF on my R5 out of curiosity. I doubt if the end photo would be better than cropping but I might see more details as I'm composing. In any event, its interesting to experiment. I'm not expecting to get a RF extender in the near future. I haven't even tried my 100-400 with a 1.4X extender on my R5 yet. I expect it to work just as Alan has shown.


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## AlanF (Oct 10, 2020)

Mt Spokane Photography said:


> I have a older 2X II TC for my EF lenses. It seldom gets used. I did not upgrade it to the version III on purpose, it stacks with my 1.4X TC III while the newer version will not stack. I've only used them stacked to play with the AF capabilities of my R. I might see what happens with AF on my R5 out of curiosity. I doubt if the end photo would be better than cropping but I might see more details as I'm composing. In any event, its interesting to experiment. I'm not expecting to get a RF extender in the near future. I haven't even tried my 100-400 with a 1.4X extender on my R5 yet. I expect it to work just as Alan has shown.


The stacked 1.4x2xTCs should work. As I have posted previously, a 3x Kenco TC, which was sold for only manual use with DSLRs, focusses well on my 100-400mm II and R5. I really am impressed with what Canon has done with the R5 AF.


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