Are we still going to get teleconverters for the RF mount?

Kit Lens Jockey

EOS 7D MK II
Nov 12, 2016
528
190
People have talked a lot about the impressively small size of the new RF 70-200 f2.8. But now I'm starting to think... Is there still room in the back of the lens to ever put a hypothetical teleconverter on the back of it? If not, will we see RF teleconverters come out someday that have a very slim profile that don't need to extend into the back of the lens? Is the concept of the teleconverter just going to die out with the RF mount?

I really like the ability to carry around a 70-200 f2.8 with a 2x teleconverter when traveling, and essentially have it perform almost the same duties as a 100-400 lens when I need it to by throwing a teleconverter onto the back of it. I'd hate to lose this if I ever change over to the RF 70-200.
 

Kit Lens Jockey

EOS 7D MK II
Nov 12, 2016
528
190
I've been looking for a photo of the back of the RF 70-200 with the cap off, and I can't find one. I'm curious how much room there is in the back of the lens, and if it varies depending on where the zoom is at.

But of course even if there isn't a lot of room, it could just be that any RF teleconverter they come out with will have much less protrusion out of the front of it.
 

Viggo

EOS 5D SR
Dec 13, 2010
4,212
773
I've been looking for a photo of the back of the RF 70-200 with the cap off, and I can't find one. I'm curious how much room there is in the back of the lens, and if it varies depending on where the zoom is at.

But of course even if there isn't a lot of room, it could just be that any RF teleconverter they come out with will have much less protrusion out of the front of it.
Hopefully they will make the converters in such a way they will practically fit any RF lens.
 

Mt Spokane Photography

I post too Much on Here!!
Mar 25, 2011
15,519
748
Generally, TC's were designed for 100mm and longer focal lengths. Sometimes they fit lenses with much shorter focal lengths, but those tend to be unusual examples, like using one with a tilt-shift lens. Most people don't have a T-S lens.

I think that the protrusion is a attempt to make the TC as short as possible, but it might also solve some issue that I am not aware of.

In any event, someone will come out with a TC. If not Canon, then a 3rd party.
 

Michael Clark

Now we see through a glass, darkly...
Apr 5, 2016
990
484
People have talked a lot about the impressively small size of the new RF 70-200 f2.8. But now I'm starting to think... Is there still room in the back of the lens to ever put a hypothetical teleconverter on the back of it? If not, will we see RF teleconverters come out someday that have a very slim profile that don't need to extend into the back of the lens? Is the concept of the teleconverter just going to die out with the RF mount?

I really like the ability to carry around a 70-200 f2.8 with a 2x teleconverter when traveling, and essentially have it perform almost the same duties as a 100-400 lens when I need it to by throwing a teleconverter onto the back of it. I'd hate to lose this if I ever change over to the RF 70-200.
Technically, Canon makes no teleconverters. They make extenders. The difference being the part that extends into the rear of the adapted lens.

The lens elements of teleconverters for EF lenses from third parties do not extend past their own flange.
 

Michael Clark

Now we see through a glass, darkly...
Apr 5, 2016
990
484
In the past Canon has made a few decisions that seem to indicate they do not want to make it easy for users to avoid paying them the "telephoto tax" to get very long reach with less than very expensive high end lenses.

No non-L lens has ever been officially listed as compatible with Canon's extenders. No prime lens shorter than 135mm, and no zoom lens shorter than the 70-200 series has ever been listed as compatible. Even the EF 70-300mm f/4-5.6 L IS has never been officially listed.

When the APS-H 1D line, along with the FF 1Ds line, were superseded by the FF 1D X the wildlife/birder/sports shooters were making the same kind of noise that 7D users are now making, complaining Canon was taking away the extra reach they were getting with the 1.3X crop factor that was nearly the same as an EF 1.4X extender without the loss of maximum aperture.

To make matter worse for those shooters, Canon initially limited the 1D X PDAF system to lenses and lens/extender combos that were f/5.6 or wider instead of f/8 as had been the case with recent 1D and 1Ds series bodies. No more putting a 1.4X extender on an f/5.6 lens such as the EF 400mm f/5.6 L and having AF. No more putting a 2X extender on a lens like the EF 300mm f/4 L IS and having AF. There were a LOT of birders and sports/action shooters using the very economical 400/5.6 and 300/4 lenses with 1.4X and 2X extenders attached to 1D Mark IV or earlier APS-H bodies. The HOWLS of protest were everywhere. Canon eventually relented and issued a firmware update that gave the center AF point the ability to at least try to AF with f/8 lens + extender combos.

This philosophy, it seems to me, may be at least part of the reason behind the separate EF-M and RF mounts with no way to (easily) adapt RF lenses to APS-C sensor EF-M cameras.

It also seems to be behind the lack of any obvious plans to offer an APS-C RF mount camera, or to no longer update the 7D Mark II now that Nikon has announced they are not updating the D500. Since there are, as yet, no RF lenses in the focal length range for which EF lenses are compatible with EF extenders, it makes sense that Canon has not yet released any RF extenders. (The RF 70-200mm will be the first such lens, but it has not yet begun shipping to end users.) I expect we'll see an RF 1.4X and RF 2X at about the same time as we see an RF 300mm f/2.8 or other Super Telephoto lens in the RF mount.
 

Kit Lens Jockey

EOS 7D MK II
Nov 12, 2016
528
190
I think you've jumped a little too deep into the conspiracy theory that Canon is somehow hamstringing their lens and teleconverter lineup to con their users into buying expensive super telephotos. And yes, Canon makes teleconverters, they just call them extenders for some reason. Plenty of other manufacturers make teleconverters with front elements that "extend" out beyond the front of the teleconverter. They don't call them extenders. Below is a Tamron teleconverter with an element that sticks out past the front. So when you say the lens elements of teleconverters for EF lenses from third parties do not extend past their own flange, this is completely false.

Next, let's just dispel this ridiculous idea that a crop sensor is truly giving any lens any more usable reach... A lens gathers light and projects it onto a sensor. A lens made for full frame is projecting a full frame image circle onto whatever sensor you put it in front of. If you put a full frame sensor behind that lens, you capture all of the light that the lens is gathering. If you put a crop sensor behind the lens, you are losing some of that light. That's all there is to it.

Pixels gather light, and their size determines how good they are at gathering light. If you made a crop sensor with the same size pixels as a full frame sensor, it would be lower resolution than a full frame sensor, negating the advantage of having that crop sensor which appears to give a telephoto lens more reach. You can make a crop sensor with a similar resolution to a full frame sensor, which would effectively give you a higher resolution image of whatever is in the center of your frame. But the pixels would need to be smaller, which reduces their ability to gather light, making your image noisier.

You aren't really getting any benefit putting that full frame lens on a crop sensor. Crop sensors can't work magic. A crop sensor with similar pixel size to a full frame sensor would just result in an image that is literally cropped down from what you would have gotten with a full frame sensor, and a crop sensor with smaller pixels and similar resolution to the full frame sensor would result in a noisier image.

As far as Canon limiting AF to certain apertures, they aren't doing it just to screw over their customers, they're doing it because they don't want people trying to use AF at an aperture that they know it won't work worth a damn at. They choose to keep their performance standards up as opposed to letting people use AF at less than optimal apertures. The EOS R, with its more sensitive on-sensor AF points, allows you to use AF down to f11. So it blows your theory that Canon is nefariously limiting AF options out of the water. They're just limiting based on what they feel that the camera hardware will actually perform at. This also explains why they don't officially list any non-L lens as compatible with the teleconverters... None of them have apertures wide enough to result in an acceptable aperture that will work with AF when you put a teleconverter on them.
 

Attachments

Last edited:

Jethro

EOS R
Jul 14, 2018
235
113
Also here is an article from Canon specifically touting how you can now use adapted EF extenders with somewhat slower lenses on the EOS R. Their example would allow you to have an 800mm full frame reach without buying an expensive 800mm prime.

Interesting point: "AF points on the EOS R are compatible with maximum aperture f/11 at all AF positions".
 

AlanF

Canon 5DSR II
Aug 16, 2012
5,745
3,072
Found it to be better to crop 1.4x than use an extender with my 200 f2.0.
One example with one lens doesn't warrant a generalisation that all teleconverters suck. Some of my lenses take TCs very well on some of my bodies. Others don't, and I had one bad copy of a 1.4xTCIII.
 
  • Like
Reactions: Michael Clark

Michael Clark

Now we see through a glass, darkly...
Apr 5, 2016
990
484
I think you've jumped a little too deep into the conspiracy theory that Canon is somehow hamstringing their lens and teleconverter lineup to con their users into buying expensive super telephotos. And yes, Canon makes teleconverters, they just call them extenders for some reason. Plenty of other manufacturers make teleconverters with front elements that "extend" out beyond the front of the teleconverter. They don't call them extenders. Below is a Tamron teleconverter with an element that sticks out past the front. So when you say the lens elements of teleconverters for EF lenses from third parties do not extend past their own flange, this is completely false.
I think you're reading more in my comment than what is there. Canon is not trying to "con" anyone into anything. They're making decisions based on what they think will maximize their profits. That's why they exist.

That includes being concerned with preserving their reputation as the maker of the world's finest Super Telephoto lenses. That's why they don't want to make it easy to use their products in a way that gets less than the best results for a particular focal length. They'd rather a customer use a 200mm f/2.8 lens than put a 2X TC between the camera and a 100mm f/2 lens. They'd also apparently rather a customer use a 400mm f/5.6 lens than put a 2X extender between a 70-200mm f/2.8 and the camera, even though they would make more on the 70-200/2.8+2X than they make on the 400/5.6.

The "some reason" Canon calls them extenders is because they extend into the specific lenses for which they are designed to be compatible. You can claim that is completely false all you want, but that's exactly why Canon calls them "extenders" in English speaking countries.

Just because another maker chooses to call them by the more generic "TC" does not mean that the reason Canon calls them "extenders" is for any other reason than because they extend into the lenses they're made to work with. Your example of a third party TC with an extension, buy the way, is not made for Canon EF lenses. According to Tamron it is only compatible with specific Tamron lenses that use the EF mount (but that does not make them EF lenses, only Canon makes EF lenses). The vast majority of third party TCs made to work with Canon EF lenses (even those that Canon does not list as being compatible with Canon extenders) have no elements that protrude past the the front of the flange. For my assertion to be, as you put it, "completely false", every single TC ever made by a third party must have elements that extend into the lens attached to them. That is almost entirely *not* the case.

Next, let's just dispel this ridiculous idea that a crop sensor is truly giving any lens any more usable reach... A lens gathers light and projects it onto a sensor. A lens made for full frame is projecting a full frame image circle onto whatever sensor you put it in front of. If you put a full frame sensor behind that lens, you capture all of the light that the lens is gathering. If you put a crop sensor behind the lens, you are losing some of that light. That's all there is to it.

Pixels gather light, and their size determines how good they are at gathering light. If you made a crop sensor with the same size pixels as a full frame sensor, it would be lower resolution than a full frame sensor, negating the advantage of having that crop sensor which appears to give a telephoto lens more reach. You can make a crop sensor with a similar resolution to a full frame sensor, which would effectively give you a higher resolution image of whatever is in the center of your frame. But the pixels would need to be smaller, which reduces their ability to gather light, making your image noisier.
In the context of discussing Canon's APS-H camera bodies, which is the comment you're trying to argue with based on more recent models rather than what was available prior to 2012 when the 1D X was introduced and Canon ended their APS-H camera line, it was the case that their cropped bodies had higher pixel density than their 1 Ds series FF bodies that existed when the 1 D series were APS-H bodies.

Even today, Canon's top APS-C sports body (20.2 MP 7D Mark II or 32.5 MP 90D, take your pick) have as many or more pixels packed onto a 332mm² sensor as the top FF sports model (20.2 MP 1D X Mark II) has on an 864mm² sensor .

You aren't really getting any benefit putting that full frame lens on a crop sensor. Crop sensors can't work magic. A crop sensor with similar pixel size to a full frame sensor would just result in an image that is literally cropped down from what you would have gotten with a full frame sensor, and a crop sensor with smaller pixels and similar resolution to the full frame sensor would result in a noisier image.
Today, the EOS 5Ds and the EOS 7D Mark II have the same pixel density. Putting the same lens on the APS-C 7D Mark II allows one to shoot at 10 fps for 30+ raw frames or to shoot at 10 fps saving JPEGs until the memory card is full or the battery is dead. Try to keep up with that frame rate on the 5Ds that can only go at 5 fps for 14 raw files or 510 JPEGs before the camera bogs down. So yes, there can be a benefit to putting a FF lens on a crop sensor. You can get shot sequences with the faster camera that you can not get with the slower one.

As far as Canon limiting AF to certain apertures, they aren't doing it just to screw over their customers, they're doing it because they don't want people trying to use AF at an aperture that they know it won't work worth a damn at. They choose to keep their performance standards up as opposed to letting people use AF at less than optimal apertures. The EOS R, with its more sensitive on-sensor AF points, allows you to use AF down to f11. So it blows your theory that Canon is nefariously limiting AF options out of the water. They're just limiting based on what they feel that the camera hardware will actually perform at. This also explains why they don't officially list any non-L lens as compatible with the teleconverters... None of them have apertures wide enough to result in an acceptable aperture that will work with AF when you put a teleconverter on them.
Again, you're arguing with a straw man you created, not what my comment above said.

Nowhere did I say Canon was "nefariously" doing anything to "screw over their customers."

What I actually said was , "In the past Canon has made a few decisions that seem to indicate they do not want to make it easy for users to avoid paying them the "telephoto tax" to get very long reach with less than very expensive high end lenses."

I observed that when Canon introduced the 1D X they reduced the narrowest maximum aperture that would allow AF to function to f/5.6. It seems Canon underestimated the usefulness to many of their customers of making AF available with f/8 lens+extender combinations. Canon heard those customers loud and clear and gave them what they wanted. How is citing that inferring that Canon was trying to "nefariously" "con" their customers?

I pointed out that once Canon heard the complaints from a vocal segment of their customer base, they issued firmware updates to enable AF using the center AF point with the 1D X and the 5D Mark III. That's a far cry from presenting a "... theory that Canon is nefariously limiting AF options." The only thing being blown out of the water are the imaginary arguments you're making up.

The firmware updates that enabled f/8 AF also actually work "at an aperture that they know it won't can work worth a damn at (sic)." You know, with those lens+extender combinations like the EF 400mm f/5.6 L + EF1.4X and the EF 300mm f/4 L IS + EF2X that you claim do not "... have apertures wide enough to result in an acceptable aperture that will work with AF when you put a teleconverter on them?"

Since that time, Canon has introduced several upper tier models that also allow the AF system to function with f/8 lens+extender combos with an increasing number of AF points that function at f/8. I guess that blows your little theory (that Canon knows f/8 lens+extender combos don't work worth a damn) out of the water, huh?
 

AlanF

Canon 5DSR II
Aug 16, 2012
5,745
3,072
Michael, Where have you read that extenders are called extenders because they extend into a lens? According to the introductory paragraph explaining teleconverters or extenders in Canon's Infobank https://cpn.canon-europe.com/content/education/infobank/lenses/extenders.do

"Extenders, generally known as teleconvertors, increase the effective focal length of lenses. Canon Extenders are available in two strengths, 1.4x and 2x. As the name suggests, the 1.4x Extender extends the focal length of your lens by a factor of 1.4, and the 2x by a factor of 2."

Maybe you are correct and Canon has forgotten why?
 
  • Like
Reactions: SecureGSM