Pros: Doubles focal length, Weather-sealed
Cons: Requires realistic expectations, Protruding front-element limits lens options
The Canon Extender EF 2x II is one out of two teleconverters made by Canon for their lenses. Canon has both a 1.4x teleconverter, as well as this one. It works by doubling the effective focal length range of the lens. Since I do tend to shoot at longer telephoto lengths outdoors some of the time, I decided that this would be the perfect companion to my Canon EF 70-200mm F2.8L IS USM Lens. I primarily shoot events indoors, but every now and then take pictures outdoors at long focal lengths (i.e. vacations, beach, etc.) However, I do not take enough shots outdoors to justify purchasing a dedicated super telephoto zoom such as the Canon EF 100-400mm F4.5-5.6L IS USM lens. Therefore, for those that own a Canon 70-200mm medium telephoto zoom, a Canon Extender EF 2x II makes an economical alternative versus purchasing a dedicated lens. The Canon Extender EF 2x II can also be used with Canon's super telephoto prime lenses. I have only used this teleconverter extensively with my 70-200mm lens, and have not used it with any other lenses. For anyone that owns any EOS body, the Canon Extender EF 2x II combined with a Canon EF 70-200mm F2.8L IS USM Lens is the most economical setup which allows one to maintain full Image Stabilizer and autofocusing mechanisms.
I have used the Canon Extender EF 2x II extensively on both vacations and also when shooting outdoors for any other random occasion. I do not shoot professionally for money, which is yet another reason that I opted for the teleconverter versus a dedicated super telephoto lens (I will explain this later).
This review is divided into two parts... The first part of the review is meant for those who are not too familiar with SLR photography, and the second part explains the product in ways that those familiar will understand.
--For Beginners Only--
So you're probably wondering what goes into the name of the teleconverter, so here is what everything means...
Canon - The Canon Extender EF 2x II is meant to work with Canon telephoto lenses. I have not tried it on any third-party lenses, such as those from Sigma or Tamron, so if you're interested in buying this teleconverter, I would check to make sure that it works with your lens.
Extender 2x - The Canon Extender EF 2x II is one of two teleconverters available from Canon. This is the longest, which effectively doubles the focal length of your range. So let's say you're using it on a 70-200mm lens, the focal length range will be multiplied by two to become a 140-400mm lens. Unfortunately, your maximum aperture will also be doubled... So let's once again pretend you're using the Canon EF 70-200mm F2.8L IS USM Lens, when coupled with this teleconverter, your fast medium-telephoto will become a slower super telephoto zoom (maximum aperture cut by two-stops) with the following characteristics: It becomes a 140-400mm f5.6 lens (or with a prime such as a 300mm f2.8, that becomes a 600mm f5.6). The mission of the lens changes. It comes from being an indoor/events lens to an outdoor lens. It becomes somewhat similar in characteristics to the dedicated super telephoto zoom, a Canon EF 100-400mm F4.5-5.6L IS USM. Obviously, the 70-200mm coupled with the teleconverter is lacking in many aspects, it is far more affordable than purchasing an entirely new lens. However, you should maintain realistic expectations and understand that the 2x teleconverter will lead to a considerable amount of quality loss. I have also read on forums online that numerous 70-200mm owners aren't overly impressed with the quality when their lens is coupled with the Canon Extender EF 2x II. I have heard different stories from those coupling the Canon Extender EF 2x II with prime lenses such as the Canon EF 300mm F2.8L IS USM or Canon EF 400mm F2.8L IS USM which are sharper than the 70-200mm to begin with. So for those that shoot for fun and want to economically extend their lens' capabilities, the Canon Extender EF 2x II is a great way to do it at $290.
Of course you can also get the shorter Canon EF 1.4x Extender II. It will only multiply the focal length range by 1.4x. Therefore, your Canon EF 70-200mm F2.8L IS USM Lens will now become a 98-280mm f4 lens. This is a dramatically shorter focal length range. However, there is less depreciation in image quality with this. The lens will also be a bit faster. Therefore, if you are looking for better quality images, a 1.4x teleconverter will essentially do less "damage" than the 2x. But my philosophy is that I would rather have an important shot, even if there is more depreciation in image quality, then no shot at all. I do enjoy being able to take my lens this long. And since I am using the images for my own personal pleasure and am not selling the images for money, I am not too concerned with the quality loss.
So you can go two ways then... You can take the Canon EF 1.4x Extender II which will give you less quality loss and a larger maximum aperture, but a significantly shorter focal length range. So you pick... What's more important to you?
EF - The Canon Extender EF 2x II is meant to work with EF lenses (L-Series only), which will allow them to maintain autofocus and other functions such as Image Stabilization (dependent on camera body).
It can only be used on certain lenses. Then, you will need to make sure that you will still maintain both autofocus and Image Stabilization. For example, the Canon EF 70-200mm F2.8L IS USM Lens can be used with the Canon Extender EF 2x II on any EOS body, and it will still maintains both autofocus and the Image Stabilizer. On the contrary, the Canon EF 70-200mm F4L IS USM will maintain its autofocus with only the Canon EOS 1D# body which can maintain autofocus with a minimum aperture of f8. Other EOS bodies can only maintain autofocus with a minimum aperture of f5.6. However, if you use the shorter Canon EF 1.4x Extender II, it will allow the lens to maintain its functions. Retaining my lens' capabilities is one of the reasons I opted for the F2.8L variant.
Therefore, before purchasing the Canon Extender EF 2x II, I would strongly recommend looking to make sure if your lens is compatible, and making sure that will retain all functions that you need it to. I know that there are some photographers that do not mind losing autofocus with their lens when using it with a teleconverter, but I do care. So please, please, please (I can not stress this enough), make sure your lens will work as desired with the teleconverter before buying it.
II - This is the second variant in the series that replaced the older ones. The older variant of this teleconverter would be the Canon EF 2x Extender. I have never used the original, so can not say if there is a significant difference in image quality. If you are purchasing the Canon Extender EF 2x II new from a dealer, then you should have the latest version.
The Canon Extender EF 2x II is a very interesting piece of equipment. It allows you to go so much further with your lens (literally), yet it still has drawbacks. If you have realistic expectations, you will enjoy this teleconverter. Otherwise, you will hate it. Here are some misconceptions that you should be aware of:
1. The teleconverter should allow my lens to retain its original image quality.
By using a 2x teleconverter, it will cause the image quality to depreciate considerably. You will notice a loss of sharpness and an increase in the flaws of the lens. You will find an increase in chromatic aberrations and other such flaws. I instantly noticed a dramatic decrease in the quality of my images. However, I found the image quality to still be acceptable and even quite good in many cases. I found that when I shoot in aperture-priority mode at f8.0, the image quality is still decent, and I do get some pretty good shots. Some even come out sharp.
I have not yet used the Canon EF 1.4x Extender II, but am assuming there will be better image quality, though at the cost of focal length range. I would rather take the hit on quality than images that would otherwise not be possible due to a much shorter focal length.
2. The telecoverter should work on any lens that Canon makes.
Unlike the third-party teleconverters from Sigma or Tamron, the Canon Extender EF 2x II has a protruding element. Therefore, if you try using it with any lens, you might hear the horrible sound of expensive glass grinding against each other. Therefore, the one great limitation that the Canon Extender EF 2x II has versus third-parties, is that it can only be used with specific lenses. In regards to Canon, it can only be used with L-Series telephoto lenses. If you look at the mount on your lens, you will notice that there is a large space which would allow the protruding element to fit into. Thus, the Canon Extender EF 2x II is meant to be used with Canon's most expensive lenses. I think you might also get the hint since the color of the teleconverter is the same as Canon's white L-Series telephotos. It would look sort of funky on any other black lens.
If you are looking to use a teleconverter on something other than an L-Series telephoto, I would recommend looking at Tamron with their higher-end teleconverters, since they do not have a protruding front element which would prevent them from being mounted onto any lens. While I have not personally used them, I have heard generally favorable things about them.
3. My lens should function 100% with the teleconverter.
This is one thing that you must be very careful with! Just because you might have a lens with Canon's Image Stabilizer doesn't mean that you will retain its function. For example, if you plan on using the Canon EF 70-200mm F4L IS USM with the Canon Extender EF 2x II, then you will not retain Image Stabilizer or autofocus when using a non-EOS 1D body. While some photographers can certainly deal with the loss, I can not, and am sure others can't either. Also, you must understand that even though you will retain autofocus with a f2.8 or larger lens on any EOS body, the autofocus will become slower due to the 2-stop loss in maximum aperture. I found that autofocus was considerably slower when I tried the duo indoors under decent light. While the mechanism was still silent, it was much slower and hunted a bit before reaching its target. I find that outdoors in excellent light; the autofocus is still quick.
So be aware that using the Canon Extender EF 2x II can limit, or even entirely eliminate, the abilities of your lens. It is all dependent on the camera body you use, as well as the lens you use. So please be sure to research before you buy. Wikipedia has a very good compatibility chart for the Canon EF Extenders if you look it up there. You can also find others online, which I believe include Sigma and Tamron lenses that are compatible with the Canon Extender EF 2x II.
The Canon Extender EF 2x II is a piece of work... It allows you to double your effective focal length range which is a godsend for many people. Those who dished out a lot of money for a lens like the Canon EF 70-200mm F2.8L IS USM Lens will be happy that they can squeeze out 400mm at the long end without having to drop over $1,000 for a new lens like the Canon EF 100-400mm F4.5-5.6L IS USM. If you are very rich and own a wide-aperture super telephoto such as a Canon EF 300mm F2.8L IS USM, using a Canon Extender EF 2x II is MUCH MUCH MUCH cheaper than buying a Canon EF 600mm F4L IS USM!!!
But you must be aware that using this teleconverter will cause image depreciation. You will not have the same image quality as your original lens. The Canon Extender EF 2x II will have poorer image quality than the Canon EF 1.4x Extender, but of course at the obvious cost of focal length range. So it can definitely be a difficult choice between the two. The Canon Extender EF 2x II will also cast greater limitations on Image Stabilization and autofocus depending on which lens and camera you are using. So definitely make sure that it all works.
If you are using a Canon EF 70-200mm F2.8L IS USM Lens to make a living, I would be wary of using the Canon Extender EF 2x II for "money shots" due to the definitely noticeable depreciation in quality. If you shoot for a career and need those super long shots, buying a dedicated lens might be a better idea. Otherwise, you can get some pretty decent or even "good" shots by using the teleconverter. 400mm will take you considerably further than 280mm by using a 1.4x teleconverter on the lens. It's the difference between getting a shot and missing one. Therefore, in conclusion, if you need to shoot far and take pictures for your own personal hobby, the Canon Extender EF 2x II is a very economical alternative versus purchasing an expensive super telephoto lens. If you shoot for a living, perhaps purchase a dedicated lens or consider the 1.4x teleconverter which technically maintains better image quality.
--FOR PHOTOGRAPHERS FAMILIAR WITH THE SLR FORMAT-
The Canon Extender EF 2x II is a very interesting tool to have in your camera bag. You have the ability to dramatically increase your focal length range by double! Though, there are some drawbacks to this setup since it will cause a 2-stop loss in maximum aperture as well as lower the overall image quality considerably. Therefore, the Canon Extender EF 2x II is definitely not for everyone, but with the right expectations, it can let you do a lot that was not possible before.
-Who this teleconverter is for...
I realize that the Canon Extender EF 2x II can have uses for photographers utilizing many different settings. I use mine exclusively with the Canon EF 70-200mm F2.8L IS USM Lens lens. If you read about using this lens with the teleconverter, there are many mixed thoughts. Based on my own usage, I would have to say that the images are satisfactory for my own personal usage, but I would not be selling these images as prints.
Therefore, for hobbyist photographers like me, who simply can not afford to purchase an additional super telephoto zoom, this would be an excellent choice. For professional photographers that need to make money with the images, there are other options out there, such as the Canon EF 100-400mm F4.5-5.6L IS USM lens which has many happy owners. The Canon EF 1.4x Extender II also seems to be a pretty interesting option, where many users are satisfied, though I have not used it with my lens.
I would assume that the Canon Extender EF 2x II would work rather well with some of Canon's highest-end super telephoto lenses. Such lenses include the Canon EF 300mm F2.8L IS USM and Canon EF 400mm F2.8L IS USM. I have not personally used these lenses (but I would love to!), but am sure that the sharper primes will still produce fine images even with the teleconverter. It is also very economical for professionals that are already in the range of using multi-thousand dollar lenses. For example, slapping the Canon Extender EF 2x II on a Canon EF 400mm F2.8L ISM USM will result in a 800mm f5.6 lens. This set-up will cost $7,090 ($6,800 for the lens and $290 for the teleconverter) instead of paying an additional $10,750 for the Canon EF 800mm F5.6L IS USM. Therefore, you are saving well over $10,000 by using this set-up!
Therefore, professionals that are using Canon's finest prime L-Series super telephotos can benefit by using the Canon Extender EF 2x II which leads to extensive cost and weight savings. It is then up to them and customers if the images produced are good enough to be sold. Then a professional can decide if it is truly worth using a converter instead of an additional lens. The Canon Extender EF 2x II adds tremendous flexibility for a small price to pay.
So ultimately, who is the teleconverter for? It is for hobbyists that want to extend the focal length range of their lens without paying a hefty sum for a brand new additional lens (i.e. 70-200mm owners). It is also useful for professionals that want to double the range of their telephoto. Only they can tell, however, whether this type of set-up is better than purchasing an additional lens. Outdoor photographers would benefit most from the teleconverter since it does slow the set-up by two f-stops. I found myself achieving the best results outdoors in broad daylight by shooting at low ISO in aperture-priority mode at f8.0. Therefore, sports photographers or those shooting on vacation will benefit most. I have used the Canon Extender EF 2x II only a handful of times indoors since the slow maximum aperture makes the setup less than desirable. Luckily, I find the 200mm long-end of the Canon EF 70-200mm F2.8L IS USM Lens to be satisfactory for most situations. If you are an exclusive event photographer, there might be better options such as the Sigma 120-300mm f/2.8 EX DG IF HSM APO lens which maintains a constant f2.8 aperture all the way to 300mm.
It also depends heavily on what type of set-up you use. For example, using the Canon Extender EF 2x II with a Canon EF 70-200mm F4L IS USM with a non-EOS 1D body might work for some, but not for others. Thus, those with f2.8 and faster lenses will benefit the most, while its usefulness for slower lenses such as f4 (on a non-EOS 1D body) might be a bit more questionable. Also, if someone needs to extend their range but not as far as 2x, the 1.4x variant might be a desirable choice since there is essentially less depreciation in image quality.
The Canon Extender EF 2x II will set you back $290. Interestingly, it is the same in price as the Canon EF 1.4x Extender II. Is it worth it? If you have realistic expectations and need to double the range of your L-Series telephoto, then it is. If you don't necessarily need a 2x increase, then the 1.4x variant should serve you quite well since it would cause less depreciation in quality. If you only want to use this with L-Series telephotos, then I would purchase this since many people find comfort in using all Canon products in their kit.
However, be aware that the protruding front-element prevents its use with other lenses from both Canon and other manufacturers. If you intend on using this with other lenses, then there are other teleconverters that you can choose from. One popular option that I nearly purchased is the Tamron SP Autofocus 2x Pro Teleconverter. There is no protruding front-element with this so it can be used with a variety of lenses. Sigma also has the Sigma APO Teleconverter 2x EX DG. The other option is from Kenko, which is the Kenko Teleplus Pro 300. Those options will all set you back around $210 which would save you $80 over the Canon Extender EF 2x II. Which is the better option? If you intend on using the teleconverter with other lenses, then perhaps it is worth looking at them. The only other lens that I can really use a teleconverter with is my trusty Canon EF-S 17-55mm f2.8 IS USM lens, but that would be extremely pointless. So if you're planning on using it with a fine L-Series zoom only, then I would probably stick with Canon. I guess there is some psychological gratification of having mostly Canon products for some people. If you're really curious to see how the Canon Extender EF 2x II performs against third-party teleconverters, then buy one and try it out! Then send whichever you don't like.
For the price though, it's a very reasonable way of getting almost an entirely new lens for a fraction of the price! Definitely look into the Canon Extender EF 2x II if it falls within your expectations. It can save you hundreds if not thousands of dollars over buying a brand new lens to fit the new focal length. Not to mention it may do your back a favor.
The Canon Extender EF 2x II is built quite well. When you expect to use it on very expensive L-Series lenses, could you expect anything less? The Canon Extender EF 2x II comes in an attractive off-white finish to match any off-white telephoto lens that you decide to use with it. You will notice that there is a gasket at the camera mount. Now, what is that for? This allows the Canon Extender EF 2x II to complete the weather-sealing of any L-Series lens attached to it! This means that the Canon EF 70-200mm F2.8L IS USM Lens as well as any other weather-sealed lens will retain the sealing with the telecoverter. But remember, the weather-sealing must be completed with a weather-sealed body such as the Canon EOS 1D. Nonetheless, this is quite handy to have, especially for hardcore professionals that are using 1D's with high-end lenses in poor weather. As you would expect, the camera mount is made of metal. Then the front of the teleconverter which goes into the lens is rubberized around the protruding front-element. This is nice since it rubs softly against the mount of the lens. There is a release switch on the side which allows the lens to be easily removed from the teleconverter.
The Canon Extender EF 2x II is not a short piece of equipment. It adds considerable length to the lens. I have to be extra careful when using it with the Canon EF 70-200mm F2.8L IS USM Lens on my Digital Rebel XTi body. I am cautious since I am afraid of the duo ribbing the lens mount out of the camera since the Digital Rebel XTi is made of plastic. I would feel a bit more secure if I were using a Canon EOS ##D made of magnesium, but still must be very careful.
Overall, the build quality of the Canon Extender EF 2x II is nothing short of excellent. It maintains the same metal body as L-Series lenses and holds them quite securely. There is nothing "plasticky" about this teleconverter at all whatsoever. You will be satisfied with the overall build quality.
There's not much to the teleconverter. It just doubles the length of the lens. The resulting performance is dependent on the lens and then the camera body at the other end. As I have mentioned earlier in the review, some lenses have functioning Image Stabilization and autofocus, and some don't. For example, the Canon EF 70-200mm F4L IS USM will retain both its autofocus and Image Stabilizer with the Canon EF 1.4x Extender II, but will not be able to use either with the Canon Extender EF 2x II mounted on a consumer or prosumer body such as Canon EOS ###D or ##D. On the contrary, the Canon EF 70-200mm F2.8L IS USM Lens maintains both its autofocus and Image Stabilizer on any camera body at all. There are charts online that show compatibility, and it would be helpful to look at before purchasing the Canon Extender EF 2x II.
Aside from this, the Canon Extender EF 2x II does feature a well-made metal body with a metal lens mount, a rubberized front element which allows you to safely attach the teleconverter to a lens without worrying about scratching the sides. It also provides weather-sealing which will help complete the weather sealing of any weather-sealed lens assuming you have a weather-sealed body (wow, how many times can I say weather-sealed in a single sentence!). And to top that all off, it comes with a nice little pouch. I wish it came with a closeable case, but this is a nice finishing touch!
The Canon EF 2x Extender does what it's supposed to. It extends the focal length range of the lens by two. But of course the images are different coming through a teleconverter and lens combination versus using the lens alone.
Before going any further into this, I would like to say that I only shoot in RAW format and do all post-processing with DXO Optics Pro.
-The Good Stuff-
There are some things that the Canon Extender EF 2x II does quite well.
*2x Increase in Focal Length - As you might have guessed, the Canon Extender EF 2x II actually does what its supposed to do by increasing your focal length range by two! So if you're using the 70-200mm lens series, it will become a 140-400mm. A 300mm will become a 600mm and so on... So when you're doing this, you must realize that there will be some drawbacks which are mentioned later.
*Image Stabilizer & Autofocus - These continue to work depending on the lens. Please check your setup before purchasing to make sure everything works.
*Color Rendition - The colors do not take a hit. I still was able to dramatically boost the saturation using DXO Optics Pro when editing. So even if you are plagued by image softness when shooting wide-open with the Canon Extender EF 2x II, the colors will still be very good and definitely better than a poor quality consumer lens. I find the color rendition to be just as good as with the lens that I am shooting. Colors are very important to me. This is the area where I get many of my compliments. And images taken with the Canon Extender EF 2x II get complimented as well.
*EXIF Data - The camera reads this lens with absolutely no problems. When looking at the EXIF data on my images, there are absolutely no problems. Everything is read correctly. Therefore, the Canon Extender EF 2x II essentially works seamlessly with the camera.
-The Bad Stuff-
I can't stress enough that you must have realistic expectations when purchasing the Canon Extender EF 2x II. It will double the effective focal length range of your lens, but this comes at a cost! These factors are mentioned below...
*Image Stabilizer & Autofocus - Image Stabilizer doesn't work on certain setups. Autofocus slows down a bit. Indoors this is especially noticeable where the camera tends to hunt. I have not had any issues using it outdoors and haven't noticed it to be dramatically slower. On slower lenses such as the Canon EF 70-200mm F4L IS USM, the autofocus will not work on a consumer or prosumer body. Please check your setup before purchasing to make sure everything works.
*Sharpness - Uh oh... Here is the area where the Canon Extender EF 2x II tends to struggle a bit. I found that sharpness took a definite hit. I can honestly say that many of my images come out quite soft. Though, overall, the images do still look quite decent. I am sure that I will not be selling any of the images taken with the teleconverter (as of yet, maybe my technique can become better over-time), but I still enjoy them for my own personal pleasure. I still do manage to shoot some "very good" images though. How do I this? I shoot in broad daylight in aperture priority mode at f8.0 and with low ISO. I have had some pretty sharp images doing this. So if you are planning on using this outdoors versus indoors, you can get some pretty decent images assuming that there is enough light to allow for a fast-shutter speed (over 1/400) at a maximum aperture of f8.0. Wide-open, the results are less than stellar, and this tends to occur when shooting indoors. Therefore, indoor event photography is not something the Canon Extender EF 2x II would be ideal for, especially if using a lens like the Canon EF 70-200mm F2.8L IS USM Lens.
You can of course help improve sharpness through post-processing. I have had some luck with this while using DXO Optics Pro. Though, using the teleconverter won't allow you to fully take advantage of a program like DXO Optics Pro (more on this a bit later).
If you are using a prime lens, which in this case is sharper than a zoom like the 70-200mm. you will probably achieve better results. At this point, especially if you are a professional, it is up to you to decide if the results are satisfactory or not.
In conclusion, if you can stop-down with the Canon Extender EF 2x II in good lighting conditions, you can get some pretty decent results when it comes to sharpness. You can also help sharpen an image during post-processing, which is what I do. Unfortunately, there is no cure for the loss of sharpness. This is just one of the factors that comes into play when using the Canon Extender EF 2x II. You can also choose the 1.4x variant which should lead to less softening of the image, though you will lose a considerable amount of focal length range by pursuing this option.
*Chromatic Aberration (CA) - This is the fringing of colors, which is a defect. This does make an image look softer. I notice slight chromatic aberration when using the Canon EF 70-200mm F2.8L IS USM Lens as a stand-alone lens. When coupled with the teleconverter, the CA becomes more present. With post-processing in DXO Optics Pro, I am able to correct much of it when using the lens as a stand-alone. With the teleconverter, CA becomes more of an issue and something that you have to live with. While it's not horrible, it is present.
*DXO Optics Pro - I use DXO Optics Pro as my lifeline for editing photos. It is my best friend when it comes to photo processing. It works extremely well with my Canon EF 70-200mm F2.8L IS USM Lens since there are specific modules for this lens. Unfortunately, when using the teleconverter, the lens becomes the Canon EF 140-400mm F5.6L IS USM lens. But... Wait a minute... There is no such thing! Therefore, when processing the images in DXO Optics Pro, the RAW files are no longer read as being from the Canon EF 70-200mm F2.8L IS USM Lens lens. Therefore, there are no specific modules that would offer fine-tuned editing. It just shows up as a 140-400mm lens in DXO. Therefore, I am no longer able to produce better sharpening results (with DXO sharpening) and can't effectively correct chromatic aberration which would be non-problematic with the original lens. The best I can do is unsharpen mask and tinker with the contrast and colors. So while I can do some editing with the images to make them look better, I do not get the ultimate power from DXO Optics Pro via the Canon EF 70-200mm F2.8L IS USM Lens module. I am unfamiliar with other software. But if they operate the same way via modules, then you will not get the most out of your software when using the teleconverter.
The Canon Extender EF 2x II is a very fascinating piece of equipment. It can effectively double your focal length range. This can be a money-saving initiative when one can't afford a lens that falls within the desired focal length. I know that this was the case with me since I could not afford an additional Canon EF 100-400mm F4.5-5.6L IS USM on top of the Canon EF 70-200mm F2.8L IS USM Lens that I already own. This can be even more important with professional photographers since purchasing a 600mm or 800mm can set someone back thousands of dollars!
But before using this, especially if you shoot professionally for a living, you must realize that the Canon Extender EF 2x II does not magically double your focal length without any negative impact. In the end, while you will have a much longer lens, at the same time you will have a lens that is slower by two f-stops, and it will be slower with more defects, like chromatic aberration, being present. These are limitations within themselves. Therefore, I find myself only using the Canon Extender EF 2x II in good weather where I can shoot at a constant aperture of f8 and with low ISO in order to get the best possible results. Indoors, I almost never bust out the teleconverter.
If you are turned off by the negative aspects of the teleconverter, it might be better to purchase the actual lens that fits the desired focal length range (expensive), or you can of course try the Canon EF 1.4x Extender II which might provide better results. However, you will be losing a lot of focal length range potential by using the shorter teleconverter.
Otherwise, if you full understand the drawbacks of the Canon Extender EF 2x II, then you will learn to appreciate it. It will make your lens much longer and will give the opportunity to take photos that you otherwise would not have been able to. Sometimes it is better to take a decent, mediocre, or even bad shot then no shot at all. That is probably the best way at look at it.
**CHECK OUT EOS-MOUNT ITEMS**
Canon EF-S 17-55mm f2.8 IS USM Lens
Canon EF 24-70mm F2.8L USM Lens
Canon EF 24-105mm F4L IS USM
Canon EF 28-135mm f/3.5-5.6 IS USM Lens
Canon EF 28-105mm f/3.5-4.5 II USM Lens
Canon EF-S 18-55mm f/3.5-5.6 USM Lens
Tamron SP AF17-50mm f/2.8 Di-II LD Lens
Canon EF 70-200mm F2.8L IS USM Lens
Canon EF 70-200mm F2.8L IS USM II Lens
Canon EF 70-300mm f4-5.6 IS USM Lens
Canon EF 75-300mm f4-5.6 III Lens
Canon EF 35mm F1.4L USM Lens
Canon EF 50mm f1.8 II Lens
Sigma 50mm f1.4 EX DG HSM Lens
Sigma 12-24mm f4.5-5.6 EX DG HSM Lens
Tokina 10-17mm f3.5-4.5 AT-X 107 AF DX Lens
Canon Speedlite 580EX II Flash
Canon Speedlite 430EX Flash
Metz Mecablitz 58 AF-1 Flash
Canon Gadget Bag 100DG