Canon EF 70-200mm L IS USM f2.8 with 2X teleconverter Home » Forums » Photography » Lenses

I decided to buy the Canon 70-200 f/2.8 IS L USM lens as my first professional lens, because I knew I would always need a general purpose telephoto lens, even though 200 mm is not normally considered a good lens for bird photography. I bought the Canon 2X II teleconverter, giving me a 400mm lens, even though I had seen this article

http://photo.net/equipment/canon/tc1/

which is very negative about this lens/teleconverter combination, and the user discussion afterwards is about the same. But I hoped I could get better results than in the article. For one thing, how scientific is testing lenses and comparing photos of a moving object? But in fairness to the author, this was my only criticism of his testing methods.

The discussion references this article, which is a more general discussion, and not about the specific parts I am using.

http://www.bobatkins.com/photography/tutorials/tc3.html

I think that a teleconverter is something that if it works, it will just barely work. So trying to use one by a different manufacturer is just asking for trouble.

At this point I had read from many people who don't have anything great to say about teleconverters with the 70-200 f/2.8 lens, and my results for the most part hadn't been much better. I should qualify that as I have taken very sharp photos with the teleconverter, but rarely if ever at 400mm, and I am looking for the kind of extreme sharpness seen in the images below. Taking photos at 400mm (200mm lens with the 2X teleconverter) is much much harder than at 200mm. First, you have just a fraction of the light you have at 200mm, requiring a much longer shutter exposure, which makes any vibration or movement more noticeable. The additional distance of the subject also amplifies any vibration. I am usually shooting hand-held or with a travel tripod or beanbag, so I wondered if maybe I just didn't have a good enough platform for my 400mm shots.

Another issue is keeping all of the lenses clean. I am always removing and replacing the teleconverter, and imagine any dust could be magnified by the lens combinations.

On birdphotos.com are some super-sharp photographs taken with different Canon teleconverters and lenses, by different photographers, so I was still optimistic. I know both of these photographers have sturdy tripods. Check the pixels on these photos, two of which are at 1000mm, and one at 600mm. Recently I've written an article about the 300mm f/2.8 and the 2X teleconverter, a great combination.

http://www.BirdPhotos.com/photos/index.php?q=gallery&g2_itemId=5094
http://www.BirdPhotos.com/photos/index.php?q=gallery&g2_itemId=5094
http://www.BirdPhotos.com/photos/index.php?q=gallery&g2_itemId=5693

I was also hopeful when I came across an article by local nature photographer Peter Schultz.

http://peterpeterpeter.com/pages/teleconvertors.htm

He writes that teleconverters don't work well at 'open' f settings (2.8 for example), so recommends shooting one 'stop' or one higher f-setting over the minimum possible with the telconverter. His article is about Nikon lenses, but this is consistent with the first article indicating f11-f16 was the best range. The Canon 2X teleconverter takes away 2 'stops'. or f-settings, so the Canon 70-200 f2.8 lens turns into a f4 and then f5.6. I had generally used the teleconverter at f5.6 because I knew it was taking a lot of light, and I wanted to keep as much light I could. But now I will just use it at f8 to f11 with the sun behind me.

I know everyone is waiting for a conclusion or an answer, but I don't have that yet. Unless sample images are provided, or the writer is known to be knowledgeable, it is hard to know what is credible information on the internet. In the origianal article, for example, one person posted a fuzzy image to show how sharp the 2X teleconverter was.
I have seen several discussions that maybe the 2X and the Canon 70-200 are not the best combination. http://www.tomshardware.com/forum/31138-5-canon-telextender
is one example. My intuition is that this is the case, and probably the 1.4 Extender is the best choice for this lens. I will be doing field testing, but not having a 400mm lens makes it hard to know if any sharpness issues are from the lens or the technique. My first tests looked like the problem was not with the sharpess, but the focal point being in the wrong place. So stay tuned for testing results.

But if it is true that a f-setting above 8 is needed to get good results, then the teleconverter is already a very limiting device, compared to for example the Canon 400 f2.8 lens. Shooting at f8 is fine when you have enough light to get a good shutter speed, but sometimes this is not possible.

Here are Amazon links to some of the lenses discussed:
Canon EF 2X II Extender
Canon EF 1.4X II Extender
Canon EF 70-200mm f/2.8L IS USM Telephoto

Another recent article on naturescapes.net

concluded the same as I, that this lens and the 2X converter just aren't a good combination.

300/f4 with 1.4x

I've been using this combination, giving me 420 at f/5.6 and am quite pleased. It is not the same as having a 300mm f/2.8 lens or a 500mm f/4 lens, but I am getting much better results than the 200mm with 2x, and the lenses mentioned are a few thousand dollars more.

Teleconverter wth 300 f/4 L IS lens

I rented a 300 f/4 lens and with the teleconverter at 600mm I had better sharper results than I had with my 70-200mm lens with the teleconverter. But I could not use automatic focus with this lens and the 2x teleconverter. This is consistent with my theory that the 70-200mm lens just doesn't work well with the 2X.

One other variable is the camera. My camera has a small image sensor and hence small pixel size. A top-of-the-line Canon camera might produce better results.