2 x converter

[NIVEA]

Hiya everybody, I have a question for you camera buffs. Ive got a Canon EOS 7D and ive currently got a 70-210mm lens on it and my question is this - If I add a 2 x converter to the lens what benefits would I gain from using that add on ? Thanks in advance for any help on this.

 

[SCraig]

In many cases the deficits outweigh any benefits.

Pro ...
You will increase the focal length of your lens from 70-210mm to 140-420mm.

Con ...
1. You will lose two complete stops of light. So if the lens is an f/2.8 lens it will suddenly become an f/4 lens wide open. With slower lenses this will frequently affect the ability to autofocus, especially in less than bright conditions, since there is not enough light reaching the autofocus sensor.

2. Image quality can suffer dramatically. In many cases better image quality will result from cropping the image without the teleconverter as opposed to using it. If you get a good one (read "Expensive") that is matched to the lens this can be less of an issue but any time you add more layers of glass you increase the likelihood of decreased image quality.

3. Some lenses (and I have NO idea what they would be in the Canon line since I shoot Nikon) will not work with some teleconverters since the rear lens element conflicts with the front element of the teleconverter.

 

[480sparky]

.....1. You will lose two complete stops of light. So if the lens is an f/2.8 lens it will suddenly become an f/4 lens wide open. ...........

Um......... f/5.6, not f/4.

 

[Derrel]

Yes, the f/2.8 maximum aperture of the main lens will be reduced two full f/stops, to f/5.6 nominally, and perhaps due to surface-to-air in say a 7-element teleconverter, plus the 17- to 21-elements found in a typical 70-200 f/2.8 lens, the actual T-stop, or Transmission Stop, will allow in even _less_ light than the mathematical f/5.6 value!

Often a better solution is to go with a camera-maker, fully compatible 1.4x TC unit, which costs not two, but one, full f/stop of light transmission. But, as was mentioned above, it might actually be better to crop-in using only the main lens, and no TC unit; this is especially true these days, now that we have high megapixel count sensors. In the days of 6- and 8- and 10-MP sensors, using a TC unit was, I think, a better trade-off. However, today, with 24- to 36-MP cameras, I think it makes much more sense to crop-in on the image made with just the main lens, rather than use a teleconverter.

Let me state this: there are good teleconverters, and fair ones, and poor ones. Generally, a 2x TC is worse than a 1.4x, when used with any lens, but especially with a zoom lens. Many people find camera maker 1.4x TC units to be acceptable with 70-200mm f/2.8 zooms. With those generalities out of the way, keep in mind too that the very newest Canon 70-200/2.8 and the newest TC units are better than the ones that were offered for decades prior; the same goes for the newer Nikkor zooms paired with the newest, aspherical-element Nikon-made teleconverters.

Lastly: for some types of work, the performance of a zoom + TC might be acceptable, or even good; it depends on the lens+ converter pairing, and the subject matter, and the shooter's own preferences.

 

[NIVEA]

Thank you very much for the information that you have given me on the 2x converter. I now understand the differences and that will help me make my mind up . . . . . . . EXCELLENT INFORMATION

 

[photoflyer]

Thank you very much for the information that you have given me on the 2x converter. I now understand the differences and that will help me make my mind up . . . . . . . EXCELLENT INFORMATION

Don't know if you pulled the trigger but I have the Canon 70-200 2.8 and the 2x converter so for what it is worth...

I did this because it was the cheapest way to get 400mm and while the results are very good (they were specifically designed to work together) I have no illusions that this combo is a substitute for a native 400mm L series lens prime or zoom.

Would I spend the $400 again? Yes.

 

[zombiesniper]

I have borrowed a canon version 3, 2x converter for the last 2 weeks and have used it on my 500mm F4 and the 70-200 F4 with my 7DmkII and 80D. It is does make the image larger but unfortunately it also makes it quite a bit less sharp. So much so that it is sharper when I crop my 500mm images to 1000mm.
I have in the past tried a version 2 and 1. The version 2 was the best 2x canon converter for my set up. Overall though if you have quality glass give it a try.

The key to making it work? A really good camera shop. Try each converter until you find the one that works best with your set up then buy it. Not all shops will let you unbox a bunch of gear. Luckily my local shop is excellent.

If your lens isn't top quality a converter will only be a waste of money since it will also magnify any flaws in the glass. A converter isn't going to give you a quality 600mm equivalent lens if you start with 300mm of mediocre.


Good luck

 

[sniper x]

I use both a 1.4x and 2.0 but ONLY use the 2.0 when I can use manual focus, and have plenty of light as described above. BUT with todays cameras with their great detail even at super high ISO that doesn't make a lot of difference. Soooo, you can use a 2x without it being broad daylight, however you need to use manual focus.