2x teleconverters

macs

macs

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Hi, I'm playing around with the idea of getting one of these as a cheaper option to getting new lenses.

Are there any drawbacks to using these? Are they all really poor quality? Do the have any adverse affects on image quality? Or other technical aspects eg aperture? Are some better than others? Which brands should I look out for and which should I avoid?

If it makes any difference it'll be used on my 18-55 kit lens and 55-200.

Thanks
 
For reference, not many lenses can use a 2x TC and still retain AF, when you add the TC the maximum aperture will change and once it gets to f8 most bodies will refuse to AF.
Certainly Canon ones anyway, not sure about Nikon.
 
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As above really and far as I'm aware these wont work with a TC. The TC may not even fit

Unfortunately, I don't think this is the best way forward - I think you need to be looking for a new lens ...
 
As a general rule of thumb, (for Canon), a constant F4 lens will take a 1.4TC and become an F5.6 lens, a constant F 2.8 will take either a 1.4 or 2 TC and become an F4 or F5.6. These will still then AF on your body - as I said, a general rule of thumb, because there are some anomalies with other TC makes
 
Nikons are a little more forgiving in terms of retaining AF but be aware of the physical limitations of fit - some lenses simply can't take telecons or at least not Nikon telecons. The lenses' manuals should tell you of any issues - if you haven't got the manuals, look on Nikon's website to find downloadable ones. I know for certain that the 70-300 VR cannot take Nikon telecons - the rear element of the lens actually makes contact with the front element of the converter. The lens will accept a Teleplus 1.5x converter though but the r5esults are poor - better to crop into the unconverted image.

Telecons tend to work better with primes than with zooms (with exceptions, mainly among higher end zooms) and also work best with lenses they're designed to work with (ie Nikkor telecons are the best match for Nikkor lenses [where suitable], Sigma telecons with Sigmas etc).

http://www.nikonsupport.eu/europe/Manuals/EGhNxSbbrW/TC-14EII-17EII-20EIII_(80)05.pdf
 
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I use a Nikon TC-20E III AF-S 2x Teleconverter on my 70-200 f2.8 VRII.
It makes it a f5.6.
I really think it's does a fantastic job of giving me the extra reach with a reasonable outlay in price.
On DX this gives me a 600mm equivalent and good reach for airshows/wildlife .etc
 
macs said:
If it makes any difference it'll be used on my 18-55 kit lens and 55-200.
Thanks
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Don't think they (definitely not Nikon) will be compatable with those lenses, especially the 18-55mm.

The Kenko one might with your 55-200mm but don't waste your money. TCs are designed for fast focusing prime lenses because they can handle the drop off in autofocus speeds and loss on IQs.

If you have said Nikon 70-200mm f2.8 then no problem, all 3 nikon TCs work, or the Kenko ones, but not the 55-200mm.
 
Hi, its been suggested that I get a x2 TC for a 70-200 f2.8 as I'm missing range with my 55-200. Its either that or get a 150-500 lens which would work out cheaper second hand the a nikon TC2 new (they don't come up often it would appear).

I also saw the Kenko and read some good reviews on it saying it focused better then the Nikon.

Can you explain in more detail why the camera won't focus on the kit lens? Mine finds focus indoors at 200mm f36. Is this comparable scenerio?
 
Peter69 said:
Can you explain in more detail why the camera won't focus on the kit lens? Mine finds focus indoors at 200mm f36. Is this comparable scenerio?
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From my little technical knowledge I understand this is because the camera receives too little light and therefore contrast to be able to decide where to focus.
Your focus works at f/36 because the lens is wide open at the time it focuses - the lens only stops down to f/36 when the shutter operates, or you press the DoF preview button.

I too was initially interested in TCs to increase my reach but soon realised that ideally you need constant f/4 or better still f/2.8 lenses (lots of £!)

The xx-500mm lens options might be a better option if you need/want the length.
 
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Thanks Simon.

I now understand the loss of light a bit more.
I will be getting the 70-200 f2.8 so if I can get a TC cheaper enough I think I'll give it a go.

Any feedback on Kenko would be great though
 
I have no technical knowledge but I have owned a 2xTC and a 1.4xTC both Kenko pro and used them on a nikon 80-200 f2.8 and although both retained autofocus the 1.4xTC shown no loss of image quality but the 2xTC was definately not as good, needless to say I still have the 1.4xTC.
 
Thanks Paul.

so in your opinion the Kenko x2 falls short of expected quality. Have you any images I can view?

Did you buy a 400mm to replace the x2 ?
 
Just to confirm the above, there's no TC available I have found which will fit on a EF-s lens, that back element just sticks out too far.
 
Peter69 said:
Thanks Paul.

so in your opinion the Kenko x2 falls short of expected quality. Have you any images I can view?

Did you buy a 400mm to replace the x2 ?
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I didnt buy a 400mm and I didnt replace the 2XTC because with the crop factor on my Nikon D300 sensor and the fact that my 80-200 f2.8 is a 35mm (the old two touch version) I felt that the 1.4XTC was more than ample for what I needed but thats not to say that I dont still lust after a Bigma:)
sorry I dont have any examples but my Kenko is the teleplus pro300dg
 
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