Questions about Canon EF 2x III teleconverter

I assume you mean the EF 70-200mm f/2.8L IS II USM. The converter is compatible with me in this combination. However, I was not satisfied with the image quality (especially the sharpness). I like the result very much with fixed focal lengths.

In theory, yes, according to this link https://www.canon.co.uk/pro/infobank/lens-extenders/, but there may indeed be problems with light and therefore autofocus. We'll have to see in practice, depending on the conditions.

Yes, we're in.

No. Teleconverters from camera manufacturers only fit a few top lenses from the manufacturer and never for lenses from other manufacturers. A 2x teleconverter on a low-light zoom like the 18-400 is completely pointless anyway, but beginners always ask this question. This would result in an ultra-dark zoom with miserable image quality.

No

No

Yes, this is normal with most Canon DSLRs. They can no longer focus at f11.

Will not work.

Yes compatible but without autofocus

Yes, the converter fits this lens. I myself also use the converter with this lens. However, you have to focus manually. At least with a Canon 5D Mark IV, the "normal" autofocus can no longer be used with this converter. Alternatively, you can use the LiveView to focus or, if you have connected the camera via WiFi, also via the phone or tablet with the appropriate Canon app.

Yes is compatible with the EF 70-200 2.8 IS III USM but not with the 24-70. That makes no sense on the 24-70

I should remark that I bought the doubler as a way to get to 400 mm without either spending a fortune or having to carry another heavy lens. So far I have been very impressed indeed with the quality of the results when using it with an EF 70-200 F 4.0 L IS USM. Thus, I can recommend the price/performance of the doubler without reservation. Of course, using a doubler halves the amount of light, so the max aperture of my 70-200 is reduced from F4 to F8. This will surly kill the auto focus as Marcel (above) remarks. The AF at F8 does work perfectly with my EOS-R, but that is a very different question. Thus: 1. The doubler will work with the 500D I think, but with the problem mentioned concerning AF. 2. & 3. I have an EOS 70D with an EF-S 15-85 F 3.5-5.6 IS USM. However, I do not believe that this will work with the doubler because the rear element of the EF-S lens sticks out too far. This is presumably the same reason that an EF-S lens cannot be fitted to a Full Frame Canon body. Thus, I doubt that either of the EF-S lens mentioned will work with the doubler, although you may be able to check compatibility with Canon. A quick Web search gives the same opinions. 4. If the Tamron is designed for a Full Frame "EF" body, which I think it is, it will probably work. Check that the rear element does not protrude further back than the seating flange. However, halving the aperture of an F5/6.3 lens will leave very little light, especially given the issue of noise with an 11 year old sensor.

Sorry for the question who seeks finds .... https://store.canon.ch/fr/canon-multiplicateur-canon-ef-2x-iii/4410B005/ EF 600mm f/4L IS USMEF 400mm f/2.8L IS III USMEF 600mm f/4L IS III USMEF 800mm f/5.6L IS USMEF 500mm f/4L IS II USMEF 500mm f/4L IS USMEF 400mm f/5.6L USMEF 400mm f/4 DO IS II USMEF 400mm f/4 DO IS USMEF 600mm f/4L IS II USMEF 135mm f/2L USMEF 300mm f/2.8L IS II USMEF 300mm f/4L IS USMEF 200mm f/2L IS USMEF 200mm f/2.8L II USMEF 300mm f/2.8L IS USMEF 400mm f/2.8L IS USMEF 400mm f/2.8L IS II USMEF 180mm f/3.5L Macro USMEF 28-300mm f/3.5-5.6L IS USMEF 70-200mm f/2.8L IS II USMEF 70-200mm f/2.8L IS III USMEF 70-200mm f/2.8L USMEF 70-200mm f/4L IS USMEF 70-200mm f/4L IS II USMEF 70-200mm f/4L USMEF 100-400mm f/4.5 - 5.6L IS II USMEF 100-400mm f/4.5 - 5.6L IS USMEF 200-400mm f/4L IS USM Extender 1.4x

As far as I know, there is no difference other than magnification. With the 2x you have 140-400 mm, with the small 98 - 280 mm. The speed also decreases with the factor. The converter turns 2.8 into 5.6. Since your lens already covers the range 98-200 without the converter, I would recommend the 2x. Note: the thing also works with the 105 mm macro. With a 210 mm macro you can turn a mosquito into a sperm whale. However, the handling is extremely demanding. Have fun with it!

Unfortunately, I can't tell you. Ask digitec customer service.

Hello, in the manual for the EOS 1DX Mk II the following 70-300mm lenses are listed as compatible: (this manual is more up to date than the manual for the extender) EF 70-300mm f/4-5.6 IS USM * EF 70-300mm f/4-5.6 IS II USM EF 70-300mm f/4-5.6L IS USM EF 70-300mm f/4-5.6 DO IS USM

Yes

No. These adapters were made for lenses with an aperture of 2.8. If you use this adapter, your light will be halved -> you will then have to multiply the 100-300 f4.5-5.6 by 2. This means that your camera will no longer be able to focus. They can only focus up to f/8 at the most. Better buy a 150-600mm from Tamron or Sigma... the cheapest costs 900.- €.

Yes you can use it, but the autofocus will not work, as it will give an f10-12.6 and it works up to f8 (painfully) depending on the camera!