Teleconverter x2

Started Mar 7, 2017 | Questions
jennyb New Member • Posts: 1
Teleconverter x2

I have just purchased a Tamron x2 teleconverter to use with my Tamron 70-300mm lens on my Sony a58. I don't seem to be able to take pictures in 'auto' mode. I am not a very accomplished photographer and do rely heavily on auto settings at the moment. Is this not an option with a teleconverter or is there a way to fix the problem?

Thanks

 jennyb's gear list:jennyb's gear list
Sony SLT-A58 Tamron SP 70-300mm F/4-5.6 Di USD Sony 28-75mm F2.8 SAM Tamron SP 2X Pro Teleconverter
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Sony SLT-A58 Tamron SP 2X Pro Teleconverter
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Sandy Senior Member • Posts: 2,157
Re: Teleconverter x2
1

Remember you lose 2 stops of light with a 2x TC.  So, your f5.6 will become f11 and the lens will not autofocus.  The usual limit on AF is f8.

I would caution against TCs in general unless you are using a high quality lens and a TC designed for it.  I guess there are VERY few 2xTC and lens combos that actually work better then a crop of the image without the TC.

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Sandy

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Douglas F Watt Veteran Member • Posts: 3,784
Re: Teleconverter x2

Sandy wrote:

Remember you lose 2 stops of light with a 2x TC. So, your f5.6 will become f11 and the lens will not autofocus. The usual limit on AF is f8.

I would caution against TCs in general unless you are using a high quality lens and a TC designed for it. I guess there are VERY few 2xTC and lens combos that actually work better then a crop of the image without the TC.

+1 on all that!  I might add that even with my best telephoto primes, I no longer really attempt to use the TC2.0, but will use the TC1.4 sometimes.  But again, only on the best primes.  Would not recommend using even those on many zooms.  May be a couple that are good enough.  But not many.

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Sony A99ii-A77ii-RX10III-RX100III
Sigma: 8-16 f4.5-5.6, 500 F4.5 EX DG APO
Tamron: 70-200 f2.8 USD
Sony ZA: 24 f2, 85 1.4, 135 1.8, 24-70 2.8 SSMII
Sony: 16-50 f2.8, 100 f2.8M, 70-400 f4-5.6 G2
Minolta: 600 f4, 70-210 f4 ('Beercan'), 28-135 f4-4.5 ('SH')
DFW

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lhkjacky Senior Member • Posts: 2,918
Re: Teleconverter x2

jennyb wrote:

I have just purchased a Tamron x2 teleconverter to use with my Tamron 70-300mm lens on my Sony a58. I don't seem to be able to take pictures in 'auto' mode. I am not a very accomplished photographer and do rely heavily on auto settings at the moment. Is this not an option with a teleconverter or is there a way to fix the problem?

Thanks

Personally, I do not recommend using 2x TC on small aperture zoom lens.
TC is only good for large aperture tele prime lens.

2x TC reduce 2 stop of max. aperture, camera cannot focus if the max. aperture is too small.

Kenko Teleconverter is a special case. It can still AF with Sony 70-300 G in good light, but the AF speed is super slow.

 lhkjacky's gear list:lhkjacky's gear list
Sony a77 II Sony DT 16-50mm F2.8 SSM Tamron SP 70-200mm F/2.8 Di VC USD Tamron SP 150-600mm F/5-6.3 Di VC USD Ricoh GR +6 more
Lensmate
Lensmate Veteran Member • Posts: 4,636
Re: Teleconverter x2

jennyb wrote:

I have just purchased a Tamron x2 teleconverter to use with my Tamron 70-300mm lens on my Sony a58. I don't seem to be able to take pictures in 'auto' mode. I am not a very accomplished photographer and do rely heavily on auto settings at the moment. Is this not an option with a teleconverter or is there a way to fix the problem?

Thanks

+1 on all of the above answers, and as an extra point, [depending on how/what you shoot] bear in mind the atmospheric refraction one incurs by increasing the focal length with a TC. The 'seeing' may become an issue compounded by the addition of a TC.

-Martin P

https://www.flickr.com/photos/photosauraus_rex/

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sybersitizen Forum Pro • Posts: 17,764
Re: Teleconverter x2

jennyb wrote:

I am not a very accomplished photographer and do rely heavily on auto settings at the moment.

You cannot rely on autofocus with that combo, but I assume you can still rely on autoexposure.

QuietOC
QuietOC Veteran Member • Posts: 4,190
Re: Teleconverter x2

jennyb wrote:

I have just purchased a Tamron x2 teleconverter to use with my Tamron 70-300mm lens on my Sony a58. I don't seem to be able to take pictures in 'auto' mode. I am not a very accomplished photographer and do rely heavily on auto settings at the moment. Is this not an option with a teleconverter or is there a way to fix the problem?

It should take pictures. It sounds like the camera isn't communicating with the lens through the teleconverter. I have a teleconverter with flaky electrical contacts. If I twist it just right it will make contact and the camera will read the lens. If you enable "release without lens" the camera should still take a picture.

If your Tamron is very sharp at 300 mm, it might be usable at 600 mm, but you will be magnifying all the defects in the lens. I find the background rendering looks pretty bad from my 55-300 on a teleconverter.

It is possible the Tamron teleconverter isn't fully compatible with your Tamron lens. AF worked for me with the Kenko DGX teleconverters and the Tamron SP 70-300 USD. I didn't find that lens to me sharp enough at  the long end to be worth using on a teleconverter.

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