t6i compatibility with tamron 160-600mm G2/ with teleconverters

[flyers1kak]

hi everyone, 

I was hoping someone may have an answer for this tough one.

I have a Canon Rebel t6i, and currently have the original Tamron (A011) 150-600mm lens. It works great, however it leaves a little to be desired at 600mm (a little soft). Understandable for a lower end telephoto lens. I am looking to upgrade to the newer version of this lens, the G2, which I'm told has compatibility with the Tamron 1.4x and 2.0 teleconverters, extending my zoom range to 800mm if I went with the 1.4x. I have read many reviews that the camera does not autofocus with these teleconverters however. I reached out to Tamron and you can see their response below. So my question is, does the Rebel T6i have an F8 compatible camera sensor?

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As long as you have an F8 compatible camera sensor the lens and tele will AF up to F8.

Ali 
Customer Service

Subject: RE: Tamron SP 150-600mm G2 Autofocus with 2x extender?

Will autofocus still work with the 2x extender and the 150-600mm lens? I have heard MANY reports that it does not

Best regards,

From: Ali 
Sent: Friday, December 22, 2017 1:28 PM
To: Kevin
Subject: RE: Tamron SP 150-600mm G2 Autofocus with 2x extender?

Yes the newer version of the 150-5600 model A022 will be compatible with both teleconverters.

Ali

Tamron USA, Inc. 10 Austin Blvd, Commack, NY 11725 www.tamron-usa.com

From: Kevin
Sent: Thursday, December 21, 2017 2:40 PM
To: Custserv Dept <custserv@tamron.com>
Subject: Tamron SP 150-600mm G2 Autofocus with 2x extender?

Hi there,

I have the original model (A011) of this lens and have a question about the newer model. I have read reports that the 1.4x and 2x extenders do not allow autofocus with my current model. Does autofocus work with the G2 model paired with the teleconverters? I am looking to upgrade to the new lens but only if I can use it with the 2x teleconverter while using autofocus. Thanks!

[ebiggs1 · Accepted solution]

Let's consider a few things.  First on a Rebel T6i with the big G2 you are looking at nearly 1000mm of focal length.  That is already a bunch to deal with.  Adding the 1.4 tel-con puts you into the 1350mm range.  If the T6i can AF with that much focal length the loss of aperture isn't the real question.  That much focal length has other issues to overcome besides.

You will need extraordinary skills to handle that much FL.  The atmosphere will rare its ugly head now just for fun.

If memory servers me the T6i is limited to f5.6.  If that is true you will not have AF or anything that resembles decent AF.

As for the 2x tel-con you are looking at nearly 2000mm FL and there is no way I would recommend that on any camera.

[flyers1kak]

Thanks for the reply ebiggs! I am fairly new to photography and I don't think I understand your reply completely. How will the G2 give me 1000mm of focal length if it is a 150-600mm (without a teleconverter)? Wouldn't it be the same focal length as the 150-600mm that I currently have? I was under the impression that if I upgraded to the new lens, and purchased the 1.4x teleconverter, my max focal length would be 840mm.

At the end of the day, regardless of focal length, the fact that you say my camera is limited to f5.6 pretty much means I shouldn't upgrade lenses, so thanks for saving me some cash!

[ebiggs1]

You have to add this factor to any lens that you use on Rebel which your T6i is of course.  It has a 1.6x benefit from the use of telephoto lenses.  Let's consider, 600mm x the 1.6x factor = 960mm equivalent.  This reall y has nothing to do with the Tamron model G2 or the original.  Just that you are dealing with 600mm.

Now add a tel-con. 960mm x 1.4x tel-con = 1344mm.  960mm x 2x = 1920mm.  The actual FL of the Tamron (G2) does not change.  That is impossible but what the T6i sees does.

This also effects the other end when you are wanting a WA lens.  Let's say an 18-55mm kit lens for instance.  Actual equivalent FL is 28-88mm approx.  Remembe the FL of the lens, any lens, can not be changed just what the T6i sees.

[flyers1kak]

makes sense thank you!

[ebiggs1]

You may ask if my camera has to have at least f5.6 to AF how can the big Tammy AF when it slides down to f6.3 at the 600mm end?  Easy, the lens lies to the camera!  It tells the T6i that a f5 lens is still attached.  There are 'ways' to make a f8 or even f11 lens AF on cameras that don't offer that feature.  However the AF isn't very good and it is very slow.  Not really recommended you do it.  You can manual focus,however.

[diverhank]

I'd advise against using a teleconverter on such a lens...I doubt if the G2 version will give you noticeable improvement over the version 1 @ 600mm.  A teleconverter will further decrease IQ, coupled with reduced AF performance - in your camera - non-existent AF...