EF 100-400mm F4.5-5.6L IS II USM + Extender EF 2x III + Rebel EOS T7I

[sridzyowski]

Hi Everyone,

Im new to photography. My Wife loves to take pictures of flowers and insects however I mainly like to take pictures of Birds from a distance and other things further away like the moon with my powershot sx60 

SO MY QUESTION IS. 

I just purchased the new Rebel EOS T7I .. Love it. but looking to ger the   EF 100-400mm F4.5-5.6L IS II USM .. but i was also looking into purchasing an extender with it and figured why not get the   Extender EF 2x III . Would all this be possible and work with my T7I .. or would i just need to get the 1.4x ? 

All answers are helpful as well as any suggestions. 

Thanks Ahead of time

[cicopo]

That depends on a few things but the most important one is whether or not the camera can AF at F 8 or F 11 which iswhat the 2 TC's you mention make the widest aperture that lens can give with a TC added to the light path. It's doubtful that body can AF at F 8 but if it can it will be too slow for birds in flight.

[sridzyowski]

I just did some research and found this.

Canon EOS Rebel T7i (800D), 77D, 80D

TODO: Expand with lens group information

45 points are available at all apertures f/5.6 or wider, 27 at f/8. With certain exceptions, the following apply:

• If f/2.8 or wider, all 45 points are cross-type; additionally, the center point is high-precision dual cross-type.
• If f/5.6 or wider, all 45 points remain cross-type but the center point is standard-precision single cross-type.
• If f/8 or wider, 27 points remain available, 9 of which are cross-type.
• Autofocus does not function with lenses narrower than f/8.
  
  
  
  So does this mean that it will autofocus in the f/8/11?

[Waddizzle]

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@sridzyowski wrote:

I just did some research and found this.

Canon EOS Rebel T7i (800D), 77D, 80D

TODO: Expand with lens group information

45 points are available at all apertures f/5.6 or wider, 27 at f/8. With certain exceptions, the following apply:

• If f/2.8 or wider, all 45 points are cross-type; additionally, the center point is high-precision dual cross-type.
• If f/5.6 or wider, all 45 points remain cross-type but the center point is standard-precision single cross-type.
• If f/8 or wider, 27 points remain available, 9 of which are cross-type.
• Autofocus does not function with lenses narrower than f/8.
  
  
  
  So does this mean that it will autofocus in the f/8/11?

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It does seem to say that.  But, only use the 1.4x with 100-400mm.  The 2x should be used with f/4 lenses, or faster.

Be aware that the 100-400mm is a pretty hefty lens, and can take marvelous pictures of flowers due to its' relatively short MFD, Minimum Focusing Distance.

Shot with a 7D Mark II and the 100-400mm.  Didn't plan to use it that way.  The nearby bird pond was empty.

[RobertTheFat]

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@sridzyowski wrote:

I just did some research and found this.

Canon EOS Rebel T7i (800D), 77D, 80D

TODO: Expand with lens group information

45 points are available at all apertures f/5.6 or wider, 27 at f/8. With certain exceptions, the following apply:

• If f/2.8 or wider, all 45 points are cross-type; additionally, the center point is high-precision dual cross-type.
• If f/5.6 or wider, all 45 points remain cross-type but the center point is standard-precision single cross-type.
• If f/8 or wider, 27 points remain available, 9 of which are cross-type.
• Autofocus does not function with lenses narrower than f/8.
  
  
  So does this mean that it will autofocus in the f/8/11?

---

No. It says definitively that the camera will not autofocus with lenses narrower than f/8. The 100-400 with a 2X is about f/11 at the long end. With a 1.4X, it's barely under f/8 at the long end and therefore should work (but is likely to focus slowly).

[ebiggs1]

"Would all this be possible and work with my T7I"

It might work but it will not be nice!  I would not do it.  I have not used that combo but do have some experience. It will probably work OK with the 1.4x extender, however.

Let me suggest some alternatives if you need more focal length.

Either one of the Tamron or Sigma 150-600mm zooms.  Nearly identical so it is a 'your choice' decision.  In a prime lens, the ef 400mm f5.6 prime.  Even with a 1.4x extender, it is a good choice.

Keep this in mind, a 400mm lens on your T7i is equivalent to a 640mm lens on a FF.  This is serious focal length.  It will bring its own problems by itself.  If you choose the Sigma or Tamron 150-600mils you have a max focal length of 960mm.  This will take some work to use effectively.

 If you could use the 2x on the 400mil, it is 1280mm and going to be very difficult to use.  Even if it would work.

You might ask, well what is the solution?  The solution is free, doesn't cost a thing.  Get closer !

[sridzyowski]

I also Have the Sigma 150-600 we used it in hawaii for whale watching on our honeymoon. So The 1.4 Extension would work with that lense? Basically with my set up i dont really need the 2x ? 

[kvbarkley]

I have used the 1.4X on my 150-600 (T6S) and it works.

[diverhank]

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@sridzyowski wrote:

I also Have the Sigma 150-600 we used it in hawaii for whale watching on our honeymoon. So The 1.4 Extension would work with that lense? Basically with my set up i dont really need the 2x ? 

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You use the 2X only if you don't mind manual focusing.  I have both the 1.4x and the 2x and I hardly ever touch the 2x even with my 600mm f/4 lens where I can still atofocus with it.

In my experience, IQ remains decent with the 1.4x...focus speed suffers some but it's usable.  With the 2X, IQ suffers more...often very noticeable.  For the 100-400, focus won't work with it.  Even with an f/4 lens where you can still focus (in my case the 600mm f/4), the focus speed is not fast enough for sports or in my case, birds in flight.  

So my recommendation is to save your money on not getting the 2X.

[TCampbell]

When you use an extender / teleconverter (focal length multiplier) such as the 1.4x or 2x then in addition to multiplying the focal lengths you must also mutliply the aperture.

A 5.6 lens becomes an f/8 lens when used with a 1.4x extender.

Only a few of the newest cameras support this... most DSLRs are limited to about f/5.6.

It's not easy to do this -- even in the days of manual focus with the split-prism focusing aid, using a high focal ratio resulted in not being able to use the split prism (one half would go black.)

The 100-400mm f/4-5.6 combined with the 1.4x is a fairly common configuration provided the camera can auto-focus at f/8 (your does).

You will not have working auto-focus with that lens if you use the 2x extender.  That's really only for use with f/4 or f/2.8 lenses.