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Esteemed Contributor
Posts: 4,279
Registered: ‎06-25-2014

Re: Camera upgrade advice, please!


@Stephenwrote:

The T3i came out before our STM lens technology and before the advances we made in both Dual Pixel Auto Focus. That means that it has to hunt to focus and compare the contrast in the scene using the DIGIC IV processor (we're up to DIGIC 8). That means it can take a few seconds, using Live View (the LCD).

 

For best results, when taking photos, you want to use the viewfinder - it will use its separate focusing system (rather than the DIGIC processor) and will focus nearly instantly, given proper lighting.

 

When taking video, it will still use the phase contrast method of focusing and will hunt. We recommend using manual focus, or pre-focusing your subjects, otherwise you will lose focus and hear the lens during recording. 

 

As a note, all of our newer Rebels that end in "i" like the T6i and T7i support our STM lenses, and the Rebel T7i has our groundbreaking Dual Pixel Autofocus technology that allows for near instant (and silent with an STM lens) focus, whether you're taking photos with the viewfinder, or shooting videos. You can even touch the LCD screen to manually focus on a specific item. 


Huh?? Do earlier and "non i" Rebels not support the STM lenses? What happens if you try to use one?

 

For years we've been telling all who inquired that Any EF or EF-S lens can be used on any of Canon's APS-C cameras. Have we been wrong to preach that sermon?

Bob
Boston, Massachusetts USA
Moderator
Posts: 1,150
Registered: ‎10-25-2012

Re: Camera upgrade advice, please!

Hey Bob!

 

All EF/EF-S lenses work (fit, achieve focus and all normal functions) on our APS-C cameras (Rebels and XXD cameras).

 

If a lens has an STM motor, anything older than the T4i and non "i" models like the T5, T6 and T7 won't be able to take advantage of that technology (instant silent focusing during Live View or Video), but normal focusing will work just fine! 

 

Sorry if I wasn't clear on that! 

Esteemed Contributor
Posts: 4,279
Registered: ‎06-25-2014

Re: Camera upgrade advice, please!


@Stephenwrote:

Hey Bob!

 

All EF/EF-S lenses work (fit, achieve focus and all normal functions) on our APS-C cameras (Rebels and XXD cameras).

 

If a lens has an STM motor, anything older than the T4i and non "i" models like the T5, T6 and T7 won't be able to take advantage of that technology (instant silent focusing during Live View or Video), but normal focusing will work just fine! 

 

Sorry if I wasn't clear on that! 


I'm still confused. Do STM lenses have two autofocus motors - one STM and one not? Or do the older cameras work with manual focusing only? Sorry to be such a blockhead, but I've had no experience with STM lenses. I graduated out of Rebels before they came along.

Bob
Boston, Massachusetts USA
Highlighted
Moderator
Posts: 1,150
Registered: ‎10-25-2012

Re: Camera upgrade advice, please!

[ Edited ]

Hey Bob!

 

The STM lenses just have the stepping motor. The difference is that the older and entry-level cameras can't take advantage of the stepping motor in video mode or Live View (whenever you're using the LCD). The stepping motor acts just like a DC motor when you use the viewfinder to take a normal photo. Auto focusing works just like any other non-STM lens on an older/entry-level camera.

 

What this means is that for normal viewfinder photo taking, an STM lens will work just like any other lens. When using for video or Live View, the camera doesn't know how to use the electronics of the STM motor, so it will treat it like a DC motor and it will still hunt for focus, and during the hunt you will hear the lens focusing. It seems odd, but I just tested it with an STM motor on a T2i. It's quieter, but you can still hear it, while you hear nothing with the same lens on a T7i. The T2i just doesn't know how to handle the STM electronic components, so it pretends they're not there. 

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