# Videos and AutoFocus



## Leadfingers (Feb 22, 2012)

I recently learned that none of the current cameras in the Canon lineup offer auto-focus while filming video. 

Is there any indication that any of the new 5D or T4i bodies will support autofocus?

(I do just enough video recording that Im thinking about getting an entry level Nikon, just for this purpose...)

When I saw this, it got me wondering...



> EF-S 18-135 II
> This lens will have a silent autofocus motor geared to video. It will arrive with the new Rebel T4i. This has shown up in a US retailer inventory system. No price for the kit with the T4i.



Afterall, what use is a silent motor if it doesn't focus while recording...

/crosses fingers


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## AnthonyWithNoH (Feb 22, 2012)

I've been wondering this myself for a while... no rumors have led to this belief though it's not out of the question considering Nikon has had it since the D7000 in 2010. Nikon's isn't very impressive... I would stick with Canon for video due to the fact of the full manual exposure on it's cropped image sensor models. Silent motors aren't just for video, but photography too. It would definitely make sense though that they sell a Silent motor lens with an auto-focusing body. I'm looking forward to Nikon's next cropped image sensor DSLR though it probably won't come out till late 2012.


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## Drizzt321 (Feb 23, 2012)

The problem with auto-focus during video is that dSLR auto-focus really require the use of a slightly transparent spot on the mirror to divert a small amount of the light onto the auto-focus sensor. The other option (which mirrorless cameras including P&S use) is called contrast detect (I think) which means it's actually analyzing the image while recording. Plus, the problem with a video auto-focus is if it has to hunt for focus, it looks pretty crappy. 

Granted, dSLR's need better focusing help, especially if you need to rack focus, and also an embedded 10x zoom of a part of the frame would be extremely helpful. But, that's why we have MagicLantern!


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## NormanBates (Feb 23, 2012)

I wouldn't be surprised if they were putting a lot of effort into video AF, but I don't want it: serious video doesn't usually use autofocus, and I certainly don't need it or want it

now, 5x-10x zoom-in while recording, and focus peaking, would be very, very nice


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## JR (Feb 23, 2012)

I would love Canon to include in its firmware a feature whereby when we manual focus in live view it would highlight someone on the LCD screen the element that are in focus. Sure if you have a pro-video setup with a larger monitor to do fucos you dont need this, but for us mortals, it would be very useful.

Actually because of the potential limitation of autofocus in video, I would prefer this feature over autofocus to help in live view mode - isn't magic lanthern doing something like this for some Canon model? If so Canon just go a buy the software from them!

:-\


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## Leadfingers (Feb 23, 2012)

Magic Lantern has a feature where you can pick a section and it will magnify it 5x in the corner of your LiveView screen, and surround that with a green border when it's focused. It's a very poor man's solution.

For the moment, I subscribe to the school of thought that there's enough CPU power in the universe that we should be able to compute autofocus in something the size of a camera. I'm just hoping Canon is up to snuff.


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## Mt Spokane Photography (Feb 23, 2012)

The main advantage of a mirrorless camera is that AF for video is practical. Contrast detect AF is very slow for large sensors, but easy for very small ones as in camcorders. This is due to the huge depth of field and only a few lens focus positions.

We see lots of research and patents, but so far, nothing practical for a traditional DSLR. Thats why I'm not excited about DSLR video, I do not have the inclination to fool around with manual focus, even if I could see well enough to do it.

AF is of no importance to Movie makers, its not accurate enough. They have developed a system for manual focus and it gives them what they want. Thats why the HDDSLR is popular for budget film makers, low cost, high quality, and they can adapt cinema quality lenses if they need them, or use the relatively low cost Canon lenses, at least for 35mm and longer.

All this refinement is totally lost on me, I'll not be making any movies. My grandson, however, may indeed be filming movies, he is in college now and has written, directed, and filmed his work. I certainly encourage him and others to learn.


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## Mt Spokane Photography (Feb 23, 2012)

Leadfingers said:


> For the moment, I subscribe to the school of thought that there's enough CPU power in the universe that we should be able to compute autofocus in something the size of a camera. I'm just hoping Canon is up to snuff.



The problem with a camera computer is power and heat. Progress is being made, but not so much that it really makes a lot of difference. A super powerful 8 core processor might use up a battery in 5 minutes or less, if it did not cook everything first.


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## psolberg (Feb 23, 2012)

Mt Spokane Photography said:


> The main advantage of a mirrorless camera is that AF for video is practical. Contrast detect AF is very slow for large sensors, but easy for very small ones as in camcorders. This is due to the huge depth of field and only a few lens focus positions.
> 
> We see lots of research and patents, but so far, nothing practical for a traditional DSLR. Thats why I'm not excited about DSLR video, I do not have the inclination to fool around with manual focus, even if I could see well enough to do it.
> 
> ...



you know how I know a film was shot with a DSLR...because half the time they are out of focus....so yeah. bring it on. panasonic's m4/3s cameras use contrast detect that is as fast as phase detect.


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## Leadfingers (Feb 23, 2012)

With respect, Mt Spokane, I stand by my position. There are phones coming out this quarter based on nVidia's Tegra3 quad-core chip. If there's room in a phone for that, then there's certainly room for similar power in a camera.

ESPECIALLY in the larger SLR's that have multiple CPU's and card slots. 

I'm passionate about this because I split time between photo and video and can't afford two separate cameras. I totally get the old school mentality that scorns the use of an SLR for video. But it's a new world...and none of our kids are going to make those kinds of distinctions...

:O


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