# Canon EOS 70D DPAF video tracking: STM vs USM lenses sample video



## xvnm (Aug 25, 2013)

I posted a video comparing DPAF video tracking with STM and USM lenses: http://youtu.be/djOPPQycZ8g


----------



## trav.cunningham (Aug 25, 2013)

Thanks for sharing. You can definitely see (and hear) the difference.


----------



## Jim O (Aug 26, 2013)

xvnm said:


> It's also sad that the 40mm STM changes focal length with focus; a very disturbing effect in a lens that otherwise was quick and silent to focus during video.


Focus breathing in the 40mm pancake? I'm shocked!

Seriously, did you expect better in a $199 lens (I got mine on sale for $149 a couple of months ago and it's worth every penny!)? It's well known and mentioned in at least one online review, probably dozens.

You can't buy a Kia and complain that it doesn't handle like a Ferrari. Well, you can, but you'd sound silly. This is not a multi-thousand dollar video lens on a professional video body being operated by experienced professional videographers. This is an inexpensive lens on a camera that's designed primarily for taking stills. You may find it "disturbing" but that's just the nature of optics, and it's hard, and expensive, to prevent/correct.


----------



## paul13walnut5 (Aug 26, 2013)

Jim O said:


> xvnm said:
> 
> 
> > It's also sad that the 40mm STM changes focal length with focus; a very disturbing effect in a lens that otherwise was quick and silent to focus during video.
> ...



Yes, I agree that focus breathing is acceptable in a lens, for that price, however I also agree with XVNM that this is dissapointing regardless.

If the point of making an STM lens is to permit smooth video focus, then you really are wasting your time if the shot size changes with focus, as this is as much of a distraction as af hunting, in my opinion.

The 40mm looks great at auto-focusing, and the footage looks good on a small viewer, I wonder how much the breathing would affect it on a 50" plasma?

Of course, this may well be a moot point, as the folk who are very serious about video will not use AF anyway, and probably wouldn't want a focus by wire lens either, but it's a shame Canon couldn't make this a perfect casual video users lens. That takes nothing away from it's excellence as a stills lens.

Another point with the test... and it's a double edged sword...

The depth of field charachteristics of each of these lenses is totally different.

The subject size varies according to focal length, which I guess means that at least the camera position was kept consistent, but the proportion of the mechanical focus throw would be different. Especially with the telephoto lenses such as the 85mm compared to say the 11-22 zoom.

The depth of field on a 40mm @ f2.8 will be much greater and much more forgiving than on an 85mm @ f1.8, so the 85mm would have a hell of a lot more shifting to do.

It's a very useful and stark test, I would like to know a bit more about parity of settings (for example the 11-22 is max f4, were all lenses used at f4? this would have a bearing on how much movement the focus elements have to do as the toy moves)

The STM looks a great improvement, and will no doubt be of great use to casual video users, this test is a story worth telling, but I don't think it's the whole story.

And the issue of focus breathing *is relevant* particularly so for video users, a tool is either right for the job or it's not. STM thumbs up. Focus breathing, thumbs down.


----------



## Jim O (Aug 26, 2013)

paul13walnut5 said:


> Yes, I agree that focus breathing is acceptable in a lens, for that price, however I also agree with XVNM that this is dissapointing regardless.


Again, I disagree. While the motor may be good for video because of its sound, or lack thereof, it's a $199 lens! Even lenses that cost thousands of dollars exhibit focus breathing.

The Kia Rio starts at $13,600.

The Ferrrari 458 Speciale probably costs 20x that.

You might be _disappointed_ that the Kia can't take a corner at 60 mph or go 0-60 in a couple of seconds, but you should be just as disappointed that Santa Claus and the Easter Bunny don't really come and bring toys and candy to little boys and girls. None of these expectations are *realistic*.




paul13walnut5 said:


> And the issue of focus breathing is *relevant* particularly so for video users



I didn't say that it wasn't. I said/meant/implied that being surprised/disappointed by it in a sub $200 lens was ridiculous.

Back when I shot film, Canon made a piece of crap plastic 28-70 3.5-5.6 lens (the so-called "plastic fantastic" that was literally a throw in/throw out lens) and a 28-70 2.8 L lens. If you got a good copy of the latter (which I did) you could make some really nice images. If you had the former and compared them, even at f/5.6 it was Ford Pinto vs Mercedes SL class convertible (I guess I'm in a car mood today). Maybe even a bicycle vs the Mercedes. You shouldn't expect to be able to extract gold from a pile of manure and be disappointed when you can't. That's like, well, being disappointed after staying up all night and seeing that Santa did not shimmy down your chimney.

And, btw, focus breathing can be observed in the 24-70 2.8 II at all focal lengths, as well as in the 70-200 2.8 II. 

Just because a relatively cheap lens has an STM does not mean it's not going to be a relatively cheap lens designed primarily for still cameras, STM or not.

Canon's Description:


> A unique and indispensable addition to Canon's series of EF lenses, the new EF 40mm f/2.8 STM offers an ultra-slim and lightweight design. Incredibly compact in size, the EF 40mm f/2.8 STM delivers high image quality from the center to the periphery thanks to its advanced lens configuration including an aspherical element, a bright 2.8 aperture, and optimized coatings that minimize ghosting and flare while providing exceptional color balance. The EF 40mm f/2.8 STM's unobtrusive design helps the photographer avoid overwhelming their subjects with a large lens and to remain discreet in sensitive shooting situations with no compromise in performance. Its diminutive design is complemented by features such as a newly developed stepping motor for smooth and quiet continuous AF while capturing video with the Canon EOS Rebel T4i DSLR, a circular aperture (7 blades) for beautiful soft-focus backgrounds, and a short minimum focusing distance of only 0.98 ft./0.30 m.



It delivers the "smooth and quiet continuous AF while capturing video...". I don't see it promising more than that. In fact, it seems to me that it delivers well on its promises.


----------



## neuroanatomist (Aug 26, 2013)

Jim O said:


> ...you should be just as disappointed that Santa Claus and the Easter Bunny don't really come and bring toys and candy to little boys and girls. None of these expectations are *realistic*.



Watch it, Jim, my _kids_ might read this!


----------



## Chosenbydestiny (Aug 26, 2013)

Jim O said:


> paul13walnut5 said:
> 
> 
> > Yes, I agree that focus breathing is acceptable in a lens, for that price, however I also agree with XVNM that this is dissapointing regardless.
> ...



I disagree, my particular copy of the 40mm pancake performs more like a skateboard. ;D ;D


Anyways, you're right about having ridiculous expectations for such a cheap lens, despite the incredible value it actually is. Many people in these forums tend to have ridiculous expectations


----------



## pedroxha1 (Aug 26, 2013)

The DPAF seems to be very good. It's making me question my choice of buying a canon XH-A1 camcoder recently. However, the 'Instant AF' on the XH-A1 works in a way like Phase AF and does keeo up and tracki fairly well from the testing I've done so far.


----------



## paul13walnut5 (Aug 27, 2013)

Jim O said:


> paul13walnut5 said:
> 
> 
> > Yes, I agree that focus breathing is acceptable in a lens, for that price, however I also agree with XVNM that this is dissapointing regardless.
> ...



My point is that STM is great for video. Brilliant.
Canon make an af system that is great for video.

Super.

And its cheap.

Super.

But whether it costs £4 or £4000 focus breathing will still look crap on an hd telly!

Is it a concession most folk will live with? Yep.

Do a lot of other canon lenses exhibit focus breathing? Absolutely.

Have any other EF lenses been so specifically targeted at video users to the point if designing a whole new motor type and live view af system? No.

It's just a shame. Thats all.

My Kia Rio was a bit more expensive that that (i went for the very very clean 1.1 diesel)
I've never driven a ferrari, but in my capacity as a cameraman editor for Europes largest publisher I shot a video review of a jaguar f-type last week. More like 6x the price of my Rio than 20x.

The Jag was beautiful, very very fast (though not 'racy') beautiful to look at, but in all seriousness I prefer my Rio.
Can't fit anything in the jags boot. A set of tyres would mean baked beans on toast for a month. I went a 220mile drive on saturday there, to Tighnabruich, Portavadie, Arrochar, Dunoon, and my plucky wee rio sipped about a quarter tank. I don't pay any road tax because the emissions are so low and the insurance, despite my 'risky' occupation is low.

We call her Tinky, and she's great. She also has a good boot for all my recording gear.

Heres the rub though, my Kia Rio, the jaguar f-type has got £~<{ all to do with lenses.

Focus breathing has got a lot to do with vidro quality, especially attached to video af which seems to track very quickly.

I don't care all that much, for video I use MF, I don't do rapid pull / rack focus as its very distracting and disconcerting.
In my shooting style focus breathing wouldn't be all that apparant anyways.

I would be interested to see how stm works with say usb focus pullers or via eos utility, that is useful snd has potential.


But for those seduced by the speed and silence of stm for video af, well they are going to have other problems.
Dare I say that if the breathing is very pronounced it will make the video quite difficult to watch, its an oversight.

If this is acceptable to you, then hell go for it.
Just don't say it isn't an issue for anybody else because the product cost x... 

And it's really got nothing to do with cars.


----------



## trav.cunningham (Aug 27, 2013)

Has anyone tried the video with the 18-135 STM? The reviews indicate that it does not have any focus breathing.


----------



## paul13walnut5 (Aug 27, 2013)

It does have 2 stops of f-drop however.


----------



## tcmatthews (Aug 27, 2013)

I am waiting a test with one of the new IS primes or at least a new lens design. No offence to the 50 1.4 and 80. 1.8 they are great lens but they have dinosaur USM drives.


----------



## Cptn Rigo (Aug 27, 2013)

Thanks for the video!


----------



## Don Haines (Aug 27, 2013)

neuroanatomist said:


> Jim O said:
> 
> 
> > ...you should be just as disappointed that Santa Claus and the Easter Bunny don't really come and bring toys and candy to little boys and girls. None of these expectations are *realistic*.
> ...


Careful Neuro..... You shouldn't let you kids read this forum..... The might start to complain about sensor technology and DR......


----------



## Bruce 101 (Aug 27, 2013)

trav.cunningham said:


> Has anyone tried the video with the 18-135 STM? The reviews indicate that it does not have any focus breathing.



I put my Sl-1 on the dashboard with the new 18-135 STM mounted as I drove across the Chesapeake Bay Bridge in Maryland.

The focus did breathe a bit but I was reasonably happy with the result. Of course, the car bounced about every three seconds based on the road surface of the bridge, so take that into consideration as you watch this:

http://youtu.be/I9wweFNMDN0


----------



## garyknrd (Aug 27, 2013)

Haven't listened to that song in years. Don't know about the AF but the song rocks...


----------



## ajfotofilmagem (Aug 27, 2013)

Bruce 101 said:


> trav.cunningham said:
> 
> 
> > Has anyone tried the video with the 18-135 STM? The reviews indicate that it does not have any focus breathing.
> ...


I also loved the music of "The Doors". Breathing focus lens is uncomfortable for the video. But a little hunting focus happen with any high end shoulder camcorder. With APS-C and its shallow depth of field it is quite normal. Therefore Cinema seriously only use manual focus in the last 100 years.


----------



## Bruce 101 (Aug 27, 2013)

Switch the YouTube setting to 1080p and it looks better.


----------

