Comments on: Faster Autofocus for Canon EOS DSLR Live View Mode

By: Micah

Micah — Fri, 13 Feb 2009 12:04:46 +0000

That’s a very good point about video. If the camera could capture video in this mode, it could AF. AF during video would be a killer feature. That is, if it can keep at least 90% of the light going to the sensor and still work. Otherwise video quality might suffer from the loss of light. Also AF might not work so well in low light if the light is all going to the sensor. Catch-22.

It’s good to see that Canon is innovating. Both big camps are.

By: Sergey

Sergey — Thu, 12 Feb 2009 08:57:26 +0000

But for me the main reason to greatly improve AF is to shoot video mode with fast AF. This is what everyone wants.
However, the mirror in front of the sensor will reduce the image quality, so it is useless for this purpose.
So, to improve AF in video they’ll have to invent something else. Or just implement what they use for pro camcorders – external AF module.

By: Photographer / Videographer

Photographer / Videographer — Thu, 12 Feb 2009 08:43:14 +0000

For FF camera bodies, they should make them bit bigger to allow this system get inside.

Otherwise it would be Terrible (and Ridiculous) to have Faster LiveView AF in xxD than in xD DSLRs !!

By: Van Hanja

Van Hanja — Thu, 12 Feb 2009 07:58:03 +0000

I ha ve owned a eos RT (real time) that was a camera that use a semi translucent mirror to reflect 1/3 of the light to the visor and 2/3 to the film.

one word : it was fantastic, fast, silent,lightweight, and one of the best camera i ever had….

c’mon Mr Canon, with the increase of sensibillity of the sensor, if it had worked fine with the Velvia 50 it should work with the Cmos of the 5 D MKII :

a EOS RTd = 21mp/ 6fps- no black frame-100% visor-Cfast slot-manual control of speed/aperture/iso/wb/AND PLEASE GIVE ME BACK THAT 1/500s FLASH SYNC

that would be a killer

By: Brendan Simons

Brendan Simons — Thu, 12 Feb 2009 05:15:22 +0000

I never understood why contrast-detect autofocus performs so badly in SLRs. On my compact, the contrast-detect method works in the blink of an eye. The point may be moot though. Canon’s most recent SLRs have a “fast autofocus” mode that drops the mirror for focussing. This interrupts the live view, but its so fast its hardly noticeable.

By: Photographer / Videographer

Photographer / Videographer — Thu, 12 Feb 2009 01:02:00 +0000

It’s clear that Canon is developing a faster AF system for LiveView (they already stated that months ago at Photokina) as well as improving Movie mode, because they know that those features will have Huge future and demand

LiveView has enormous potential.
Sometimes is impossible to use the viewfinder, or just much easier to use LiveView.
Also the information displayed in LiveView can be a lot more than in the Viewfinder.

Each way to frame and shoot has its own advantages, so they both MUST be available considering the customers have a very wide range of different needs / tasks / jobs

Thinking that a feature “should not” be included in a DSLR just because “it does not belong to the DSLR world” or one doesn’t use it, it’s a mistake due to having somewhat narrow perspective of other people’s needs, the trends of technology, the demand and the companies’ business.

This improvement indeed will help a lot the Movie/Video mode in DSLRs, wich is also going to be improved and implemented in future DSLRs, despite some people like it or not.
(if you don’t like, just don’t use the feature. It’s that simple. And if you don’t want to pay “more”, don’t worry, it won’t make much difference to today’s DSLRs, so the “extra” price won’t show up)

LOT OF CUSTOMERS, both Amateurs and Professionals (Photographers and Videographers) can get lot of advantages of such implementations, wich will offer a level of quality and features that are not still available under several thousands dollars (and some are even inexistant yet)

So, GREAT NEWS that Canon is really working on it.
Hope that Nikon and other companies do the same.

By: Micah

Micah — Wed, 11 Feb 2009 19:20:24 +0000

@Eric: I think you might misunderstand the standard SLR AF technology. At least that’s the impression I get from reading this.

Current SLR tech is to put the AF sensor in the bottom of the mirror box. The middle of the main mirror allows some light to pass through to a secondary mirror that is positioned at a right angle to the main mirror. This secondary mirror reflects light down onto a sensor at the bottom of the mirror box.

An AF sensor in the bottom of the mirror box is the norm. Nikon, Canon, Pentax, Sony/KM, and even Olympus use this arrangement. The first four definitely never put an AF sensor above the mirror. Olympus I’m not sure about.

There are two detriments to this standard layout: most of your light is reflected up into the mirror box, and only a small amount is picked up by the af sensors. This is why lenses of 5.6 and higher suck for AF in low light.

The novel part of the patent above seems to be that they are using a mirror that is partially transmissive in a different configuation for live view. It looks like the mirror flips in the opposite direction for live view and the AF sensor is positioned optimally for this, with the secondary mirror’s placement higher up the main mirror compared to the standard position of center.

There are some up sides and down sides to this. On the plus side:
a) fast AF in live view!
b) potentially better low light AF
c) the placement of the secondary mirror is closer to the pivot point of the main mirror, which could on it’s own enable higher frame rates.

On the down side:
a) much more complexity, which increases the chances for catastrophic failure
b) the increased complexity could add weight to the mirror assembly which could negate any increase in frame rate and maybe even lower it
c) this is only optimally applied to a crop sensor. This could make even a 1ds series camera even more bulky. This is useless on a 1d series camera.

By: Anonymous

Anonymous — Wed, 11 Feb 2009 16:35:40 +0000

I think live view is great for hard to reach places, however the Live view on my D3 isn’t something I use to any regular degree at all.

Personally I think Sony has already hit the nail on the head with their live view Autofocus. In their system they move a Smaller CCD sensor into the viewfinder which is what feeds your live view display while the rest of the camera (including AF module, and Metering system) function the way they are intended. If you really want to use LiveView isn’t that what we are looking for anyway?

There’s no need to redesign the wheel. Just my 2 cents.

By: Jim Esten

Jim Esten — Wed, 11 Feb 2009 15:37:02 +0000

Live View would be a VERY useful feature for people like me whose aging eyes can benefit from this technology.

By: Barry Stewart

Barry Stewart — Wed, 11 Feb 2009 15:22:31 +0000

Looks very much like the Olympus E-330 — which people panned as looking weird, as it didn’t have a pentaprism hump.

For me, the 330’s live view works very well and I’m not sure why Olympus has gone away from that kind of LV, leaving it to Sony and now Canon to carry on. Surely it’s more expensive to build — but the advantages are great.