How is the OMD so fast

Started Jan 7, 2013 | Discussions thread
CharlesTokyo
Contributing MemberPosts: 701Gear list
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Re: How is the OMD so fast
In reply to AndyGM, Jan 7, 2013

AndyGM wrote:

papillon_65 wrote:

It is CDAF only because all m4/3's lenses are designed for CDAF focusing. Combining CDAF and PDAF on a sensor is a kludge which means that you are forced to use larger lenses which are designed for PDAF.

Well, you are not forced to use large lenses when combining PDAF and CDAF, that is incorrect. With a hybrid system, CDAF is still used for part of the focusing (usually for a final accuracy check) so everything you say about small lens elements that have to be able to move back and forth fast still applies. PDAF does not mean big lenses, look at the Nikon 1 system. Should an m43 camera get hybrid PDAF/CDAF in the future, the existing small CDAF optimised m43 lenses should still work with it, so the ability to track subjects moving toward or away with continuous AF should improve for the m43 system as a whole.

Are you sure about CDAF being used for part of the focusing? Maybe on some systems, but I doubt all of them. Although the interaction with the hardware is important, as is the sensor readout CDAF is software based and can use all of the data the sensor has (at least as much as it reads out when focusing) It will improve as algorithms and processing power increase and it's quite possible it's tracking will be better than PDAF in the long term because of the extra data it has available. When using CAF normally the distance moved may be small, and possibly more in the area of CDAF than PDAF.

The other advantage is the camera can switch to a PDAF only mode when used with adapted lenses that were only designed for PDAF, like the Four Thirds system lenses. The intention of doing this is not to stop m43 lens development because we will be expected to just use the larger Four Thirds lenses that already exist. The intention is to give existing Four Thirds camera body owners an upgrade path where they can continue to use the Four Thirds lenses they already have (and that were usually bought at great expense).

Yes, if you use use PDAF lenses. It's attractive at the moment because of the high quality lenses, but the size certainly doesn't appeal to m43s users. PDAF is also inherently less precise then CDAF. CDAF tends to cluster more closely where PDAF can sometimes be off quite a way. CDAF (assuming a proper focusing point size, against probably a processing issue) is more accurate and doesn't suffer from front and back focusing problems that PDAF does. I'm not eager to see m43s adapt PDAF and I have to go back to calibrating all my lenses again.

If very well may be they use PDAF to allow use of older lenses in a new 43s or hybrid body, but I'm not sure I'd call it a step forward.

I believe that CDAF systems will overcome this with time though it doesn't bother me personally. So while other systems will enable you to use pdaf you lose the size advantage of the smaller lenses, so why not just use a DSLR instead?

I really don't think this issue of at least knowing if the subject is moving toward or away is ever going to be overcome with CDAF, as Paul has explained in a later post. Hybrid CDAF/PDAF for m43 is therefore not a kludge, its an inevitability.

Yes, it may not be an easy solution, but I do see them over coming it. I don't see m43s ever going to a hybrid solution with PDAF for m43s lenses and I'd gamble that other mirror systems will move strictly to CDAF over time as other companies catch up.

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