A99 & Lens Firmware

Started Sep 21, 2012 | Discussions thread
Kappels Contributing Member • Posts: 796
Re: A99 & Lens Firmware

Not sure I understand your question, but Sony made it clear that NOT all lenses will function with the double AF system. There are some that will be supported next year and there are others where this is very doubtful, if not to say impossible.

David Kilpatrick, from photoclubalpha is actually slightly pessimistic; See page 21, top thread here:

http://www.dyxum.com/dforum/a99-announcement-details-and-short-preview_topic91320_page21.html

I quote:

"My original comments and conclusions about the PDOS system were based on a brief reading of the patent a few weeks ago. It's very clear and the first paragraph of the entire document - top right - sets out exactly how Sony's system enables operation, and also exactly why some lenses will never be compatible.

In the patent, three pixel pairs are shown for each PDOS AF point. This would correspond to, for example, a close exit pupil, medium exit pupil and distant exit pupil. If this system was used with a typical zoom, as you zoom it might seamlessly switch from one pair to the next. If you refocus a considerable amount, it may also switch.

That's why the A99 has two functions - the AF range limiter (it's an essential function of the PDOS design to keep the lens within a certain focus range to maintain the use of one pixel pair), and the lookup table of compatible lenses which contains data about which pixel pairs to activate, controlled by the zoom and focus distance setting as well as the lens identity. So that's a pretty complex table and may also involve the aperture in use and the position of the PDOS sensor.

The limitations, however, are not firmware fixable. If a lens has an exit pupil or focus range/pupil combination which does not match any of the three pixel pairs, it will never be usable with AF-D. What we don't know is whether the omitted lenses are in this group, or just a bit complex to get programmed into the firmware.

When Sony says the lens compatibility is going to be updated during 2013 you can be pretty sure they mean new hardware lens designs, not new lens chipping or firmware fixes.

I can tell you already that Sigma has a partial fix for all these problems, you'll learn about it after photokina, but it will not apply to their old (current) lens range. Tamron may not need a fix, as any NEX system owner with an 18-200mm Tamron can confirm - Sony recognises that lens and even corrects its CA and distortion as if it was a Sony LE (which it basically is). Tuesday morning will bring a lot of news, I'll be there on Monday and with the speed stuff appears on the net, I'm not even sure I want to spend precious hours putting up posts identical to everyone else. I'd rather just sit and stare at some of the new stuff and work out what it all really means.

Wildcard - the patent shows three pairs of pixels per point. But that's just an expression of principle. It may be that Sony has put five or seven pairs of pixels per point and not even built the complex processes to bring these into play. The sensor may have unused capacity to handle many more lenses than the launch list, but rather like DxO taking five years to profile enough lenses to be a useful program, Sony may have hundreds or thousands of hours of lab time needed to built the big 3D LUTs required to make the maximum number of current lenses work.

David"

Stef.
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Canon PowerShot G10 Sony Alpha DSLR-A100 Sony Alpha NEX-5 Sony SLT-A77 Sony Alpha a99 +21 more
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