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Is OSPDAF ever used in AF-S?

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QuietOC View Drop Down
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Post Options Post Options   Quote QuietOC Quote  Post ReplyReply Direct Link To This Post Topic: Is OSPDAF ever used in AF-S?
    Posted: 29 December 2021 at 22:53
I use the dock fairly often. I had two of them for awhile. Elite bundles them with lenses at their Rokinon webstore. I already said I have never detected a change after an update. It might help if they published more specifics about what was being changed. The issues I have noticed have not been fixed so far.
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Miranda F View Drop Down
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 29 December 2021 at 22:08
Originally posted by QuietOC QuietOC wrote:

Samyang lenses require their dock for firmware updates. I don't think the lens has any influence on the camera's AF choices other than reporting it's focal length, aperture, and focus position. Maybe it sends some info about its motor?

Thanks.
Has anyone here used the Samyang lens station? How much difference did the updates make?
Miranda F & Sensorex, Sony A7Rii, A58, Nex-6, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras ...
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Post Options Post Options   Quote QuietOC Quote  Post ReplyReply Direct Link To This Post Posted: 29 December 2021 at 21:18
Samyang lenses require their dock for firmware updates. I don't think the lens has any influence on the camera's AF choices other than reporting it's focal length, aperture, and focus position. Maybe it sends some info about its motor?

Edited by QuietOC - 29 December 2021 at 21:21
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 29 December 2021 at 21:13
Originally posted by addy landzaat addy landzaat wrote:

AFAIK:
AF-C with native lenses is PDAF only with lenses/bodies who support it.
AF-S with native lenses is PDAF with CDAF finetuning with lenses/bodies who support PDAF.
PDAF with the A7r2 is only below f/8. Above it is CDAF.

Do you have the latest firmware for your Samyang lenses? It might make a difference. The Sony E 50/1.8 OSS does not use PDAF in firmware 1.0 only in 2.0 - I do not know about all Samyang lenses, but the 45/1.8 with original firmware is not that good AF-wise.


Good questions. I haven't tried all my lenses. I did try the Samyang 35mm f2.8 FE and the Sony 50mm f1.8 FE - both AF with PDAF up to and including f8 in AF-C but not at any aperture in AF-S. Both lenses are at v03 and the camera is v4.01; I see from Samyang the 35mm f2.8 is now up to v6 with AF upgrades, so I'll try that if I can figure out how to update Samyang firmware (can I do it through the camera?)
I suspect it won't change the issue I noticed, though, which seems to be a choice made by the camera, unless I am mistaken.
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Post Options Post Options   Quote Kilkry Quote  Post ReplyReply Direct Link To This Post Posted: 29 December 2021 at 15:24
Originally posted by QuietOC QuietOC wrote:

Originally posted by Kilkry Kilkry wrote:

The Sony 90G will not AF lock at all if the object aimed at is within a meter with the a7rii


Interesting. Some E-mount lenses don't allow AF at their minimal focus distance, but I don't think that is true for that lens. The effective aperture gets smaller at closer focus, and the phase detect of the A7RII only works up to f8, but contrast-detect should continue working.

https://helpguide.sony.net/ilc/1520/v1/en/contents/TP0001087184.html


Yes it tries, and it isn't always that it cannot seem to lock but pretty often still, and if the AF limiter isn't set it takes time to go through the entire range, back and forth. It doesn't happen if what it is aimed at is further off but it could be something with the aperture and distance I guess. So usage now is with MF and a tripod when it isn't windy, else with the A9.
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Post Options Post Options   Quote QuietOC Quote  Post ReplyReply Direct Link To This Post Posted: 29 December 2021 at 15:08
Originally posted by Kilkry Kilkry wrote:

The Sony 90G will not AF lock at all if the object aimed at is within a meter with the a7rii


Interesting. Some E-mount lenses don't allow AF at their minimal focus distance, but I don't think that is true for that lens. The effective aperture gets smaller at closer focus, and the phase detect of the A7RII only works up to f8, but contrast-detect should continue working.

https://helpguide.sony.net/ilc/1520/v1/en/contents/TP0001087184.html
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Post Options Post Options   Quote Kilkry Quote  Post ReplyReply Direct Link To This Post Posted: 29 December 2021 at 14:59
Originally posted by Miranda F Miranda F wrote:



Or does everyone else with an E-mount camera just leave it set in AF-C and ignore the problem with AF-S?


I was never very annoyed with the "defocus-focus" behaviour of my A7rii, at least it was accurate. Then I purchased the Tamron 28-75 which front focuses most of the time at 75mm and only at 75mm on that camera (AF-C or AF-S does not matter). The Sony 90G will not AF lock at all if the object aimed at is within a meter with the a7rii (I think I need educating on why something being photographed is called a "subject" since in the English language the subject is usually the doer, i.e photographer I would think :) )

Since I also acquired a used A9 I've kept the A7rii in MF. It's stellar with manual focus lenses, newer as well as older. (The mentioned lenses have zero AF issues with the A9).

The A9 is set to AF-C, I see no reason to use AF-S.

Edited by Kilkry - 29 December 2021 at 15:06
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Post Options Post Options   Quote QuietOC Quote  Post ReplyReply Direct Link To This Post Posted: 29 December 2021 at 14:25
Interesting. Thanks! The A6000 is where I really noticed the wobble in AF-C when using the 55-210 OSS. I found AF-C 4D Focus pretty awful on that camera--worse than the A77II. Maybe Sony is doing less contrast-detect now.
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Post Options Post Options   Quote addy landzaat Quote  Post ReplyReply Direct Link To This Post Posted: 29 December 2021 at 14:15
Oh, and the A6000 does not do PDAF with the adapters. Unfortunately.
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Post Options Post Options   Quote addy landzaat Quote  Post ReplyReply Direct Link To This Post Posted: 29 December 2021 at 14:13
Originally posted by QuietOC QuietOC wrote:

Sony hasn't stated anywhere that there is phase-detect only AF for any E-mount camera except when using the A-mount adapters.
Here you are. Sony states the A6000 does "Focal plane phase-detection AF only" or "Focal plane phase-detection AF + Contrast-detection AF" and it "Automatically selects optimal AF method depending on scene". So, Sony stated there is phase-detect only AF depending on situation.

I am sure some review mentioned what I described, but I do not have a source - hence the AFAIK.
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Post Options Post Options   Quote QuietOC Quote  Post ReplyReply Direct Link To This Post Posted: 29 December 2021 at 13:04
I keep updating Samyang firmware but haven't found any changes from those updates so far.

Sony hasn't stated anywhere that there is phase-detect only AF for any E-mount camera except when using the A-mount adapters. Sony has had contrast-detect only AF-C. The cameras without phase-detect sensors have AF-C.

FWIW: I've hearing about sales on the Sigma 45mm F2.8 Contemporary down to $250. It is still my favorite normal prime, and it also has very little breathing. People do report AF issues with it too. It has a good amount of under corrected spherical aberration.

Edited by QuietOC - 29 December 2021 at 14:20
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Post Options Post Options   Quote addy landzaat Quote  Post ReplyReply Direct Link To This Post Posted: 29 December 2021 at 12:59
AFAIK:
AF-C with native lenses is PDAF only with lenses/bodies who support it.
AF-S with native lenses is PDAF with CDAF finetuning with lenses/bodies who support PDAF.
PDAF with the A7r2 is only below f/8. Above it is CDAF.

Do you have the latest firmware for your Samyang lenses? It might make a difference. The Sony E 50/1.8 OSS does not use PDAF in firmware 1.0 only in 2.0 - I do not know about all Samyang lenses, but the 45/1.8 with original firmware is not that good AF-wise.
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Post Options Post Options   Quote QuietOC Quote  Post ReplyReply Direct Link To This Post Posted: 29 December 2021 at 11:29
My understanding is Fast Hybrid AF will use PDAF initially and then use contrast-detect for final step. At least some cameras seem to do a small contrast detect wobble during AF-C.

DC motors are slow for contrast-detect hunt.

The A7RII has the AF System menu option that allows switching between contrast-detect and phase-detect for the LA-EA1/3/5. There's no Fast Hybrid support for A-mount lenses. I believe the A7RII will switch to contrast-detect if the maximum aperture is less than f8 or in movie mode. Recent camera models have gotten rid of all contrast-detect for A-mount.

I use AF-S most of the time except if I am shooting action. Some people claim to use AF-C all the time. The Samyang lenses often lock just out of focus in AF-S to the side that they start focusing from. Like the stepper motor is one step off. Sony lenses always seem to be spot on. I had some AF-S issues with the FE 85 F1.8 on the A7III, but it wasn't an accuracy issue.

My Samyang 24mm F2.8 has very little breathing. It is one of least breathing primes. Its breathing is mostly just a change in distortion.


Edited by QuietOC - 29 December 2021 at 12:00
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 29 December 2021 at 10:51
I have noticed that on the A7Rii, AF-S appears to operate only in CDAF, not PDAF, so the lens focuses backwards and forwards every time the shutter is pressed. This is particularly noticeable on lenses with a lot of focus breathing such as the small Samyang FE primes (18mm, 24mm, 35mm f2.8) where the whole image shivers during AF, every time.
Has anyone else noticed this? Do other A7 models behave differently?

The image shivers much less in AF-C and clearly the PDAF is being used then. I wonder why the choice was made not to use PDAF in AF-S mode, and whether this a decision by Sony or Samyang?
The same behaviour is apparent on other E-mount lenses including the Sony 50mm f1.8, where AF is appallingly slow on AF-S, especially at f8 or larger, but okay on AF-C.
But weirdly, using an A-mount lens like the 85mm f2.8 or 55-200mm DT on the LA-EA1 the camera always uses PDAF and gets the direction of travel right every time, obvious with the much slower A-mount in-lens motor!

Or does everyone else with an E-mount camera just leave it set in AF-C and ignore the problem with AF-S?
Miranda F & Sensorex, Sony A7Rii, A58, Nex-6, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras ...
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