Sony Need advice from Sony users

jyc860923

Veteran
Aug 29, 2018
104
Shenyang, China
贾一川
I've read people complaining about Sony's stop down focus accuracy issue, unlike Canon that opens up the aperture fully during AF, Sony stops down the lens during continuous AF if you set a smaller aperture value for capturing, e.g. studio work. The reason being Sony does this to avoid heavy focus shift at different f stops on some lenses, at the expense of unreliable AF especially in low light.

Further research leads me to another issue, unlike in AFC mode, in AFS mode, the lens will open up to focus and then stop down to capture but the aperture delay on some lenses is huge.

What do you think about this issue, is it really as bad if you often need to work with stopped down aperture? Is it avoidable using Sigma, Tamron or Samyang lenses?
 

davidzvi

Top Veteran
Apr 18, 2014
104
Boston Burbs
David
Not a Sony user but this is an interesting bit of information. It kind of defeats one of advantages of "fast glass".

I'll have to see if I can figure out if my X-E3 or EM1.2 act the same way.
 

jyc860923

Veteran
Aug 29, 2018
104
Shenyang, China
贾一川
Not a Sony user but this is an interesting bit of information. It kind of defeats one of advantages of "fast glass".

I'll have to see if I can figure out if my X-E3 or EM1.2 act the same way.
Having shot m43, mainly Panny and Fuji XE3 in the past, I know that newer m43 glasses like 12-60, and 2.8 zooms have extremely fast aperture movement that won't slow down burst shooting while most of the primes and earlier lenses do have slower aperture mechanism, m43 bodies focus wide open and stop down before taking the photo. With Fuji XE3 I haven't experienced aperture lag and I think the aperture stops down when you hold the shutter button half down, and doesn't open up fully during burst, it isn't perfect for tracking but at least there's no aperture lag that I can tell.
 

MoonMind

Hall of Famer
Dec 29, 2013
124
Switzerland
Matt
Having shot m43, mainly Panny and Fuji XE3 in the past, I know that newer m43 glasses like 12-60, and 2.8 zooms have extremely fast aperture movement that won't slow down burst shooting while most of the primes and earlier lenses do have slower aperture mechanism, m43 bodies focus wide open and stop down before taking the photo. With Fuji XE3 I haven't experienced aperture lag and I think the aperture stops down when you hold the shutter button half down, and doesn't open up fully during burst, it isn't perfect for tracking but at least there's no aperture lag that I can tell.
On :mu43:, the issue as described above actually leads to the dreaded "rattle-snaking" - depending on what you do, the aperture opens and closes and is audible every time it does that, very off-putting. The worst offender was/is the Panasonic 20mm f/1.7 - and some of its "slow AF" issues may even be down to the aperture mechanism and the paradigm itself.

On Sony, some lenses take quite some time to open the (partially) closed aperture on start-up (most notably, my most used FE lens, the Samyang 35mm f/2.8). This slows down deploy time noticeably. I'll watch out for the behaviour described in the first post, too - never occurred to me that it might be an issue, but I'd like to make sure.

M.
 
Oct 20, 2012
104
The Netherlands
Ad Dieleman
Sony stops down the lens during continuous AF if you set a smaller aperture value for capturing, e.g. studio work. The reason being Sony does this to avoid heavy focus shift at different f stops on some lenses, at the expense of unreliable AF especially in low light.
Yes, in AF-C the lens is stopped down continuously while focussing and shooting takes place. This can be a problem for studio work with flash, where ambient light can be low and small aperture are used. I don't have problems with this in available (low-)light situations where I usually open up the aperture to larger values. My camera is the A7R2 and lenses are all Sony, FE 2.8/35, FE 1.8/50 and the F4 zooms 24-70, 16-35 and 70-200.

Further research leads me to another issue, unlike in AFC mode, in AFS mode, the lens will open up to focus and then stop down to capture but the aperture delay on some lenses is huge. What do you think about this issue, is it really as bad if you often need to work with stopped down aperture? Is it avoidable using Sigma, Tamron or Samyang lenses?
When I use AF-S I'm usually not concerned about very quick response times so the delay of closing/opening/closing of the aperture never hindered me. However, I can imagine that the delay can be annoying when you need a quick response time.

If I understood correctly, the A7R4 offers the option of choosing whether you want to focus wide-open or at the working aperture. Details unknown to me. It's something I suggested a long time ago in a Sony feedback group and happy to see they picked up on it.

I must say I almost always use MF lenses where the aperture is set by the aperture ring and not by the camera, so all this is irrelevant in that use case.
 

jyc860923

Veteran
Aug 29, 2018
104
Shenyang, China
贾一川
Thank you very much for the information, unfortunately that confirmed my concern, till this day the only review I've read discovered this issue is from DPReview, likewise, no reviewer discovered Panasonic and Fuji TTL flash auto ISO/metering problems.
 

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