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Specialist
Posts: 24
Registered: ‎03-05-2014
Message 1 of 16 (5,117 Views)

A7 series focus issues with certain lenses

[ Edited ]

There have been complaints of  how certain lenses focus on the A7 series cameras.

 

Background:

The standard way focus has been acheived with the A7ii and A7rii cameras is to open the iris of the lens when half pressing the shutter button and then closing back down to the set aperture of the lens. This has worked well and acheives the best focus for zoom and prime lenses.

 

With v1.1 of the A7Rii last September, Sony changed the behavior on certain lenses (zooms) to not open the iris as fully as the inital firmware to reduce the chance of focus shift. The focus shift complaints can be found in these threads:

http://www.dpreview.com/forums/thread/3893957

and 

http://www.dpreview.com/forums/thread/3893159

 

Focus accuracy for the zoom lenses has sufferred as a result of the v1.1 firmware and carried through to the current v3.1 firmware. For example, the SEL2470z and SEL1635z no longer open up fully upon half press of the shutter button. Now complaints are that focus accuracy has sufferred as a result. 

 

Rishi Sanyal (DPReview editor) has noticed in his review of the new FE 50/1.8 lens that iris is not opening enough to acquire accurate focus of the lens. He has said that Sony engineers have told him this is for faster speed and shot performance considerations. We as users disagree. See comments from Rishi on this thread:

 

http://www.dpreview.com/news/3613494796/hands-on-sony-fe-50mm-f1-8-and-70-300mm-f4-5-5-6

 

Please revert to the prior method of opening the lens iris more fully to acquire initial and more accurate focus on all E-mount cameras. The most notable lenses with problems are SEL2470Z, SEL1635Z and the SEL50F18F. The biggest problem is trying to acheive focus in low light with the aperture iris not opening enough. This creates more out of focus shots than desired or not being able to acheive focus at all.

 

Most in the Sony photography community believe this is the best way to acheive better focus accuracy and that focus shift was really not a problem with the zoom lenses and that the speed of focus acquisition should not warrant opening the iris by a smaller amount.

 

Current threads discussing this problem:

http://www.dpreview.com/forums/thread/3986747

http://www.dpreview.com/forums/thread/3989032

 

The A7II camera is even worse in that even primes lenses are not opening up enough to acheive initial accurate focus.

 

Proposed solution:

The A7ii version cameras have an option to adjust the priority of auto focus or speed currently. For the AF priority, the iris should open more fully so that accurate initial focus is acheived, not dependent on a zoom or prime. The current focus behavior would then be appropriate only for the balanced emphasis or release options and would take into consideration any focus shift potential which most believe was not an issue.

 

Regards!!

 

Enthusiast
Posts: 6
Registered: ‎12-15-2015
Message 2 of 16 (5,046 Views)

Re: A7 series focus issues with certain lenses

I and many others totally agree with the information and request in this post. Please create the firmware update we're asking for.
Expert
Posts: 889
Registered: ‎06-17-2014
Message 3 of 16 (5,006 Views)

Re: A7 series focus issues with certain lenses

Rookie
Posts: 2
Registered: ‎10-08-2015
Message 4 of 16 (4,984 Views)

Re: A7 series focus issues with certain lenses

Totally Agree! Here my findings about Firmware v3.1:

Firmware 3.1 Sony A7RII setting effects off af-s or af-c wider than F8:

with primes (28 fe, 35 f2.8, 55 f1.8): camera acquire focus wide open and close to the working aperture before you shoot. That means that if you are using AF-C with Af-lock-on  and F8 the first acquisition will be wide open than if you are tracking a moving object the camera will do that at the working aperture of F8...not really good for low light sport! In that case i would rather use an adapted lens that is working wide open and closing to working distance just after shooting!

with 24/70 f4: the lens try to focus at the working aperture(just open 0.5 stop from the working aperture) so in really low  low light it's almost useless if not wide open...before upgrading to Fw 3.1 it was behaving like primes…

And i would also add we really need some sort of external flash  AF-assist light to help focus in very dark conditions.... 

Apprentice
Posts: 8
Registered: ‎02-16-2014
Message 5 of 16 (4,675 Views)

Re: A7 series focus issues with certain lenses

[ Edited ]

I do not agree with the request to revert to focussing wide-open. My experience with the A7R2 and the native zoom lenses (16-35/4, 24-70/4, 70-200/4) is that focus shift is relevant and I'm very happy that the A7R2 now focusses with the working aperture. I have no experience with native prime lenses so can't comment on that.

 

I agree with the request to include the option for the user to choose between focussing wide-open or at working aperture. I think as a setting I'd prefer a maximum aperture setting per lens: either the lens focusses wide-open or uses the maximum set aperture, e.g. f/5.6, when the working aperture is smaller than that. This would be especially helpful when working at very small apertures like f/16. It is then possible for each user to set his or her preferred operation.

 

Edit: To elaborate a little further, let's take the FE 24-70/4 as an example. When the setting is set to wide-open, the lens focusses at f/4, irrespective of the working aperture, i.e. the aperture set for shooting. When I set the max. focussing aperture to f/8, the lens will focus at f/8 for a working aperture of f/8, f/11 or f/16. When the working aperture is set to f/5.6 or f/4, the lens will also focus at f/5.6 or f/4; the lens opens up for focussing to the max. focussing aperture or the working aperture, whichever is larger (smaller f-number).

Rookie
Posts: 2
Registered: ‎07-02-2016
Message 6 of 16 (4,349 Views)

Re: A7 series focus issues with certain lenses stopping down all the time

I concur that this is a valid problem. And, let me explain a definite situation where it creates a serious issue. I was shooting in my studio a couple of days ago and the shoot required me to shoot at F16 in order to obtain enough depth of field. I was using the 24-70 2 G master at F16 and 100 ISO. The lens remained stopped down to F16 even though there was no where near enough ambiant light untill the strobe fired. This created an impossible situation.  It was impossible to shoot because even thoght the camera would try and boost the stopped down image for viewing the grain it produced resulted in making the task of focusing impossible; For both manual and AF. The only work around I've found is to use certin adapters and aftermarket lenses that will alow me to shoot with out the lenses stopping down on me. Please provide a work arround so that I might be able to use my sony lenses in the studio again.

Enthusiast
Posts: 3
Registered: ‎07-09-2016
Message 7 of 16 (4,299 Views)

A7RII can't focus in studio at f16 with G lens

Yes - SO Frustrated!  I flew to Melbourne last week from LA for a studio shoot for a campaign.  I decided to go with my new Sony 24-70G over using my Canon 24-70II and adapter.  I was shooting at f16 to get depth of field and I could not acquire focus to save my life.  It took me to a while to realize that the aperture was no longer opening up.  

I can focus FANTASTIC wide open with the Canon 24-70 ... but can't use the SonyG in studio closed down - that's TOTALLY NUTS!?! 

 

Had to manually focus!

 

VERY disappointing!

Enthusiast
Posts: 4
Registered: ‎08-29-2016
Message 8 of 16 (3,823 Views)

Re: A7 series focus issues with certain lenses

Has this issue been resolved yet?  People who work in low light really should be able to set their system up to open the aperture fully for auto focus.  I am interested in getting the a7ii, but this seems like a very badly handled issue.  Best thing would be to make it optional so people with focus shift issues would be happy without crippling low light AF for those who don't.

Rookie
Posts: 1
Registered: ‎11-04-2016
Message 9 of 16 (3,051 Views)

I second that !

I second the original poster request: please add an option in the menu, if to focus stopped down or wide open.
With my A7RII, I often take portraits in my studio. I use studio strobes, which have a pilot light of course.
At studio portraits, I like to shoot at f/8 for optimal detail rendition.
The problem I have now with my A7RII is that eye focusing in continuous autofocus mode does not really work at f/8, because after the inital focus catch the lens remains stopped down at f/8, so eye autofocus does not catch anymore the movements of the model.
This is a big problem because it makes eye autofocus pretty much useless in the studio environment! I'm sure that there are many portrait and fashion photographers who make studio sessions at or around f/8 which is sort of the standard aperture for fashion studio photography, and I'm sure that they are disappointed just like me that they can not use eye autofocus in AF-C mode because of this absurd limitation in the firmware.

So please, Sony, please: give us the option in the firmware, if to accept the stopped-down default focusing setting, or if to overcome it and have the lens always focus wide open, which means staying wide open all the time in AF-C mode.
Please!!

Enthusiast
Posts: 3
Registered: ‎07-09-2016
Message 10 of 16 (3,045 Views)

Re: A7 series focus issues with certain lenses

No, unfortunately this issue hasn't been looked at.  It could be EASILY fixed... the camera used to work better, but in someone's infinite wisdom, they made it worse.  I won't actually use the Sony's on a studio session anymore.... unacceptably disappointing!  

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