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Big issue with new 85 and 24-70 GM Lenses


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This is a brief summary of the problem:

The megaissue is with the Sony A7rII (but guess it’s applicable to other ILCEs too) and the two new GM lenses (24-70 and 85). Maybe it's applicable to other lenses too but I can't confirm as I don't have them. I confirm there are no issues with old Sony Zeiss 55 and 16-35 zoom.

The issue is related to the the iris not opening while focusing with the 85 1.4 and 24-70 2.8GM. Setting Effect ON/OFF toggle setting has no effect (mine is always on OFF anyway).
Practically speaking, you can’t focus accurately in normal dimly lit studio situations when shooting over f4.
Iris stay closed while focusing and focus accuracy and speed drop.
If you have to shoot at f8 (and in studio that’s the norm, but f5.6 proved impossible too) you can’t really focus at all unless you’ve a lot of ambient light too, even manually because the same accuracy drop is in the viewfinder, stopped down you can’t see the exact focus point even in manual focus when zoomed because the image is too coarse and spoiled by digital grain.
It's a total show stopper. Previously I was using a Metabones/Canon 24/70 and Canon 85 combo with optimal results but I mistakenly thought that the new Sony duo would have been a wonderful choice and actually they are, but only when shooting wide open or almost wide open. Stopped down the focus is simply unusable and even worse prone to errors.

My question is: does anybody know if Sony is aware of the issue and is going to fix it?
Why they did such a big mistake with the new GM lenses?
I’ve checked online and it's not my problem, other people working professionally noticed the very same issue.
You can find a detailed description of the issue on diglloyd just to quote one.
http://diglloyd.com/blog/2016/20160419_1756-SonyA7R_II-SonyGM-focusingBug.html
He finds that even at f4 accuracy drops below the acceptable range. My results at f4 were slightly better but probably because people moves all the time so there are more chances that they move also towards the focus point.

If I need to shoot at f8 with studio flashes how can I focus this way? I can't realistically open iris and then close before every single click. Des somebody know of any engineer’s email that I can contact about this?
Is there a way to contact a Sony developer directly? You know, writing to support emails is totally useless for such critical but very peculiar issuers…

Thanks everybody for any help.

Maurizio Camagna
http://camagna.it

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I use 4 different Sony bodies, altho none are your model,  

nor your lenses. But I do notice that on some models that  

iris behavior is linked to the choice of mode [PASM]. IIRC  

one of them switches off the auto iris function in A-mode.  

  

Check thru all 4 modes on your camera using GM lenses,

to see if the problem occurs in every mode, or not.

  

Hypothetical example, simply a jump off point for thinking

outside the box to seek a work-around:

 

Suppose you find that the problem goes away in S-mode.

  

Agreed that S-mode is not a seemingly logical choice for

studio flash use. But, you can mimic manual mode while

in S-mode. Set the AEL to "Hold". Set the shutter speed

you prefer. Aim your camera at a light or whatever, so as

to cause the camera to select the f/stop you prefer. Lock

that f/stop in place using the AEL-Hold.

 

I emphasize that the above is an example of what MIGHT

happen. It's just an example of experimenting beyond the

obvious, and not a tested/proven prescription ... not at all.

Good luck.  Experiment madly !

  

`

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Tried everything. Won't work. No way to turn off the Auto Iris and the S mode in not usable. With a static subject you could temporarily open the iris to 1.4, focus, and then close and that's the only possible workaround. That's even acceptable in a still life situation. But with people you need a continuos AF working in the DSLR way and you need to shoot FAST.

By the way, I've tried in very good light to focus at F16 and it's totally impossible as too little light and too little contrast reaches the sensor. I can't believe that at Sony NOBODY noticed that.

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With the 70-200 G4 I notice the following with an A7m2:

 

A-mode with Setting effect ON - half press, aperture opens slightly, focuses (I look in the lens and see the internal optics move), and remains open, shutter released aperture closes a little.

 

A-mode with Setting effect OFF - aperture is fully open, half press, aperture remains fully open, focuses (I look in the lens and see the internal optics move), shutter then closes to target aperture, shutter released aperture opens fully again.

 

 

So, I have read that Setting effect has no impact, from Mr Smith no less IIRC, and clearly _he_ is wrong. But, the behaviour that Mr Lloyd expects was _also_ not what I observed, so he is also probably wrong.

 

Guess what, I have a Batis 25mm, and I test that one too. It behaves exactly the same way as the 70-200G4.

 

Well ... that makes some sense, but also not some sense, so I tried again ... and now I found that:

 

Effect Setting ON, on half press the aperture opens slightly, focuses, remains open, and on release closes a little.

Effect Setting OFF, aperture opens and closes according to ambient light, presumably to keep the LCD image correctly exposed for the reasons of being able to compose a shot and focus (camera needs contrast to focus), on half press the aperture remains more or less where it was, focuses, aperture then closes to the target setting, and on release opens again.

 

 

So _clearly_ Live View Display with "Effect Setting ON" is offering DOF preview and focus is acquired at the target aperture. And when this setting is set to OFF the focus is being acquired at what we can call the "optimum" aperture and then the target aperture is set.

 

 

 

Probably your GM Lens is working exactly the same way. Some cameras do open and close the aperture when acquiring focus, but apparently not this one. So probably Sony is happy with things as they are. They _might_ change it in the future, and call it Improved Predictive AF, so that we feel compelled to upgrade our expensive 2 year old cameras with even more expensive new cameras ...

 

 

My personal experience is that with Low contrast subjects and smaller apertures, the camera struggles to focus.

 

 

In summary, Setting Effect OFF is probably going to help you a little. Try again and see, look in the lens and see.

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Thank you but with GM lenses Setting Effect ON/OFF has no effect at all apart from showing the approximate exposure on the viewfinder. It's not of any use when using lights anyway because it must stay off all the time otherwise you'll see just a black square.

As I said in my other thread (unfortunately a delay in publishing here made me duplicate the same post) the behavior is bad also with the SonyZeiss 55 1.8 since some of the latest firmware upgrades (it was ok before, probably before 3.1).

The other thread has more details, so please read and post there.

Thanks!

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I would suggest to use Setting Effect OFF, it should be better AFAIKS. Setting ON in your case would be pointless, f8 and dark, camera has no chance.

 

Reality is if there is not enough light on the sensor then Contrast based AF will not work, and IIRC even the phase detect will probably not work at the smaller aperture.

 

You might be able to trick the camera by setting the Auto ISO to go unto 6400 or similar for getting focus, and then perhaps when you take the shot with the flash it would select a much lower ISO ... perhaps some combination of the so called "Back Button Focus", what you want to do is separate the exposure evaluation from the focus aquisition. So move the focus away from the shutter button and perhaps move it to the rear button OR on the GM lens you can move it to the Lens button.

 

Something like:

 

Setting Effect Off

Focus to Lens Button

AutoISO to 6400

Shutter button then evaluates exposure and takes the shot.

 

Worth a try.

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Setting Effect Off

Focus to Lens Button

AutoISO to 6400

Shutter button then evaluates exposure and takes the shot.

 

Worth a try.

 

Try the following

 

Inside, enough light to focus usually. Manual exposure, shutter at 1/160, aperture at F/11. Try to achieve focus. You will fail. Applies to GM lenses and Sony 55m. F/1.8 with firmware V2.

I just did the following outside

 

Manual exposure, afternoon light, F/22 (yeah, I know, I don't shoot at F/22, this is to prove a point) - camera will use only CDAF, and hunt badly.

 

Why is this a problem? Try to kill the ambient light in a studio at F/8. Can't be done with these lenses and cameras. That is INSANE! Sony messed up their GMs and the Firmware update for the 55mm at least (haven't tried my 35m yet).

 

Clue to Sony: You step down the aperture when I press the shutter. NOT A MICROSECOND before that. This is what ALL camera manufacturers do. Anything else is absurd.

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  • 2 weeks later...

Probably your GM Lens is working exactly the same way.

 

They are not. On the A7R2, with the latest firmware, the following lenses will stop down to taking aperture before focusing (in AF-C, and this applies to AF-C ONLY).

 

The 55mm ZA, the new 50mm, the 85mm GM and the 24-70 GM. This is a serious bug, and Sony should fix it. No other camera manufacturer does this, and for good reason.

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...........

 

Why is this a problem? Try to kill the ambient light in a studio at F/8.

Can't be done with these lenses and cameras. That is INSANE! ...............

........

  

The problems you describe certainly DO need fixing, like

yesterday if not sooner. But as to ambient studio light that

influences your image at f:8 ... this is not the fault of the

cameras. This is shortcomings of the studio flash system. 

  

Two shortcomings: 

 

1. The modeling lights on good studio strobes will dim as

the flash triggers. If they do not, don't blame the camera.

  

2. If you hafta use f:8, you don't have enuf watt seconds.  

   

One CAN work without self-dimming modeling lights and

be just fine at f:8, or even f:4 ... only with a leaf shutter :-(  

 

One CAN work with only 1200WS but it will introduce so  

many headaches, such as ambient light problems. 800 to

1200WS is basically for small tight tabletop product shots

where hot lights would overheat the subject ... a problem

that can now be solved by LED lighting.  

 

OK so much about "f:8". Back on point, Sony's idea about

how to sequence the operations of the camera and lens

are, just as you said, INSANE. I love using my Sonys, just

as years ago I loved using my Pen-F kit. Just as I'd never

expect a Pen-F to serve in a studio environment, likewise

a Sony is a fun-times mistress and not a wife. So, I'm lucky

to never experience these problems first hand. But I hafta

agree: Sony seems to know NOTHING about photography,

and even worse, seems to stubbornly refuse to learn. That

their stuff works at all is just dumb luck. OK for fun, but not

always OK on the job. For some jobs not OK at all ... ever.  

   

Uber drivers may well drive a Prius or such, but REAL taxi

drivers drive a Crown Victoria [on the job].

 

`

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Looking analytically at the currently-stupid Sony

interaction between lens iris and AF-C, and also

foolishly giving Sony the benefit of the doubt, I'm

imagining some kernel of a good idea, but very

poorly engineered or implemented. 

 

AF-C, as a typical AF mode for action, often with

high shutter speeds resulting in little DoF, would

often encounter difficulty acquiring a recognition

of an intended subject, especially when the initial

view of the subject is rather fuzzy.

  

Some sort of brief increase in DoF, just to get a

bit clearer view of the subject so that the AF-C

can lock on, could be facilitated by a momentary

stop down, maybe a rapid close to waaaay down

that equally rapidly re-opens to almost wide open

to assure really accurate focus ... finally followed

by the actual exposure at the proper f/stop.

  

So I'm picturing the above good idea gone awry,

resulting in the current insane hardware actions.

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My understanding is that the lens works as it should if you use AF-S, correct?

 

I agree this is an issue that needs to be fixed.  Why don't we get a list together of people and mass email Sony?  Posting on this board is unlikely to change anything. 

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  • 2 years later...

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