Today i want to show you my results from yesterdays portrait and streetshoot with the new little FE50 1.8 + Sony A7II. Check out my experience using the Face Detect + Eye AF. I will update this post a lot in the next days http://www.dsphotoblog.com/?p=1405 ‪#‎photography‬

 

this lens has the worst AF aquisition I have seen lately.

I use the 55mm Zeiss over the 50mm Sony, much much better 

 

Check out my top 5 lenses for Sony Alpha http://blog.danmleephotography.com

this lens has the worst AF aquisition I have seen lately.

I have A7 and AF-S hunts everytime - in corners newer lock. But AF-C its great - 4x faster! I Sold A7R + 55/1,8 and bought A7 + FE28/2 + FE 50/1,8  and I'm happy. A7+50/1,8 its faster and more accurate then A7R +55/1,8

IQ is fantastic. If Sony fixes AF in a FW update, it's a killer lens.

 

Have you tried the battery reset trick that someone suggested in the other 1.8/50 thread in this forum?

I have A7 and AF-S hunts everytime - in corners newer

lock. But AF-C its great - 4x faster! I Sold A7R + 55/1,8

and bought A7 + FE28/2 + FE 50/1,8  and I'm happy.

A7+50/1,8 its faster and more accurate then A7R +55/1,8

I don't have that particular lens [i use the Maxxum 50]

but by your report, I'd have no problem at all with its

AF behavior. You say it's terrific in AF-C ? Well, as a

dedicated user of Back Button AF, I'm always in AF-C.

 

It seems that BBAF is quite popular, so there must be

lotsa happy AFers using that lens and never knowing

of its AF-S shortcomings . With BBAF, AF-C functions

equally and simultaneously as both AF-C and as AF-S.

I did notice AF is a lot faster at f/4, at f/1.8-3.0 it's noticeably slower. Doesn't bother me either way. Great image quality.

I did notice AF is a lot faster at f/4, at f/1.8-3.0 it's noticeably

slower. Doesn't bother me either way. ...........

  

That's just weird. That's like saying your AF is affected by

your shutter speed setting. The shutter speed setting is a   

user input for an action that will only happen AFTER the

AF has completed. I think everybody knows that, and so  

will not suspect the shutter speed setting of affecting AF

performance.

 

Saying that AF is affected by the f/stop settings is just the

same as saying AF is affected by shutter speed settings.

As with the shutter action, the actual f/stop action happens

only after AF has completed. The f/stop dial does not alter

the size of the aperture when you dial settings on it. Same

as the shutter speed dial, it's a user input for an action that

will occur at the correct future moment. Nothing changes

as you twirl the dial.

 

The aperture stays fully open [f/1.8 in your scenario] so as

to provide minimal DoF to the AF, or eyeball, that's judging

focus acquisition. It also provides more light to the viewing

system that way. The dialed-in f/stop physically exists only

during the exposure. 

  

++++++++++++++++++++++++++++++++++++++++++++ 

  

Even selecting " Live View > Setting Effect ON " does not

close the iris before the exposure. The screen darkens and

lightens artificially, to show you the exposure level that your

settings will produce. Exposure level is only brightness, it's

NOT action blur [shutter] and NOT DoF [f/stop]. These are

not previewed in " Setting Effect ".    

  

If your AF is really clearly better at f/4, if it's not an illusion,

I suspect you have a malfunction. What I suspect could be

either a malfunction, or an ingenious intentional function of

the AF system.  

 

Given sufficient light [doesn't hafta be sunny], AF detectors

often perform WORSE if shown very minimal DoF to focus

with. If AF worked slowly and carefully, like we do when we

MF by eyeball, then minimal DoF would provide terrific AF

accuracy. Cuz AF does not focus leisurely, AF "sees better"

if details are visible. AF misses lock-on and keeps hunting if

it's trying to find details in the extra fuzzy world of minimal

DoF.  IOW, with sufficient light, it's "vision" is clearer at f/4

than f/1.8, as it views a defocused scene and seeks details

that it can sharpen up.

  

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So, given the above, maybe when the camera sees that the

lighting is better-than-dim, and it also sees that the user has

input f/4 [or even smaller] then the camera enables the AF to

see more details and less fluffy fuzz, by dropping the viewing

f/stop down to about f/4 [f/4 even if you set f/16]. And it must  

do that only for AF. For eyeball MF, we want minimal DoF,

so we wanna do MF wide open.

 

Trouble is, I doubt that Sony is all that clever. So in that case,

if Sony is only as clever as we think they are, you may have

a malfunction that lets the auto-iris kinda droop a bit, unless

it's set to f/2.8 or wider. You could test that visually. If the iris

is drooping to about f/4 when you dial for smaller stops, you

will see a slight difference in DoF occur in the viewfinder, as

you dial from 1.8 to smaller stops.