Indoors with small apertures e.g. f16, I notice that when this is set to Focus Priority the viewfinder image does not degrade when focusing (using BBF). When it's set to Standard, the viewfinder image degrades markedly, presumably because the lens is stopping down during focusing. So why use anything else but Focus Priority? What am I missing?
I just found this today. The manual says if set to focus the lens will make more noise as it is opening/closing the aperture. I set mine to Focus. Wish I knew this 2 weeks ago when I was trying in my studio. Good I wasn't shooting f8.
Aperture Drive:
Standard, the f/stop stays closed when focusing wide open through f/11. f/13 or above the aperture opens a bit to speed up focus.
Focus priority, f/stop opens a bit to focus regardless of f/stop
Silent priority, the f/stop does not move when focusing so there is no noise.
I don't see why you would see such a big difference between Standard and Focus Priority, since according to Friedman they seem to operate the same above f/11.
In practice, when Aperture Drive is set to Standard, the lens stops down and this produces a flickering degraded viewfinder image when activating BBF or pressing the shutter button. When it's set to Focus Priority, the aperture remains wide open which yields a better viewfinder image.
In practice, when Aperture Drive is set to Standard, the lens stops down and this produces a flickering degraded viewfinder image when activating BBF or pressing the shutter button. When it's set to Focus Priority, the aperture remains wide open which yields a better viewfinder image.
I am not sure why I would want to use Standard...
Set to standard there’s no danger of focus shift. Focus priority will give faster and more accurate focus on a lens with no RSAs or other source of focus shift, but less accurate focus at some apertures with lenses that do exhibit focus shift. In principle this could be el imitated with a look up table that compensates for the focus shift but AFAIK Sony hasn’t done that.
Thee is also an issue about when you want to hear the slight noise of the aperture mechanism - at taking time, or earlier.
DavidBM wrote:
Set to standard there’s no danger of focus shift. Focus priority will give faster and more accurate focus on a lens with no RSAs or other source of focus shift, but less accurate focus at some apertures with lenses that do exhibit focus shift. In principle this could be el imitated with a look up table that compensates for the focus shift but AFAIK Sony hasn’t done that.
Thee is also an issue about when you want to hear the slight noise of the aperture mechanism - at taking time, or earlier.
Thanks, interesting.
Are some lenses more subject to FS than others? Is it known which are which? Is it predictable or idiosyncratic? Would be good to know...
The focus sequence is complicated and depends on the lens and camera model. It also depends on whether your are in AFC or AFS and whether setting effects is on or off. Some months ago, based on some comments on threads in this site, I started a project to catalog the performance of the lenses and bodies I own. I did this by watching the lens aperture as I varied the f/#, half pressed and fully pressed the shutter release. It was very tedious! I found lots of variation from lens to lens and body to body. I could find nothing in Sony documentation. I assume the lens to lens variation is dependent on the amount of focus shift in the lens. After getting through 3 of my 8 lenses I gave up. I did not get to the the 55/1.8, which is what the OP is using.
For example, here is what I found for the 24-70/2.8 GM with the A7R4 in AFS.
1. Focus Priority, Settings Effect on or off, The iris is set for f/# less than 5.6 it stays at that setting. If iris is set for greater that 5.6, it stays at 5.6 until focus is achieved, then closes to the set aperture.
2. Standard, Settings Effect off, The iris remains fully open until the shutter is pressed. If the iris is set for 5.6 or less, it closes down to that setting, focuses and then releases the shutter. If iris is set for greater that 5.6, it closes down to 5.6 until focus then closes to the set aperture and releases the shutter.
3. Standard, Settings Effect on, the iris remains at the set f/#.
Unfortunately I found that other lenses behaved differently. For example, the 200-600 was simple. It was always open until focus beep then closed. The 70-200/2.8 was similar to the 24-70/2.8 but the f/# breakpoint was f/11 instead of f/5.6. The results with the A9 were not always the same as the A7R4. I could not tell what was happening in a rapid sequence of shutter releases.
By the time I had done the work on these three lenses for the A7R4 and A9 I gave up.
It is not clear to me whether these differences are in the camera firmware of the lens firmware or both. Sony, as per usual, is not forthcoming with information. I suspect that firmware updates may change the performance with no notice to users.
Is anyone aware of an official list of lenses that actually support the "Aperture Drive in AF" feature? I found a screenshot someone posted on dpreview that appeared to have a link to a list from the a9 firmware download but that does not appear when I go to that page today.
The 7RM3 offers "Standard" and "Silent Priority" options with my SEL200600G lens. But the option is disabled with all other Sony lenses I have tried: SEL2470Z, SEL1635Z, SEL100400GM.
I reached out to Sony support and they had to escalate my question up the chain so I'm awaiting a response.
jeffbuzz wrote:
Is anyone aware of an official list of lenses that actually support the "Aperture Drive in AF" feature? I found a screenshot someone posted on dpreview that appeared to have a link to a list from the a9 firmware download but that does not appear when I go to that page today.
The 7RM3 offers "Standard" and "Silent Priority" options with my SEL200600G lens. But the option is disabled with all other Sony lenses I have tried: SEL2470Z, SEL1635Z, SEL100400GM.
I reached out to Sony support and they had to escalate my question up the chain so I'm awaiting a response.
Scroll down to *8. You see a compatible lens list highlighted in blue. Click on it to show the lenses.
I don’t know how complete or accurate the list is. I tried both my 85 GM and FE 35mm f1.4 on my A9II. And both appeared to work in Focus priority under Aperture Drive.
Scroll down to *8. You see a compatible lens list highlighted in blue. Click on it to show the lenses.
I don’t know how complete or accurate the list is. I tried both my 85 GM and FE 35mm f1.4 on my A9II. And both appeared to work in Focus priority under Aperture Drive.
Aha! Thank you. The Sony Japan site has different content than the US site. Much appreciated.
I guess the important takeaway is that not all FE lenses are compatible. While the "Help Guide" notes "Silent Priority" may be slower focusing I would like to experiment with this a bit. The reasons behind the aperture fluttering open and closed during focusing and pre-exposure has always been a bit of a mystery for me. As dclark noted the behavior is different with each combination of camera, lens, mode and exposure so it is difficult to predict.
Until now I have always been an advocate of using the "Setting Effect ON" options available on mirrorless cameras to get a preview of the exposure in the viewfinder. But I do wonder if that option in combination with others potentially slows AF in some situations.
Are some lenses more subject to FS than others? Is it known which are which? Is it predictable or idiosyncratic? Would be good to know...
Yes it varies between lenses between none and lots, but it is an optical feature so consistent.
Sorry I don’t know which AF lenses have it or how much.
DClark; Your initiative of sorting the matter (and communication about it) is remarkable.
Would You please consider sharing a proposition how to go about to practically compile a sorting grid (excell) as a first step or approach towards perhaps "standardize" populating and sharing observations more easily (if so, then also taking into accout dates of the Year and firmwares and state of unknowns about firmware influence..) ?
BTW I think over the years a same lens from Sony could suddenly behave differently i.ex also relative to phase or contrast AF detection at witch f-(or t?) stopp and/or indeed if at real apperture or not, it seemed to me (access to "preview" or not the DOF was then also somewhat "erratic" if not knowing all the subtelties to sort out...)
Myself now happen to have replaced some Sony lenses with DN's from Sigma. I sometimes wonder if someday their performanse could get altered in eighther way after a futur camera-firmware update. For this reason also, a collaboratve webpage collecting references could also be very positive.
(Reminds me of the site that collected the following data from camera owners:
- what is your camera model (SN?) ?
- how many exposures (internal count if extractable/shown by camera body) has (the mechanical) shutter made ?
- Does your shutter still work properly ?
The compilation of these answers to these very few simple questions easely introduced gave tremendous public insight as to the expectable longevity of their camera/shutters - often much longer longevity then was announced in specs ( artificial obsolecence was not really a specific/public notion then.)
DavidBM wrote:
Set to standard there’s no danger of focus shift. Focus priority will give faster and more accurate focus on a lens with no RSAs or other source of focus shift, but less accurate focus at some apertures with lenses that do exhibit focus shift. In principle this could be el imitated with a look up table that compensates for the focus shift but AFAIK Sony hasn’t done that.
Thee is also an issue about when you want to hear the slight noise of the aperture mechanism - at taking time, or earlier.
