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Sony FE 35/2.8 ZA Issues with focusing and color shift

ZoranC

New member
While examining shots I have taken over last week or so with my SEL35F28Z on A7R I have noticed two issues:

1. Often enough focus is missed. For example, if I take 3 shots in a row of same "target" often at least one of them is misfocused by amount that is noticable.

2. In some scenes I am noticing color shift toward magenta in quite a part of the frame, way one would get them when trying to use M wide glass.

Has anybody else experienced same? Any thoughts?
 

ZoranC

New member
I got question about color shift answered over on FM (looks like not only 35/2.8 exhibits them but so does 55/1.8), but no experiences shared on misfocuses yet. Does that mean everybody else's 35/2.8 is focusing perfectly 100% of time?
 

jfirneno

Member
While examining shots I have taken over last week or so with my SEL35F28Z on A7R I have noticed two issues:

1. Often enough focus is missed. For example, if I take 3 shots in a row of same "target" often at least one of them is misfocused by amount that is noticable.

2. In some scenes I am noticing color shift toward magenta in quite a part of the frame, way one would get them when trying to use M wide glass.

Has anybody else experienced same? Any thoughts?
ZoranC:

I remember back in January there was a lot of talk about the A7R missing focus with the 55mm more than with the 35mm. The A7 was decided to be the one with the more accurate (and rapid) af in good light. In bad light neither one is stellar. I think folks compensate by half pressing the shutter button a couple of times to make sure the focus is on the correct point. I often check with the focus aids (magnified focus or eye focus for portraits) to ensure critical focus. As far as color shifts, you'll have to consult the more color sensitive membership of the forum but actually reading over the discussions of the 35 and 55mm FEs I don't remember them getting much criticism on the color shift front.

Regards,
John
 

ZoranC

New member
ZoranC:

I remember back in January there was a lot of talk about the A7R missing focus with the 55mm more than with the 35mm. The A7 was decided to be the one with the more accurate (and rapid) af in good light. In bad light neither one is stellar. I think folks compensate by half pressing the shutter button a couple of times to make sure the focus is on the correct point. I often check with the focus aids (magnified focus or eye focus for portraits) to ensure critical focus. As far as color shifts, you'll have to consult the more color sensitive membership of the forum but actually reading over the discussions of the 35 and 55mm FEs I don't remember them getting much criticism on the color shift front.

Regards,
John
John, thank you for your input :) I do remember that while ago there were some reports of autofocusing issues but IIRC they were mentions by some of the journalists from Sony's Nashville PR event and were that A7 is having problem autofocusing, while A7R is not, with no comments that issue is with the lenses. Are you talking about some different reports? If yes do you happen to have link to those discussions, please? Thank you again!
 

jfirneno

Member
John, thank you for your input :) I do remember that while ago there were some reports of autofocusing issues but IIRC they were mentions by some of the journalists from Sony's Nashville PR event and were that A7 is having problem autofocusing, while A7R is not, with no comments that issue is with the lenses. Are you talking about some different reports? If yes do you happen to have link to those discussions, please? Thank you again!
The missed the focus was from threads on this site.
 

thomas

New member
In some scenes I am noticing color shift toward magenta in quite a part of the frame, way one would get them when trying to use M wide glass.

Has anybody else experienced same? Any thoughts?
for the FE 2.8/35 ZA you definitely need a neutral white plexi plate with high diffusion to make white reference shots. Look for "Lens Cast Calibration" and/or "White Shading". Capture One and Lightroom provide tools to correct light falloff and color cast based on white reference shots. Capture One's so called "lens cast calibration" tool is very mature... it works excellent. I've heard mixed things about Lightroom's "Flat Field" Plugin... but I haven't used it yet, so I can't comment on it.
I would recommend to switch on the internal camera correction for vignetting and just correct the remaining light falloff in post (together with the color cast).
 

ZoranC

New member
for the FE 2.8/35 ZA you definitely need a neutral white plexi plate with high diffusion to make white reference shots. Look for "Lens Cast Calibration" and/or "White Shading". Capture One and Lightroom provide tools to correct light falloff and color cast based on white reference shots. Capture One's so called "lens cast calibration" tool is very mature... it works excellent. I've heard mixed things about Lightroom's "Flat Field" Plugin... but I haven't used it yet, so I can't comment on it.
I would recommend to switch on the internal camera correction for vignetting and just correct the remaining light falloff in post (together with the color cast).
Thank you! IIRC RX1 had color cast issues too, and Imaging Resource claimed they were only if you used in camera correction for vignetting. With A7R allegedly cooking this in RAW when enabled I might try it disabled and see does color cast go away.
 
1. Often enough focus is missed. For example, if I take 3 shots in a row of same "target" often at least one of them is misfocused by amount that is noticable.



Has anybody else experienced same? Any thoughts?
I have substantially improved my success rate by putting the camera into MF mode and using AF/MF button only to autofocus. I found that using the shutter button to autofocus even small movements of the subject (or o the camera) cause unnecessary focus hunting and hence misfocus when shooting fast.
 

ZoranC

New member
I have substantially improved my success rate by putting the camera into MF mode and using AF/MF button only to autofocus. I found that using the shutter button to autofocus even small movements of the subject (or o the camera) cause unnecessary focus hunting and hence misfocus when shooting fast.
Hmmm... I gotta try this, thank you for the tip :) So you are saying that camera will continue to hunt for the focus even while shutter is half-depressed and focus mode is AF-S?
 

Guy Mancuso

Administrator, Instructor
I have substantially improved my success rate by putting the camera into MF mode and using AF/MF button only to autofocus. I found that using the shutter button to autofocus even small movements of the subject (or o the camera) cause unnecessary focus hunting and hence misfocus when shooting fast.
Marc mentioned this and I converted my cam this morning to that button and work in MF mode but Im having issues with my custom function setup. I need a rundown on menu setting for this as I lost my ability to move my focus point or my focus area that I had for C3 but if I go to AFs or DMF its there. Im not sure what setting for AF/MF button. I have it set for AF/MF Control hold.


Any guidance on this setup would be nice. Here is my problem along with others Im sure i have 3 manual focus lenses a FE than 2 A mount lenses and I want them to act the same.

What I am not fond of with the FE is if I touch the lens it goes into zoom and I would rather do that like I do with the rest of my glass. Bottom line a simple 1 /2 punch for all the glass.
 
My settings for focussing:

C1 set to Focus Setting

C3 set to AF/MF toggle

Central Button set to Standard

AF/MF central button set to AF/MF Control Hold

MF Assistant ON

In MF: C1 activates the zoom , AF/MF central button activate the AF, the focussing point can be moved using the left-right- up-down button or with the front and back dials if the zoom has been activated , or with a push on the central button. Turning the focus ring on the lens activates the zoom only if MF assistany in ON
 

Guy Mancuso

Administrator, Instructor
Thanks Ario let me try that. . My central button is set to hold let me fix this. Thanks appreciate the help.
 
At the moment I use C2 for Zebra (100+ for ETTR or OFF). I find the position of C2 not very convenient so I prefer not to assign it to something I use frequently and I have to oprate quickly.
 
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