Well, I guess I could use AF-C with it if I buy it. I usually use AF-S, but not much is lost with AF-C.
-
Welcome to the new forums! Please read this first. For known issues we are working to resolve, click here.
Sigma 16mm 1.4 - focus problems at 2.8 and 5.6 in AF-S
- Thread starter CyeJoeBob
- Start date
zackiedawg
Forum Pro
Unfortunately, this mystery issue goes deeper than that, because there are still many who have different Sigma and Sony lenses which should be experiencing this issue, yet are not...even with all of the settings of the camera set to those that should be forcing this issue.
To say that you can only get accurate focus at F1.4 or F8 with these lenses in AF-S is simply not true for all users of these lenses...so the issue is more elusive than that. I shoot exclusively AF-S with the Sigma 16mm F1.4, and I shoot with live-exposure settings on, I do not use DMF or manually adjust my focus, and I've shot every aperture range of the lens from F1.4 to F16, and haven't yet encountered this focus problem.
I would no more say that someone else isn't having any issues than I would want someone claiming I am when I'm not - so I think more vital is to keep trying to analyze EVERY possible setting of each person's camera when this problem arises, as well as how much light is in the scene, the subject distance, and so on - to try to isolate just what may cause it. So far, it doesn't seem to be just a particular aperture, or just the AF-S setting, or the live exposure sim setting...or a combination of the 3. Something else seems to be coming into play. What shooting mode (I've shot in P & A with the Sigma so far), is Pre-AF on or off (mine's off), what focus area chosen (I use flex spot - medium, on center point), and so on.
So far, no subject, no lighting situation, and no aperture or camera settings have caused me to see any missed focus in AF-S on my Sigma 16mm F1.4, on my A6300.
To say that you can only get accurate focus at F1.4 or F8 with these lenses in AF-S is simply not true for all users of these lenses...so the issue is more elusive than that. I shoot exclusively AF-S with the Sigma 16mm F1.4, and I shoot with live-exposure settings on, I do not use DMF or manually adjust my focus, and I've shot every aperture range of the lens from F1.4 to F16, and haven't yet encountered this focus problem.
I would no more say that someone else isn't having any issues than I would want someone claiming I am when I'm not - so I think more vital is to keep trying to analyze EVERY possible setting of each person's camera when this problem arises, as well as how much light is in the scene, the subject distance, and so on - to try to isolate just what may cause it. So far, it doesn't seem to be just a particular aperture, or just the AF-S setting, or the live exposure sim setting...or a combination of the 3. Something else seems to be coming into play. What shooting mode (I've shot in P & A with the Sigma so far), is Pre-AF on or off (mine's off), what focus area chosen (I use flex spot - medium, on center point), and so on.
So far, no subject, no lighting situation, and no aperture or camera settings have caused me to see any missed focus in AF-S on my Sigma 16mm F1.4, on my A6300.
snapa
Veteran Member
I believe you could use AF-S if you use DMF with magnification to resolve this issue. That way, you could MF with magnification to make sure you get critical focus on your subject. Maybe if anyone with this lens could test it to confirm this, it may be a good workaround? If true, maybe the same can be done with the Sigma 30 f1.4 in its F stop issue range.
Personally, I use DMF with magnification all the time, since I like to critically focus on very specific spots within my frame. I really does a good job when critical focus is important, IMHO. It would be interesting to me, since both the 16 & 30 f1.4 lenses are so good but have such a bad issue in certain F stops. Especially since I only use AF-S in those focal and aperture ranges.
Thanks for your efforts! I note that you used Flexible Spot small for this testing. Personally I’ve found that a bit unreliable, on all lenses not just the Sigmas, especially if contrast is a bit low. So I stick to Flexible Spot Medium. If I need to focus on a more specific area then I use AF in Focus Mag.
Using Flexible Spot Medium I found AF-S to give accurate results at all apertures outside of the problematic f2.5-2.8 range, though admittedly I did not test in as controlled manned as you did. Anyway, I use AF-C most of the time and only switch to AF-S at narrower apertures in low light when AF-C might hunt.
CyeJoeBob
Active member
There are not so many downsides.
First, I can't focus and recompose. Yes, I can use BBF, but I don't like it as I want to just hammer down the shutter button sometimes. Moveover it occupies a function button. Lock-On AF is also not always 100% reliable.
Second, I can't use self-timer in AF-C. Though that is only a minor problem, it can be annoying.
Third, it probably needs more power ?! Though I couldn't find any test, I think it needs a bit more power. That's critical if I'm on a hike in a remote area.
Overall I can live with that and hope that a firmware will fix these problems. Nevertheless I will return my Sigma 16mm and try a second one at the store, because I'm still not sure wheter all lenses are affected or just a few as many don't have any problems.
I’m also not a fan of BBF especially as it would be harder for my wife and others to take a photo of me using the camera.
Though, I see not being able to focus and recompose as a positive, haha... well I think focus and recompose at wide apertures is asking for trouble.
Fair point!
It might, logically, though I’ve not noticed any difference in battery utilisation.
Would be good though won’t hold my breath. I hope Sigma and Sony can find a solution for future lenses. Sigma is releasing a lot of fast FE primes and I wonder if they will also be affected by the same issue.
I suspect all are affected as I can’t see this being something limited to a faulty batch, especially as it’s the same issue that occurs on the 30/1.4. If the second one has the same issue perhaps you can keep the sharper copy
Everybody is a bit different. However, doesn't AF-C use up battery faster, which is an issue with these small batteries? Battery changes with these cameras is always expected, but the less often the better. Also, focus hold and/or exposure hold off-center become more tedious and time consuming. Some of the many features they put in these modern cameras are useful to many and some are mostly curiosities for most and clutter the controls. Back in the day there was only aperture, shutter speed and focus to worry about. Somehow a lot of great pictures were taken, even of sports. Take a look, e.g., at the 1950 Pulitizer Prize for news photography. It was taken with an old 4x5 Crown Graphic.Most of the time it’s very still subjects. No technical reason why DMF is unusable. Just personal preference that since I know the camera can AF the lens with 100% accuracy in AF-C, in about 1/10th of a second, I rather do that than use AF-S to get an out of focus image that I then have to manually adjust and then check the magnified image, possibly adjust it back and forth a fraction of a millimetre until I’m satisfied it’s the very best focus, which I might fuss over for 10 seconds or more and perhaps take a few shots to focus bracket just in case.... I kind of dislike manually focussing
Last edited:
CyeJoeBob
Active member
I returned my Sigma 16mm 1.4 now and bought another one. The systematic problems at f/2,8 are completely gone now. The AF-S is much more reliable. Only at f/5.6 the focus misses sometimes when using the display to focus. But it's not as bad as before.
So if you buy this lens better test it before keeping it.
So if you buy this lens better test it before keeping it.
That’s good! Strange though.
Yours is now accurate with AF-S using EVF at all apertures f1.6 through f2.8?
CyeJoeBob
Active member
I did some more testing and unfortunately f/2,8 is still out of focus, but only at closer distances <5m.
At first I only testet the infinity focus, which seems to work well at all apertures using the EVF and AF-S. At closer distances, the systematic out of focus problem increases from f/2 to f/2.8 from only slightly out of focus to completly out of focus.
100% center crop: top left - f/2.0, top right - f/2.2, bottom left - f/2.5, bottom right - f/2.8
At first I only testet the infinity focus, which seems to work well at all apertures using the EVF and AF-S. At closer distances, the systematic out of focus problem increases from f/2 to f/2.8 from only slightly out of focus to completly out of focus.
100% center crop: top left - f/2.0, top right - f/2.2, bottom left - f/2.5, bottom right - f/2.8
That’s bad. What’s the point of having a sharp lens, if it cannot focus?I did some more testing and unfortunately f/2,8 is still out of focus, but only at closer distances <5m.
At first I only testet the infinity focus, which seems to work well at all apertures using the EVF and AF-S. At closer distances, the systematic out of focus problem increases from f/2 to f/2.8 from only slightly out of focus to completly out of focus.
100% center crop: top left - f/2.0, top right - f/2.2, bottom left - f/2.5, bottom right - f/2.8
Except it can focus fine with AF-C or the LCD.That’s bad. What’s the point of having a sharp lens, if it cannot focus?I did some more testing and unfortunately f/2,8 is still out of focus, but only at closer distances <5m.
At first I only testet the infinity focus, which seems to work well at all apertures using the EVF and AF-S. At closer distances, the systematic out of focus problem increases from f/2 to f/2.8 from only slightly out of focus to completly out of focus.
100% center crop: top left - f/2.0, top right - f/2.2, bottom left - f/2.5, bottom right - f/2.8
It's not a Sigma lens issue, it also happens with my Sony E 50/1.8 OSS
trenzterra
Leading Member
This is interesting because I've never noticed the issue at f5.6. unfortunately there is no centralised sigma support email (I tried emailing the US side but was told to find my own country instead) so it is very difficult to highlight to them that it's an issue with their own lens.
trenzterra
Leading Member
Would be great if Sony can be informed of this issue. Unfortunately I am unable to reproduce this on my 50mm.Except it can focus fine with AF-C or the LCD.That’s bad. What’s the point of having a sharp lens, if it cannot focus?I did some more testing and unfortunately f/2,8 is still out of focus, but only at closer distances <5m.
At first I only testet the infinity focus, which seems to work well at all apertures using the EVF and AF-S. At closer distances, the systematic out of focus problem increases from f/2 to f/2.8 from only slightly out of focus to completly out of focus.
100% center crop: top left - f/2.0, top right - f/2.2, bottom left - f/2.5, bottom right - f/2.8
It's not a Sigma lens issue, it also happens with my Sony E 50/1.8 OSS
I have not seen the issue with my 50mm either and based on the SEL50 test pics I have seen here, the issue with the 50mm lens is nowhere near as severe as the Sigma issue. I did notice the Sigma issue w/o even knowing it existed in less than one hour of ownership.Would be great if Sony can be informed of this issue. Unfortunately I am unable to reproduce this on my 50mm.Except it can focus fine with AF-C or the LCD.That’s bad. What’s the point of having a sharp lens, if it cannot focus?I did some more testing and unfortunately f/2,8 is still out of focus, but only at closer distances <5m.
At first I only testet the infinity focus, which seems to work well at all apertures using the EVF and AF-S. At closer distances, the systematic out of focus problem increases from f/2 to f/2.8 from only slightly out of focus to completly out of focus.
100% center crop: top left - f/2.0, top right - f/2.2, bottom left - f/2.5, bottom right - f/2.8
It's not a Sigma lens issue, it also happens with my Sony E 50/1.8 OSS
Some have said they don't see it with their Sigmas either. With mine the issue is very slight and I really had to hunt for it the first time I tried to find it after reading about it here but now that I know what to look for I can find it easier.Would be great if Sony can be informed of this issue. Unfortunately I am unable to reproduce this on my 50mm.Except it can focus fine with AF-C or the LCD.That’s bad. What’s the point of having a sharp lens, if it cannot focus?I did some more testing and unfortunately f/2,8 is still out of focus, but only at closer distances <5m.
At first I only testet the infinity focus, which seems to work well at all apertures using the EVF and AF-S. At closer distances, the systematic out of focus problem increases from f/2 to f/2.8 from only slightly out of focus to completly out of focus.
100% center crop: top left - f/2.0, top right - f/2.2, bottom left - f/2.5, bottom right - f/2.8
It's not a Sigma lens issue, it also happens with my Sony E 50/1.8 OSS
I don't use AF-S anyway so it doesn't impact me.
Sigma has already responded that it's a camera issue.
Similar threads
Keyboard shortcuts
- f
- Forum