ilkka_nissila
Offline
• • • •
Upload & Sell: Off
|
 p.1 #2 · Tips for consistent EyeAF with Z8 | |
I think the shutter speed is low and a faster speed is likely to improve sharpness (in some case it is difficult to distinguish between blur due to misfocus and due to subject vs. camera motion). I would try again at 1/400s or faster and see if that improves the results. 1/125s is way too slow.
Since the camera's phase-detection sensors detect vertical lines in horizontal orientation and horizontal lines when the camera is in vertical orientation, eyebrows are prone to be picked by those sensors. However, I do not see this as a significant issue in the finished picture. To improve this and other similar issues, I would hope Nikon implements cross-type sensors. Priotitising contrast detection and more precise identification of the iris may help but I expect PDAF to handle approaching subjects better. Adapted lenses are likely to work better based on PDAF rather than CDAF data as the focus system on those lenses was developed for PDAF.
Jman13 wrote:
So, I am no stranger to the EyeAF algorithms of mirrorless cameras. I shot Sony for many years, and their EyeAF became quite good, though not entirely perfect. I shot Canon for several years recently, with the R5 and R8, and there, the EyeAF was essentially flawless. I could rely on the camera absolutely nailing focus on the eyeball with near 100% accuracy, even with ultra-fast lenses and very shallow depth of field. I shot an event for two hours with the 50/1.2L and 85/1.2L on the R5, shooting about half the images wide open, and I think I missed focus on 3 shots total in the entire event, and that was with people milling about, not posing, etc.
I've recently transitioned to Nikon Z (though I still have my R8 and my portrait primes for the moment), and picked up a Z8. Overall, I really like the Z system, and the quality of the files is incredible on both the Z7 II and the Z8 (perhaps the best of any cameras I've ever owned), and I love the lens lineup.
However, I'm struggling with EyeAF even on the Z8, for portraiture with shallow depth of field. The system seems to have a VERY strong preference for the eyebrows or lower lashes as opposed to the iris, but it's inconsistent in that regard. I've tried using AF-S, AF-C, 3D tracking with subject recognition, wide area and spot area tracking, and while it grabs the eye visually quickly, surely and confidently, ultimately, about half my images are consistently missing critical focus, and instead jumping forward to the eyebrow. For instance, I picked up a 105mm f/1.4 to rent and try out, and in single shot or AF-C with a normal focus point, it is consistently accurate and sharp, and I have no issues. Turn on subject detection, though, and the behavior I've described happens. I did some quick portraits with my son this afternoon (he was less than thrilled to be the model), to test out the lens, and I had it set to wide area tracking with people detection, AF-C shooting at f/1.4. I took 12 shots with him leaning against a fence, with me moving forward and backwards sometimes between shots a little, but always shooting from a stable, static position. Below are crops on the focused near eye for all 12 shots...as you can see, only 6 of the 12 are what I would consider in perfect focus. 2 more are close, but not quite there and the other 4 are quite clearly focused forward of the eye, mostly on the eyebrow.
https://www.jordansteele.com/2023/EyeAF.jpg
So, that's a perfect hit rate of just 50% on a static subject, and I have to say it's a bit frustrating. I know this is very shallow depth of field, but this situation would result in essentially perfect focus every time with my RF 85L and the R8, even at f/1.2. Equally frustrating are the four full body shots I took, that still grabbed the eye in the EVF, but every single one was focused in front of him to varying degrees. I know the lens can focus accurately at these distances because all non-EyeAF shots at various distances are always dead-on. Do you have any tips with this AF system to increase the accuracy in these situations. I can use single small point AF, and that seems to work better, but of course isn't using Eye tracking at all, and is not realiable for quick changes in position, such as may be needed for events or candids.
Note also that I have similar experiences with native Z lenses like the 85/1.8S and 50/1.8S. I'm just hoping there's something I'm doing wrong, or a setting I can change that will improve things.
Btw, here's the full shot of one that nailed focus:
https://www.jordansteele.com/2023/x_fence.jpg...Show more →
|
