I’m thinking about a switch from Sony to Nikon.
I noticed something really annoying when trying out the Z8 in the store:
When you magnify the liveview (to manual focus/check focus) it gets terribly laggy.
When I do this on my A7RV I don’t have this issue which makes manual focus a lot more enjoyable.
Is there a workaround for this or am I missing something?
It’s not something I’d expect from such an advanced camera like the Z8.
Really disappointing.
Such a smooth and responsive EVF that has a separate feed from a stacked sensor… limited by that weird behavior. Reviewers seem to ignore it?
i wonder if this same lag is applicable to the EVF? i would reckon that the EVF would be less laggy (if at all)? that said, i don't even notice let alone find this as an issue for a lot of my use case (macro of still life subjects and/or wide apertures for portraits) but I understand why this would be an issue for some.
It’s equally applicable to the EVF and the LCD. It has to do with sensor read out which displays equally to both.
I even tested setting the EVF display size to small to see if that would enhance performance, it did not.
dalegaspi wrote:
i wonder if this same lag is applicable to the EVF? i would reckon that the EVF would be less laggy (if at all)? that said, i don't even notice let alone find this as an issue for a lot of my use case (macro of still life subjects and/or wide apertures for portraits) but I understand why this would be an issue for some.
EVF delay is harder to measure optically. But the EVF is also an LCD display with magnitication optics in front of it.
There is always some delay in LCD/EVF. It seems the Z8/Z9 full frame view live view has extremely short delay; even as an OVF buff I can't notice the delay in normal operation. Only on occasion does it happen that the camera shows a slow sequence of moments when first picking up the camera and looking through. I am not sure what is causing this, but once the camera gets properly started the distinct nature of the frames disappears.
I also have the Zf and to my surprise its EVF (despite using a slower sensor and presumably lacking parallel EVF data stream from the sensor) doesn't have such a delay that I would mind.
So they have done a good job with the Expeed 7 generation of bodies. The Z6 II EVF + shutter delay was long enough that it really threw my timing off and I couldn't get the kind of single shot timing that I'm used to. With the Zf and Z8 I can.
When you are using the EVF normally, the sensor leverages some combination of pixel skipping, pixel binning, etc. in order to read faster and more power efficiently. In other words, not every single pixel of the sensor might be read individually. If you have a 45MP sensor, maybe the sensor only reads like ~every other GRBR pixel horizontally & vertically (10MP) or even half of this (2MP). The EVF is only around 1MP anyway. This is also how even the Z6 or Z7 can display high framerates in the EVF, even if these exceed the framerate of the full sensor scan.
However, when you zoom in during viewfinder usage, the sensors typically switch to a full-readout mode, where they read every single individual pixel and then crop from that. If they didn't, it would enhance the artifacts from skipping/binning pixels. I don't think there is currently a way for them to read only a crop of the sensor instead because panning around would require instantly scanning a different part of the sensor and they would have to find some way to define and build around all of these combinations of read modes.
So essentially, magnified EVF view will usually have similar lag to whatever the highest quality video mode for that camera is. For example, on the Z6, the highest quality video mode is low-framerate 4K (which itself is oversampled from 6K--the full width of the sensor). I've measured this lag at around 0.25 seconds:
Jim Kasson has also done measurements and comparisons to magnified view on his Z7, which are similar to what I've found on my Z6:
https://blog.kasson.com/nikon-z6-7/z7-magnified-lcd-lag/
BTW, because the lag is roughly 8x worse, we can guess that the Z7 sensor is probably reading somewhere around 8x less data (again through combinations of skipping or binning or whatever).
The user in your link is experiencing something similar on the Z9. Whatever he's experiencing will probably also be the Z9's 8K or oversampled 4K video lag. (Oversampled, because line skipping & binning are also how they can reduce lag in video as I showed in my link above, when one records higher framerate video).
RoamingScott wrote:
This is a post on DPR with some supposition on what might be happening, and might explain why a lower megapixel camera isn't displaying this behavior.
When you are using the EVF normally, the sensor leverages some combination of pixel skipping, pixel binning, etc. in order to read faster and more power efficiently. In other words, not every single pixel of the sensor might be read individually. If you have a 45MP sensor, maybe the sensor only reads like ~every other GRBR pixel horizontally & vertically (10MP) or even half of this (2MP). The EVF is only around 1MP anyway. This is also how even the Z6 or Z7 can display high framerates in the EVF, even if these exceed the framerate of the full sensor scan.
However, when you zoom in during viewfinder usage, the sensors typically switch to a full-readout mode, where they read every single individual pixel and then crop from that. If they didn't, it would enhance the artifacts from skipping/binning pixels. I don't think there is currently a way for them to read only a crop of the sensor instead because panning around would require instantly scanning a different part of the sensor and they would have to find some way to define and build around all of these combinations of read modes.
So essentially, magnified EVF view will usually have similar lag to whatever the highest quality video mode for that camera is. For example, on the Z6, the highest quality video mode is low-framerate 4K (which itself is oversampled from 6K--the full width of the sensor). I've measured this lag at around 0.25 seconds:
Jim Kasson has also done measurements and comparisons to magnified view on his Z7, which are similar to what I've found on my Z6:
https://blog.kasson.com/nikon-z6-7/z7-magnified-lcd-lag/
BTW, because the lag is roughly 8x worse, we can guess that the Z7 sensor is probably reading somewhere around 8x less data (again through combinations of skipping or binning or whatever).
The user in your link is experiencing something similar on the Z9. Whatever he's experiencing will probably also be the Z9's 8K or oversampled 4K video lag. (Oversampled, because line skipping & binning are also how they can reduce lag in video as I showed in my link above, when one records higher framerate video)....Show more →
It's not a readout issue since even the lowly Z6 can fully sample the sensor at full bit depth in 1/20 (50ms) yet its 100% magnification LV lag is 200ms. Even less true for the Z8/Z9, which can fully sample at 1/270 (3.7ms).
I wasn't aware that this has been an issue with Nikon since the original Z7.
The first time I magnified the EVF to manual focus on the Z8 I really thought it was a bug or some weird quirk.
I even took the battery out and tried again. But now I know it's "normal" (thanks again for the info).
The view gets terribly choppy.
My A7RV, with a very slow reading 61MP sensor and much higher res EVF does this so much better and that just doesn't make sense to me. The Z8 and Z9 are so much more powerful, with a lower resolution (than the A7RV), fast reading stacked sensor with a direct feed to the LCD/EVF (which is much lower resolution as well).
It's good that I know this before potentially buying the Z8. I didn't notice any talk about in the reviews.
Nikon has a few features that seem “ported” from the much weaker Z6/Z7 line where they didn’t bother to optimize for the new technology. This is one such item.
Jochenb wrote:
I wasn't aware that this has been an issue with Nikon since the original Z7.
The first time I magnified the EVF to manual focus on the Z8 I really thought it was a bug or some weird quirk.
I even took the battery out and tried again. But now I know it's "normal" (thanks again for the info).
The view gets terribly choppy.
My A7RV, with a very slow reading 61MP sensor and much higher res EVF does this so much better and that just doesn't make sense to me. The Z8 and Z9 are so much more powerful, with a lower resolution (than the A7RV), fast reading stacked sensor with a direct feed to the LCD/EVF (which is much lower resolution as well).
It's good that I know this before potentially buying the Z8. I didn't notice any talk about in the reviews. ...Show more →
There are two issues at play here - throughput and latency. The Z8/Z9 have no issues with throughput since the sensor can fully sample at 1/270, and Expeed 7 can push a lot of pixels. The issue is latency, which is how long it takes from the end of an exposure until the camera has a fully-formed processed image. It takes many steps to get from sensor readout to the processed image, many of which have to be done sequentially due to the nature of image processing. Each step is performed by Expeed and includes operations like WB scaling, demosaicing, NR, picture control application, lens corrections, encoding/compression, etc.. They are performed in an assembly-line fashion and are referred to as the "imaging pipeline". Because the steps are sequential they're limited by the total processing time of each step. Expeed is very fast but it's benefit is mostly in its parallel operation - it can operate on multiple images at the same time, at various stages of the pipeline for each image.
For more details on how the image pipeline likely works, see my XQD/CFE deep-dive conclusion post here. It's quite long but will give you a good idea on how the camera gets from sensor scan to written image on the card.
As fast as the Z8/Z9 are, its total image pipeline is approximately 50ms, which is comparatively slow. This is why the 20fps requires shutter speeds >= 1/200 - any slower and it cuts into the pipeline time. I describe this in detail here.
Even at 50ms for the total pipeline, the Z8/Z9's LV magnified latency shouldn't be as long as it is. I'm guessing its running a non-optimized path through Expeed or even the general-purpose CPU. I'm also guessing Nikon may not be using the window-mode available on most image sensors, which allow a subset of the sensor to be read at much higher rates, but that likely has only a small effect on the total latency.
Long story short is all the fancy pixel binning that happens during normal non-zoomed operations ceases when you punch in, and much more data flows into the viewfinder, slowing down refresh rate. I've noticed the lag is least present when IBIS is off.
