Responsiveness
Input lag
A small utility called SMTT 2.0 was used alongside a sensitive camera to analyse the latency of the Q3279VWF, with over 30 repeat readings taken to improve accuracy. Using this method, we calculated 3.95ms (under 1/3rd of a frame at 75Hz) of input lag. This value was not influenced by enabling one of the ‘Game Mode’ presets in the OSD. We have no way to accurately measure input lag in the variable refresh rate and frame range environment under which FreeSync would be active, however. This value is influenced by both the element you ‘see’ (pixel responsiveness) and the element you ‘feel’ (signal delay). It indicates a very low signal delay, which even sensitive users shouldn’t take issue with.
Perceived blur (pursuit photography)
In our responsiveness article we explore the key factors affecting monitor responsiveness. One of the key concepts explored here is ‘perceived blur’, which is caused predominantly by the movement of your eyes as you track motion on the screen. It is also influenced by pixel responsiveness, although this is generally a less significant (but still important) factor on modern monitors. We also explore ‘pursuit photography’, a technique which uses a moving camera to capture motion on a monitor in a way that reflects both of these elements of perceived blur. This is something that normal static photography or video can’t capture.
The following images are pursuit photographs taken using the UFO Motion Test for ghosting, with the test running at its default speed of 960 pixels per second. This is a practical speed for taking such photographs and sufficient to highlight both elements of perceived blur. The UFOs move across the screen from left to right at a frame rate matching the refresh rate of the display. The monitor was set to 60Hz and 75Hz using the full range of ‘Overdrive’ settings; ‘Off’, ‘Weak’, ‘Medium’ and ‘Strong’. All rows of the test were used, with the backgrounds showing various shade levels (dark, medium and light). The final column shows a reference screen (Dell S2417DG), which is able to perform pretty much optimally at 60Hz without obvious weaknesses in pixel responsiveness.
At 60Hz you can see that the object itself looks relatively soft and unfocused, without clearly defined details. This reflects a moderate amount of perceived blur caused by eye (camera) movement. You can also see various degrees of trailing behind the object. The boldest and most extensive trailing can be seen for the dark background, shown in the top row. This is reduced slightly by increasing the ‘Overdrive’ setting, although it is replaced with a dity-looking trail of inverse ghosting (overshoot) for the ‘Strong’ setting. The medium cyan background (middle row) shows some improvement using the ‘Weak’ setting compared to ‘Off’, whilst the ‘Medium’ setting increases the levels of overshoot (dark shadowy trailing) behind the cockpit area in particular, without really reducing the conventional trailing. The ‘Strong’ setting introduces obvious bright and colourful overshoot. For the lightest background, there is little difference between ‘Off’ and ‘Weak’, whilst ‘Medium’ is also fairly similar but has slightly increased levels of overshoot. The ‘Strong’ setting again introduces obvious overshoot.
At 75Hz the object itself becomes marginally narrower, although it still remains rather unfocussed. This reflects a slight reduction in perceived blur, but still a moderate amount compared to what you’d see at significantly higher refresh rates. The trailing characteristics are fairly similar to at 60Hz. However; because the object itself is narrower and the screen updates more frequently, the pixel responsiveness requirements are increased. You can see the trailing becomes slightly more extended, again boldest with the dark background. The ‘Medium’ setting again looks similar to ‘Weak’, but with a bit of extra overshoot. Whilst the ‘Strong’ setting remains utterly useless due to extreme overshoot. We studied a much broader range of pixel transitions not specifically documented here, both in game and using TestUFO, and came to the conclusion that ‘Weak’ is the optimal setting on this monitor. There was a noticeable reduction in trailing compared to ‘Off’ for quite a few pixel transitions (especially where various ‘medium’ shades were involved), without troubling levels of overshoot being introduced. The ‘Medium’ setting did little to reduce conventional trailing, it simply intensified the overshoot. Whilst ‘Strong’ sort of speaks for itself even in the more limited pursuit photography testing above. Note that we will not be including a section on ‘overclocking’ in this review as the monitor lost signal when set much above 75Hz.
Responsiveness in games and movies
On Battlefield 1 (BF1), the 75Hz refresh rate provided some advantages over a 60Hz refresh rate. Where the frame rate kept up, at least. Most noticeably, the ‘connected feel’ as you interacted with your character in the game was improved. The precision and ‘flow’ as you move your character in the game, particularly with the mouse, is improved. There was also a slight decrease in perceived blur, with the monitor pumping out more information every second and therefore reducing eye movement. The monitor also provided a decent enough performance for quite a few pixel transitions to make good use of its 75Hz refresh rate. For most pixel transitions, between medium and lighter shades, there was very little between the performance of this and the fastest 75Hz LCDs. There was a bit of extra powdery trailing for some transitions and also some overshoot (bright trailing), but neither issues was particularly eye-catching with the ‘Weak’ overdrive setting, in our view. Individual sensitivity to such things does vary, however.
There were definite imperfections where darker shades were involved in the transitions, however. Some of the pixel transitions were noticeably sluggish, giving some ‘smeary’ trailing that even appeared ‘smoke-like’ in the worst cases. There was also some ‘break-up’ trailing, whereby colours that appear almost black but contain other hues (such as red or purple) will have the more colourful hue appear to leach out. We liken this to wetting fountain pen ink on paper, where the ink will run a bit. These imperfections occur to a degree on all VA panels, but were more pronounced and widespread on this model compared to some other large VA models we’ve used recently. Such as those using AUO’s AMVA+ panels or curved Samsung SVA panels. For example the Samsung C34F791 and the AOC AG322QCX). The weaknesses were not as pronounced as we’ve seen on various older VA models (EW2430 and older) nor on the recent but rather sluggish Philips BDM4037UW. The video below runs through these imperfections and provides visual demonstrations. It also stresses the important point that not everybody will find these imperfections bothersome and given the other strengths of the monitor, don’t automatically dismiss it because of these weaknesses.
We tested a range of other titles, such as Dirt Rally, and found similar strengths and weaknesses became apparent on the monitor. Dirt Rally is quite unforgiving when it comes to high-contrast transitions, particularly when racing at night where they were very widespread. Looking at trees against a dark hill in the background or that same hill against a blue midnight sky created an almost watercolour painting effect. Quite a bit of smeary trailing and a generally more dizzying experience than was necessary. We’d still consider the game playable, but these imperfections were difficult not to notice in such scenarios. Driving in the daytime generally presented transitions the monitor was more comfortable with, with weaknesses being restricted to a bit of inverse ghosting or some light powdery trailing in places.
We also tested our Blu-ray film titles, which didn’t highlight the weaknesses in the same way. That is because the 24fps or so at which these titles run essentially breaks up the action and reduces the pixel responsiveness requirements for ‘optimal performance’ quite considerably. So, for the most part, things looked about as good as you’d usually see when watching these films. There were some pixel transitions that were slow enough to cause some slight issues here, though. There was a little bit of ‘break-up’ trailing in places, with some dark objects appearing with a slight and non-extensive ‘fringe’ of purple, red or other colours. This was shortlived, sharp and overall quite tame compared to the ‘break-up’ trailing observed at higher frame rates. There were also occasional after images, particularly where the scene would change from very dark to very bright quickly. This was a momentary effect and quite faint, but still something we observed. We sometimes saw this when scrolling through content on the internet as well, but didn’t find it bothersome. It should be noted that, although a lot of movie content is ~24 – 30fps, some runs at a higher frame rate such as 50fps or 60fps. This would introduce the sort of weaknesses observed when gaming at higher framer rates, where pixel responsiveness requirements are tighter.
