Here are my own first impressions of the BasICColor DISCUS meter after receiving it and a couple of nights playing around. Up until now I've been using a couple of i1d3s, with an i1pro / i1pro2 as a reference. Please note I don't have any high-grade meters; but my i1d3's and the i1pro/2 all agree pretty strongly with each other. Mainly I calibrate my JVC X30 projector, though I also calibrate my old Sony CCFL daytime viewing TV.
Bought from Light Illusion Friday 15/9/17, meter was dispatched by BasICColor directly from their German office on Monday. Arrived via UPS on Thursday, well packed.
On opening the box I was greeted by a "Certificate of Performance" (valid for 18 months from date, which was the day of dispatch of the meter from what I could see). See copy of the certificate (S/N removed). Judging by the details on the certificate, the meter had read around ~1800 patches across 4 sample monitors, simultaneously with a CAS140CT lab spectrometer. The kind of numbers on it look pretty impressive. The meter and hockey-puck and tape counterweight were well presented in a custom foam insert, which is glued in the carton.
On removing the meter from the insert I immediately thought "this is a seriously engineered piece of kit". The finish was flawless, with a beautiful action on the rotating base plate which switches between closed / calibration dark measure, ambient light diffuser and open. The laser is also exposed in both ambient light and open positions.
The meter body is threaded at the "top" to take a small knurled thumbscrew, which attaches it to the tape / hockey puck assembly for contact measurements. The "bottom" of the meter has a 3/8" threaded hole, into which a 1/4" removable reducer is fitted. These two arrangements do have a couple of limitations.
The 1/4" thread reducer isn't completely flush with the bottom of the meter, which coupled to the circular nature of the bottom means that attachment to a tripod quick release plate is a little fussy, with limited contact. On my plates (Manfrotto) the reducer would bottom out before the body of the meter was tightly gripped by the rubber mat on the quick release plate. I remedied this by building up the surface of the quick release plate a little with some cloth tape. It only needed a couple of layers.
The hockey puck assembly is a nice idea, but I found that it doesn't actually work on the only TV I have - an older Sony "Picture Frame" style KDL32E4020. This has an (abnormally) deep Aluminium bezel assembly (probably 12-15mm from the bezel to the screen surface). In fairness my i1display pro is not super secure on it either, but it does just about sit flush. The i1pro2 mount works great on it, however, so clearly a good universal mount can be designed to cope with such sets. In any case I'd probably limit myself to non-contact measurements on a tripod, so it isn't really a big deal.
Connecting the meter up it worked straight away with Lightspace HTP (the minimum license needed to do 3DLUT with DISCUS). On connection you are asked to rotate the cover to take the required dark measurement, less than half a minute later it lets you know it is done, and you rotate the cover to open the lens. The Lightspace "Enable Visual Feedback" button toggles the aiming laser on / off (the manual explains the offset from the measurement centre).
My findings on performance of the DISCUS mirror those of
Straight away when doing the contrast measure off screen you could see this meter was effortless in reading dark patches, and it felt quick in operation. There are 4 preset modes for taking readings, with either "short" or "long" integration, averaging a lower or higher number of measures. In preset 0 - the fastest - it was easily able to read the JVC black at <0.003cd/m2. In doing a 21pt grey + primary sweep you could clearly see the lamp colour temperature bias coming through in the very dark patches. I'd not easily been able to make this out previously on the i1d3 meter - the readings in the very lowest 5% patches would be all over the place usually, and getting a reading at all from black was challenging.
Preset 0 readings took 4m07s to read the 81 patches for 21ptGS /RGB. This was with a 0.5s patch delay. With 0.75s reads configured on the i1d3 this could be completed in 3m05s with the same delay. However on the i1d3 the black reading was miles off (about 3 times too large), the dark patches seemed to only approximately be reflecting what you'd expect to see as a lamp bias (the x,y varied quite a lot from what you'd expect) and the resulting measured RGB separation up to around 15% white had a noticeable difference between the white patches and the expected RGB values. On the DISCUS the RGB separation was basically perfect down to 0.
Increasing the i1d3 reading times (either using the new beta auto integration time, or setting a large fixed time) would yield better results - but the reading time would increase to somewhere between 8 and 9 minutes, and the results still didn't look very clean at the very low 0-10% end.
A larger optimised patch sequence of approximately 4000 patches took a little over 3hrs to read on the DISCUS.
So I think re: reading times; it is safe to say that you can drive an i1d3 faster than the DISCUS, the dark readings will definitely be poor. The quickest reading mode on the DISCUS yields slower performance than the fastest possible on the i1d3, but you gain dark readings that look very sensible. Trying to get good dark readings out of the i1d3 and you rapidly end up with much worse reading times than the DISCUS, and still don't have the quality of dark readings of the DISCUS.
thought his meter was faulty due to the discrepancy to his spectro - and having played with the meter I'm not sure his was particularly bad to be honest. A post in the ArgyllCMS mailing list from a previous DISCUS owner says he found the same ( https://www.freelists.org/post/argyl...DISCUS-meter,6
). None of the built-in presets seem to be particularly good matches for my i1pro2 when measuring the "probe matching" patches for my Sony CCFL or JVC X30 projector, whereas my i1d3 meters did correlate strongly.
There is an extensive database of (mostly pro graphics) monitors which have detailed matching done, with matrixes built in, and some "generic" LCD profiles for various backlight types. A utility allows you to swap in additional calibrations (though these are called user calibrations, I'm yet to find how to create them myself). The matrix upload utility came with some "LCOS" matrices, but these also didn't seem to be great matches for my JVC.
Of course this doesn't matter if you have an i1pro/2 spectro for profiling (and I can't imagine anyone going for a high-end colorimeter doesn't already have a spectro). I have the i1pro so I'll gladly take the improved dark performance in exchange for creating my own profiles.
One other little gripe is that there isn't support for the device in ArgyllCMS. These days I mostly use Lightspace (and CALMAN is also supported), but it would be nice to have the option to use the meter within HCFR / displayCAL / etc, which ArgyllCMS support would facilitate.
In summary - I think from what I can tell that if you want quality very dark readings this is probably the only game in town until you get up to the dizzy heights of the CR100/K10A meters. I'm not going to be able to justify one of those for my hobby purposes any time soon - even this was a bit of a stretch - so the above are probably all best thought of as acceptable compromises given the performance, rather than issues.
In a bit of daytime downtime I made myself up a little calibration kit with the i1pro2, DISCUS and an i1d3 for good measure, using the great value Peli-knockoff MAX430 case ( https://www.amazon.co.uk/Max-MAX430S...words=max+case
). See attached. Really good case for the money, made in Italy no less.
I'll try and upload some useful data at some point.