When facing the screen the distance does not make a difference, unlike when facing the projector.
That may be the case, but JVC recommends placing the Spyder X at 30cm (12" or 1ft) from the screen.I've just done an Autocal for my SDR BT2020 Gamma 2.4 calibration in high lamp with all the meters at 1ft and I got the best results ever, both for gamma (Spyder X) and color (i1pro2).At the distance though, it's not always easy to position the meters so that they don't read their shadow. It's easier to pull back a bit. Usually I get good results with the meters at 1-1.5 foot.
But how do you know they are the best results?I assume that you are verifying the calibration with the meter from the same 1ft position and angle.In that case all your are verifying of course is does the meter read a consistent value from what it read during calibration. It doesn't help tell you how the calibration looks from your seating position.For example my screen is 1.1 gain, and I can see there is a slight color shift when viewing the screen at an angle.If I put my meter 1-2ft away from the screen, then it has to view the screen from the bottom at a really sharp angle looking up in order not to read the shadow, and this affects the accuracy of the color reading as compared to viewing my screen from my seats which are much more of a straight on angle to my screen.Because of this I put my i1 Pro 2 about 6-7ft back so that it is perfectly in line with my eye from my seating position to the center of my screen. Put another way, From my seat, I can "look through" my meter and see the middle of my screen. At this distance I get no shadow whatsoever anywhere on my screen.And moving it back like this has no affect on the meter's luminance reading or the position it shows in JVC's autocal window.Later when I verify my calibration with my i1d3 trained to the i1 Pro 2 with both the training and the verification with the i1D3 from this same 6-7ft position, I get under 1.5dE for all measurements, so I know that the calibration is just as good and that it looks this good from my actual viewing angle from my seating.If I autocal with my meter 1-2ft away looking upward at the screen and then verify with the meter from my actual viewing angle, the results are not nearly as good, 3-4dE in some cases at worst.
If I put my meter 1-2ft away from the screen, then it has to view the screen from the bottom at a really sharp angle looking up in order not to read the shadow, and this affects the accuracy of the color reading as compared to viewing my screen from my seats which are much more of a straight on angle to my screen.
I zoomed in with the SpyderX and that eliminated the red push. I assume that you do not zoom in using the i1Pro. Is that correct?
This seems to confirm that the meter sensitivity was indeed the cause of the red push. What were the peak white luminance levels, zoomed and unzoomed?There shouldn’t be any need to change the zoom for colour Autocal.
Didn’t you zoom out to make the image smaller and brighter? Zooming in makes the image bigger and less bright instead.Anyway, you are confirming my suspects about inaccuracy of low lights readings and this is enforcing my conviction that it is preferable to use the spyder 5 to get a more accurate gamma. in addition, I would say that I’m not even 100% sure that measuring levels with zoom and iris positioned so differently from the normal usage is not impacting the gamma calibration.
Again, you are measuring something different from the image you normally project.Spyder 5 can clearly improve the things for sure, because facing the lens you don't have issues with low lights for sure. And you don't have to position the lens and the iris differently from your normal settings. As reported in previous posts, iris aperture can impact gamma and we have to set it as close as possible to the level used during autocal.if you had both (like me), which one would you use?