Radiance 3D LUT (5x5x5 Cube) Calibration with CalMAN 5 - Page 17

There is an option it CalMAn that enables you to pick the size guy want it to use. Unfortunately it doesn't keep this setting and set it to your preferred size after you exit and later restart CaAN which is really annoying. A feature request to fix this was out in a while ago, so I'm hoping the next version willrber the preference.

Can I auto-calibrate my gamma to a higher value without messing up the color cube? In other words, do I have to re-do the color cube after a gamma change? I want to go from 2.0 to 2.2 or 2.4.

How would you change the gamma if not recalibrating?

You can just tweak things like the gamma factor in the radiance, but you'll be introducing error when you make those changes.

If you want it to be dead on, then you'll need to run through the process again doing both the grayscale ramps (where gamma is accurately established) and the Cube (which has to be cleared before you can calibrate the gamma).

Yep... that's what I thought. Makes total sense. Just wanted to be sure before I went through the process.

So the Lumagen Mini 3D has 10 slots I think? Can't I just use a new slot to keep my 2.0 calibration as long as I don't touch the projector's settings? I'd like a 2.0, 2.2 and 2.4 calibration available at the push of a button to see how they compare.

Yes that should work.

There are 8 CMS (0-7) slots.

Thanks. I'm only up to slot #3 on my current calibration and now I'm going to go back and recycle some of the earlier calibrations.

Here's a fairly big attachment showing my exploration of gamma calibration results. It looks pretty reasonable because the Radiance is making small changes to get my projector to a gamma of 2.4 after I tweaked the projector to get close. The first graph looks reasonable. But the second graph, a plot of the differences, is pretty rough. Is this measurement error showing up or something else? If what I'm looking at in the second graph isn't clear, gamma.jpg 188k .jpg file let me know and I can detail it.

To be honest, both graphs look poor to me... it's just the scale of the graphs that is different.

I would expect a much better results that that for accurate calibration

I would agree, CalMAN doesn't leave a radiance with that kind of correction.

I think that is the user's manual calibration.

Notice, that's an excel doc and not CalMAN data.

Thanks, sotti. That data was transcribed from the DCC window after an automated calibration. It is possible to get raw data out of CalMAN to analyze myself without transcribing it?

Did you use gamma factor?

AutoCal only works when gamma factor is at 1.

I know lumagen frequently recomends using gamma factor as it's a continuous function and their grayscale point are implemented in piece wise liner.

Changing the gamma factor changes where the patterns line up with the control points.

Yes. The gamma factor is 1. I will look at the calibration data again after this most recent calibration when I get a chance.

Hopefully someone can help a newbie out on a fist time calibration… I just bought the Calman 5/C6 combo and already have a Radiance mini with the most resent firmware. I have a JVC RS48 in a near cave like environment antique black tin ceiling, dark blue walls, dark gray soffit with a black diamond 2.39 126” screen. I have been through this thread and also the calman v5.1 software and have seen people discussing doing a 21 point grey scale first and then the 125 point auto cal. The auto cal seems to be easy enough to perform and I already have my brightness/contrast setting down using the avs pattern disk but I can’t seem to figure out how to add the 21 point grey scale calibration to the autocal workflow or run it before??? Any help and any other suggestions for my environment/projector screen combo would be great. I am still waiting on my usb to serial adapter, forgot to purchase it with the kit so maybe this will be cleared up when I get it tomorrow.

Thank you,

Use the Color Cube workflow.

And you'll need to make sure 21-point is also selected in CalMAN's Program Settings. It defaults to 10-point there. Otherwise, you'll get an error message when the grayscale portion starts.

It's not a problem in 5.1, we prompt at the start of AutoCal and make sure the points line up.

I guess the prompt is the "error message" I'm referring to...

No in CalMAN 5.1, any autocal procedure starts off with a prompt to let you pick the settings, and then updates the options to ensure AutoCal simply works.

The error message should only occur in 5.0 or 4.x, go grab CalMAN 5.1 it's a very good upgrade.

Unbelievably good!

I already have it, but have done only one calibration with it, just for fun. Because of my experience with the older versions and grayscale point mismatch, I just automatically changed the point settings before starting so didn't see the new prompt. Sorry for giving out old/bad info...

No sweat.

We are always trying to make CalMAN better, so we make changes. We knew that particular point was a huge pain for many users, so we changed it to try and smooth out the user experience.

sorry if my question is more common than Calman or Radiance related.
I run a Color Cube on my VT50 in THX mode with Calman 5.1 last weekend and the post calibrated greyscale and gamma was much much better than than with 5.04. Many thanks to Spectracal!

As I own a EU model I also tried to calibrate a more brighter picture mode, but the pre calibtrated gamma of all the bright modes are a mess and THX cinema bright room was best.


due to the big gamma corrections that needs to be made to get a gamma of 2.2, it ends with strong posterisation in dark movie scenes. So if I can not use the gamma correction factor, how to calibrate with such pre calibration results?

Can I compensate the pattern issue Sotti has mentioned when I use a corrected gamma target?
E.g. (real) gamma target should be 2.2, gamma correction factor of the Radiance is 1.3. Will I get a real 2.2 gamma by setting the target in Calman to 2.86 (2.2x1.3)? Or does this not work?
Edited by DrFaxe - 3/11/13 at 9:30am

But Operator Error is always present!
Saturday night AutoCal Grayscale, set to 21 Points, and then went downstairs to do something else. Came back up after a half hour, only to find I forgot to Click on OK! Duhh!

Well yea there is always that. My best one is forgetting to place the meter on the screen.

My best is forgetting to cut the lights in the theater. I do calibrations from the projection booth and I don't have a window into the theater. Lots of cursing and head-scratching before I finally went back in to check on the meter. Head-slap!

I would think this would be addressed best by manipulating the TV.

I've seen on the VT50 EU's that you need to turn it's gamma setting up to 2.4 to get a 2.2 gamma on the lowend.

Your idea's about tweaking the targets and gamma factor won't work, it would just make a mess.

Hi Sotti,

thanks for reply. But in THX mode You can't tweak gamma, no such setting. In the other modes You can set gamma up to 2.6, but it will not get any better than the screenshot is showing. Gamma still much too low. Think I will stuck in the THX cinema mode, the only one with acceptable brightness and accuracy, with 100 nits (only) if no one has some other ideas. EU models really suck...