Focus Calibration

Hello,

I have successfully calibrated my Sigma 18 - 35 Zoom lens with the Camera Calibrator for all the zoom levels (with the 6 steps - but they all have the focus value at 0 despite having the correct tracking input etc.).

For my focus tracking to work, I needed to change/edit the profile with the Basic Calibrator and exchange the calibration data if I'm not mistaken. At first, I thought that doing an additional calibration with the Basic Calibrator wouldn't be necessary. But what happens with the data listed from the calibration with the Camera Calibrator? When I just add new points to the profile and let the old ones remain, I have 6 (or 5 deducting the starting point) jumps back to 0 when turning the focus wheel. Thus, I deleted 5 of them. Is this how I'm supposed to do it? I guess I can delete the 6th as well because apart from the focus distance all the other values align anyways ...

It seems to work this way and I can perform the focus tracking within the LED wall project coming from my FIZZ 2 lens data tracker. Zoom is working as well. I'm just confused because I didn't want to delete the data from the Camera Calibrator ...

Best wishes 

   Martin Pater

コメント

Eifert@Aximmetry
  -  

Hi Martin,

Currently, the Camera Calibrator does not support focus calibration. You need to perform focus calibration within the Basic Calibrator instead.

I'm not sure how you are deleting the calibration points or how you would obtain accurate focus data simply by deleting calibration points, unless your tracking device is already sending properly calibrated focus data.

To add focus calibration in the Basic Calibrator, you should introduce three to five additional calibration points for each zoom calibration point that the Camera Calibrator has generated. Each new calibration point should have a different focus value, distributed across the range of focus your lens can use. Additionally, you should use the existing zoom calibration points created by the Camera Calibrator and set the first focus value in them.

Warmest regards,

Martin Pater
  -  

Thank you for your response. Good to know.

I'm sorry for the misunderstanding: I got the zoom points (6 levels) from the Camera Calibrator. I then calibrated everything with the Basic Calibrator. But then I had the data from the Basic Calibrator and the 6 points from the Camera Calibrator setup. The latter ones had no focus data values though (They were still set to 0.). Thus, when reaching a certain zoom level, the focus jumped back to 0. Therefore, I had to delete these ones from the data sheet (the ones from the Camera Calibrator). If I'm reading your comment correctly, I could still use the 6 zoom points from the Camera Calibrator and just add the focus levels that I got from the Basic Calibrator. But I guess that this won't be necessary since I have done the whole procedure with the Basic Calibrator anyways. Please correct me if I'm wrong.

And a quick question on the side: Is it okay to use anamorphic lenses? Do I have to be careful with the stretch or anything else? I'm using the Sirui 1.33 set and the BMPCC4K for this. The image comes in desqueezed with its special aspect ratio.

Best wishes 

Eifert@Aximmetry
  -  

Hi Martin,

Yes, you are correct, you could have added focus values to the calibration points you got from the Camera Calibrator.

I think what is important to understand is that changing the zoom also affects how the focus behaves. Therefore, you need to calibrate focus values for each zoom position. This means you should duplicate each zoom calibration point with different focus values, as many times as needed to achieve the desired level of precision.

You should be able to use anamorphic lenses. However, please note that anamorphic lenses are edge cases, so some features may not work as expected or might appear incorrect in certain monitor views. Additionally, you may receive a non-matching aspect ratio warning within the camera compound even if the setup is correct.
If you experience any issues with anamorphic lenses, please report them, and we will look into them.

Warmest regards,