Using SpyderLensCal for Video Focus Control

Datacolor’s SpyderCheckr is used to check the auto-focus on still cameras, and to micro-adjust the auto-focus on cameras with micro-adjustment controls in their in-camera menu. However, there are other uses for LensCal. This article describes how to use it to assist with focus setting in video, TV, and cinema capture workflows.


SpyderLensCal showing Depth and Center of Focus

Videography is based on manual focus methods, but SpyderLensCal can still be useful for video capture. Lets start by considering how focusing is done with a video camera. Video focus is manual, and occurs by rotating the focus ring on the camera lens, or manipulating a “follow” device connected to the focus ring.


Geared Ring added to a DSLR Lens, Follow Gear on Far Side

The results of these adjustments are viewed on the LCD on the back of the camera, or on a portable video reference display screen attached to the camera framework. These screen range from small to tiny, so it can be difficult to determine focus on such screens. It is possible to zoom the view on the camera-back display, and sometimes on the reference display, to enlarge a small part of the screen to more effectively check focus. A larger video reference display is sometimes used as well, either in real time, or with a delay, but these screens are not available to the cameraman adjusting the focus controls.


Reference Display mounted on a Camera

Here’s how one or more SpyderLensCal units can improve the accuracy of focus with a video camera. Lets envision a shot where the camera remains stationary, no pan, no zoom, but the focus moves from a glass with lipstick on it in the foreground of the shot, to the face of a woman wearing the same color lipstick in the middle ground. This configuration simplifies the description, as other adjustments to the lens or camera are not needed in this scenario.

To determine the ideal focus for the beginning of the shot, a LensCal is placed on the table next to the glass, and its target plane is aligned with the surface on the glass with the lipstick stain. The camera is is then focussed on the LensCal target, and can be checked, either at full size on a large remote reference display, or by zooming in on the small target bullseye and sloped scale on the camera LCD. The sweet spot in the intentionally shallow focal range will register on the LensCal scale, and the sharpness of the focus will be clear on the target. Adjustments can be made as needed. This position can then be marked on the follow-focus device, or noted on the focus ring. Cinema lenses, with their longer throw, will increase the level of precision possible.

Next a LensCal unit on a light stand beside the actress in the middle ground will be focused on, repeating the process of checking the focus, and marking the correct location. An advanced follow-focus tool with hard stops available at each end would make this process even simpler. Now both LensCal units are removed from the set, and the shot is made, using the start and finish references to assure accurate focus at each end. This technique can also be used for single focus shots, but is particularly useful when there are multiple functions occurring in the shot; being able to remove two variables allows the cameraman to “focus” on the other functions.

So, don’t leave your SpyderLensCal in the dark when shooting video, get it out and put it to use checking the focus on your shallow-focus shots, and improve the sharpness of your video.

Credits: C. David Tobie, Copyright 2013. Website: Return to Blog’s Main Page


Using SpyderCheckr Camera Calibrations with Video

Datacolor’s SpyderCheckr produces color correction presets for Lightroom, ACR, and Phocus. These presets are typically applied to still images processed in these applications. Now that Lightroom 4 can catalog, clip, and even make basic adjustments to your video, the question of using SpyderCheckr Lightroom Presets to correct color for your video cameras arises. This possibility is particularly interesting when it comes to adjusting video capture from different types of cameras, such as GoPro cameras and DSLRs, or different types of DSLRs, to match their color as closely as possible.

The answer is: yes, it is possible to apply an existing SpyderCheckr preset, from a still image shot with your camera, to video shot with the same camera. However, since that preset was most likely shot in RAW, and certainly as a still image, its best to start from scratch, and shoot the SpyderCheckr target in a video clip, to capture the actual video workflow for color correction.


Video of The SpyderCheckr, to Color Correct the Camera

You can then capture a still frame from the video, and process that still frame the same way you would any SpyderCheckr target shot.


The Capture Frame Option, to Grab a Still Frame from the Video

The resulting Preset can then be applied to a still image, and by selecting that still image and one or more video clips, the Sync Settings button can then be used to apply the color corrections to video clips.


The Sync Settings Option, used to Apply the Calibration to Videos

The dialog box shown below will appear, showing which of the Lightroom Development Settings can be applied to video. Be sure the Color Adjustments box is checked, so that the HSL Adjustments from SpyderCheckr will be applied to the video clips.


The Synchronization Dialog Box, Where the Settings are Selected

Once the clips have been color corrected for the camera they have been shot with, they can be exported from Lightroom for processing in any other Video Editing application you use. Be sure to check the Include Video Files checkbox. Versions of Lightroom 4, up to 4.4 appear to have a bug when Video Export is set to Original in Lightroom 4. If your video clips appear to render instantly, without taking the necessary time to apply the corrections to each frame, it may be necessary to choose another Export format in order to have your Lightroom Cuts and Adjustments (including your Color Correction) applied to your video clips.
It may also be possible to force the edits to render, even in Original format, if you first flag the video clips. However, the flag icons are conditional in Lightroom 4 Library mode, and disappear when a video is the selected item. So instead, set the Painter tool to Flag, and “spray” the videos you wish to flag, so that a flag icon appears in the upper right of each in grid and filmstrip mode. These flagged videos should (this may be a conditional bug, so no guarantees) render with edits in the Original format.

The Video Format section of the Export Dialog

A future article will focus on the process of tuning output from different cameras for use in the same video project.

Credits: C. David Tobie, Copyright 2012.   Website:   Return to Blog’s Main Page