No matter how complex some make it sound, lens calibration is not rocket science!
So relax, follow these simply directions and start taking sharper images today!
Place Focus Pyramid on a flat surface
Place camera on a Tri-Pod at an average distance from the target
When determining distance, some say anywhere between 25 to 50 times the focal distance to the target. We believe the best distance to set your autofocus is at a distance which you normally use the lens. Example: 70-200mm lens used mainly for portraits at 180mm
In this case, simply set your lens to 180mm and place at your normal portrait distance away from the subject (target) say 4-5ft, which you use the lens
When in doubt, try and fill the frame with the Focus Pyramid
Align camera directly with the center of the Focus Pyramid (use bubble level if available)
For optimum results the base of the Focus Pyramid should be square with the camera lens/sensor
Set camera to manufacture’s preferred ISO (example 100, 160, 200)
Set lens aperture wide open (example: 1.2, 1.4, 2.8, 3.2 etc)
Set lens to it’s longest focal distance or preferably to a distance which you normally use the lens
Set camera to One Shot, Center Weighted Focus (NOT AI or SERVO)
Place AF Box squarely over the center diamond and black line
Make sure lens is set to AF (autofocus)
Set Camera to Av (+0 to +1) Exposure Compensation (the pyramid should be well lit but not over exposed as you will need to be able to see the fine details on the chart)
Use your camera’s built-in timer to take a shot to eliminate camera shake (recommended LARGE .JPG instead of RAW as you will not need to process)
NINJA TECHNIQUE: * Instead taking the shot simply use tethering, if available, and zoom in on your screen to review Auto Focus *
Load image into computer and review baseline image (ZOOM IN 200% – 500%) taking note of focus location
Return to camera and take 4 additional shots setting your AF Compensation to +15, +7, -7 and -15 (This will assist you in determining the amount of front or back focus compensation required to calibrate the lens)
Since the method of setting custom autofocus micro adjustments vary from camera to camera we suggest consulting your manual or contacting the manufacture regarding the process
HINT: It’s easier to see which line is in focus by checking which opposing lines are out of focus (see below images depicting this)
Example: If +5 and +25 are slightly blurry and +10 and +20 are more clear; most likely in the center of the two at +15 is where your clearest focus point would be indicating a bad back focus problem)
Adjust autofocus compensation until focus aligns DEAD CENTER of the center black line (see below for tips)
Follow this simple procedure for each lens in your kit
Here’s an easy way to find focus ” without looking for it “.
These images are from a Canon 300mm 4.0L which you can see from the original image has a plagued by a good amount of front focus. This means every time I would focus on a models eyes, the tip of her nose would be perfectly in focus while her eye where alway a bit soft. BUT NOT ANYMORE! When looking at the first image you can imagine her nose being where the -12 is and the 0 of black line would be where her eyes were.
Lens Calibration is greatly beneficial to ”Fast Glass” 4.0f and below with very narrow depth of field so we used this 300mm 4.0 at 8ft away as a worst case scenario to help show how to find focus even when it’s not so obviously. To make things easy we suggest you NOT look for the EXACT point of focus but two equally out of focus locations on the top and bottom of the Focus Pyramid. Simply dividing these two locations in half will get you there every time! When shooting 1.2f, 1.4f, 2.0f, 2.8f, etc the amount of difference is much more profound and is why custom lens calibration for each and every lens is so critical to getting the most of these expensive lenses!
That’s It! We at Focus Pyramid thank you and wish you sharper images!