It’s the most frustrating thing to get home after a long day of shooting and find yourself with blurry images. Most of the time, a blurry image is a sure sign of a ‘missed focus’.
If this is happening across multiple images, then it might not be down to your focusing skills. Lens calibration is important to ensure your lenses can focus on a subject correctly.
Read on to find out how to use lens calibration to get sharp images and eliminate focus issues.
How to Calibrate Your Lenses
When most people hear the word ‘calibrate’, they think of something obtrusive and difficult to complete. With lens calibration, it’s actually very simple.
It isn’t a risky adjustment that tinkers with the inside of your DSLR camera. That’s reserved for calibrating manual focus, not autofocus calibration.
Calibrating your autofocus system is a lot easier and less risky for your camera gear.
Calibrating your lens is very important for a correct focus. Every lens needs to be calibrated to each camera it is used with, otherwise you risk inaccurate focus and subsequent blurry images.
Many new photographers assume that their new camera lens is ready to go. This is rarely the case, so take a few minutes to ensure yours is correct.
Thankfully, this is something that doesn’t need specialist attention. You don’t need to send that expensive lens away, or pay money for a repair shop to fix it. You can do it in the comfort of your own home.
Use a Calibrator
The first thing you need is a lens calibration chart or focus pyramid. This works best with a few minutes in a quiet environment. You can get the lens calibration chart which costs around $8.
There are more expensive expensive options, but this works well at focusing lenses. You can even make your own using a ruler.
We use the DSLRKIT Lens Focus Calibration Tool, and it works perfectly.
Set Up Your Camera and Calibrator
To start calibrating your lenses, set up your camera on a tripod or a flat surface. A table is fine. Ensure both the camera and ruler are level, exactly perpendicular and at the same height.
Then, place the focus pyramid on a level surface about six feet from your lens front. If you feel more comfortable at a different distance, then use that.
It doesn’t matter if it is six or ten feet away. The correction is universal to all distances.
Set the lens to the widest aperture to obtain the shallowest depth of field. This will make it easier to determine if your lens is focusing accurately.
Focus using the viewfinder, not Live View as the focusing might not be accurate. Don’t use it throughout the entire process.
While using the viewfinder, auto focus on the cross hair at the centre of the ruler, then take a photo. This is the center focus point.
Inspect the photo to see if focusing is accurate. It is recommended that you do this on a computer since you will be able to see better on a bigger screen.
You can actually do this in a tethered manner, meaning, piping the images straight to your computer. For this you will need to:
- Check here to make sure your camera is supported;
- Connect the camera to your computer or laptop using the supplied USB cable;
- Go to File>Tethered Capture in Lightroom.
Review the image.
If focusing is accurate, the ‘0’ on the lens calibration chart should be the sharpest point on the image. The other should numbers get blurrier as you move away from the ‘0’.
If any number above the 0 is clearer, then your lens is doing something called back focus. Otherwise, if any number below the 0 is clearer, it’s front focus.
In either case, you need to correct your lens for sharp focus. You do this using the auto-focus micro-adjustment parameters on your camera body.
Adjust until you are able to obtain a picture that is sharpest at the ‘0’ on the ruler.
Fixing the Problem: Nikon DSLRs
On Nikon cameras, you are looking for the AF fine-tune menu in the camera settings. You can find this by clicking on the menu button, and then selecting the wrench section.
When you click on this setting, you are presented with some changeable settings. Ensure the AF fine-tune is ON. Here, you only want to change the ‘Saved value’.
Your camera will remember the changes each time you place that lens on your camera. So you only need to use the focal lens calibration once for each lens.
Fixing the Problem: Canon DSLRs
For Canon Cameras, start by accessing the Menu, and scroll to the Function area, then Auto Focus settings. Make sure the Autofocus AF Microadjustment is enabled.
Use the Adjust by lens values to correct and fine-tune your focusing. And that’s it, AF calibration complete.
You should be set and ready to shoot. Do this for every lens, and then again if you have multiple cameras.