Having trouble with the autofocus on your camera lens? Is the focus always off? No worries, this guide will walk you through lens calibration, and get that blurry focus back into sharpness.
AN HONEST DISCLOSURE
Quick, hide your wallets! I am an affiliate partner of Google, eBay, Adobe, and more. There are affiliate links and advertisements on this page. Whenever you buy things from the evil links that I recommend, I will make a commission.
Nah. These are just things to keep the blog going, and allows me to give more good stuff to you guys - for free. So thank you if you decide to pick up my recommendations!
WHY IS THE AUTOFOCUS OFF?
First off, let us satisfy the curiosity of those who are interested to know more. Skip this section if you just want to calibrate your lens. Why is the autofocus inaccurate? Will it happen again after the calibration? The best way I can explain, is that there are several possible factors that can affect the accuracy of autofocus.
- Using a third party lens that may not be fully compatible with the camera.
- Using a lens adaptor, which may not be fully compatible again.
- A firmware update that is not friendly towards third-party or older lenses.
- Physical damage to certain parts of the lens.
- A corrupted electronic circuit on the lens.
- Or just a plain stupid autofocus system that is always inaccurate…
Most of the time, a simple calibration can correct an autofocus skew. But there are no guarantees that it will be a permanent fix as there may be more underlying issues.
WHAT YOU NEED
Thankfully, calibrating a lens is very easy. All you need is:
- Your lens and camera. Of course.
- Lens Focus Calibration Chart – You can get one of these on eBay, or the cheap way is to use a ruler as a substitute.
- Using a tripod is recommended.
STEP 1) SAMPLE THE AUTOFOCUS
Do the calibration in a well-lit place. Start by switching the camera into the single focus mode, set the focus point to the center, and shoot in wide-open aperture. Put the Lens Focus Calibration Chart on a table, or you can use a ruler as a substitute, placed at a sloping angle.
Next, the use of a tripod is recommended. Make sure that the camera is a comfortable distance away from the calibration chart, and lined up perpendicular to it (the focus point in the camera should be targeting 0). If you are using a ruler, you can use any marking on it as the “0 point”, for example, 5 inches.
Let the autofocus do it’s thing, take a picture, and this will tell you how much of an autofocus error you have.
STEP 2) ADJUSTMENT
If the picture that you just took is spot-on sharp at the 0 mark, congratulations, there is no need for further calibration. If the picture is focused before the 0 mark, your lens has a front focusing issue. Vice versa, if the focus is after the 0 mark, it has a back focusing issue. Fixing this is pretty simple.
- Nikon: Setup Menu > AF Fine Tune > Set AF Fine-Tune On > Saved Value.
- Canon: Autofocus Menu > AF Microadjustment > 0:Enable > Adjust by Lens.
- The rest of the camera brands: I believe Sony, Pentax, and Olympus also has a similar AF Adjustment function.
- For front focused lenses, put in a positive value.
- For back focused lenses, put in a negative value.
STEP 3) REPEAT
The final step is very straightforward. Repeat the take test photo and readjust cycle until you nail the calibration.
NO MORE FOCUS WOES, HOPEFULLY
We have come to the end, and I hope this has solved your autofocus woes. As for the last bit of information, most modern lenses have an embedded electronic circuit and unique serial number. Your camera should be able to detect and apply your manual calibration accordingly; You do not need to change the calibration settings upon switching lenses.
Stay awesome and shoot on!