November 20, 2009

Lens AF Alignment..a couple ways.

If you want to go about checking your Auto Focus accuracy with your particular Camera/Lens, here are a couple ways to go about it.  One is free and one is not.

If your camera has LiveView go to http://www.northlight-images.co.uk/article_pages/cameras/1ds3_af_micoadjustment.html#AF_test_image and download the test image on his page,  then follow his instructions...the page is a little messy to follow, so I copy and pasted the section of his site I followed.  I suggest you still look at the whole post he has, as he shows you what the moire pattern should look like focused and lots of other tidbits there.  He is a Canon shooter, but the instructions work just fine for Nikon bodies.

...[The principle is that you display the square GIF image (at 100% full size) and focus on the computer screen, using liveview (zoomed if need be) and maximise the appearance of Moire interference patterns.

You will need to have the camera mounted on a tripod and directly facing the computer screen. Take some care to get the screen square on and lined up with the camera.

The interference patterns come about from the interaction between the image pixels on your screen and the pixels of your sensor. They may not look exactly the same as in the examples below, but you should notice a distinct peak in the amount of detail visible - that is the focus point.

You then switch off liveview and part press the shutter button to activate AF.

Look carefully at the lens distance indicator as you do this ... if the lens and camera combination is spot on, then there will will be no movement of the lens focusing ring and the image will not change.]...

If you are more technical and don't trust the above you can purchase or rent the LensAlign pro kit.  Visit the company's website for more information on this method. If you have used the LensAlign products, let us all know about it here!

Happy micro-adjusting!

Later,

Mike