Back focus problems EX1R

Jonathan77 · Post by **Jonathan77** » March 8th, 2012, 5:53 pm

Hi everyone!

I just got a new Sony EX1R for my job and it's a great camera but I have a big problem with back focus.
I zoom in to the object I want to film and focus to get a sharp image but when I zoom out the image isn't sharp anymore.
I just did a back focus adjustment on the camera but it didn't help.
Have someone experience the same problem? and what can I do to fix this?

Sorry if my english isn't that great.

Jonathan

Simon Wyndham · Post by **Simon Wyndham** » March 10th, 2012, 11:13 am

Are you absolutely sure that the back focus procedure completed properly? I have found that sometimes it needs a few goes to properly lock. What type of back focus chart are you using? With my EX3 I found a stark difference in accuracy between two charts I used. One was more contrasty than the other. It shouldn't really have mattered too much, but I found that it did.

Jonathan77 · Post by **Jonathan77** » March 10th, 2012, 1:22 pm

Hi Simon,

The back focus procedure did complete properly, I have done the procedure several times with different lights and back focus charts. The only thing what made a little difference is putting the camera a little further from the back focus chart (about 4 meters).
You say that sometimes it needs a few goes to properly lock, I'm going to try that!

Simon Wyndham · Post by **Simon Wyndham** » March 10th, 2012, 6:14 pm

Yes. I found the back focus procedure to be quite variable in the results that I achieved. You have to make sure that there is nothing else in the frame that the camera could accidentally focus on too. Strangely the only way I got a good result was with the back focus chart supplied with Doug Jensen's book. And I always worried about ending up needing to do a back focus operation in the field because the results I got were so variable.