Back focus problem on ex1r

[Giannis Pass]

Hello,
i have serious BF problems with my ex1r.
I am net in tele but not in wide.
So, i have to follow the BF procedure.
I need your help in this.
In which distance i have to put the paper with the printing from the ex1?
Any other suggestions?
Thanks in advance

[Ronnie Martin]

about 10 feet or 3 meters.... Here is a link about Back focus and how to use it.


BackFocus Adjustment for the Sony EX-3 - Final Cut Studio, Avid, Adobe, and Video Streaming

Good luck

Ronnie
www.ramtv.tv

[Zsolt Gordos]

Is this procedure not specific for EX3? The question was about EX1r.
I have the same problem with my EX1r and I dont remember lens menu....

[Ronnie Martin]

I have the Ex-3 ... You need to go to your manual in the EX-1r.... and search this forum.. Sorry that I could not provide any better help...

Ronnie

[Andrew Stone]

Put some studio lights on the target, if you haven't already and, of course, make sure the light is evenly spread.

Here is another page with a backfocus target:

http://www.dsclabs.com/free_charts.htm

[Pietro Jona]

Watch this:
Adjusting Back Focus On An XDCAM EX Camera | CineTechnica
To access the hidden menu on the EX1 / EX1R, hold the Menu, Scroll Wheel, and Cancel button at the same time.

Pietro

[Zsolt Gordos]

Thanks for the info Pietro, the link is very useful.

[Jeroen Wolf]

Originally Posted by Giannis Pass

Hello,
i have serious BF problems with my ex1r.
I am net in tele but not in wide.
So, i have to follow the BF procedure.
I need your help in this.
In which distance i have to put the paper with the printing from the ex1?
Any other suggestions?
Thanks in advance

Are there backfocus problem examples? Is there any backfocus footage out there so I can check if I have an issue? I have some footage that shows completely blurry faces and oranges and I wonder if that is a backfocus problem. In one shot I was using the autofocus (actually for the first time) but in the other shot I was on full manual and the focus was definitely not on target... but this goes beyond soft focus... the lighter parts like faces, hands become complete blurrs...?! It's also quite a contrast with square, static objects in the same shot that look much, much better.

[Doug Jensen]

Your description doesn't sound like a back focus problem. Back focus problems are mostly evident at wide focal lengths and will cause the entire pciture to look soft. Were the shots you are describing wide or tight?

Why don't you most some frame grabs, or better yet, upload a few clips to Vimeo so we can see it in action. It's impossible for us to diagnose the problem without seeing it, but it doesn't sound like back focus to me.

[Jeroen Wolf]

Doug, here's a grab from one shot. The face of the speaker is smeared, as well as other faces closer up and pay attention to the hand of the man in the public. I don't understand that certain parts like the blond hair looks -at least partly- to be in focus. Also the picture is soft as a whole, but the difference between corners and straight lines and faces and hands is enormous, whether it be in the foreground or in the back.
I was pretty much completely wide in this shot and open. I focused the way I always do: in this case zoom in on the speaker, focus, zoom out.

[Pietro Jona]

Slow shutter speed/shutter off?

[Bob Hart]

There appears to be motion blur on the lecturer and a person in the room.

Backfocus seems to be not quite right. There is chromatic abberation out towards the corners in the image.

I don't know enough about the camera to think that this is due to backfocus or is a normal characteristic of the camera in low light conditions.

[Doug Jensen]

It might be motion blur or it might be a problem with the lens, but it's not a normal back focus problem. It's too hard to diagnose from one freeze frame. My advice is to get the camera out and test it right now while you're not in the middle of a real shoot. If you can recreate the problem, then you are on your way to troubleshooting what causes it and under what circumstances.

[Doug Jensen]

I believe I have pinpointed the source of Jeroen's problem.

He sent me a link this morning to a :40 video clip so I could see the problem in action.
A freeze frame from the clip can be seen in post #10 above. What you might not notice from the freeze frame, but it's pretty apparent when you see the video clip play, is that everybody's skin is soft. Take a close look at the speaker's face, his hands, and the faces of some of the audience. It's all mush, while most of the rest of the picture is fairly sharp.

In the video clip, when the speaker turns away from the camera to look at the PowerPoint screen, the hair on the back of his head is pretty sharp. Then when he turns back towards the camera, his face goes to mush.

I asked Jeroen if maybe he had Skin Tone Detail turned on, and he sent me all of his PP settings. Not only was Skin Tone Detail turned on, he had is set to -99. To make matter worse, he also has the camera's Detail setting to -15. No wonder everyone's skin looks like mush! There are other things about his PP settings that I don't recommend, but I'm certain that Detail and Skin Tone Detail are the culprits for the problem he's experiencing.

Personally, I would never use Skin Tone Detail in any situation. But even if someone does choose to use Skin Tone Detail, you need to relaize that it is designed to be used for close-up interviews and head shots ONLY. And it must be set for each individual person on each individual shot. You can't just turn it on and leave it turned on -- or you get the problems that Jeroen is seeing.

The bottom line is: If you're using Skin Tone Detail, STOP IT!
:-)

[Jeroen Wolf]

Thanks Doug, for your expertise. I told Doug I copied these settings somewhere a while back, convinced as I apparently was that these were the right settings for me... It just goes to show, even if the story sounds convincing, doublecheck any information you're about to appropriate and that is vital to one's operation.