Focus Bar

Q

qatarshooter

Member
this may seem like a noob question but my focus bar never gets more than half way no matter what, usually its stuck down at about a quater. i have tried all sorts of tests zooming in completely on the siemens star and getting tack sharp focus and it will be stuck between a quater and half at best. am i completely missing the point or do I have an issue? or is there some setting I am missing. my understanding was the fuller the bar the better the overall focus of the image. it seems to me that according to the bar I am never in focus.
 
Same deal here - it never goes much past 50% for me either. I guess that's the way it's supposed to work. I only use it as a rough estimate anyway.
 
ok this makes me feel much better, especially since noone is giving a technical reason. i looked for some description of operation and all i could find was the basic it gets longer when in focus
 
one of my biggest complaints is that neither the focus bar or crop/overscan guides are able to display on the sdi/composite feed
 
Focus bar is a simplified version of another focus aid used on the HMC150, I don't remember its name, one that shows a 2D graph. If I understand correctly how the graph works, it shows level of sharpness in one direction and the relative area of the frame that is sharp, in other direction. Barry describes it in his book, but I still don't understand in full detail what each axis exactly describe.

Anyway, the bar is a simplified version of this graph. I suppose if you have a fine-detailed object that covers full surface of the frame, then the bar can reach the far right end when the sharpness is maxed out. In real life, even if you focusing on a wall, some objects will be detailed enough like paintings or cabinets, other objects like a flat wall, will never be detected as sharp, hence the bar does not reach the far right end.

I suppose this tool is most useful when you have focal planes clearly separated, with shallow DOF. Then when you focus on say foreground object, your goal is to make the bar as long as possible while this object is being focused. The bar has a marker that shows the most recent max position, so you can see if you overshot. Then, when you rack focus to the background object, the focus bar will first become short, then it will grow again, showing increase in sharpness for background object. If two objects are clearly separated and have no objects between them, you can easily see what object you are focusing for. If you have a busy scene with lots of objects and with deep DOF, then you would not know which object is being focused.

Bottom like: my opinion is that the bar is great for clearly separated fore/back objects and is useless for busy scenes with long DOF.

EDIT: Funny, I thought this thread was about the HMC40 ;)
 
Last edited:
Just as a sidebar, the focus-in-red function on the BTLH monitors is simply fantastic. Producers kinda freak out if they aren't expecting to see this though. :)

e
 
You must log in or register to reply here.
Back
Top