View Full Version : Focusing


William LiPera
December 4th, 2006, 07:45 PM
I noticed that when focusing to a distant object in the background and then zooming out the distant object gets a bit soft as if the back focus was slightly off. Is this normal?

Sam Jankis
December 4th, 2006, 09:08 PM
Are you noticing this phenomenon through the viewfinder/lcd or is it on the actual footage when viewed on a monitor/tv?

William LiPera
December 5th, 2006, 05:32 AM
I notice it when the footage is played back on a consumer HD tv or on a plasma tv. The images are of trees in the background. First I zoom in focus,that's sharp, but then as I zoom out it gets a bit soft.

Robert Lane
December 5th, 2006, 09:46 AM
There are other things to consider:

- Are you focusing manually or in AUTO? If you're in AUTO the camera will continually hunt for the focus point as you zoom which will cause it to lose the exact thing you focused on when zoomed in close.

- Distant objects will naturally become soft as you pull back in zoom; as the object takes up less space in the field of view fewer pixels on the imaging chip are available for resolving it, so getting "soft" is actually normal as you pull away.

One way to check to make sure your lens isn't out of adjustment is to use MANUAL focus, zoom in on your subject and get sharp focus, pull back (wide angle) and then zoom back in to your orignal start point. If when you zoom back in the subject has lost it's focus completely then you've got a lens issue. (a little-off focus is normal for just about any zoom - this unintentional loss of focus is referred to as "lens breathing")

Andy Nickless
December 5th, 2006, 11:24 AM
I noticed that when focusing to a distant object in the background and then zooming out the distant object gets a bit soft as if the back focus was slightly off. Is this normal?
It's normal with lower end professional - or "prosumer" shudder (I hate that word) cameras.

I only collected my HVX yesterday and am still familiarising myself with its many many functions, so I haven't had time to check the quality of the lens yet, but I'd be VERY impressed if the Leica held its focus throughout the zoom range.

(Oh - I'd LOVE to be wrong though!).

Andy

Robert Lane
December 16th, 2006, 03:31 PM
William,

I did some rack focus/zoom tests today just to see if I noticed anything more about this:

I zoomed in on a distance object, focused and zoomed out (wide) and back to full zoom (tele) several times and never lost my focus on the subject (manual focus).

If your HVX is losing focus when you zoom back in then you've got a lens/focus controller issue.

William LiPera
December 16th, 2006, 05:05 PM
When I zoom back in it's fine, it's just a bit soft when it's zoomed out. Not enough pixels I guess.

Robert Lane
December 16th, 2006, 08:03 PM
When I zoom back in it's fine, it's just a bit soft when it's zoomed out. Not enough pixels I guess.

Well, not exactly, it's a natural side-effect when the subject becomes smaller in the field of view. The same holds true for any camera, digital or film, it's not specific to the HVX.

However my hypothesis is: that if you're used to SD cameras/output and the HVX is your first HD camera then out-of-focus elements - or elements that don't have enough resolution in the frame - are more noticeable to you than objects that have greater detail. Chances are if you did a same-scene comparison between your HVX and whatever camera you're used to you'd notice the same loss of resolution with distant objects in both cameras, but the HVX would make this distinction more obvious.