Focus Problems / How can I be sure?
 

I shoot documentary work where we spend a lot of time setting up an interview, one of the last things I do before we start rolling is check the focus. 95% of the time everything works out fine but sometimes when I get home to review the footage for whatever reason the focus is a bit off making the subject a tad blurry (usually on wide or medium shots of a subject). How can I make sure 100% every time that my focus is correct? Yes I am using the fold out LCD (xha1), but sometimes its hard to tell exactly if it's perfectly focused (my vision is 20/20).

I don't like using the AF button becuase it has no idea what I am trying to focus on (background / foreground), and leaving it on Auto Focus is trash. I saw a guy a while back that would zoom completely in on the subject face, focus and then pull out. That seemed like a good idea but it doesn't work so well with my XHA1, sometimes when I pull back it looses focus. The only thing that works for me 100% of the time is to bring a small CRT monitor which is tough when most of my shooting is out of town where I must travel on a plane.

Any help or techniques that could help me achieve perfect focus all the time?


update: just found this
http://www.ehow.com/video_2370002_fo...-canon-xh.html

I find the Peaking function most helpful, it gives a kind of hard outline to what is in focus. The peaking and magnification buttons are on the left side of the camera just in front of the power knob. /Battle Vaughan/miamiherald.com video team

Hi Oliver.............
 

The answer is simple and as old as the hills, if a tad updated.

Get yourself a "focus puller" (as was) aka a Laser Rangefinder, that will work at the distances you usually use.

I use a Nikon 1200 with my XH A1. The upside is it is accurate to half a meter from 10 metres to 1.2 kilometres, the downside (for you) is that it will not work closer than 10 metres, so not much good for interview work (most of my work is wildlife where getting closer than 10 metres can be a tad dangerous).

There are many on the market that will work far closer and to much closer accuracy but do not have nearly the far distant range.

Most finders have a socket in the base to allow for mounting on a 1/4" tripod screw, you can get an adapter which will allow you to mount it on the hot shoe (which puts it pretty well spot on for the CCD block) and has the added advantage of keeping it still - they usually have something like 5 X magnifcation and hand held can be a problem when extreme accuracy is required.

The distance figures on the A1 are exceedingly accurate.

Simply measure the distance to your target (usually the eyes for interview work) with the rangefinder lined up approx where the CCD block is, then dial that figure into the focus ring, keeping an eye on the distance readout on the LCD.

Do set the focus speed to "slow" and set the focus distance in the menu to "always on".

Voila. Perfect focus every time.

Can't get much simpler or accurate than that.


CS

Chris great info bro, thanks. Sounds VERY accurate but not sure about the simple part...lol. I have never hard of this in my life so it sounds a bit complicated on the 1st read.

Could you provide a link (B&H?) to this focus puller / Laser Rangefinder your speaking of that would work well with interviews.

Thanks again.

Ok.....
 

Bosch DLE150 Connect Laser Rangefinder (DLE-150)

Bosch DLE 50 Pro Laser Rangefinder - Screwfix.com, Where the Trade Buys

http://www.quantumgear.com/catalog/b...sto_family.pdf


CS

Back focus ?
 

Oliver,
As I started reading your description of the problem, I thought ... "He needs to adjust the back focus!" But reading further, I saw that you had a camcorder with permanently attached lens. So I suppose improper back focus (also called flange focus) adjustment is not a likely cause, but it might be worth doing a test at home under controlled conditions. Just focus on a test target while zoomed in, then zoom out and see if focus is still sharp. Of course, if back focus really is the problem, that would mean sending your camcorder in to Canon.

Good luck, and hope it's not a back focus problem!
Ken

I will try that Ken, thanks.

And thanks Chris for the links, I totally understand now.

I agree with Ken, it does sound like back focus, however it may be a camera issue.I have not used that model, so you would have to check.Do the test as Ken suggests making sure all auto features are off.Also remove any filters.I f it fails I would send it in to Canon.
All this aside, doing interviews , I strongly suggest a monitor anyway.It may be a bit of a pain, but do it right and the extra effort will come back to you.

Zoom in, focus, zoom out
 

Does the zoom in, focus, zoom out technique always work for manual focusing?

Do you always have to zoom in to maximum magnification for it to work?

Hi Stuart.........
 

Yes.

Yes.


CS

That was a very prompt and informative response

My filmmaking would be terrible without you great guys on DVi

Thanks Chris! :)