Back focus, am I soft?? - Page 3 at DVinfo.net

Go Back   DV Info Net > Sony XAVC / XDCAM / NXCAM / AVCHD / HDV / DV Camera Systems > Sony XDCAM EX Pro Handhelds

Sony XDCAM EX Pro Handhelds
Sony PMW-300, PXW-X200, PXW-X180 (back to EX3 & EX1) recording to SxS flash memory.


Reply
 
Thread Tools Search this Thread
Old October 28th, 2010, 12:07 PM   #31
Regular Crew
 
Join Date: Aug 2010
Location: Abbotsford, British Columbia, Canada
Posts: 172
Darren -- very good thread. l just got an EX1R recently and haven't tested back focus yet. Will be printing out a chart. Going to do some reference shots and frame grabs so I have something to compare to in the future.
The attached JPEG is the before & after shots you posted - put into a single 1920x1080 image. I desaturated it to make it a little easier to concentrate on the focus.
To me the 2nd one has a lot more contrast which might make it seem like it has better focus. When I zoom in they look pretty close to me. The candelabra and the text on the CD spine labels seem about the same.... the jaggies on the test pattern seem about the same. I didn't adjust the image in any way other than desaturating it.
Attached Thumbnails
Back focus, am I soft??-test-comparedesat.jpg  
Keith Dobie is offline   Reply With Quote
Old October 28th, 2010, 01:55 PM   #32
Regular Crew
 
Join Date: Sep 2008
Location: Southend, UK
Posts: 165
Hi Keith,

Desaturating looks a good move to help test the focus. I think I have it as close as I can to being a good adjustment. What did you think of the stills? When you do get some grabs post them up, I'd love a look at what you have got.

The thing is I have nothing to really compare mine too.
Darren Ruddock is offline   Reply With Quote
Old November 10th, 2010, 01:15 PM   #33
New Boot
 
Join Date: Jul 2009
Location: Los Angeles
Posts: 23
Darin

I am an EX1 owner of over a year, My back focus has gone out a couple of times and I have fixed it using the auto back focus adjustment successfully. One thing I notice about your environment is there is an awful lot of clutter behind your chart. I always go out of my way to do the test on a smooth white wall. I use three Fuji chart which they gave to me for free. One in the middle and two off to the sides. I tech the camera at 7' because that is an actual number on the lens.
Bob Hayes is offline   Reply With Quote
Old November 12th, 2010, 09:54 AM   #34
Regular Crew
 
Join Date: Sep 2008
Location: Southend, UK
Posts: 165
Hi Bob,

The pictures I posted were not where I actually did the test. They were just shots to try and get an idea of the focus after the test. The procedure was carried out on a blank wall.

Got a job on next week so hoping my back focus is ok for that.
Darren Ruddock is offline   Reply With Quote
Old November 18th, 2010, 11:41 AM   #35
Regular Crew
 
Join Date: Oct 2010
Location: Copenhagen Denmark
Posts: 70
I want to propose a new method.. This is for the Ex1. Not tried on any other.

All previous attempts have failed for me. They seem to work, but only with approx 90% sharpness.

First perform a test where you place your star chart (or some object) 5 feet away. Zoom all the way in. Focus. Then zoom all the way out. Now move your focus wheel up to infinite. If you experience a sharpness gain, Then your BF is not 100% in place. (this may be hard to see on the camera LCD)

Therefore I did a new attempt. And here is what I did.

Put this chart on a computer LCD monitor: http://www.bealecorner.org/red/test-...ull-600dpi.png

Make sure the lcd is located close up against a wall. Turn down the brightness so it dosnt over expose compared to the background wall.
Place your camera exactly 5 feet away, target it on the lcd, and turn your manual focus marker to 5 feet(focus ring to Full Manual setting). Zoomed in focus should be optimal.
Run the auto BF adjustment. Using an LCD as a backfocus target, seems to work perfect. Not only does the chart itself help, but so does the aliasing and CA from the monitor. You wont be in doubt when the backfocus is spot on.

How do you test?

After the auto BF adjust.. Zoom in.. Focus. Take notice of the area of confusion (the area that looks blurred in the ceter). While zooming out look on your camera lcd. The area of confusion may not change size. (meaning may not change size compared to the camera screen size, not the chart)

Then you can run another test by moving your focus ring back and forth while zoomed out.. If you end up with the sharpest image (smallest area of confusion) at 5 feet. You have a perfect backfocus.

Last edited by Dominik Krol; November 19th, 2010 at 06:24 AM.
Dominik Krol is offline   Reply With Quote
Old November 18th, 2010, 04:07 PM   #36
Regular Crew
 
Join Date: Sep 2008
Location: Southend, UK
Posts: 165
Hi Dominik,

Sounds interesting. May give it a go.

What do the rest of you guys think??
Darren Ruddock is offline   Reply With Quote
Old November 18th, 2010, 06:52 PM   #37
Trustee
 
Join Date: Feb 2006
Location: USA
Posts: 1,684
I haven't looked over this whole thread so I don't know if it was mentioned earlier but I was having trouble with the auto-back focus until someone explained to me the extremely important caveat that:

All settings on the camera must be on auto
auto focus
auto iris etc
maybe even auto white

Doesn't work otherwise - God knows why.

Lenny Levy
Leonard Levy is offline   Reply With Quote
Old November 19th, 2010, 05:56 AM   #38
Regular Crew
 
Join Date: Oct 2010
Location: Copenhagen Denmark
Posts: 70
Which infact is wrong since the camera takes control of these no matter what your settings are. Only Servo Zoom is nessessary.
Dominik Krol is offline   Reply With Quote
Old November 19th, 2010, 09:17 PM   #39
Trustee
 
Join Date: Feb 2006
Location: USA
Posts: 1,684
Dominik, were you responding to me? If so, I have no idea what you're talking about - don't understand what you mean about servo zoom.

Looking back over this thread I see that it was explained that you had to be in auto focus - missing from the Abel Cine video .

I was told by a sony repairman in LA and another tech at a shop I use that the camera had to be in all auto functions for the auto back focus to work. When I did that that the process worked fine. Don't have any idea why. It may be that only autofcus is important but why not just go full auto. I did it at 24P and it worked fine but it makes sense to go 60i as the autofunctions just work better in 60i as it samples more often.
Leonard Levy is offline   Reply With Quote
Old November 20th, 2010, 08:35 AM   #40
Regular Crew
 
Join Date: Oct 2010
Location: Copenhagen Denmark
Posts: 70
Yes Leonard I was replying to you. The servo zoom is the only switch that cant be overridden electronically (and the ND filters ofcoruse). Thats why its the only one that counts..

If you don't believe me, take your camera and perform some tests. Close down the iris, put your focus to infinite, change your shutterspeed to something rediculous, go full manual on all functions and then perform the Auto FB.

I can assure you that what instantly will happend is for the Iris to go wide open. Your focus to go macro, your shutter go to something that wont over or underexpose, and if the setting is to dim, it will add some gain. The only function that will NOT let you perform the FB is if your zoom is set to manual.

Please do not reply to this untill you have tried it out. (there is a slight chance that an older firmware requires you to go full auto, but if you have updated it to the latest, then my argument holds up).

Last edited by Dominik Krol; November 20th, 2010 at 09:07 AM.
Dominik Krol is offline   Reply With Quote
Old November 20th, 2010, 12:14 PM   #41
Regular Crew
 
Join Date: Sep 2008
Location: Southend, UK
Posts: 165
There seems to be a lot more stipulations, with regards to completing a successful back focus adjustment, every time I read something on this thread.

Would probably help if Sony actually issued some definitive information!
Darren Ruddock is offline   Reply With Quote
Old November 20th, 2010, 07:13 PM   #42
Trustee
 
Join Date: Feb 2006
Location: USA
Posts: 1,684
Dominik, Yeah you might be right. I'm not planning to try it again though as its working.

I don't remember how I was set up when the procedure didn't work but its possible that I didn't even have the focus barrel pushed into place for auto. I usually leave the servo on and the focus barrel disconnected for manual. I'm just passing on what I was told by the Sony repair department though and when I tried all Auto it worked. I'm not really sure what I changed after talking to him.
Leonard Levy is offline   Reply With Quote
Old November 21st, 2010, 08:31 AM   #43
Inner Circle
 
Join Date: Aug 2006
Location: Poland
Posts: 4,086
Dominik has it right here. The only prerequisite is sliding the zoom switch on (with it at off position, the Flange Adjust will be grayed out in the Maintenance Menu, and thus inactive).

All the other settings will be taken care of by the procedure itself.

While we're at it: does anyone know what prerequisites are necessary for the Auto Black procedure to become active?
__________________
Sony PXW-FS7 | DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive
Piotr Wozniacki is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > Sony XAVC / XDCAM / NXCAM / AVCHD / HDV / DV Camera Systems > Sony XDCAM EX Pro Handhelds

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 07:03 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network