Need advice on backfocus, Sony F350 at DVinfo.net

Simon Denny · November 18th, 2009, 02:57 AM

I need some advice on setting the backfocus on my Sony F350.
This is what i'm doing.

Set up a chart or something with sharp writing, expose to the scene around f4, zoom in and focus with peaking on, zoom out and adjust the backfocus, zoom in re-focus. This still seams to be out of focus when I zoom in, pull focus, zoom out again and frame up.

Any suggestions.

Cheers

Brian Drysdale · November 18th, 2009, 06:52 AM

When setting the back focus, you should have the lens aperture wide open.

Simon Denny · November 18th, 2009, 03:01 PM

Thanks Brian,

So wide open hey, maybe this is where I have been going wrong.

Cheers

Doug Jensen · November 18th, 2009, 03:46 PM

How far away is the chart? You want it to be at least 10-15 feet away.

Keep the peaking off or at least minimized. If it's up too high, peaking won't give you an accurate reading of what is really in focus.

Be very careful not move the back-focus ring when you tighten it back down.

And, as Brian says, the lens should be wide open.

Peter Beeh · November 18th, 2009, 03:47 PM

Also, are you using a siemens star? And be careful with your peaking. If you wind it up too much it could mislead you.

Steve Phillipps · November 18th, 2009, 04:17 PM

On the back focus adjustment ring there is a "macro" setting, make sure this is clicked in or it'll knock focus way off. You probably know this anyway, but just in case.
Steve

Simon Denny · November 18th, 2009, 04:53 PM

Thanks,
I have had the peaking turned all the way up when back focusing and this must be miss leading me when I pull out to check the BF. I'll do some more tests today.

I have to say I find this camera going soft when the focus is just off and the noise level, grain in low light is bad when using even 3db of extra gain.

Cheers.

Doug Jensen · November 18th, 2009, 05:45 PM

Yeah, the 300 series of cameras are well-known for having noisy blacks, but you can hide it somewhat by having the right paint settings and always shooting at -3db whenever possible.

Simon Denny · November 19th, 2009, 04:10 AM

Hi Doug,
Noisy blacks are really apparent in low light with gain on, do you have any particular paint settings that you would care to share?

Cheers

Anton Strauss · November 19th, 2009, 04:24 AM

Quote:

Originally Posted by Simon Ash

I need some advice on setting the backfocus on my Sony F350.
This is what i'm doing.

Set up a chart or something with sharp writing, expose to the scene around f4, zoom in and focus with peaking on, zoom out and adjust the backfocus, zoom in re-focus. This still seams to be out of focus when I zoom in, pull focus, zoom out again and frame up.

Any suggestions.

Cheers

even with back focus spot on, I managed to bring home soft focused shots in low light situations, you really need to look very carefully in your viewfinder

I never brought home a soft focus shot with any other 2/3 camera in my whole live

this is the first and last 1/2" camera that I will own, I have no idea what Sony were trying to save in production cost

Doug Jensen · November 19th, 2009, 05:45 AM

Anton,

You must have a problem with your camera or your lens. There is nothing inherently wrong with the 1/2" XDCAM products except for a little noise in the blacks. I've had my F350 since 2006 and I've never come home with soft footage, except for a couple of follow-focus shots where it was clearly operator error.

I think it is wrong to damn the whole product line just because you're having some troubles. If anything, the 1/2" XDCAM HD cameras are easier to focus than an equivalent 2/3" HD camera.
Do you have a good HD lens or are you trying to skimp with an SD lens? No offense, but I've seen people do that and then blame the camera.

You don't say if your previous 2/3" cameras were HD or SD. The F355 takes more skill and attention than a D600.

If you're sure it's not operator error, get your camera or lens checked because the F3XX series is a solid product line.

Doug Jensen · November 19th, 2009, 05:52 AM

Quote:

Originally Posted by Simon Ash

Hi Doug,
Noisy blacks are really apparent in low light with gain on, do you have any particular paint settings that you would care to share?
Cheers

I can't remember the specifics now. My F350 has not been used for more than a 14 months and I don't have time to get it out and look at my scene files. Basically you just need to drop the blacks a little bit. The factory-default blacks are too high and there isn't enought contrast. That is one of the reasons you see noise. When setup properly the camera looks pretty damn good.

Simon Denny · November 19th, 2009, 06:29 AM

Thanks Doug,

It's funny you mention lowering the blacks as I have just started doing this in an attempt to lower the noise in blacks. I also own a sony EX1 and I do this also.

Just out of curiosity what lens are you using with the f350?

Thanks

Greg Boston · November 19th, 2009, 07:03 AM

Simon,

I'll save Doug some typing. He is using the same lens as I am. The Fujinon HSs18x5.5 which is/was about the best lens available back in 2006 when we got our F350 cameras.

Dropping the blacks will help with the noise as well as using the Noise Suppression feature that was added via a firmware update awhile back. It does help.

As to back focus, I recommend at least using a Siemen's Star chart. It will really let you see the focal point on a full wide shot. In HD, back focus needs to be dealt with on a more consistent basis due to the revealing nature of focusing flaws.

-gb-

Doug Jensen · November 19th, 2009, 08:59 AM

Greg is correct. It's the Fujinon HSs18x5.5. Fantastic lens.
Which is for sale, by the way, along with my F350.
Please send me an email if anyone is interested. Both are in mint condition.

November 18th, 2009, 02:57 AM	#1
Simon Denny Trustee Join Date: Jul 2007 Location: Australia Posts: 1,409	Need advice on backfocus, Sony F350 I need some advice on setting the backfocus on my Sony F350. This is what i'm doing. Set up a chart or something with sharp writing, expose to the scene around f4, zoom in and focus with peaking on, zoom out and adjust the backfocus, zoom in re-focus. This still seams to be out of focus when I zoom in, pull focus, zoom out again and frame up. Any suggestions. Cheers

November 18th, 2009, 03:46 PM	#4
Doug Jensen Vortex Media Join Date: Jan 2009 Location: Florida Posts: 3,442	How far away is the chart? You want it to be at least 10-15 feet away. Keep the peaking off or at least minimized. If it's up too high, peaking won't give you an accurate reading of what is really in focus. Be very careful not move the back-focus ring when you tighten it back down. And, as Brian says, the lens should be wide open. __________________ Vortex Media http://www.vortexmedia.com/ Sony FS7, F55, and XDCAM training videos, field guides, and other production tools

November 18th, 2009, 03:47 PM	#5
Peter Beeh Regular Crew Join Date: Jan 2009 Location: Sydney, Australia Posts: 52	Also, are you using a siemens star? And be careful with your peaking. If you wind it up too much it could mislead you. __________________ Peter Beeh, Lighting Camera/DOP www.peterbeeh.com.au

November 18th, 2009, 05:45 PM	#8
Doug Jensen Vortex Media Join Date: Jan 2009 Location: Florida Posts: 3,442	Yeah, the 300 series of cameras are well-known for having noisy blacks, but you can hide it somewhat by having the right paint settings and always shooting at -3db whenever possible. __________________ Vortex Media http://www.vortexmedia.com/ Sony FS7, F55, and XDCAM training videos, field guides, and other production tools

November 19th, 2009, 05:45 AM	#11
Doug Jensen Vortex Media Join Date: Jan 2009 Location: Florida Posts: 3,442	Anton, You must have a problem with your camera or your lens. There is nothing inherently wrong with the 1/2" XDCAM products except for a little noise in the blacks. I've had my F350 since 2006 and I've never come home with soft footage, except for a couple of follow-focus shots where it was clearly operator error. I think it is wrong to damn the whole product line just because you're having some troubles. If anything, the 1/2" XDCAM HD cameras are easier to focus than an equivalent 2/3" HD camera. Do you have a good HD lens or are you trying to skimp with an SD lens? No offense, but I've seen people do that and then blame the camera. You don't say if your previous 2/3" cameras were HD or SD. The F355 takes more skill and attention than a D600. If you're sure it's not operator error, get your camera or lens checked because the F3XX series is a solid product line. __________________ Vortex Media http://www.vortexmedia.com/ Sony FS7, F55, and XDCAM training videos, field guides, and other production tools

November 18th, 2009, 06:52 AM	#2
Brian Drysdale Inner Circle Join Date: Feb 2006 Location: Belfast, UK Posts: 6,152	When setting the back focus, you should have the lens aperture wide open.

November 18th, 2009, 03:01 PM	#3
Simon Denny Trustee Join Date: Jul 2007 Location: Australia Posts: 1,409	Thanks Brian, So wide open hey, maybe this is where I have been going wrong. Cheers

November 18th, 2009, 04:17 PM	#6
Steve Phillipps Inner Circle Join Date: Apr 2006 Location: Wales Posts: 2,130	On the back focus adjustment ring there is a "macro" setting, make sure this is clicked in or it'll knock focus way off. You probably know this anyway, but just in case. Steve

November 18th, 2009, 04:53 PM	#7
Simon Denny Trustee Join Date: Jul 2007 Location: Australia Posts: 1,409	Thanks, I have had the peaking turned all the way up when back focusing and this must be miss leading me when I pull out to check the BF. I'll do some more tests today. I have to say I find this camera going soft when the focus is just off and the noise level, grain in low light is bad when using even 3db of extra gain. Cheers.

November 19th, 2009, 04:10 AM	#9
Simon Denny Trustee Join Date: Jul 2007 Location: Australia Posts: 1,409	Hi Doug, Noisy blacks are really apparent in low light with gain on, do you have any particular paint settings that you would care to share? Cheers

November 19th, 2009, 06:29 AM	#13
Simon Denny Trustee Join Date: Jul 2007 Location: Australia Posts: 1,409	Thanks Doug, It's funny you mention lowering the blacks as I have just started doing this in an attempt to lower the noise in blacks. I also own a sony EX1 and I do this also. Just out of curiosity what lens are you using with the f350? Thanks

November 19th, 2009, 07:03 AM	#14
Greg Boston Wrangler Join Date: Oct 2003 Location: DFW area, TX Posts: 6,117 Images: 1	Simon, I'll save Doug some typing. He is using the same lens as I am. The Fujinon HSs18x5.5 which is/was about the best lens available back in 2006 when we got our F350 cameras. Dropping the blacks will help with the noise as well as using the Noise Suppression feature that was added via a firmware update awhile back. It does help. As to back focus, I recommend at least using a Siemen's Star chart. It will really let you see the focal point on a full wide shot. In HD, back focus needs to be dealt with on a more consistent basis due to the revealing nature of focusing flaws. -gb-

November 19th, 2009, 08:59 AM	#15
Doug Jensen Vortex Media Join Date: Jan 2009 Location: Florida Posts: 3,442	Greg is correct. It's the Fujinon HSs18x5.5. Fantastic lens. Which is for sale, by the way, along with my F350. Please send me an email if anyone is interested. Both are in mint condition. __________________ Vortex Media http://www.vortexmedia.com/ Sony FS7, F55, and XDCAM training videos, field guides, and other production tools