Focus Issues or Just Me? at DVinfo.net

Brandon Wood · June 26th, 2006, 02:51 AM

I've had my PD170 about a year and have always found the focus (both manual and autofocus) heck to use. The autofocus seems to hunt too much, and I can never seem to get the manual focus quite right.

Take for instance a pageant I shot last weekend. I was about 15 ft. away from the stage, and there were girls walking across the stage from left to right (about 25 ft.) and back to front (about 20 ft). Because I would have constantly been having to ajust focus in manual since there was constant panning for motion, and since it seems impossible for me to pull focus consistently with the focus ring, I had to use auto much of the time. Of course the backgrounds and any other girls coming into frame made the camera want to hunt.

I also have tried to use the focus assist in manual mode but it seems to be very weak since a lot of my shots still look soft; and not to mention the little LCD which serves only to help frame the shot rather than focus it. If I had a field monitor to help focus I'm sure that would be great but of course that's not practical either pocketbook-wise or field-wise.

Any clues as to what I could be doing wrong or could it be the Sony? (I use my camera ALL the time btw) I have found very little on any issue like this in the forums (except for the age old question of auto vs. manual) although I have seen a few things about focus issues with PD150's a couple years back.

Any advice would be greatly appreciated.

Vincent Croce · June 26th, 2006, 07:45 AM

I know this isn't helping you figure out your problem, but I've never had any focus problems in manual or auto with either one of my PD170s. Like everyone else, I'd like the zoom transition to be a bit smoother and not so stepped, but the focusing is good. Might be your cam. Maybe rent or borrow another one to compare it to.
Vin

Mike Rehmus · June 26th, 2006, 08:28 AM

Like Vincent, I too have no problems focusing my 150 in reasonable situations. However, in the situation you describe, the little Sonys are hard to use. Very hard to use.

However, if you are generally having problems with focus, then there are some tests to be made.

1. Focus the eyepiece by adjusting the diopter control until the text inside the Viewfinder is crisp. Not a scene, just the text from the camera that overlays the image. If you don't do this, all bets are off.

2. Place your camera on a tripod and set it up square to something like a bookcase (the print on spines of books makes a great target) about 20 feet away.

3. Set your camera to auto focus and check the image quality in the viewfinder (ignore the lcd, it is almost worthless for focus). Record a minute of footage.

4. Set your camera to manual focus and zoom in to set focus in the viewfinder. Record a minute of footage.

5. Zoom part way out, leave the focus alone, record a minute of footage.

6. Zoom all the way out, leave the focus alone, record a minute of footage.

7. Now go check the recorded footage for sharpness.

If footage from step 3 is soft, then you have a camera problem

If step 3 is crisp and step 4 is soft, then the viewfinder is misadjusted or you are having difficulties focusing the camera. Practice and or training may solve the problem.

If steps 3 & 4 are crisp, I'd expect the 5 & 6 to be crisp. If they are not, you have a back-focus problem and the camera will have to go in for adjustment.

Note that this assumes that the sharpness in the menus hasn't been set all the way to soft and that your editing system is capable of displaying a sharp image. You really cannot use the camera to make a good judgement about recorded video.

Greg Boston · June 26th, 2006, 08:41 AM

Quote:

Originally Posted by Mike Rehmus

1. Focus the eyepiece by adjusting the diopter control until the text inside the Viewfinder is crisp. Not a scene, just the text from the camera that overlays the image. If you don't do this, all bets are off.

You're the first person other than me that I have ever seen recommending this method. I sort of figured it out on my own thinking that the text is a good reference image and is at the same focal plane from my eyes as the actual image so why wouldn't it be a great idea.

And yet, all the camera manuals I have seen tell you to focus an image in the vf and then set the diopter adjustment.

regards,

-gb-

Brandon Wood · June 26th, 2006, 08:55 AM

Thanks for the suggestions...I should have asked earlier. I'll certainly try your method Mike and let everyone know in case anyone else has this problem (hopefully not).

Mike Rehmus · June 26th, 2006, 09:23 AM

Quote:

Originally Posted by Greg Boston

And yet, all the camera manuals I have seen tell you to focus an image in the vf and then set the diopter adjustment.
-gb-

Focusing on a scene makes no logical or optical sense (as you point out). The method taught in film school is to focus on something in the viewfinder and not on the scene.

Boyd Ostroff · June 26th, 2006, 09:38 AM

Just another thought... in spite of the fact that people are always trying to acheive shallow depth of field, your situation is an example of one where you can take advantage of the camera's inherent great depth of field. If possible, shoot at a small iris opening. Of course this may not be possible in a dark place, but if you have the choice then use manual iris and stop down as much as you can.

June 26th, 2006, 02:51 AM	#1
Brandon Wood Regular Crew Join Date: Apr 2005 Location: Mauriceville, TX Posts: 146	Focus Issues or Just Me? I've had my PD170 about a year and have always found the focus (both manual and autofocus) heck to use. The autofocus seems to hunt too much, and I can never seem to get the manual focus quite right. Take for instance a pageant I shot last weekend. I was about 15 ft. away from the stage, and there were girls walking across the stage from left to right (about 25 ft.) and back to front (about 20 ft). Because I would have constantly been having to ajust focus in manual since there was constant panning for motion, and since it seems impossible for me to pull focus consistently with the focus ring, I had to use auto much of the time. Of course the backgrounds and any other girls coming into frame made the camera want to hunt. I also have tried to use the focus assist in manual mode but it seems to be very weak since a lot of my shots still look soft; and not to mention the little LCD which serves only to help frame the shot rather than focus it. If I had a field monitor to help focus I'm sure that would be great but of course that's not practical either pocketbook-wise or field-wise. Any clues as to what I could be doing wrong or could it be the Sony? (I use my camera ALL the time btw) I have found very little on any issue like this in the forums (except for the age old question of auto vs. manual) although I have seen a few things about focus issues with PD150's a couple years back. Any advice would be greatly appreciated.

June 26th, 2006, 08:28 AM	#3
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	Like Vincent, I too have no problems focusing my 150 in reasonable situations. However, in the situation you describe, the little Sonys are hard to use. Very hard to use. However, if you are generally having problems with focus, then there are some tests to be made. 1. Focus the eyepiece by adjusting the diopter control until the text inside the Viewfinder is crisp. Not a scene, just the text from the camera that overlays the image. If you don't do this, all bets are off. 2. Place your camera on a tripod and set it up square to something like a bookcase (the print on spines of books makes a great target) about 20 feet away. 3. Set your camera to auto focus and check the image quality in the viewfinder (ignore the lcd, it is almost worthless for focus). Record a minute of footage. 4. Set your camera to manual focus and zoom in to set focus in the viewfinder. Record a minute of footage. 5. Zoom part way out, leave the focus alone, record a minute of footage. 6. Zoom all the way out, leave the focus alone, record a minute of footage. 7. Now go check the recorded footage for sharpness. If footage from step 3 is soft, then you have a camera problem If step 3 is crisp and step 4 is soft, then the viewfinder is misadjusted or you are having difficulties focusing the camera. Practice and or training may solve the problem. If steps 3 & 4 are crisp, I'd expect the 5 & 6 to be crisp. If they are not, you have a back-focus problem and the camera will have to go in for adjustment. Note that this assumes that the sharpness in the menus hasn't been set all the way to soft and that your editing system is capable of displaying a sharp image. You really cannot use the camera to make a good judgement about recorded video. __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

June 26th, 2006, 07:45 AM	#2
Vincent Croce Major Player Join Date: Oct 2005 Location: Fort Myers, FL Posts: 263	I know this isn't helping you figure out your problem, but I've never had any focus problems in manual or auto with either one of my PD170s. Like everyone else, I'd like the zoom transition to be a bit smoother and not so stepped, but the focusing is good. Might be your cam. Maybe rent or borrow another one to compare it to. Vin

June 26th, 2006, 08:55 AM	#5
Brandon Wood Regular Crew Join Date: Apr 2005 Location: Mauriceville, TX Posts: 146	Thanks for the suggestions...I should have asked earlier. I'll certainly try your method Mike and let everyone know in case anyone else has this problem (hopefully not).

June 26th, 2006, 09:38 AM	#7
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	Just another thought... in spite of the fact that people are always trying to acheive shallow depth of field, your situation is an example of one where you can take advantage of the camera's inherent great depth of field. If possible, shoot at a small iris opening. Of course this may not be possible in a dark place, but if you have the choice then use manual iris and stop down as much as you can.