Accidently Adjusted Flange Focal Length

Bruce Rawlings · August 12th, 2009, 09:23 AM

It may be worth digging out an old EX1 thread regarding back focus calibration and trying that before sending the camera in. Basically you need a few charts on a a clear wall with the camera on a tripod at F1.9 and then go through the EX3 back focus procedure. If it is still wrong then off to the service centre.

Glynn Morgan · August 13th, 2009, 04:39 AM

A few charts? Oh no, I already sent the camera in. And there's an 88 dollar fee if theres no fault found. I hadn't thought of using multiple charts :/

I just hope they are as meticulous as I am, before dismissing it. Naturally at 1080P you want a sharp wide angle image that can be focused in telephoto. I did tell them it is noticable on a computer screen grab.

Oh well, at the worst, my camera will come back fully adjusted.

Glynn Morgan · August 28th, 2009, 01:39 AM

I received the EX3 back from the service centre. My in-camera tests passed, with peaking on and the DOF indicator on. I couldn't get the peaking to increase any more than when I initiall zoomed out of a subject, so it seemed to me to be ok.

Looking at the footage on the computer, the wide shots lack definition. Maybe its because I'm watching it in clip browser and close ups always look good when you have a shallow depth of field.

Will report back with results from looking in an NLE and Rendered footage.

Vincent Oliver · August 28th, 2009, 02:06 AM

Glynn,

TRy feeding your camera directly into a HD TV and see the quality leap. Using clip browser to judge is a no, no, this generally displays a proxy version, as does your video editing application.

Vincent Oliver · August 28th, 2009, 02:37 AM

I assume you are not using an aperture of f11 - f16, both will produce soft results.

Glynn Morgan · August 29th, 2009, 01:15 AM

Double post

Glynn Morgan · August 29th, 2009, 01:38 AM

What about using the clip browser to take a screenshot?

For instance, this wide shot (attached) had decent peaking after focusing in tele, yet it still looks softish onscreen.

Albeit I did shoot this on SP 50i.

I didn't know about that proxy business, can I watch a high res version on my computer anywhere if not on an NLE or clip browser?

I never shoot lower than F8, always use ND filters.

Edit: I added a HQ 50i tele and wide of my dog while it was still. Does that wide look sharp? The peaking said so, but I keep thinking it should be a bit clearer.

Vincent Oliver · August 29th, 2009, 03:29 AM

Glynn,

Looking at the sample pictures, it does look like you have a "Late Friday Afternoon" lens. I suspect you are looking at the footage on a frame by frame basis rather than viewing the movie as a whole. I have just done a frame grab with my lens set to wide, and yes it also looks soft, but when viewed as a movie it is as sharp as pins.

You might also try doing a Progressive capture, this will produce a sharper picture.

Here are a few sample pictures shot at full wide with the EX3 720p@50fps (plane is a telephoto shot)

Glynn Morgan · August 29th, 2009, 04:03 AM

So you think it looks ok then? Some of your shots are quite crisp, though i can see your point in wales.bmp You no doubt have mastered your camera and your shots are great, but it looks a little soft yeah your right.

PS: what's late Friday afternoon mean?

PPS: Does keeping the aperture between f8 and f4 make it sharper? Im afraid the examples above were closer to f1.9 - I read that somewhere on this site today.

Vincent Oliver · August 29th, 2009, 06:18 AM

Full aperture (f1.9) is never going to give you the sharpest result, aim to keep between f4 and f8.

Late Friday Afternoon is when the workers have their minds fixed on weekend activities.

Doug Jensen · August 29th, 2009, 10:55 AM

I have to disagree with that advice.

On the EX1 and EX3, f/4 is already approaching the outer limits of what you can get away with.

If you want sharp video, I recommend f/2.8 to f/4 and never anything smaller than f/5.6 under any circumstances.

David C. Williams · August 29th, 2009, 05:46 PM

Doug has the right of it. Diffraction limiting on green wave lengths for 1/2" starts to soften the image around F5.6, and wider than F2.8 you start to use the outer edges of the lens, which aren't as clean.

Glynn Morgan · August 30th, 2009, 03:13 AM

Interesting points, thankyou so much.

Never really knew that aperture could muck around with your "in focus" sharpness as much as it seems to do. Why do they even bother having f8 and below?

Vincent Oliver · August 30th, 2009, 07:57 AM

Who am I to doubt you Doug?

On still camera lenses the optimum aperture is usually f5.6, I would have expected the same to be true for video lenses.

I must conduct a set of lens tests for myself.

Good question Glynn, why bother with f11 & f16, even on still cameras these apertures can be soft, but they do produce a greater depth of field (not to be confused with sharpness)

Doug Jensen · August 30th, 2009, 09:08 AM

Quote:

Originally Posted by Vincent Oliver

Who am I to doubt you Doug?

On still camera lenses the optimum aperture is usually f5.6, I would have expected the same to be true for video lenses.

Vincent, I am wrong on a lot of things, but I know I am right on this one because I saw the results first hand when I started shooting with a pre-production EX1 exactly two years ago next week. Hard to believe it has been that long!

f/5.6 might very well be the "sweet spot" for the optics of some lenses, but you have to consider the tiny 1/2" sensors of the EX1 and EX3. Yeah, they're bigger than 1/3" sensors on other handycams, but they are still quite a bit smaller than 35mm film, digital SLRs, or 2/3" cameras. The small sensor size makes them vulnerable to diffraction problems at small apertures. I'm sure someone else can explain it better than I just did, but all you need to know is to keep the iris larger than f/5.6 all the time -- and preferabally around f/2.8.

August 28th, 2009, 01:39 AM	#33
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	Recieved camera I received the EX3 back from the service centre. My in-camera tests passed, with peaking on and the DOF indicator on. I couldn't get the peaking to increase any more than when I initiall zoomed out of a subject, so it seemed to me to be ok. Looking at the footage on the computer, the wide shots lack definition. Maybe its because I'm watching it in clip browser and close ups always look good when you have a shallow depth of field. Will report back with results from looking in an NLE and Rendered footage.

August 28th, 2009, 02:06 AM	#34
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	Glynn, TRy feeding your camera directly into a HD TV and see the quality leap. Using clip browser to judge is a no, no, this generally displays a proxy version, as does your video editing application. __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes

August 28th, 2009, 02:37 AM	#35
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	I assume you are not using an aperture of f11 - f16, both will produce soft results. __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes

August 29th, 2009, 01:15 AM	#36
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	Double post Last edited by Glynn Morgan; August 29th, 2009 at 01:44 AM. Reason: double post

August 29th, 2009, 01:38 AM	#37
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	Thanks! What about using the clip browser to take a screenshot? For instance, this wide shot (attached) had decent peaking after focusing in tele, yet it still looks softish onscreen. Albeit I did shoot this on SP 50i. I didn't know about that proxy business, can I watch a high res version on my computer anywhere if not on an NLE or clip browser? I never shoot lower than F8, always use ND filters. Edit: I added a HQ 50i tele and wide of my dog while it was still. Does that wide look sharp? The peaking said so, but I keep thinking it should be a bit clearer. Attached Thumbnails Last edited by Glynn Morgan; August 29th, 2009 at 02:37 AM.

August 12th, 2009, 09:23 AM	#31
Bruce Rawlings Major Player Join Date: Feb 2008 Location: Cardiff, Wales, UK Posts: 410	It may be worth digging out an old EX1 thread regarding back focus calibration and trying that before sending the camera in. Basically you need a few charts on a a clear wall with the camera on a tripod at F1.9 and then go through the EX3 back focus procedure. If it is still wrong then off to the service centre.

August 13th, 2009, 04:39 AM	#32
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	A few charts? Oh no, I already sent the camera in. And there's an 88 dollar fee if theres no fault found. I hadn't thought of using multiple charts :/ I just hope they are as meticulous as I am, before dismissing it. Naturally at 1080P you want a sharp wide angle image that can be focused in telephoto. I did tell them it is noticable on a computer screen grab. Oh well, at the worst, my camera will come back fully adjusted.

August 29th, 2009, 03:29 AM	#38
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	Glynn, Looking at the sample pictures, it does look like you have a "Late Friday Afternoon" lens. I suspect you are looking at the footage on a frame by frame basis rather than viewing the movie as a whole. I have just done a frame grab with my lens set to wide, and yes it also looks soft, but when viewed as a movie it is as sharp as pins. You might also try doing a Progressive capture, this will produce a sharper picture. Here are a few sample pictures shot at full wide with the EX3 720p@50fps (plane is a telephoto shot) Attached Thumbnails __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes

August 29th, 2009, 04:03 AM	#39
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	So you think it looks ok then? Some of your shots are quite crisp, though i can see your point in wales.bmp You no doubt have mastered your camera and your shots are great, but it looks a little soft yeah your right. PS: what's late Friday afternoon mean? PPS: Does keeping the aperture between f8 and f4 make it sharper? Im afraid the examples above were closer to f1.9 - I read that somewhere on this site today.

August 29th, 2009, 06:18 AM	#40
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	Full aperture (f1.9) is never going to give you the sharpest result, aim to keep between f4 and f8. Late Friday Afternoon is when the workers have their minds fixed on weekend activities. __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes

August 29th, 2009, 10:55 AM	#41
Doug Jensen Vortex Media Join Date: Jan 2009 Location: Florida Posts: 3,417	I have to disagree with that advice. On the EX1 and EX3, f/4 is already approaching the outer limits of what you can get away with. If you want sharp video, I recommend f/2.8 to f/4 and never anything smaller than f/5.6 under any circumstances. __________________ Vortex Media http://www.vortexmedia.com/ Sony FS7, F55, and XDCAM training videos, field guides, and other production tools

August 29th, 2009, 05:46 PM	#42
David C. Williams Major Player Join Date: Jun 2008 Location: melb.vic.au Posts: 447	Doug has the right of it. Diffraction limiting on green wave lengths for 1/2" starts to soften the image around F5.6, and wider than F2.8 you start to use the outer edges of the lens, which aren't as clean. __________________ www.davidwilliams.com.au

August 30th, 2009, 03:13 AM	#43
Glynn Morgan Regular Crew Join Date: Feb 2009 Location: Australia Posts: 119	Interesting points, thankyou so much. Never really knew that aperture could muck around with your "in focus" sharpness as much as it seems to do. Why do they even bother having f8 and below?

August 30th, 2009, 07:57 AM	#44
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	Who am I to doubt you Doug? On still camera lenses the optimum aperture is usually f5.6, I would have expected the same to be true for video lenses. I must conduct a set of lens tests for myself. Good question Glynn, why bother with f11 & f16, even on still cameras these apertures can be soft, but they do produce a greater depth of field (not to be confused with sharpness) __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes