Focus issue solved, faulty camera now replaced

Tom Roper · December 30th, 2006, 01:45 PM

Wait...Alex, tell me how you want me to run the test, so I can best duplicate the conditions.

Philip Williams · December 30th, 2006, 02:30 PM

Quote:

Originally Posted by Tom Roper

<snip>
I will try 24F and 30F shortly and report my observation here.

Looking forward to your findings Tom. I've been able create shots that have focus pulsing in 24F but nothing but perfect focus in 60i (haven't tested 30F).

Tom Roper · December 30th, 2006, 02:34 PM

I just shot the 24F. Need a few minutes to capture and play it back.

Indoors on tripod
OIS off
F3.7
1/100th
-3db
Diffuse light from window
10 ft focal distance
zoomed from 30% to 95% at preset zoom speed 4

etc...

Now to review the result, standby...

Tom Roper · December 30th, 2006, 03:57 PM

First observation...Wow...24F is gorgeous! The only other time I tried it was when I posted IMATEST MTF50 resolution results which showed the vertical resolution to have a drop of 10.6%. But I don't know how you can spot it in actual video. Beautiful!

Second Observation: I did (5) zooms from about 30% to 95%. The first zoom I did with the remote control, and it was faster than the zoom (4) setting on the rocker switch for some reason, too fast in fact. On the second and third zooms I used the rocker but realized OIS was on. There was no deleterious effect from OIS being on. Great! Only the 5th zoom was OIS off. Really no difference or harm having it switched on while on the tripod. Where it likely would pose the problem would be when panning. Anyway, I do mostly the run 'n gun shooting so OIS is always on for me.

Third Observation: I'm saying this as honestly as I can, but I think the autofocus while zooming in 24F from what I just saw is awesome. I viewed the playback footage on a 50 inch DLP from 7 ft. I wouldn't fathom returning this cam for such an alledged defect. Does that mean I saw no focus pulsing? No, because actually in about 3 of the zooms I can see some extremely minor pulsing during the zoom. It took 4-5 viewings before I spotted anything at all. In one case, I can see an extremely minor pulsing after the zooming stopped. In other cases after the zooming stops, it looks like a still photograph, perfectly motionless. In all instances, it was pixel peeping carried to the extreme. Does this mean that Alex, Michael and Philip are more sensitive or bothered by it? It's really hard to know because we are not looking at the same cam or the same conditions. I'm trying to rule out things that are already acknowledged to be autofocus exceptions like poor contrast or vertical patterns, so the cam has a fair chance to find its expected focus. The test scene presented no problem for the cam.

Fourth (a speculation): This is the one I can't discount. Alex's first cam. The picture of a black nylon bag laying on a wood deck in flat light, a very featureless scene. The focus was simply jumping up and down like hot oil on a frying pan. I've yet to remotely see anything that duplicates that ugly behavior. Now Alex has a replacement camera, and I thought he acknowledged it was substantially better. But is it a case where you are so traumatized by the recollection that you continue to see it everywhere? The cliche' is, if all you have is a hammer, then everything starts looking like a nail!

Fifth observation: In the test scene next to Santa's right ear, there is a gold ribbon that is 1/4 inch wide. Zoomed in from 10 feet, you can see incredible detail to the weave. I'm going to post a 100% crop of that detail at its sharpest and at its worst to illustrate the focus pulsing delta. It isn't much.

Michael Mann · December 30th, 2006, 04:47 PM

Quote:

Originally Posted by Tom Roper

But if I felt as strongly about it as you do, I would return or sell the A1 and go back to the Z1.

No, Tom, you probably got me wrong. From the first moment I watched 25F clips of my new A1 on my computer display, I had no more intention at all ever to go back to the FX1. The overall image quality is so much better.

But I might return my A1 if there is a realistic chance that I get a "non-pulsing" unit in exchange, like Alex tried.

So, thanks for you testing, Tom. Could you upload one of your 24F demo clips?

Tom Roper · December 30th, 2006, 04:50 PM

Being objective means remaining open minded about observations. It's a work in progress to remain unbiased, and the opinion has to be open to change as the data accumulates.

What I said in the previous post is how I feel about it viewing 24F on the 50 inch big screen in motion. Looks great.

But what's become obvious using the NLE to step through the frames is the image is going out of focus about every 3-5 frames during the zoom, exactly as has been noted. It's subtle, but undeniable.

The pulsing stops when the zooming stops.

Philip Williams · December 30th, 2006, 05:44 PM

Yes, sometimes its so subtle that its really not noticeable. As I stated earlier in this thread, I plan to just use manual focus in 24F mode from now on anyway, so its a moot point for me. But if I felt the need to use auto focus in 24F I'd certainly do so; the pulsing I've seen isn't a show stopper and I don't exactly record THAT many zooms anyway :)

As for the overall quality of 24F, yes its amazing. The detail is stunning, the motion is perfect and I have yet to break the codec in 24F mode (I've tried).

Tom Roper · December 30th, 2006, 05:58 PM

Quote:

Originally Posted by Michael Mann

So, thanks for you testing, Tom. Could you upload one of your 24F demo clips?

Yes, I have an m2t clip to upload. It's 45mb and I'm on dialup so this could take awhile, be patient it's coming.

Brad Tyrrell · December 30th, 2006, 06:28 PM

Quote:

Originally Posted by Tom Roper

Yes, I have an m2t clip to upload. It's 45mb and I'm on dialup so this could take awhile, be patient it's coming.

45 meg on dial-up? You are a brave and patient soul sir.

Tom Roper · December 30th, 2006, 07:07 PM

Quote:

Originally Posted by Brad Tyrrell

45 meg on dial-up? You are a brave and patient soul sir.

What? I'm 28% there! Only 2.5 hours to go!
Lol...

Tom Roper · December 30th, 2006, 09:52 PM

Right Click, Save Target As...

http://vsdrives.com/movies/StNick.m2t

Alex Leith · December 31st, 2006, 06:17 AM

Quote:

Originally Posted by Tom Roper

Wait...Alex, tell me how you want me to run the test, so I can best duplicate the conditions.

Sorry I didn't reply (I was asleep)! :-)

Thanks very much for running the test Tom. Yes, I agree with you that there is a tiny amount of pulsing in the clip - but it's barely visible... very comperable to the amount of interference I see on my camera.

I really appreciate the fact that people have been working together to discover one of the limitations of this camera. It's only by knowing what you can and can't do that you end up being more assured of coming home with usable footage when you're out in the field.

Personally, what I'm taking from this is that when in frame mode AF definately stays off, and I'll spot focus with the IAF button.

That matches how I work normally anyway, but it's good to know what I can and what I can't rely on.

Even with AF on I agree that the pulsing is probably going to be barely noticable in 99% of situations.

Once again, for me this "quirk" does not devalue the camera. The images are absolutely gorgeous and blow my FX1 out of the water!

Michael Mann · December 31st, 2006, 07:30 AM

Tom, thanks for sharing your clip. After watching it my impression is that "my" pulsing is stronger than yours. Anyway, I will not return my A1 since I don't consider it very likely now that the AF of the exchange unit will work any better. AF during zooms stays off from now on.

Quote:

Originally Posted by Alex Leith

I really appreciate the fact that people have been working together to discover one of the limitations of this camera. It's only by knowing what you can and can't do that you end up being more assured of coming home with usable footage when you're out in the field.

Yes, that's how I feel about it, too. I very much appreciate this kind of regardful constructive cooperation - the more when it's about possible malfunctions. (It's very easy - but not very rewarding - to praise benefits together. It's much more delicate when it's about limitations - but it pays off!) Thank you, Tom. Thank you, Alex.

Quote:

Originally Posted by Alex Leith

Personally, what I'm taking from this is that when in frame mode AF definately stays off, and I'll spot focus with the IAF button.

I never used the IAF botton before - for me it was either AF or manual focus. But since I will stick with the A1 (and with 25F!), I want to learn to work that way (Manual focus plus IAF botton when changing focus plane). I' d love to sharing experience in working that way.

Tom Roper · December 31st, 2006, 10:19 AM

I totally agree with you both. I'm especially relieved you saw what you needed so as not to needlessly return the cam for service based on opinions alone. The video clip I think really helped there.

Jay Fisk · December 31st, 2006, 08:58 PM

If you just have to use IAF on a slow zoom, try changing the AF response speed from the Cam Controls menu. It makes any 'focus pulse' artifact less noticeable. Unfortunately it also retards the IAF push-button when in Manual Focus mode. I kind of like the slow focus mode but would like the IAF button to be fast during over-ride. Only two speeds here, fast or normal (slow...)

Full manual focus/exposure for zooms with any complexity seems to be best.

I just woke up from a strange dream where Microsoft had redesigned the menus on the A1 - it kept popping up confirmation and password screens everytime I changed a parameter. Too scary!

December 30th, 2006, 03:57 PM	#64
Tom Roper Trustee Join Date: Jun 2004 Location: Denver, Colorado Posts: 1,891	Results in... First observation...Wow...24F is gorgeous! The only other time I tried it was when I posted IMATEST MTF50 resolution results which showed the vertical resolution to have a drop of 10.6%. But I don't know how you can spot it in actual video. Beautiful! Second Observation: I did (5) zooms from about 30% to 95%. The first zoom I did with the remote control, and it was faster than the zoom (4) setting on the rocker switch for some reason, too fast in fact. On the second and third zooms I used the rocker but realized OIS was on. There was no deleterious effect from OIS being on. Great! Only the 5th zoom was OIS off. Really no difference or harm having it switched on while on the tripod. Where it likely would pose the problem would be when panning. Anyway, I do mostly the run 'n gun shooting so OIS is always on for me. Third Observation: I'm saying this as honestly as I can, but I think the autofocus while zooming in 24F from what I just saw is awesome. I viewed the playback footage on a 50 inch DLP from 7 ft. I wouldn't fathom returning this cam for such an alledged defect. Does that mean I saw no focus pulsing? No, because actually in about 3 of the zooms I can see some extremely minor pulsing during the zoom. It took 4-5 viewings before I spotted anything at all. In one case, I can see an extremely minor pulsing after the zooming stopped. In other cases after the zooming stops, it looks like a still photograph, perfectly motionless. In all instances, it was pixel peeping carried to the extreme. Does this mean that Alex, Michael and Philip are more sensitive or bothered by it? It's really hard to know because we are not looking at the same cam or the same conditions. I'm trying to rule out things that are already acknowledged to be autofocus exceptions like poor contrast or vertical patterns, so the cam has a fair chance to find its expected focus. The test scene presented no problem for the cam. Fourth (a speculation): This is the one I can't discount. Alex's first cam. The picture of a black nylon bag laying on a wood deck in flat light, a very featureless scene. The focus was simply jumping up and down like hot oil on a frying pan. I've yet to remotely see anything that duplicates that ugly behavior. Now Alex has a replacement camera, and I thought he acknowledged it was substantially better. But is it a case where you are so traumatized by the recollection that you continue to see it everywhere? The cliche' is, if all you have is a hammer, then everything starts looking like a nail! Fifth observation: In the test scene next to Santa's right ear, there is a gold ribbon that is 1/4 inch wide. Zoomed in from 10 feet, you can see incredible detail to the weave. I'm going to post a 100% crop of that detail at its sharpest and at its worst to illustrate the focus pulsing delta. It isn't much.

December 30th, 2006, 04:50 PM	#66
Tom Roper Trustee Join Date: Jun 2004 Location: Denver, Colorado Posts: 1,891	Okay, I concede... Being objective means remaining open minded about observations. It's a work in progress to remain unbiased, and the opinion has to be open to change as the data accumulates. What I said in the previous post is how I feel about it viewing 24F on the 50 inch big screen in motion. Looks great. But what's become obvious using the NLE to step through the frames is the image is going out of focus about every 3-5 frames during the zoom, exactly as has been noted. It's subtle, but undeniable. The pulsing stops when the zooming stops.

December 30th, 2006, 05:44 PM	#67
Philip Williams Major Player Join Date: Aug 2004 Location: Snellville, Georgia Posts: 614	Yes, sometimes its so subtle that its really not noticeable. As I stated earlier in this thread, I plan to just use manual focus in 24F mode from now on anyway, so its a moot point for me. But if I felt the need to use auto focus in 24F I'd certainly do so; the pulsing I've seen isn't a show stopper and I don't exactly record THAT many zooms anyway :) As for the overall quality of 24F, yes its amazing. The detail is stunning, the motion is perfect and I have yet to break the codec in 24F mode (I've tried). __________________ www.philipwilliams.com

December 30th, 2006, 09:52 PM	#71
Tom Roper Trustee Join Date: Jun 2004 Location: Denver, Colorado Posts: 1,891	Here's the Link Right Click, Save Target As... http://vsdrives.com/movies/StNick.m2t

December 31st, 2006, 08:58 PM	#75
Jay Fisk Regular Crew Join Date: Oct 2006 Location: CSL BCS MX Posts: 67	Changing focus speed ? If you just have to use IAF on a slow zoom, try changing the AF response speed from the Cam Controls menu. It makes any 'focus pulse' artifact less noticeable. Unfortunately it also retards the IAF push-button when in Manual Focus mode. I kind of like the slow focus mode but would like the IAF button to be fast during over-ride. Only two speeds here, fast or normal (slow...) Full manual focus/exposure for zooms with any complexity seems to be best. I just woke up from a strange dream where Microsoft had redesigned the menus on the A1 - it kept popping up confirmation and password screens everytime I changed a parameter. Too scary!

December 30th, 2006, 01:45 PM	#61
Tom Roper Trustee Join Date: Jun 2004 Location: Denver, Colorado Posts: 1,891	Wait...Alex, tell me how you want me to run the test, so I can best duplicate the conditions.

December 30th, 2006, 02:34 PM	#63
Tom Roper Trustee Join Date: Jun 2004 Location: Denver, Colorado Posts: 1,891	I just shot the 24F. Need a few minutes to capture and play it back. Indoors on tripod OIS off F3.7 1/100th -3db Diffuse light from window 10 ft focal distance zoomed from 30% to 95% at preset zoom speed 4 etc... Now to review the result, standby...

December 31st, 2006, 10:19 AM	#74
Tom Roper Trustee Join Date: Jun 2004 Location: Denver, Colorado Posts: 1,891	I totally agree with you both. I'm especially relieved you saw what you needed so as not to needlessly return the cam for service based on opinions alone. The video clip I think really helped there.