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Old October 19th, 2010, 11:17 AM   #1
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Back focus, am I soft??

Maybe I'm paranoid but I have always thought that sometimes shots from my EX1 look a tad soft. I don't have the benefit of a broadcast monitor and just looking on my monitor I sometimes just think the picture should be sharper.

I know FCP is no way to judge and any dvd projects I do are always delivered SD. I don't know if these stills will even help.

What do you guys think?

The first pic is zoomed right in, peaking used to focus.

Te second is full wide.

I had no picture profile on and know about the aperture range for the lens so focus is maintained.

Thanks
Attached Thumbnails
Back focus, am I soft??-close-up.jpg   Back focus, am I soft??-zoom-out.jpg  

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Old October 19th, 2010, 11:43 AM   #2
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Important. What F stop were these shots taken at - is it in the sweet spot for the lens?
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Old October 19th, 2010, 11:50 AM   #3
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Hi Andy,

Between 1.9 and 4 if I remember correctly
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Old October 19th, 2010, 11:58 AM   #4
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Good. That'll do - so that's that one eliminated. Can you post full res (1920x1080) frame grabs? - I don't think these are as when I just opened them they only filled the middle of my monitor.
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Old October 19th, 2010, 12:40 PM   #5
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I normally try to shoot between 1.9 and 5.6. is that ok? Will try and post stills
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Old October 20th, 2010, 07:53 AM   #6
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Well, those shots filled 3/4 of my 1920x1080 monitor, and compared to my own EX-1 stills shot at 1920x1080, they look DECIDEDLY soft - but again, as noted, the aperature is absolutely critical for the sharpest shots! There are plenty of targets around for resetting back focus - and it can be a pain, but have you tried a reset on back focus. Of course the gold standard to test back focus as far as this sometimes ignorant editor is aware, is to zoom all the way out at a far object with the sweet spot aperature setting and obtain the very sharpest focus using the great aids on this camera, then pull back to the widest zoom on the same scene, obtain the sharpest focus, and then zoom all the way in and see if the focus holds up! If it doesn't, then your back focus is defective.

When I first obtained my EX-1. it looked really soft, and I performed the foregoing proceedure - oooops! The backfocus was TERRIBLE. Using target cards, I reset the backfocus, and it was still
really defective, so I sent it back to Sony under warranty, and they repaired it. After I received it
back, I again tested the backfocus using the aforementioned procedure, and it was as perfect (and as sharp as could be. That was over a year ago - I haven't retested it since, but just eyeballing my
productions (1920x1080 30p) on my largest test screen (109 inches), EVERYTHING looks great,
unless I either go to one extreme or the other on aperature, or in run and gun don't have the time to first zoom all the way in for sharpest manual focus, and then pull back to compose the shot.

Your query is soooooo relevant - good luck on the eventual outcome. In its price range, as everyone
knows, when this camera is properly st up, sharpness is just awesome and can't be beat!
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Old October 20th, 2010, 10:55 AM   #7
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Hi William,

Yeah I did try a back focus but still looks the same. I have attached these images from a focus chart.

I may not be far enough away but see what you think? I thought I would easily see if I had a problem. I zoomed all the way in focussed and then out as seen in the shots.

Here are my settings...

1080 25p
1/33 shutter
F4 stop
No picture profile
Attached Thumbnails
Back focus, am I soft??-zoom.jpg   Back focus, am I soft??-wide.jpg  

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Old October 20th, 2010, 12:14 PM   #8
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Dear Darrin:

Well, I don't know what to say at this point, so I'm bowing out! That f stop of 4.0 is obviously ideal, and you used the same (very popular) back focus chart which I did - the only varience in my procedure was
that I used 12 full charts to totally fill the frame, etc.. Your wide angle shot with your equipment rack, etc., just looks decidedly soft to me.

At this point, I'll leave it to brighter editors than I, hopefully, to comment on your situation. Again, best wishes for a successful resolution (pun intended).
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Old October 20th, 2010, 12:46 PM   #9
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Thanks for your input William.

I may try back focussing again. I followed the procedure as stated here...



I'm going to go for a few tries and if not then it looks like a Sony service is need. Camera well out of warranty!!!!!!!!! Yikes......that aint cheap!
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Old October 20th, 2010, 02:40 PM   #10
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hi Darren,
If you are following the video tutorial, you are doing everything right!
The only thing that comes to mind is that you would need a lot more light to do the proper BF. Try again before you run to Sony...
Cheers
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Old October 20th, 2010, 03:14 PM   #11
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Hi Luben,

The pictures I uploaded were for focus purposes. When I did the back focus adjust I used a blank wall and had room lights on and a red head set up. I would of thought enough light and I thought over exposing might ruin the adjustment! I am a bit confused as with that much light the camera complains. Perhaps I should do it outside, what are your thoughts??

I may even move the camera slightly closer to the chart. I will definitely give it another go.

I always thought there may have been issues, at the moment I feel pretty low about the prospect of having to shell out lots to Sony.

Many thanks guys, much appreciated.
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Old October 20th, 2010, 03:35 PM   #12
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Bright day is a great idea. The distance should be no more then 3 meters or in North American terms less then 10 feet and no closer then 2 meters/ ~7 feet. Light is the key and don't forget the auto focus on the camera must be on. I am sure you've done it right the first time, but try again. I found different BF performances with different light, that why I suggested more light for better adjustment. Good luck and post results.
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Old October 20th, 2010, 03:40 PM   #13
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Thanks Luben,

Nice to get some positive feedback. I hate the feeling something is up with my camera!!!!!!!!!!!
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Old October 21st, 2010, 07:08 AM   #14
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Help! Please give your opinion re Darren's shots!

Well, Darrin, despite my bowing out, here I am again....reminds me of the old song, "The Cat Came Back...He Just Couldn't Stay Away".

Great tutorial, and it wasn't even around when I backfocused my EX-1 - thanks for the reference.

I followed a backfocus procedure that was quite similar to that on the Vimeo presentation. To be more precise (if my memory serves me well, since it was 1 1/2 years ago, when my EX-1 was 1 month old and of course well within warranty - and since we all remember traumatic experiences better than bland ones, and since this was traumatic I think I remember it well [I'm professionally qualified to make the last statement, because I'm not only an event videographer, but a licensed clinical psychologist with extensive reading in the field of neurological psychology over the last four years}) here is the procedure I followed:

Camera set up outdoors, on very stable tripod, approximately 9 feet from a very highly textured brick wall, with lens absolutely perpendicular to the wall, in mid-late morning bright sunlight shining directly on the wall. Camera auto focus set up as outlined in the Vimeo presentation. I believe, but couldn't swear that ND filter in some position was on, with aperature set to f4.0. The reason I ended up using 12 of the charts similar to the ones you exhibited above was so that the high contrast target not only filled the viewfinder when zoomed all the way in, but also a very substantial area, when zoomed out; this probably reflected my OCD (Obsessive Compulsive Disorder, of which, like most OCDs, I'm very proud, despite the dismay of all my friends), but by golly, I did it right!

Now, having followed that procedure because of the apparant soft focus of my brand new EX-1, I was chagrined that the results were negative. So I ran them twice more with the same results - and it was at this point that I decided to send the camera to Sony (good grief, even though under warranty, well over $200 shipping including insurance, for a brand new camera). After weeks at their West Coast facility, they repaired it - I ran the test again, and it was perfect! What a shame that this superb camera had so many defects straight out of the box - flaking finish, disappearing lables, etc., etc.. And from their Broadcast Division - I've never had another camera from Sony Broadcast, let alone ANY of their consumer cameras with so many defects. But then I've never had such a great camera as this! Since two trips to Sony Service under warranty, it has continued to produce absolutely stunningly positive results!

Finally, I have three concluding thoughts:

1) Unfortunately for me, the first relates to my camera, and in particular results from the comment of one of the fellows above - to wit, given that it had been over 18 months since I've run a back focus reset, and despite the fact that I think my results are sharp, its time for another traumatic test.

2) As the Vimeo presentation suggested, if your first backfocus run didn't produce the results expected, it might be worth it to run a couple more, and see if you have an improvement.

3) Most importantly: I gave my subjective opinion above about your illustrated test shots - it was just an opinion (although an informed one). But what I, and particularly you should be most interested in:

WHAT IS THE OPINION OF ALL YOU OTHER SHOOTERS OUT THERE ABOUT THE ADEQUACY AND SHARPNESS OF DARRIN'S SHOTS?????????????

Excuse the shouting, but given my as usual overwritten comments, I needed this to stand out above the static! I depend upon this forum for expert response more than any other, just because of the superb and sometimes high volume responses I've had to my queries. What do others of you see?

Last edited by William Urschel; October 21st, 2010 at 07:13 AM. Reason: Format Correction
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Old October 21st, 2010, 09:51 AM   #15
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Hi William,


A truly adorable post! Many thanks.

What a wonderful jump from clinical psychologist to videographer. I think back focus adjustment is something OCD would actually be a benefit in! The adjustment seems an acutely inaccurate science but I shall give it another try!

Just one question....when I did the adjustment I pushed the focus ring forward but does the auto focus switch have to be set to AUTO?? It isn't mentioned in the above video. Could be a major duh moment on my part!!!!!
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