I have an HD100 set to truecolor 3. I've gotten comments from others that the image looks softer than it should. I'd set the back focus some months ago and think I may not be doing it right.

Some questions-
1) should back focus be set with focus assist or eyeballs?
2) should the hashmark on the back focus ring and the hash mark on the macro focus ring normally be aligned?
3) should the spring loaded switch on the macro focus ring be disengaged when setting back focus? (if i do that, adjusting the backfocus independent of the macro focus seems to do nothing--the focus doesn't change.)
4) the manual says set the focus at a distance greater than three meters, is there and ideal distance?
5) any additional tips for setting back focus? I find the owner's manual consistently lacking in detail.

I don't know if this helps... but, here's my 2¢ and the way I know how to do it. I use a focus chart about 3 feet away. (I don't believe it should be 3 METERS or more necessarily..) I guess one can use the focus assist or eye ball it or both. Leave the macro alone and locked.

Zoom into the chart and focus, note the barrel marking, should be around 3 feet - adjust the back focus.

Zoom back all the way out and focus - play with back focus to bring it into super sharp focus.

Keep repeating until you have the back focus adjusted - both ends of the zoom range should remain in focus once the back focus is correctly set. i.e., Once you set the focus while zoomed all the way in it should remain in focus when zoomed back out to wide.

I don't know if this helps... but, here's my 2ç and the way I know how to do it. I use a focus chart about 3 feet away. (I don't believe it should be 3 METERS or more necessarily..) I guess one can use the focus assist or eye ball it or both. Leave the macro alone and locked.

Zoom into the chart and focus, note the barrel marking, should be around 3 feet - adjust the back focus.

Zoom back all the way out and focus - play with back focus to bring it into super sharp focus.

Keep repeating until you have the back focus adjusted - both ends of the zoom range should remain in focus once the back focus is correctly set. i.e., Once you set the focus while zoomed all the way in it should remain in focus when zoomed back out to wide.

I'll try that thanks. Anyone know of a downloadable focus chart I can print out?

sent you an IM

http://www.rondexter.com/intermediate/equipment/focus_pattern.htm

I downloaded a back focus chart from here.

I'll try that thanks. Anyone know of a downloadable focus chart I can print out?

Two here:

http://www.panavision.com.au/PDFs/Charts/Large_Siemen_Star.pdf

http://www.panavision.com.au/PDFs/Charts/Small_Siemen_Stars_Chart.pdf

I don't use back focus charts myself, I just use some kind of sharp edge in the distance. The depth of field is big enough on a 1/3" chip at that distance that setting the focus barrel precisely isn't as important.

Um, I adjust my back focus as I see fit for each shoot I am on.

I will change it some 5 or 6 times during the course of an evening filming a reception. I can get pretty close to someone dancing and not be happy with the focus.

Call me weird, but I could never live with a permanant setting.

I have an HD100 set to truecolor 3. I've gotten comments from others that the image looks softer than it should. I'd set the back focus some months ago and think I may not be doing it right.

Some questions-
1) should back focus be set with focus assist or eyeballs?
2) should the hashmark on the back focus ring and the hash mark on the macro focus ring normally be aligned?
3) should the spring loaded switch on the macro focus ring be disengaged when setting back focus? (if i do that, adjusting the backfocus independent of the macro focus seems to do nothing--the focus doesn't change.)
4) the manual says set the focus at a distance greater than three meters, is there and ideal distance?
5) any additional tips for setting back focus? I find the owner's manual consistently lacking in detail.

1) Only do this when your camcorder is connected to a ful resolution display (lcd, ...). You'll really need this for critical back focus setting. The focus assist is way to forgiving for back focus setting...
2) Yes, when trying to set the back focus, they should be alligned. Wouldn't make a lot of sense otherwise...
3) The macro-ring will turn when you turn the backfocusring and you should see the difference.
4) In my experience with the HD101, 2,5 to 3 meters is perfect. Don't double it, don't halve it... under 2 meters is too close: you'll notice your backfocus isn't set entirely properly...
5) that's pretty much it. Make sure your light is just right to open up your iris fully and that you have a full res monitor present. Be sure to check after you re-tightened the back focus screw...

Um, I adjust my back focus as I see fit for each shoot I am on.

I will change it some 5 or 6 times during the course of an evening filming a reception. I can get pretty close to someone dancing and not be happy with the focus.

Call me weird, but I could never live with a permanant setting.

You should use the macro for this.

One version of the Sony HDCam cameras are a nightmare regarding the backfocus, they need to be checked all the time because of the slightest temperature changes (even between takes in the worst instances).

However, most HD cameras only need to be backfocus checked if there's a lens or temperature change - usually once adjusted when the set & camera have warmed up it doesn't need to be touched (Camera assistants often check by eye at least once during the day). Each time you should carefully set up with a chart or a pattern that can act as a chart, it's not something that's done on the fly.

If you're losing backfocus that regularly it could be that the adjustment ring is slipping.

Or: intensive use of the macro can cause the backfocus-ring to get a little looser and shift a bit in position, thus resulting in an incorrect backfocus...

(don't ask me who uses a macro THAT often/intensively.... but you never know)

I'll jump in here too.

Not only do HDCAMs have a tempurature problem, many cameras do, as well as my HD100. Years ago I purchased one of those point and read infrared tempurature thermometers, and I check my camera body in the area near the CCC block and lens barrel close to the camera before every take. They must be tempurature stabilized (within a degree or two) or the BF will drift out. It takes about an hour or more of warm-up to stabilize, and if you put on a cold lens, you start all over again. (the lens is warmed by the camera body, and a cold lens will cool the camera body).

Unless you have the luxury of a 24" or larger monitor on set, then you must use the focus assist or peaking control to see the focus on the star chart. I printed out a small one and a larger one, and secured them side by side to a piece of foamcore; at full tele I focus on the smaller one, and at full wide I use the larger one which I can see better; they are the same distance from the lens. I printed them on photo paper, best settings. Also, you must go through the process 2-3 times; it is a dance until both full tele and wide BF are consistent.

Regarding the set screw Werner mentioned, I had much trouble working with the BF ring on the stock lens, and I also found the stock lens didn't always track focus through the zoom; I now have the 17x lens which is machined more like a high end lens, and tracking and setting the ring are no problem.

Without the large monitor on set, I pull focus on my subject at full tele, using focus assist if necessary, then widen to frame; my BF must be spot on. Occasionally I will use the stock lens with the Wide Converter, and I find it necessary to pull focus at frame, using peaking and (sometimes) a large monitor in that case.

Unless of course you are Tim Dashwood or Taylor Wigton, who have that magic touch many of us can only dream about. Maybe the fact that I'm nearly 64, and walk with a white cane has something to do with it. I also have someone steer the car while I'm driving.


Cheers,

Gary

I've found that with the stock lens, I check back focus every time I go out, and even on tape changes because it does seem to drift around a little.

use as a big monitor as you can find, but the focus assist will work if need be. its a bit unnerving to have to do this all the time, but its become habit. on my old sony cameras (327a) I checked it about once a month with constant use and it never seemed to go anywhere

Steve Oakley

Is this the case of the stock lens not performing well at all on the wide end?

I just got the HD110, and have been having similar problems with my backfocus being adjusted. I went through the Chart directions, setting the focus chart 3 meters away, zoom-in, pull focus, adjust bF, zoom out, adjust focus, repeat, etc.
It is really hard to see if the chart is in focus when I am wide, then when I do location shooting, and want a to frame a subject that is about 10 feet away, it seems like I can never get it in focus, really frustrating! I go in get my focus, pull out and the subject get more and more soft and blurry.

I do have a wide angle converter, and whenever I attach that, and adjust my bf,everything comes in focus and it works fine. Is it just the stock lens, or am I doing something wrong here?

no. I think the stock lens looks ok wide. I think its just a matter of it being very temperature sensitive. in any event, I've simply gotten into the habit of checking the B.F. everytime I load a new tape.


Steve Oakley

no. I think the stock lens looks ok wide. I think its just a matter of it being very temperature sensitive. in any event, I've simply gotten into the habit of checking the B.F. everytime I load a new tape.


Steve Oakley
But it seems like I am not even able to backfocus on it wide, because I can't tell if the BF is in percise focus when I go wide. And focusing the lens does not seem to be able to resolve my subject from far way (about 10 feet).

In setting my BF, when I have the chart 3 meters away and go wde, it seems like I am only able estimate its focus, as any little movement on BF ring takes the chart way in/and out of focus.
Are there any ways that you recommend to dial in the wide end, should I move my chart closer in?

But it seems like I am not even able to backfocus on it wide, because I can't tell if the BF is in percise focus when I go wide. And focusing the lens does not seem to be able to resolve my subject from far way (about 10 feet).

In setting my BF, when I have the chart 3 meters away and go wde, it seems like I am only able estimate its focus, as any little movement on BF ring takes the chart way in/and out of focus.
Are there any ways that you recommend to dial in the wide end, should I move my chart closer in?

Bring the chart a bit closer, no closer than 2 meters should be fine with a standard type zoom lens. You have to be careful, because it is a fine adjustment and the backfocus pops in and out of focus very quickly. Having a good monitor helps.

Bring the chart a bit closer, no closer than 2 meters should be fine with a standard type zoom lens. You have to be careful, because it is a fine adjustment and the backfocus pops in and out of focus very quickly. Having a good monitor helps.

Thanks, I was trying to adjust through the Viewfinder, so maybe that is the problem.

But it seems like I am not even able to backfocus on it wide, because I can't tell if the BF is in percise focus when I go wide. And focusing the lens does not seem to be able to resolve my subject from far way (about 10 feet).

In setting my BF, when I have the chart 3 meters away and go wde, it seems like I am only able estimate its focus, as any little movement on BF ring takes the chart way in/and out of focus.
Are there any ways that you recommend to dial in the wide end, should I move my chart closer in?

This is what I experienced also.

I don't see how it possible to adjust back focus without an HD monitor.

use focus assist and the LCD. its far from ideal but it works once you get the hang of it. usually I bring a 13" sony broadcast CRT as backup. I do plan to change to a LCD soon once I find something for a few hundred that has what I need.

Steve O

I think my focus is swaying a little everytime I take the camera out.
I'm currently recording 25p SD at the moment (HDV is next), the focus assist is lit up like a christmas tree but when I view the footage back home there's a definite softness/blurryness to it.
Should you expect progressive footage to be less sharp than interlaced (25p vs 50i for example?)
I've used the chart, but was advised around 30 foot away - I'm going to do this again tomorrow but at around 2-3 metres.
I have to rely on the camera's LCD and viewfinder and don't have the luxury of a quality monitor (either field of HD monitor at home). It's often difficult to even see what's coming off the camera in bright sunlight.

It's somewhat frustrating viewing such footage on a camera capable of so much...yes, I'd like to borrow guys like Tim Dashwoods head for just one day!

I'll attempt the chart again in the meantime and see if the footage improves.
Cheers.

I just read this whole thread and didn't notice a mention to open the aperture all the way when backfocusing.

On the stock lens open all the way up to F1.4 to get the shortest DOF possible. If you are outside turn on the ND filters and increase the shutter speed if necessary. I've seen people try to backfocus at F4 and F5.6 and it is totally useless at those smaller aperture settings.

The procedure is:

Warm up the camera in the shooting environment.
Open the aperture as much as possible (F1.4) and control exposure with ND or shutter.
Set your Siemens Star at around 3 meters (10 feet) from the camera.
Zoom in all the way, set the focus (NOT the back focus) on the Siemens Star.
Zoom out all the way, set BACK FOCUS adjustment for a sharp Siemens Star.
Zoom back in and confirm focus. (If necessary, adjust lens focus and repeat.)


This should be performed before every shoot or change in environment. Temperature changes will cause the mount to expand or contract and throw off the back focus.

Backfocus is a huge issue with all HD production because of the relatively short focal plane of the CCDs combined with very high resolution. Bad focus is instantly noticable on the big screen, and proper back focus should be a priority.
The backfocus problem was so bad with the Sony F900 being used in film productions, that Clairmont created their own lens mount out of "space age" materials. More info here (http://www.clairmont.com/hot_new/f-900_camera_add_info.html).

I just read this whole thread and didn't notice a mention to open the aperture all the way when backfocusing.
Excellent post Tim. I had my suspicion about the back focus on this camera as I always seem to be adjusting it. At least I know it's not my eyes that are going.

They should print your post in the manual, just below where it says, "It is only necessary to perform this when the lens is attached for the first time". Muppets.

Yes, great advice. It can get a bit lonely out there where you're convinced it's either your equipment (new at that) failing or you're going mad. Good to know these gremlins appear for other people too.
I might try and laminate a star chard and keep this in the bag for all shoots now...don't suppose the laminate 'gloss' would effect the focus? Is it possible to pick up a plastic backed star chart (as per warm/grey cards etc)?

Yes, great advice. It can get a bit lonely out there where you're convinced it's either your equipment (new at that) failing or you're going mad. Good to know these gremlins appear for other people too.
I might try and laminate a star chard and keep this in the bag for all shoots now...don't suppose the laminate 'gloss' would effect the focus? Is it possible to pick up a plastic backed star chart (as per warm/grey cards etc)?

You can buy a made up star chart from Panavision UK at the Panastore.

http://www.panavision.co.uk/

Although, it would be cheaper to print out one and get it laminated. However, one of the Panavision charts does have an Annular Focus Target as well as the star. This uses the V/F peaking to help set the backfocus - it works extremely well on the high end HD cameras, however, I couldn't say how well it would work with the JVC's focus assist.

It could be worthwhile putting this thread up as a sticky, because I gave the method of setting the backfocus on a previous thread and I expect it will be a re-occurring question.

Thanks Brian - I'll take a look and yes there are a few recent threads with priceless advice which could do with being stickies perhaps?