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-   -   Focus ring has no effect when zoomed out (https://www.dvinfo.net/forum/sony-xdcam-ex-pro-handhelds/467292-focus-ring-has-no-effect-when-zoomed-out.html)

Kyle Powers November 7th, 2009 02:25 PM

Focus ring has no effect when zoomed out
 
Sorry for the the repost on the same issue.

This is my first serious camcorder (EX3) so I'm not sure what the expect performance wise. My issue is that unless I am more than 25% zoomed in the focus ring has no impact on focus. ( can't take subject in and out of focus)One of my tests has my subject 36" away (wine bottle). At 25% zoomed in turning the focus ring results in barely perceptible changes in focus. It is only until I am more than 50-60% zoomed in does the focus ring seem to have any significant effect. Just to make sure I am not just being completely stupid here I went down to a local video store and tested a Pano PD170 and found that I could take a subject in and out of focus easily when zoomed fully out. I also tested a sony Z7 the focus ring was less effective when zoomed fully out but I was still able to take my subject in and out of focus.

Everything is in full manual (ring, switch,) macro and focus assist off and full auto button not activated. I took it to the Sony service station. They kept it for a month and told me they were going to replace the lense. When I got it back the focus issue was he same as before. At this point I'm not sure they did in fact change out the lense. They also mangaged to scratch the hell out of the underside of my camera but that's another discussion :(

Another Sony tech told me over the phone that I should be able to take a subject in and out of focus when fully zoomed out. For my test I was focussing on the 26 or so pt font on the wine bottle label at 36". for my test I had my cam connected via component to my 52" flat screen. Regarless of how far away my subject is the focus ring has no perceptible effect unless zoomed in at least 25%.

I have run the back focus adjust multiple times. It appears that when the FB adjust gets to the point where the lense is fully zoomed out it does go from out of focus to in focus on my test pattern.

I put it in full auto and when zoomed fully out it doesn't really look in focus. Of course its hard to tell as the focus ring has no effect. Are you folks able to take a subject in and out of focus fully zoomed out?

Sorry for the long post but I am unsure if my Camera has an issue or this is normal behavior for the EX3.

Leonard Levy November 7th, 2009 02:54 PM

Its hard to eveluate the problem from a distance.

Is your f stop wide open? That will make your depth of field lower. You can raise the shutter speed to open your iris if neccessary.

Its often hard to see focus changes at wide angle and it should be much more obvious as you zoom in. A 52" monitor should help a great deal although if you are using an SD video-out from the EX that would compromise your resolution. But it also sounds like you've been comparing it to other cameras so its weird that the EX is worse. A PD 150 should have more depth of field unless it has a lower f stop.

At 3' away you should see some loss of focus but it won't be dramatic at wide angle, just slightly softer.
Also try focusing on distant trees - something very far away. That should be best at infinity and worse when you are at 3' or so. If the infinity point becomes sharper when you focus closer then your back focus is off. But it will be nearly impossible to see this in just the viewfinder. Also try using your viewfinder peaking to help you see whether there is any focus change though that may not be too helpful at wide angle.

If you are still unsure try to get together with someone else who owns an EX-1 and put them side by side.

Hope this helps.

Graham King November 7th, 2009 03:49 PM

Quote:

Originally Posted by Kyle Powers (Post 1444023)
Another Sony tech told me over the phone that I should be able to take a subject in and out of focus when fully zoomed out.

They don't know what the hell they're taking about half (90%) the time. I could be wrong but it doesn't sound like anything is wrong with your camera.

1/2" chips = wide depth of field

Get a Red camera if you want to throw stuff out of focus.

Steve Phillipps November 7th, 2009 03:52 PM

Does sound like a lens fault to me, even taking into account the large depth of field of a half inch sensor.
I've an EX3 here at the moment and the standard lens has an issue too, when zoomed in about halfway or more it won't focus beyond a few feet, but is OK when wide. I have the wide angle lens and that's fine. It seems to me it's a fault with the pins that communicate between lens and camera, I don't think they're hooking up properly, maybe it's the same with you lens. One thing to remember, and something I didn't know to begin with, is that even though the focus ring is nice, smooth and has a positive feel like a "proper" lens, it is in fact just servos controlling the mechanism, so they do need to "talk" to the camera, unlike pro broadcast lenses which have mechanical focus mechanisms.
Steve

Steve Phillipps November 7th, 2009 03:59 PM

Just tried it with the camera I have here. When wide open (f1.9) and at widest angle on the standard lens a printed sheet at 3' goes noticeably out of focus when going from 3' to infinity and back, even just in the viewfinder. It's definitely a lot less nitceable at f4 or more.
Steve

Olof Ekbergh November 7th, 2009 04:07 PM

The EX3 has a pretty wide lens so if you are not monitoring on a HD monitor it will be hard to tell if it is out of focus especially if you stop down to f8 or so.

The only way to really find out is a proper HD monitor. Or transfer the footage to a computer and view at full res.

Make sure iris is wide open for these tests set iris, gain and shutter speed manually. And make triple sure you are in manual mode.

Also does your lens hold focus zoomed all the way in when panning camera to different objects at different distances? If not you are not in full manual or the camera is malfunctioning by not staying in full manual.

Steve Phillipps November 7th, 2009 04:46 PM

As an alternative to using an HD monitor, you can also crank the peaking on the viewfinder right up to accentuate differences in focus.
But as I said, I saw a very obvious difference in the VF when the lens was wide open.
Steve

Kyle Powers November 7th, 2009 06:37 PM

Quote:

Originally Posted by Steve Phillipps (Post 1444040)
Just tried it with the camera I have here. When wide open (f1.9) and at widest angle on the standard lens a printed sheet at 3' goes noticeably out of focus when going from 3' to infinity and back, even just in the viewfinder. It's definitely a lot less nitceable at f4 or more.
Steve

Thanks for checking on this Steve,

With my test I am wide open on the Iris, 3' from my printed sheet, fully zoomed out, everything manual and when I turn the focus ring it has not apparent effect on focus, IE can't take in and out of focus.

Are you able to take the printed sheet in and out of focus by turning the focus ring from 3' away fully zoomed out?

Warren Kawamoto November 7th, 2009 09:43 PM

Kyle,
I just tried the focusing test at 3' and found that focus doesn't change much, but I'm sure nothing is wrong. Depth of field is pretty deep at lens' widest setting.

To get your image out of focus at widest zoom setting, do this:
1. Push your focus ring forward. (turn off full manual)
2. Turn on macro switch.
3. Turn your focus ring as if you're trying to focus on something an inch away from your front element. (In fact, this is exactly what you're doing) and you'll see your image go blurry.

The reason why you saw the PD170 go blurry is because when you keep turning the focus closer and closer, it goes into macro focus.

Let me know if this works for you. You should be able to rack focus at wideangle now.

Steve Phillipps November 8th, 2009 04:02 AM

Quote:

Originally Posted by Kyle Powers (Post 1444078)
Are you able to take the printed sheet in and out of focus by turning the focus ring from 3' away fully zoomed out?

Yes, with the iris fully open it's quite noticeable.
Steve

Steve Phillipps November 8th, 2009 04:09 AM

Although according to a depth of field calculator i just checked it shows that infinity focus at 5.5mm f1.9 will give dof down to abot 3.8ft, so it's true that it shouldn't throw it out too much.
Steve

Duncan Craig November 8th, 2009 11:07 AM

Warren has the best advice. What you also want to do is leave the iris full open. Use NDs and some gain if you have to.

Then switch on the 'lens info'.

Now with the lens out of Manual, but with auto focus off, and macro on when you rack the focus you'll see the depth of field display moving around.

Kyle Powers November 8th, 2009 12:42 PM

Quote:

Originally Posted by Steve Phillipps (Post 1444172)
Yes, with the iris fully open it's quite noticeable.
Steve

Thanks for helping me out Steve.

So when you place your ex3 36" away from a printed sheet, everything full manual, iris wide open you are able to take the printed sheet in and out of focus right?

When I try this test I can't. Turning the focus ring has no apparent effect.

Quote:

Originally Posted by Warren Kawamoto (Post 1444114)
Kyle,
I just tried the focusing test at 3' and found that focus doesn't change much, but I'm sure nothing is wrong. Depth of field is pretty deep at lens' widest setting.

To get your image out of focus at widest zoom setting, do this:
1. Push your focus ring forward. (turn off full manual)
2. Turn on macro switch.
3. Turn your focus ring as if you're trying to focus on something an inch away from your front element. (In fact, this is exactly what you're doing) and you'll see your image go blurry.

The reason why you saw the PD170 go blurry is because when you keep turning the focus closer and closer, it goes into macro focus.

Let me know if this works for you. You should be able to rack focus at wideangle now.



As far as pushing the ring forward and turning on Macro I have been getting inconsistant behavior. During two of my tests when I did this I could take a subject at close range out of focus for a brief moment before it would auto focus but 2 other times I did this same test same conditions I could not take the subject out of focus.

I understand the the focus ring is motor driven even when in manual. Given the behavior I am seeing I am wondering if there is a problem with electronics. Thoughts?

Have any of you guys had experiences with the Sony service station technitions. They told me they replaced the lense and fully tested the unit before they gave it back to me.

Thanks for all you help you guys.

Warren Kawamoto November 8th, 2009 06:18 PM

It sounds like your auto focus switch is on "auto" instead of "manual." Put the switch in "manual" position and try it again. This is in addition to the other steps I've detailed above.

Kyle Powers November 8th, 2009 07:32 PM

Thanks for you help Warren.

Ya I must have had auto focus enabled for your test. I tried it again with the ring pushed forward and macro enabled and I was able to take my subject in and out of focus from 1" to 36" away.

So what does this all mean? Is it normal that when in full manual that I can't take a subject in and out of focus zoomed out with the EX3?

I just want to make sure there is nothing wrong with my camera.

With a subject that is say 5 to 7' away do you use the zoom all the way in to focus and then zoom back out to frame things up technique.


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