View Full Version : I can only assume this camera has no auto focus?
James Darren March 27th, 2005, 09:47 PM Hi all,
probably 80% of the time I use manual focus but when I use my cameras in water housing I have them on auto focus...
can I only assume the JVC has no AF due to it being a shoulder camera?
Nate Weaver March 27th, 2005, 09:53 PM I'd assume no AF because I've never seen a removable video lens that had it.
BUT...since you'd have to get a water housing for this camera custom made anyway, I doubt a custom made housing that size would be THAT more expensive with a focus link.
Like the difference between 5K and 6K?
Barry Green March 27th, 2005, 11:30 PM Some of the XL series interchangeable lenses include autofocus... but no indication yet as to whether the JVC camera will include similar features.
Chris Hurd March 28th, 2005, 05:03 AM Barry is right about the Canon white XL-series automatic lenses having autofocus, but I think Nate was referring to the traditional broadcast video lens category -- the standard ENG / EFP style lenses for professional shoulder-mount cameras, which is what the HD100 is using. There are some lenses of this type which include autofocus, but they're pretty expensive. There's also an add-on optical image stabilizer (http://www.usa.canon.com/html/industrial_bctv/is20bii.html) but it's fairly pricey too.
See Fujinon broadcast video lenses (http://www.fujinonbroadcast.com/).
See also Canon U.S.A’s Broadcast and Communications website (http://www.usa.canon.com/html/industrial_bctv/index.html), although to my knowledge Canon does not currently offer a 1/3rd-inch HD lens.
Barry Green March 28th, 2005, 11:45 AM Agreed. All I was saying was that just because a lens is removable, doesn't necessarily mean that you can't have autofocus. The lens and the camera would both need to be designed to support such a feature, but it can be done (and obviously, autofocus would never be possible using standard ENG lenses that don't have autofocus circuitry in them). But if JVC is having new lenses built (and with a 1/3" mount, it'd almost be mandatory to have new lenses built) then the possibility exists that they *could* design autofocus. Whether they will or not, or whether some other technilogical limitation prevents them from being able to do so, remains to be seen.
Michael Maier April 7th, 2005, 05:01 PM I don't think it will have auto focus, but again, who needs it?
Aaron Koolen April 7th, 2005, 05:16 PM <<<-- Originally posted by Michael Maier : I don't think it will have auto focus, but again, who needs it? -->>>
Well run and gun is one area. When you need a quick setup, hit a button and wham, focussed.
Aaron
Barry Green April 7th, 2005, 06:28 PM Yes, autofocus can be very handy. Relying on it in a dramatic/narrative production is foolish, but there are times when it can be useful. And, as always, better to have the option and not use it, than to need it and not have it. And focusing with HD cameras is a lot more crucial than it is on an SD camera, so it'd be nice to have the option of autofocus.
Ben Buie April 10th, 2005, 10:27 AM Unless I'm going crazy, nearly every preview/review of the camera that I've read mentions autofocus, at least with the default lens.
Ben
Nate Weaver April 10th, 2005, 10:41 AM <<<-- Originally posted by Ben Buie : Unless I'm going crazy, nearly every preview/review of the camera that I've read mentions autofocus, at least with the default lens.
Ben -->>>
You might have to back that up with a quote...I've been following things very closely and can't remember ever seeing the word.
Ben Buie April 10th, 2005, 03:37 PM <<<-- Originally posted by Nate Weaver : <<<-- Originally posted by Ben Buie : Unless I'm going crazy, nearly every preview/review of the camera that I've read mentions autofocus, at least with the default lens.
Ben -->>>
You might have to back that up with a quote...I've been following things very closely and can't remember ever seeing the word. -->>>
Maybe you are right, I just re-read a preview in DV Mag, and here is their quote:
"You probably noticed the lens first -- that's a custom-designed 16x Fujinon lens, and it's removable. The lens has automatic and manual iris control, servo zoom, mechanical focus, and backfocus adjustment."
Maybe I was thinking of automatic iris control . . . excuse my ignorance, but couldn't you have automatic focus if you have automatic iris control? I might be showing my lack of knowledge about professional lenses here :)
Ben
Nate Weaver April 10th, 2005, 10:03 PM Maybe I was thinking of automatic iris control . . . excuse my ignorance, but couldn't you have automatic focus if you have automatic iris control? I might be showing my lack of knowledge about professional lenses here :)
Ben -->>>
It's just more an issue of what's been done in the past. Very few pro lenses in that style have ever had AF...I know I've never seen a single one, and I've been shooting for a while.
David Gomez April 20th, 2005, 09:27 AM I read somewhere that interchangeable lenses sometimes do not have auto focus.
Glen Vandermolen April 20th, 2005, 10:14 AM Why would you want it?
Jiri Bakala April 20th, 2005, 10:16 AM Exactly! The same, BTW, goes for the rocker zoom on the handle. You are getting REAL lens here!
John Sandel April 20th, 2005, 10:48 AM To answer your implicit question, David: it's true, some interchangeable lenses for DV cams are manual focus.
We're all keeping our eyes on the NAB posts, esp. in this HD100 forum, to learn about the lens options. So far, two zooms have been demoed at the convention for this cam; if I recall right, both are manual focus.
That's not to say JVC won't market an AF lens for the HD100, nor that some other maker's AF lens won't be adaptable. But nobody really knows yet.
Glen Vandermolen April 20th, 2005, 11:43 AM I also have been shooting broadcast cameras for many years - decades, even. I have worked with Canon, Fujinon, Angenieux lenses...I have never come across an auto-focus broadcast-style lens. I've never worked with autofocus until I played with consumer cameras. Personally, I hate the feature and turn it off whenever I have to use a consumer cam.
I guess that is why I do not understand why some are wondering about this feature. I find it intrusive and unnecessary. I understand run-and-gun shooting. I was a TV photojournalist for 10 years. I've also shot many sports and documentary programs. I did a lot of focusing on the go. You did it by either focusing to infinity (if the scene were far enough away) or used a best-guess and focused by the numbers scale on the lens. Now, with HD the focus will be more critical. Still, I prefer to go by my instincts and/or the numbers scale on a good lens. I prefer to have full control of the lens, be it focus, iris or zoom. I always shoot in manual iris -always. This is why I prefer the JVC to the Panasonic and Sony. It has features a broadcast veteran would love. It seems so much more like a "real" camera to me.
This, by the way, has nothing to do with the original post about underwater housings. I have very limited knowledge on that subject. I can see where focusing could be a problem, though.
Jiri Bakala April 20th, 2005, 11:48 AM Thank you, Glen, well put.
Tim Le April 20th, 2005, 11:59 AM This is just my guess, but I'm 99.9% certain this camera WILL NOT have auto focus. The camera uses standard broadcast style lenses, 99% of which are manual focus only. The remaining 1% are specialty lenses such as this one by Fujinon:
http://www.fujinon.co.jp/en/news/n_040419_2.htm
Prosumer DV cameras like the XL1 and XL2 achieve autofocus by TTL-video signal detection within the camera head. So AF sensor and circuitry is within the camera, not the lens. But broadcast cameras do not have any autofocus system built inside them. This JVC is the same way.
Further evidence is the system chart for the HD100, which only list standard manual focus broadcast lenses:
http://www.jvc-victor.co.jp/english/pro/prohd/gy-hd100/sys.html
Ben Buie April 20th, 2005, 12:03 PM FYI, it has been confirmed, no auto-focus.
There is a direct quote from JVC's new HD100 web page that describes the "Full Auto" button. It basically says it is auto for everything except focus. Guess that answers that question.
I agree, it isn't needed for anyone used to shooting with a pro broadcast shoulder-mount cam.
Ben
David Gomez April 20th, 2005, 12:36 PM On some cameras I have used, when filming concerts from a distance, connected to the sound board in the middle of the hall, and I zoom out and back in, I often find I lose the focus when in manual, so I use the AF and the auto focus quickly adjusts itself. Maybe I was doing something wrong, not sure it that's supposed to happen. To me, having to deal with keeping iris at a good level for the changing stage light, and the camera steady on an ever moving lead singer, guitarist, etc, and controlling the zoom, I normally would leave the focus on auto. But I am confused as to why zooming, the camera would lose its focus in manual mode. Any explanation for this? Is that supposed to happen. BTW, none of my cameras used interchangeable lenses, often a vx2000 was used. Would losing focus be a problem with zooming on a system like the HD100?
Dominic Jones April 20th, 2005, 12:45 PM Well, I guess there are two possible options for that.
The obvious one is that you've knocked the focus ring as you zoom (assuming you're using the zoom ring rather than the rocker) - but I'd guess you've thought of that!
The more likely option is that you're setting focus on the wrong end of the zoom - were you zooming in to the tightest you could and then setting focus, or setting focus at a wide setting and then zooming in?
The correct way to set focus is to zoom right in tight and then focus before zooming back out to the shot you want. This should guarantee perfect focus. Also, this method means that focus is set well for the shortest DOF you will be getting - as the lens's focal length becomes shorter (when you widen the shot) the DOF will *increase*, assuring you a focus that is still spot on. If you approach the problem the other way, not only is it hard to set accurate focus as the subject (and detail thereof) will be very small in frame, but as you zoom in you shorten your DOF and the subject may then drift out of acceptable focus...
Other than that, I can't think how/why you should have any problems, unless the subject is moving radically nearer or farther from your camera - in which case they may just have stepped out of the split.
Heath McKnight April 20th, 2005, 12:47 PM I've done live concert stuff for jumbo vision with a betacam and never had problems with focus.
heath
Jiri Bakala April 20th, 2005, 01:35 PM That's the difference between pro cameras (betacam-type) and prosumer (i.e. VX2000, XL-1, etc.). In other words, if there is a REAL lens and if its backfocus is set properly, you won't have problems loosing focus when zooming back and forth. That's why it is so exciting to get a real lens on a $6k camera.
Glen Vandermolen April 20th, 2005, 08:34 PM On some cameras I have used, when filming concerts from a distance, connected to the sound board in the middle of the hall, and I zoom out and back in, I often find I lose the focus when in manual, so I use the AF and the auto focus quickly adjusts itself. Maybe I was doing something wrong, not sure it that's supposed to happen.
But I am confused as to why zooming, the camera would lose its focus in manual mode. Any explanation for this? Is that supposed to happen. BTW, none of my cameras used interchangeable lenses, often a vx2000 was used. Would losing focus be a problem with zooming on a system like the HD100?
In a broadcast camera, that sounds like a back-focus problem. This is easily corrected in the field (yet another reason to choose the JVC HD100), but I do not know how to correct such a condition in a non-interchangable lens.
Dave Ferdinand April 20th, 2005, 08:42 PM Prosumer cameras have auto-focus because they have to...
Pro Broadcast cameras have high resolution viewfinders that make it easy to achieve focus. Also most prosumer cameras have no focus markings for one to guide himself by.
If this camera doesn't have an excellent viewfinder and markings, no auto-focus might turn out to be a real pain.
Glen Vandermolen April 20th, 2005, 09:05 PM If this camera doesn't have an excellent viewfinder and markings, no auto-focus might turn out to be a real pain.[/QUOTE]
This camera (the HD100) does have an excellent viewfinder - 2, actually - and true focus markings. In my humble opinion, no auto focus is necessary. If it did have auto focus, I'd turn the damn thing off.
Nate Weaver April 20th, 2005, 09:23 PM Focus is a breeze on the HD100 because of the viewfinder peaking. The "focus assist" function is yet another type of peaking, just on steroids.
If you don't know what I'm talking about quite yet, trust me. Few will want autofocus after learning how easy critical focus is on a display with peaking.
Joe Hudson April 25th, 2005, 07:02 PM many SLR 35mm lenses are autofocus right? when someone releases a 35mm lens adaptor for say canon SLR lenses will that autofocus be any use? (sorry if that's a dumb question)
Barry Green April 25th, 2005, 07:14 PM Few will want autofocus after learning how easy critical focus is on a display with peaking.
Especially when peaking is implemented as well as it is on the HD100. You've got an analog dial that lets you choose from "mild" to "wild". Very nice.
Don Crockett April 25th, 2005, 08:28 PM many SLR 35mm lenses are autofocus right? when someone releases a 35mm lens adaptor for say canon SLR lenses will that autofocus be any use? (sorry if that's a dumb question)
It'll be of no use. Auto-focus lenses rely on the camera body to control the focus. For example, with the EOS adapter on Canon's XL camcorders, the auto focus is disabled even if you attach a Canon SLR lens.
Greg Boston April 25th, 2005, 10:27 PM Especially when peaking is implemented as well as it is on the HD100. You've got an analog dial that lets you choose from "mild" to "wild". Very nice.
Yes Barry, that was definitely a different experience playing with the JVC's focus assist feature. I started to feel like it was 'predator vision' hehe.
-gb-
David Slingerland April 26th, 2005, 02:55 AM "It's just more an issue of what's been done in the past. Very few pro lenses in that style have ever had AF...I know I've never seen a single one, and I've been shooting for a while."
As a matter of fact fujinon have developed together with JVC professional lenses for HD broadcast. These lenses have an auto-focus option. They have been specially developed for the japanese market where HD transmissions are a fact. The reason being that HD focus is so critical that the operators could not always see on their viewfinders and monitors whether they were completely in focus. But when viewed on large HD screens one could clearly see that focus was a little off. The developers where thinking of sport registration. (the lenses where on view at the IBC in Amsterdam.) they are 2/3 inch EFP and ENG lenses. I have tried them and they are really amazing as they work different then tradional autofocus systems where the system will continually search for focus. The new system however was able to find focus and leave it at that. It could be used semi automatic so the operator can override autofocus when needed.
It is the final step........
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