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Old March 26th, 2015, 06:02 PM   #1
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HM850 lens options

Hi- I'm very interested in hearing about lenses on the HM850 other than the stock fujinon 20x.
I've been using the 20x and on the one hand, I don't like the 'faux manual' servo-controlled functions, and have real problems working within the 3-stop range that's about all you get before you've closed the lens down too far, and horrible lens diffraction wrecks your picture.
But even within that, I've stopped trusting the reliability of the lens- finding some parts of the screen out of focus, or the par-focus not quite right, despite repeated back-focus set-up.
I've also been shooting with a stock 16x fujinon from a HD200. It feels a bit better to me - esp par-focus works ok. But it still has diffraction when closed down past f8 - something it never did on the HD200. Focus and exposure are a bit more hit-and-miss than I'm used to.
So I'd really like to know how other lenses work on the HM850? Is f8 the limit for everyone, with the 20x lens? Is it the limit no matter what lens you use? Does anyone else have the same sort of issues? Or am I simply too blind to see what I'm doing wrong, or too set in my ways to adapt? :) Are there any tricks to setting the camera up?
I will concede - when I run the camera on auto, the pictures seem ok. (I find them a little ... thin ... compared to the HD200, but nothing major.)
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Old March 28th, 2015, 05:23 AM   #2
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Re: HM850 lens options

Hi Rob,

I have the Fujinon 18x with 2x extender on my 700, a very high quality lens. It works and feels the same as any high end ENG lens that you'd find on a 2/3" camera. But it does suffer from soft corners at certain focal lengths, and vignetting wide open.

Allan Roberts tested the 850 for the EBU and suggests that f5.6 is the limit for these cameras to maintain a sharp image. Stopping down any further drops the resolution dramatically. It's probably the same for all 1/3" cameras.

Because my 700 only has 4 stops of ND, I have a 3 stop ND filter that I screw on the lens for shooting outside on bright sunny days. This allows me to keep my exposure in the f2.8 range which is ideal for these cameras.

As for setup, try using some Black Compress to add contrast and maybe add a little chroma saturation.
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Old April 15th, 2015, 05:55 AM   #3
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Re: HM850 lens options

Thanks Scott. I've been shooting with an HD200 and an HD100 for the last 5 years with some pleasure. So it's been a shock to find the HM850 delivering worse results. I've never encountered these exposure problems before and it's hard to adapt to shooting in a 3 stops range.
But it looks like it's a limitation of the camera, more than the lens. Will do some looking around to see if it is the same on other 1/3 chip cams. If so I cannot understand why the lenses close down to f16 or 22.
Cheers
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Old April 15th, 2015, 10:14 AM   #4
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Re: HM850 lens options

I've been looking at the 700 and the 800 series to replace my two 200's, and every time I get close to ordering, I read something like this. I really get on with the 200's, and the 100's before them, and I just assumed the 700 was better, and the 800 better still? The fact both the common lenses seem to have problems with edge sharpness, vignetting and overall softness worries me - fair enough, most of my work is in theatres so stopping down isn't something I do that often, but it's another bit of doubt?

How bad are these problems - something you notice only when you are aware, or something that really jumps out!
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Old April 15th, 2015, 10:49 AM   #5
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Re: HM850 lens options

Paul, I have a 700 and two 750s (stock lenses) at work and remain very happy with them. I've never noticed any of the problems some folks on here mention.
Here's an example of a piece I did recently. I shot it at 1280x720 30p and some at 60p so I could do the slo-mo segment.
https://www.youtube.com/watch?v=cLfB...ature=youtu.be
Be sure to set it to 720HD for viewing.
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Old April 16th, 2015, 01:47 AM   #6
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Re: HM850 lens options

Thanks for the link, that works fine for me. I wonder what is happened with the problems reported here?
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Old April 16th, 2015, 07:26 AM   #7
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Re: HM850 lens options

Paul, all I can think of is that mine are a few years newer than what's being talked about here and maybe JVC made some unreported fixes to the problem models. I've shot outdoors at f16 with full ND switched in and never had any problems. My lenses are the stock Canon 14X.
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Old April 16th, 2015, 03:39 PM   #8
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Re: HM850 lens options

The 850 is at least 2 stops faster(in extended mode) than the 100,200,700 series cameras. So it's difficult to keep the iris open under bright sunshine. Try using standard mode, minus gain and or higher shutter speeds to get the iris open, you should see an improvement in image sharpness.

Wide open to f5.6 is the range you want to stay in on these cameras. All lenses suffer from this issue, even 35mm. Just because the lens stops down to f16, doesn't mean you should ever do so.

Scott
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Old April 22nd, 2015, 01:46 AM   #9
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Re: HM850 lens options

On my 790 with HTs18 BERM lens, when I close down to f4-f8, in night shooting 3200k, the whole picture turns green and looses contrast. Does this on all the cameras at my station. On a vectorscope, the center blob just starts wandering down towards the green vector....annoying. You can see this in the day in bright sunlight as well. I try to shoot WIDE OPEN in daylight, pushing the shutter, because it just looks richer, deeper blacks, prettier.

Paul
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Old May 16th, 2015, 02:36 AM   #10
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Re: HM850 lens options

Thanks for the replies. I do think the 800 series made a leap towards auto ... and I continue to fight the camera.
Skin detail is very soft - I'll focus on eyes, and they stay sharp, but faces soften.
I'm not used to opening the iris right up - with the stock lens on the HD200 it didn't love that. It loved 5.6 ... but was fine 2 stops either side, and acceptable through the whole range of the iris (until just before it started closing down.)
I also find the 800 much harder to get good exposure - it likes a brighter picture, and turns to mud (and this horrible softness) when you close it down a bit.
I know it sounds a bit dumb, but I'm often too busy concentrating on sound levels, focuis and exposure, what's happening and what might happen next to notice the exact f-stop in the viewfinder and flick ND in and out or change the shutter speed. And it keeps getting me into trouble - horrible muddy softness.
Also: the menu buttons are easy to hit mistakenly - as is the shutter speed- had that one just yesterday.
Some of this is teething trouble. But I just can't see the point of a camera/lens combo that chops 3 stops off the top. On my cam f11, f16 and f22 are horrible. I've never seen this before and I don't like it one bit!
(On a positive note, it's making me really appreciate my GH1s- if double system sound wasn't so slow and painful, I'd use them for everything!)
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