DV Info Net

DV Info Net (https://www.dvinfo.net/forum/)
-   JVC GY-HM 800 / 700 / 600 Series Camera Systems (https://www.dvinfo.net/forum/jvc-gy-hm-800-700-600-series-camera-systems/)
-   -   New lens (https://www.dvinfo.net/forum/jvc-gy-hm-800-700-600-series-camera-systems/525854-new-lens.html)

Mike Bailey February 25th, 2015 08:44 PM

Re: New lens
 
I was having some of the same issues with the two 850's we have. It first appeared to us as a back focus issue, but oddly seemed to show soft areas, on the same plane as in focused areas.

JVC assured me that it was a back focus issue and to do the back focus with the iris all the way open. So far so good. I haven't seen the "soft' stuff but believe me, I'm still not sold--sad because i do like the new camera as compared to the 750's we have--but the 750's were always true.

Rob Stowell February 27th, 2015 02:09 AM

Re: New lens
 
When you go into the weird electronic backfocus process, I think the iris says wide open all the time regardless. I've done it often enough now :)
The one-push auto focus is quite good, but shooting in bright sun (and shade) today, it's not an easy combination lens and camera - unless you prefer auto settings. Not enough f-stops in the iris for me; and I find the veiwfinder and LCD both harder to read than the HD200 (the info font on the HD cams was blockier and the constrast seemed better.)
Disappointing.
The pics are pretty good though :)

Calvin Bellows March 26th, 2015 10:31 PM

Re: New lens
 
UPDATE: I've been trying the 20x lens on my 700 and couldn't get a sharp picture. The detail seemed to drop of no matter how many times we went through the back focus. I even had engineers from CBC look at it and hook it up to some very expensive monitors and they had no answers for me. I sent the lens back to JVC and am waiting for the 17x fuji lens with the actual back focus and macro control.

Paul Anderegg March 27th, 2015 01:06 AM

Re: New lens
 
I can tel you these cameras have very large variations in back-focus from unit to unit. I am on a spare camera since my stations 790 had an SDI failure. When the lens was swapped, it required about 2,mm of rotation to bring the back-focus into correct position!

Paul

Rob Stowell April 15th, 2015 05:04 AM

Re: New lens
 
If I had the budget I'd get another lens. I find the stock 20x pretty useless.
Actually if I had the choice again I'd get another camera. Still love the form factor but not much else :(
Maybe I'll learn to like it ...

Paul Anderegg December 4th, 2015 08:04 PM

Re: New lens
 
Been using an expensive HTs18x4.2BERM Fujinon for over month now on my new issue HM890, and the performance is terrible. The entire left 1/4-1/5th of the screen seemed to focus much closer than the other side of the shot, creating a very blurred left edge. It is very ugly, and ver apparent. I only know it is imaging closer because when something CLOSER is on that left edge, it is in sharp focus. This problem was also exactly the same on a JVC loaner HM890 that we put a similar HTs18x4.2BERM onto. Worth mentioning that i saw this EXACT left blur issue on a Panasonic HPX600, and it was only correctable by putting a CAC capable lens onto it, and activating CAC.

Also worth mentioning, irising down to f2.0-f2.8 reduces and eliminates the slight vertical smear apparent on the HM890 sensors when shooting at night.

Craig, please urge your tech guys to allow CAC on existing $13,000 Fujinon 1/3" ENG lenses......pretty please. :-)

Paul

Scott Berrington December 5th, 2015 06:31 AM

Re: New lens
 
I have the Fujinon HTs18x4.2BERM on my 700, and I've noticed the edge softness as well. With my lens it seems to be on both sides of the frame, and it varies with focal length and focus distance. It seems to be really bad around the 20-40mm range, with focus distances over 30ft. Hardly noticeable zoom out or at shorter focus distances.

I can only guess that this issue is caused by lens field curvature. If I set the focus to infinity, it tends to sharpen the edges up. The trick is to keep the centre of the frame in focus:(

I was very disappointed when I first noticed this issue, a $12,000 lens should not perform this way. So now I just have to be very mindful of limitations...using the focus assist really helps.

I hope the 20x works better, at least when it comes to edge to edge sharpness.

Scott

Paul Anderegg December 7th, 2015 07:12 PM

Re: New lens
 
The HTs18 is just a $10,000 HAs18 2/3" with a 1/3" compatible rear element, but it performs so poorly on these cameras.

Paul

Craig Yanagi January 25th, 2016 03:36 PM

Re: New lens
 
The 2.0 firmware upgrade will enable the GY-HM850 and GY-HM890 to engage the CAC function in the latest versions of the following Fujinon ENG lenses: HTs18X4.2BERM, HTs18X4.2BRM, XT17sx45BRMK3, XT20sx47BRM. The firmware can be downloaded free of charge at the following JVC web site: JVC Pro Software/Firmware Downloads

Please note that in order for the CAC to engage the lens must have the capability to do so, used in combination with the 2.0 firmware in the GY-HM850 and GY-HM890. CAC is also enabled for the 20x AF lens which ships with the camcorders.

I hope this is of help to you all.

- Craig


All times are GMT -6. The time now is 08:45 PM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2024 The Digital Video Information Network