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Vantage Hawk V-Series parallelogram problem

Xiaosu Han
 

Dear colleagues, 

we are currently experiencing a problem with a set of Hawk V-Series from Vantage:


The lines are all skewed to one side. The electronic level of the Alexa Mini we are using is dead center, as is the level on the tripod head.

When playing around with the lens with an open PL mount, one can move those lines, like in a parallelogram. When the PL mount is locked, nothing moves.

As said, we are using those lenses on the Alexa Mini in 4:3 mode, and are experiencing the same skewing on the 40mm, 50mm, 75mm and 100mm. (when the head is slightly tilted off-level, all the lenses are straight.)

We ran out of time yesterday and will test more today, including changing the camera body to an Alexa XT, because we've tested the lenses on an XT before and didn't experience similar issues (although at a different location.)

I will update with additional findings, but would hope for any similar experiences.

all the best
-- 
Xiaosu "Xax" Han - cinematographer - vienna, austria
phone: +43 699 11 68 7722

Ignacio Aguilar
 

Hello:

I have experienced the same thing in the past with poorly or non-serviced anamorphics. 

The problem was a misaligment of the front anamorphic element with the rear elements or prime lens, which was fixed by a lens technician. 

In my case it wasn't related to the lens mount of the camera, but if you're experiencing this effect with all lenses in the set, the camera may be faulty as well.

Ignacio Aguilar
Cinematographer / Madrid, Spain

El 30 ene 2018, a las 10:11, Xiaosu Han <busrabauer@...> escribió:

Dear colleagues, 

we are currently experiencing a problem with a set of Hawk V-Series from Vantage:


The lines are all skewed to one side. 

Mike Sippel
 

Sounds like one of the cylinder elements is out of rotational alignment.  If so, there’s very likely nothing you can do to fix it in the field.  The lens should be looked at by a Hawk-qualified optics tech.

 

Mike Sippel

Senior Field Support Technician

Arri Rental

Atlanta, GA, USA

 

Mike Sippel

Senior Field Support Technician

 

ARRI Rental
3980 Dekalb Technology Pkwy #800
Atlanta, GA 30340
Phone: (678) 248-5432
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Po
 

Hello,

Would you check is there any play from the guide pin on the PL of the camera side (around 2 o’clock position) ? or the the pin getting too shallow and not able hold the slot on the lens mount.

Cheers,
Po

On 30 Jan 2018, at 5:11 PM, Xiaosu Han <busrabauer@...> wrote:

Dear colleagues, 

we are currently experiencing a problem with a set of Hawk V-Series from Vantage:


The lines are all skewed to one side. The electronic level of the Alexa Mini we are using is dead center, as is the level on the tripod head.

When playing around with the lens with an open PL mount, one can move those lines, like in a parallelogram. When the PL mount is locked, nothing moves.

As said, we are using those lenses on the Alexa Mini in 4:3 mode, and are experiencing the same skewing on the 40mm, 50mm, 75mm and 100mm. (when the head is slightly tilted off-level, all the lenses are straight.)

We ran out of time yesterday and will test more today, including changing the camera body to an Alexa XT, because we've tested the lenses on an XT before and didn't experience similar issues (although at a different location.)

I will update with additional findings, but would hope for any similar experiences.

all the best
-- 
Xiaosu "Xax" Han - cinematographer - vienna, austria
phone: +43 699 11 68 7722

Xiaosu Han
 

Thanks so much for the answers so far.

We've managed to pinpoint the problem,

there is quite the play between the point where the lens is mounted (pin inside the Alexa is fixed, we've fastened it again, and it's definitely long enough)

Here are two videos showing the mechanical play and the result in the picture...


Looks like either we have to deal with that due to the optics being that vintage or we'll have to have them overhauled completely?

thanks again,

all the best

-- 
Xiaosu "Xax" Han - cinematographer - vienna, austria

Po
 

Good to know you locate the possible cause of the issue. There are few things you could look deeper for the causes and have better communication with rental house.

1/ The slot of the lens mount got widen due to wear.

2/ The guide pin on the camera side wear out from time to time when the lens mount hit on the pin during lens change. Usually happen this way if all your lens experience the same.

3/ the lock ring of the PL mount on camera isn't push the flange of the lens mount tight enough.

Hope this help

Cheers,
Po

Stephen Gelb
 

all possible issues. hard to believe its the pin or the mount.  arri stuff is very precise and it would be a lot of wear and tear to break steel down. 

Sent from my iPhone

On Jan 30, 2018, at 7:42 AM, Po <8888po@...> wrote:

Good to know you locate the possible cause of the issue. There are few things you could look deeper for the causes and have better communication with rental house.

1/ The slot of the lens mount got widen due to wear.

2/ The guide pin on the camera side wear out from time to time when the lens mount hit on the pin during lens change. Usually happen this way if all your lens experience the same.

3/ the lock ring of the PL mount on camera isn't push the flange of the lens mount tight enough.

Hope this help

Cheers,
Po

Steve Oakley
 

Have you gone thru tightening the fasteners in both camera and  lens mounts ? I've had this happen when flying gear. I’ve also seen this with lens adapters. 


Steve Oakley
DP / Editor / Colorist / VFX Artist
Madison & Milwaukee WI
920 544 2230


On Jan 30, 2018, at 9:42 AM, Po <8888po@...> wrote:

Good to know you locate the possible cause of the issue. There are few things you could look deeper for the causes and have better communication with rental house.

1/ The slot of the lens mount got widen due to wear.

2/ The guide pin on the camera side wear out from time to time when the lens mount hit on the pin during lens change. Usually happen this way if all your lens experience the same.

3/ the lock ring of the PL mount on camera isn't push the flange of the lens mount tight enough.

Hope this help

Cheers,
Po
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Xiaosu Han
 

Thanks everybody for chiming in,

we've decided to go with another set of lenses because we're starting the feature next week and can't risk a not completely trustworthy set of lenses.

We've tried to fasten everything on lens and camera and it has been better with a different, more sturdy lens support, but not good enough to trust them on a 6 week feature.

all the best,

--
Xiaosu "Xax" Han - cinematographer, vienna
phone: +43 699 11 68 7722