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Standard 16x Fuji on HD200 doing weird stuff - what the heck?

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Michael Brown
Standard 16x Fuji on HD200 doing weird stuff - what the heck?
on Jun 27, 2009 at 9:15:22 pm

Hello all,

New guy here - been reading for a while, but this is my first post.

I've been shooting some things with an HD200 for a bit now and have been pleased with the results. I shot some footage outdoors last week and the zoom shots show something I have never seen before. Not sure if it's the camera, bad capture, or something else. It was 95 degrees out both days also. 720/60P.

Day one I had a camera guy, he did experiment with shutter speed some on a couple shots (higher). Second day I did the camera work myself as it was short notice. I left the shutter off, which should default to 1/60.

Every zoom shot from both days looks weird. The object(s) in the shot appear to change horizontal size throughout the zoom. VERY obvious that something is not right. It looks like the object or ground steps from wide to narrow with the lens. One shot is of a truck in front of a building and the truck appears to narrow in distinct steps. Others shots have a gravel roof that distinctly steps in vertical lines. What the heck is this? Crap lens? Idiot operators?

I just recorded some shots for comparison of a chair here, and of some blinds sideways to get some lines - neither exhibit this look.


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Fred Jodry
Re: Standard 16x Fuji on HD200 doing weird stuff - what the heck?
on Jun 30, 2009 at 4:12:39 pm

Obviously you have found an (anamorphic? right word?) camera lens. Here, most of the various convex and concave lenses which make it are not simple spheres but rather oval slopes to describe them within reason. Since you`re not using it fixed settings on film then varying the vertical and horizontal scans on a flying spot scanner (like a Rank telecine) or similarly a pickup tube scanner, what you`re getting is useless. Another possible problem but not necessarily the biggest one, but again, possible, is that Fuji zoom lenses are made way too small for their job causing giant pincushion and barrel distortion. Since you`re working with a camera that runs far more scan area horizontally than vertically, these distortions, simply center to edge nonlinearity, can look like vertical versus horizontal distortion. Typically, using a physically large high quality zoom, usually with more back- focal distance will reduce this distortion a lot. I also use almost nothing but Cooke "prime
lenses" myself. (And also good lenses get you away from incapable iris and zoom servos). If you need a custom quality lens, you may e- mail me. I`ll send you to my best supplier.


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Lonnie Juli
Re: Standard 16x Fuji on HD200 doing weird stuff - what the heck?
on Jul 2, 2009 at 9:22:31 pm

Or maybe it's just your capture settings.

Unless the zoom is sticking (and you'd see that in the viefinder) this sounds more like a capture or playback issue. You may want to manually zoom the lens while looking through the viewfinder to see if there are any problems with the elements shifting due to mechanical issues. Try this with the camera in different orientations to be sure that gravity isn't a factor.

How are you capturing the video and how are you playing it back? If the GOP is long or the keyframe distance is too big you may be seeing "jumps." Also, it is possible to zoom too quickly for your frame rate just as it's possible to pan too quickly.

I would also check the shutter again by engaging and disengaging the shutter. My 200B once told me the shutter was off when it was actually set to 1/2000 second. I'll never get those three minutes of my life back.

Cookes are lovely lenses but that wouldn't really be a practical solution to your current problem. Lenses do fail and require repair but I always assume that the operator (me) screwed up until I have checked all the options.

Good luck,

Lonnie


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