focus shift during a zoom ! HVX202

Shooter

Shooter

Veteran
Has anyone experienced any focus shift during a zoom.

I was shooting a packshot yesterday and noticed a distinct into focus/ out of focus/ back into focus shift during a zoom.

The object was toothpaste tube sized placed at near minimum focusing distance , shot at F4.0 (with ND) 25 fps PAL . The zoom was from full in to full out and the focus shift occured at about 1/3rd way through the zoom.

I wil have a tech look at the lens but any feed back (or tests) would be appreciated to establish if this is an inherent lens design issue.
 
Have you definately got your autofocus set to off? I ask as I had switched the button near the lens for focus to manual, but because the auto mode switch was still engaged [the switch for all autofocus and autoexposure below the fold out colour viewfinder, last switch near the back] it was always being over ridden.

Hope that helps,

MajorMorgan
 
I have had what at first looked like a focus shift during a slow zoom from a tripod. Upon closer review it was yet another anomaly revolving around the Image stabalizer. Make sure that when you are static, and especially if you are doing a creep or slow pan to make sure that the Image Stabalizer is OFF. In fact Ive tried to ONLY use it when when absolutely neccessary.
 
The auto focus was off ...but in fact if it had of been on, it should have maintained the focus because the object was centred and well defined for an auto focus operation.

The OIS was off as is my practise on a tripod.
 
You do realize that the minimum focus distance changes from wideangle to telephoto?

Also if the focus mechanism was set close to macro, it actually starts to move the CCD imager backwards and you cannot hold focus when zooming.
 
Anders Holck said:
You do realize that the minimum focus distance changes from wideangle to telephoto?

Also if the focus mechanism was set close to macro, it actually starts to move the CCD imager backwards and you cannot hold focus when zooming.
Click to expand...

If you are correct...it looks like I discovered that for myself but I was not in a range from the subject that I would consider macro. eg 2.6 ft approx.

We had set up toapprox minimum focus on the zoom in position. Durfing the pull back the focus shifted out (for a short transitory period) and then back in .


Sorry John - no time to output the shot at the moment. Deadline looming.
 
Are you zooming manually or with the servo? I find that the servo zoom blurs the picture a bit during operation do to some form of motor vibration. Could that be what you're seeing?
 
I've had the same issue since I got my DVX (when it was first released), but I don't notice it during servo or slow zooms just during manual crash zooms in and out. The center of the frame goes noticably soft in the middle of the crash. Have no idea why, and have never had a satisfactory answer as to why the lens does this. This occurs regardless of the distance to the subject from the lens.
 
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