Zoom with 14-140 kit lense!

[Tameside]

I still never really resolved once and for all if its just my 14-140 or if it happens on all GH1's with 14-140 lens?

If you zoom with your 14-140mm in CMM or any PASM modes and even if you lock exposre, ae-l button, do you get small exposure bumps as you zoom in?

I do and its slightly maddening, and yes I know you arent suppossed to zoom in video, but sometimes it gives a nice touch, especially if you zoom out.

Please share you experience with this, as if mine is faulty I would like to get it checked out whilst its still under warranty?

 

[thisisapocalypse]

The 14-140 kit lens is not a constant aperture lens, it lets less and less light in as you zoom in, so even if you lock exposure before you start zooming, if you lock it at an aperture that the entire focal range of the lens is not capable of doing, say f/4 when you're at 14, and then zoom to say 75mm, you're going to get a "bump."

If you were to do an exposure lock at something like f/8, which the lens is capable of doing at all focal ranges, then you wouldn't get those "bumps."'

 

[Tameside]

OK, yes I realise this, but thanks for doing that, I had stopped the lens to 5.6, still does it and 6.3, still does it, but will give f8 a try too whn I get chance. Maybe it has to be way out of the core zone to be able to fully vary speeds/aperture without issue. With a conventional camcorder though, you would only get the image getting darker as you zoom in, not varying things, but I giess this is a differnt sort of lens?

 

[thisisapocalypse]

OK, yes I realise this, but thanks for doing that, I had stopped the lens to 5.6, still does it and 6.3, still does it, but will give f8 a try too whn I get chance. Maybe it has to be way out of the core zone to be able to fully vary speeds/aperture without issue. With a conventional camcorder though, you would only get the image getting darker as you zoom in, not varying things, but I giess this is a differnt sort of lens?

I can't really say, camcorders work a bit differently since they typically are driven by a variable gain function that a camera like the GH1 does not have. I would think getting way out of the "core zone" may do what you need - conversely, maybe you could set it all manually as opposed to using A/E lock? Just set the exposure to f/5.6 or f/8, set the shutter speed, and try it that way - if you've got anything else turned on (intelligent exposure, etc.) this may mess with your results and cause these "bumps."