Manual IRIS Question at DVinfo.net

Ian Richards · January 4th, 2006, 09:30 PM

I was filming a conference recently with a Sony FX1, located at the rear of the venue the light was definitely borderline for perfect results. All settings on manual I opened the iris to max; white balanced with available light and set the shutter speed to 50. My problem was when I zoomed into the presenters face the camera automatically closed the iris. Even though I had everything set to manual it overrode and changed my settings by a full stop. When I zoomed out my manual settings are back and fixed. When I use my DSR500 I set the iris to manual and no matter what I do with the focal lenght that is that, so my question is given the same situation will the Canon H1 act like the semi pro FX1 or DSR500 with respect to holding the iris settings?

Cheers, Ian

Chris Hurd · January 4th, 2006, 10:06 PM

Quote:

Originally Posted by Ian Richards

when I zoomed into the presenters face the camera automatically closed the iris.

It's important for you to understand why this is happening. Most, not all, but most zoom lenses will have different maximum aperture values at either end of the zoom range, as you found out on the FX1. The stock 20x zoom lens on the XL H1 is no exception. At full wide, the maximum aperture is f/1.6, and when you zoom in to full telephoto, the maximum aperture is f/3.5. The way to stop the exposure from changing on you is to lock the iris at f/3.5 so that it's the same whether you're zoomed all the way in or all the way out. Compensate for the lost f/stops by increasing gain, decreasing shutter speed or both.

When shooting in Standard Definition, another option on the XL H1 is to change out the lens and switch it for the black 16x manual zoom lens. This lens holds a max. aperture of f/1.6 throughout the entire zoom range. It's one of the few video lenses in this market that does. The lens on the Panasonic DVX100 series does as well. Hope this helps,

Ian Richards · January 5th, 2006, 01:14 AM

Thanks very helpful, I hope Canon make an HD version of the black 16x manual zoom lens. While discussing the lens can you tell me if what is being said about it handling like on old dog is true. And that while it’s a great camera for set pieces it might not cut the mustard for general videography work.

Thanks again, Ian

January 4th, 2006, 09:30 PM	#1
Ian Richards New Boot Join Date: Nov 2005 Posts: 5	Manual IRIS Question I was filming a conference recently with a Sony FX1, located at the rear of the venue the light was definitely borderline for perfect results. All settings on manual I opened the iris to max; white balanced with available light and set the shutter speed to 50. My problem was when I zoomed into the presenters face the camera automatically closed the iris. Even though I had everything set to manual it overrode and changed my settings by a full stop. When I zoomed out my manual settings are back and fixed. When I use my DSR500 I set the iris to manual and no matter what I do with the focal lenght that is that, so my question is given the same situation will the Canon H1 act like the semi pro FX1 or DSR500 with respect to holding the iris settings? Cheers, Ian

January 5th, 2006, 01:14 AM	#3
Ian Richards New Boot Join Date: Nov 2005 Posts: 5	Manual IRIS Question Thanks very helpful, I hope Canon make an HD version of the black 16x manual zoom lens. While discussing the lens can you tell me if what is being said about it handling like on old dog is true. And that while it’s a great camera for set pieces it might not cut the mustard for general videography work. Thanks again, Ian