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-   Sony HVR-Z7 / HVR-S270 (https://www.dvinfo.net/forum/sony-hvr-z7-hvr-s270/)
-   -   F = ? At 12x Zoom? (https://www.dvinfo.net/forum/sony-hvr-z7-hvr-s270/144598-f-12x-zoom.html)

Michael Rees February 25th, 2009 11:20 AM

F = ? At 12x Zoom?
 
Can someone please tell me how well you can open the aperture when the lens is at 12x zoom. I just read a post on the FX1000 forum, and this guy was complaining about how when he zoomed in on his subject for an extreme close up, the entire image went very dark and he could do nothing about it. Is the Z7's lens better than that for close ups. Do you have COMPLETE CONTROL over the iris and such. Help much appreciated. Thanks.

Michael

Greg Laves February 25th, 2009 06:54 PM

The standard Z7 lens goes from f1.6 at full wide, to f2.0 at full zoom. It does not change the f-stop as dramatically as the Z5/FX1000 because it isn't a 20x zoom like their lenses. Theirs go from f1.6 to f3.4. But one advantage or disadvantage, depending on how you look at it, is that the Z5/FX1000 is a wider lens than the Z7, when fully wide. When shooting in confined spaces the Z5/FX1000 would have a distinct advantage over the Z7 since their lenses can go wider by about 20% if I remember correctly. But if you wanted to zoom up on a bride for a close-up, the Z5 would have to zoom more than the Z7 to get the same shot since the Z7 starts out longer (so to speak). The more you zoom the more you lose on f-stop.

Zach Love February 26th, 2009 10:33 AM

There are very few lenses that keep thier max f-stop as you zoom. But with any of them, if you start at say f8, it will stay at f8 throuhgout the zoom.

Tom Hardwick February 26th, 2009 01:46 PM

Zach is right - for almost all of its life you won't notice lens ramping because you'll be more concerned with choosing which ND filter to switch in.

But if it's so dark that you're forced to use f/1.6 at 0dB of gain up, then at full telephoto on the Z5 you'd need to up the gain to +12dB to get the same exposure.

tom.


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