Voigtlander 17.5mm f0.95 Nokton on om-d handheld moon light pic

Started Nov 28, 2012 | Discussions thread
forpetessake
Senior MemberPosts: 3,168
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Re: A bit of analysis.....
In reply to GBC, Nov 29, 2012

GBC wrote:

ISO at 17.5mm at F/0.95 (call that f/1.0)

Equivalent 1/25 sec at f/2.0 or 1/12 sec at f/2.8

The old rule of un-stabilised hand-held would make about 1/35 sec for 17.5mm the low limit.

Stabilised for most Pens or OIS lenses can do up to 3 stops slower or about 10x longer shutter speed for about 1/3 sec or 1/4 sec at 17.5mm, and for E-M5 maybe up to 5 stops for as slow as something like 1 second should be perfectly possible with good hand-holding technique at that focal length. (OP - Try a moonlight shot but with your back to the moon).

Would it not be:
F1 @ iso 1600 @ 1/50s == F1.4 @ iso 1600 @ 1/25s == F2 @ iso 1600 @ 1/12s == F2.8 @ iso 1600 @ F 1/6s.

Considering it is f.95 and not f1, you'd be looking at just minimally slower exposure time than 1/6th of a second handheld.

In fact, better than that. Practically every fast lens has significant light losses wide open, with T-stop typically 20-40% worse that F-stop, and super-fast lenses have even more losses than average.

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