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narrow aperture/high exposure times
Posted: Wed May 02, 2007 4:48 pm
by it344x
Chaps,
When you stop down your cameras you increase your exposure time considerably - ( why tripods are essential etcetc ) , but do you go to the smallest aperture or a middle setting? and if so - what exposure times does your camera end up setting?
many thanks
Martin
(
http://www.mgnastro.org/wildlife.html )
Posted: Wed May 02, 2007 6:48 pm
by Dave McCormick
Not 100% clear on this, but my camera only goes to a 15sec exposure. When I set the camera I usually set between f2.1-f4.4 for medium exposure times e.g. 1/0000sec to 4sec and always f7.4 for anything higher, up to 15sec.
Posted: Wed May 02, 2007 6:57 pm
by Pete Eeles
I currently shoot in Aperture priority (Av) with a setting of f/22. This is somewhere close to the "middle", and I'll adjust accordingly, depending on how much of the background I want in focus. For example, if there's a distracting background, I'll open the aperture (reduce the f-stop) to give less depht-of-field.
The shutter speed I then get is dependent on the ambient light (assuming I'm not using flash) and always keep an eye on this too. It can vary from 1/400s in very bright sunlight to 1 second in overcast conditions. I've started using a tripod lately, but this doesn't help if the subject is sitting on top of a flower (say) that is blowing around in the wind.
Cheers,
- Pete
Posted: Wed May 02, 2007 8:08 pm
by JKT
I don't think I would go beyond f/16 under most circumstances. That is already less sharp than f/11 and f/22 is much worse. And that is for DSLR - with smaller sensors the situation gets worse.
My common settings are something like: ISO 400, 1/320 s & f/13. Unfortunately that requires direct sunlight.
Posted: Wed May 02, 2007 11:14 pm
by Dave
It really depends on your lens as to which f stop to use. There's usually a sweet spot if you can find it. I stick to f/8 with my Sigma 150mm combined with iso of 400 as standard (no need to go any lower unless you're printing out at larger than a5) and it seems to work just right. I always use a monopod and get shutter speeds around 1/400. I occasionally take it up to f/14 or thereabouts but would never go any higher in my experience the higher you go the less sharp the in focus bits are.