*Top Tips and Links*

[Scottes]

Thread for top tips & tricks about techniques and how to make your photos better, shooting more fun and productive.

Please limit this to the practice of Photography and all that entails.

As we have a similar thread in the EOS forum,. lets' try to keep this one unique.

[Scottes]

Basic lighting tips and tricks for controlling Specular Highlights in shiny objects.

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=007tNJ

[Scottes]

From another thread. People seemed to like the explanation.

One issue that I can't seem to figure out is how to properly expose shots on bulb setting...or longer than 30 seconds. Is there some sort of formula to use...will a light meter calculate that for me?

Easiest way is to set the camera on manual and the aperture wide open, and see what the meter says. If necessary punch the ISO up too, until you get an exposure under 30 seconds. Then start adjusting back to the aperture and ISO you really want, doubling the time for every full stop.


So let's say you have to set the aperture to f/4 and ISO 400 to get a reading under 30 seconds - for simplicity we'll say that the camera picks exactly 30 seconds. But you really want f/11 for good depth of field and of course you want ISO 100.

f/4 to f/11 is 3 stops - to f/5.6, f/8, f/11. So you have to double 30 seconds 3 times - to 1 minute, 2 minutes, 4 minutes.

ISO 400 to 100 is 2 stops - to 200, 100. So we double 2 more times - to 8 minutes, 16 minutes.

So for for our example you'd set the camera for f/11, ISO 100 and an exposure of 16 minutes.

Since 16 minutes is a long time to wait I'd cut that in half - thus underexposing 1 full stop - and do a picture at 8 minutes and check the histogram. Judging the histogram will give you an idea for the next try. Sure, the 8-minute shot might be an extra, unnecessary step, but why wait 16 minutes to find out it's messed up? Smile


Sure, a light meter would do this, too, but this way is quite a bit cheaper.


But if you want to judge the exposure only, could it be done by f/4, ISO400 for 30 seconds?

Yep. It's the same exposure. Ignoring reciprocity failure - which is a huge thing to ignore for film at such long shutter times - f/4 ISO 400 for 30 sec would produce the exact same exposure as f/11, ISO 100 for 16 minutes.

If I were in this situation - having a digital camera with a histogram - I'd do f/4 ISO 1600 for 7.5 seconds - also the same exposure - and then check the histogram and LCD image. If it looked good THEN I'd kick back for 16 minutes. Patience is a virtue. I have no virtues.