Does anyone have any hints about phopographing an entrance from the inside? Well actually you can't see the entrance from inside, but a lot of light comes in and i want to do a long exposed natural light type photo but have no idea of how long to expose it at or any of the technicalities etc, someone said about using a light metre but i don't know what that is! [/url][/list]

What sort of camera are you using?

First of all you'll have to use a tripod, or something similar to mount the camera.

Also, it's worth using a cable release or the cameras own self timer to start the shot so you don't blur the shot by pressing the shutter manually.

A light metre would probably enable you to get an accurate reading, but I've never used one personally, I've always just used the metres built into the camera. You'll need a camera that can take a long exposure, either by using presets (eg 30 seconds), or one where you can use a cable release to lock the shutter open manually for the required time.

Obviously if you're using digital then you can just mess about until you get a good result, but if you're using film then you're going to have to experiment to a certain extent, unless your cam can match the metre readings.

Also, it's probably worth using a fast film.

using pentax mx.

That should be ok I reckon - you can get a cable release that will lock open (not expensive) from somewhere like Jessops, then use the manual settings on the camera, unless of course there's enough light to just use the aperture priority mode.

I'd take a few shots at exposures above and below what the camera says just to be sure of getting a useable one.

You can use your camera meter if you don't have a handheld meter.

Go close to the areas that are lit by daylight, close enough so that the viewfinder only shows rock lit in this way.

Set the aperture to the one you want and look through the viewfinder and see what shutter speed is required. (I'm assuming your camera will show this, if not adjust procedure accordingly).

Do this at various points for areas that are lit to differing degrees, keep note of the shutter speeds.

Average out the shutter speeds.

This should give you an almost correct exposure of the scene but bracket the exposure anyway like Bubba says.

Don't bother trying to expose for the shadows as this will wash out the highlights completely and as the shadows are pretty much black anyway, there isn't much point to getting detail in them.

Which cave entrance are you thinking of photographing?

BTW. If you have a zoom lens, this gets easier as you just point at various parts of the scene and zoom in to fill the viewfinder at get a reading. But remember that the speed of the lens changes as you zoom and account for this as well.

Just the Eglwys Faen main entrance, it looks really cool the way light comes in....and no i haven't got a zoom. May have a some time if i get round to it.