Another exposure question - sorry!

[AlmightyWa]

Hello people,

I’ve been lurking here for a while and have asked a few questions, so here’s another for you generous photography gurus. Correct me if I’m wrong about anything here: -

I want to get a big motion blur on something, which means I’m going to need to leave the shutter open for a fairly long time (at a guess 2-3 seconds). If I want to do this in daylight, how can I find out a good aperture to use? Is the answer a handheld light meter? Or is it just best to start at the smallest aperture and keep working up, taking the same shot?

Secondly, my camera is ancient. It has a ‘b’ setting, which I can turn and lock, but no facility for a cable release. Will this work (it does in my head, but that’s something different)

1.Set up (aperture, focusing, shutter speed etc.)
2. Put a black piece of card in front of the lense
3. Fire the shutter and twist so shutter locks open
4. Remove card for desired time
5. Put card back
6. Close shutter

Any major problems with this?

Thanks in advance for your help

 

[ksmattfish]

Yes, if you are careful that will work. I've used that method when shooting large format with a shutter that didn't work well on bulb. I prefer to use a light proof piece of black cloth rather than a card though. You can sort of cup it around the lens, making it even harder for light to stray in.

If there is a light meter in your camera you should be able to use that. It's the same as a hand held reflective meter. If you are doing this in the daylight be sure and pick a slow ISO. If you still can't get the settings you want you can try a neutral density filter: it just blocks light, like sunglasses for your camera. There are some possible reciprocity failure issues with exposures longer than a second or so if you are using film (I don't know about long digital exposures), but at shutter speeds of 2 or 3 seconds bracketing will probably take care of them.

 

[j_mcquillen]

If you're using the card technique, you'll have to be very careful not to bump the camera, both as you move the card, and as you fire and release the shutter...

There is a type of clamp adapter you can buy (Jessops stocks them in the UK) that allows you to use a cable release on cameras that don't have a socket for them, but given your description of turning/twisting to lock the shutter open, I'm not sure if this will work on yours... Are you able to use the bulb setting and simply hold down the shutter release button to keep the shutter open?

 

[AlmightyWa]

Yeah, I just twist to 'lock' it open so that I don't have to be touching the camera when i remove the card.

I'll go and have a look for one of those this weekend I think, might make the whole process less complicated!

Thanks for the advice people