I understand. However, the only variables I have to work with are the lumens and exposure times. I've gotten some good advice and places to begin based on these.
Thanks, but this is all new to me, so I have no past pre-flashes I'm happy with! The lumens/times are from someone else, and I'm trying to adjust them to my 500 lumen torch (flashlight). D.
Interesting! I see B&H has one of these and it's 4x5 in. so I could place it inside my camera, directly over the photo paper. My question is, can I calculate time based on different scales? For example, if I used this and did a minute long exposure, and I found the most properly exposed image at...
You may be correct. In my situation, the pinhole camera I'm using, called a Pinstra, has a half inch dia. (approx.) diffuser and I hold the flashlight directly over that. My sense is that perhaps the flashlight's light is diffused or spread out over the photo paper regardless of the size of the...
You are perhaps correct, however, the information I have to work with (and talk about) is what I shared: the flashlight lumen ratings of 1000 and 500 (for my flashlight), and a 'benchmark' of:
Pre-flashing for 20 seconds with a 1000 lumen flashlight cuts your exposure time by 50%.
I...
And for my purposes, half the lumens would be twice the exposure time, correct? The 'benchmark' I have is
Pre-flashing with a 1000 lumen flashlight for 20 seconds cuts my exposure time by 50%
So, I'm assuming that pre-flashing with a 500 lumen light for 40 seconds cuts my exp. time by 50% -...
I am talking lumens, as that is what the flashlights are rated in, and that's what the instructions say.
One detail I didn't get into: I'm doing this 'flashing' with a Pinstra pinhole camera which has a diffuser setting made just for this sort of thing. That means the light from the flashlight...
As I said, I'm talking Lumens, as in the power /output of the flashlights I'm using. I don't know what you mean, that 'there could be significant nonlinearities in your emulsion response'. I'm talking about the linearity or not of the lumens, the light source.
D.
This question is part photography, part about light (and exposure times), and I assume also involves physics (or the science of light):
There is a technique in film (analog) photography called 'flashing' where you pre-expose a piece of photo paper, which cuts down on the exposure time (the...