I'm starting to play with macro photography and have a question about using the built in flash. How does the camera determine and adjust the intensity of the flash?
I have an old Vivitar Series 1 90mm f2.5 macro lens and have been experimenting with a DIY flash diffuser. It's a white/clear 35mm plastic film can placed over the flash. There is a significant difference in exposure value with the bare flash as opposed to the diffused flash.
Is this because I'm using a non-CPU lens? Is there a way around it?
If there's not enough light from the flash to use a given f/stop, exposure compensation can't help you. It doesn't make the flash fire more powerfully; it's already firing at maximum. You can increase the ISO, but you might not like the noise.
I just took another series of shots - no diffuser, diffuser with no compensation, and diffuser with +1 flash compensation. The latter two frames are identical indicating the flash unit is doing all it can.
The whole idea of diffusing the flash is simply a reaction to the thread on spiders that I reference in a previous post. The amount of light with the diffuser still seems more than adequate for a decent exposure. I'll have to experiment a bit and see how it works.
When I saw the difference in exposure I thought I had a problem with the camera. You guessed it - new guy with a D200.
Yeah, that fellow has some good shots with his "home made" gizmo. I've been experimenting with a SB-600 with a Stofen diffuser on it for macro. So far, I've just used it atop the camera. Seems to be fairly decent light with it. Just bought a SB-21 ring flash to try out, also. It can only be used in the manual flash mode, however.
What apertures are you able to use with the diffused flash?