Is there a way to simulate flash compensation with an F4 and an SB-23, even though you can't do it directly on the SB-23 unit?
If I'm doing matrix balanced fill flash and I want to "dial" the fill back by a stop, isn't there a way I can fiddle with either the ISO setting or the exposure compensation to accomplish essentially the same thing as actually dialing back the fill on, say, an SB-28?
If so, is there more than one way to do it and is one way easier than another?
I'm not familiar with the SB-23 but the standard procedure would be to set a higher ISO on the camera (e.g. set ISO 200 for a ISO 100 film for a -1 flash fill). The Nikon Speedlight thinks it's ISO 200 and will provide 1 stop less light. Then, for your ambient exposure, dial in +1 compensation on the camera body to cancel the higher ISO. The flash will not be affected by the "+" compensation on the body.
The trick is to remember to reset everything when you're done with fill flash work!
Oops, sorry Dan, my first reply was misleading. I should have made it clear that what I posted was standard procedure for much older cameras (like the FE2 which offers TTL flash metering) when paired with TTL flash units that do not offer flash compensation. When used with its dedicated Speedlight unit SB-24, the F4's body-side exposure compensation does affect the flash output. But, I don't have experience with the SB-23 and I don't know how it will react with the F4's exposure compensation. I guess what I was trying to say was give the old procedure a try and see what you get in terms of fill flash.