Using an old Sunpak slave flash.

[mongoose]

I got an old Sunpak 144PC flash from my father that I'm trying to figure out how to use with my Nikon D80. The flash has a PC cord with a "Sunpak Slave Unit" device plugged into the end of it. The flash head can be turned 90 degrees from straight ahead to straight up.

Now, maybe I'm imaging this, but does the flash operate different when turned upwards? When I keep the head angled straight ahead, it works fine for me. When I point it at an angle though, I can see it flashing but sometimes it doesn't show up in the photo. I figure it's either not putting out enough power to show up in the photo, or it's going off out of sync? It doesn't consistently do this though, sometimes it works fine, sometimes it flashes and doesn't show up.

Edit: More Info
I found out something else. When the flash head it turned straight forward, the flash always goes off as a slave flash. If it's turned up 45 or 90 degrees, it always goes off but only if I wait 30 seconds after the ready light turns on. My guess is it's not charged up fully enough for the slave sensor to react quickly enough? But then why would it always work fine when it's pointed straight forward? I need money to buy a real flash...

[Franglais]

How are you triggering the slave flash? Are you using the meter on the flash?

The right way is to set the built-in flash on the D80 to manual setting and low power (1/16 for example). You will also have to set the camera to manual and work out the right shutter speed and aperture and ISO for yourself.

The wrong way is to use the camera's built-in flash on auto. The camera uses a pre-flash to evaluate the exposure before setting off a second, precisely dosed flash with the shutter open this time. The slave flash thinks the pre-flash is the real thing and fires while the shutter is closed.

I suspect that you are using the flash meter on the slave flash. With the head set direct, the pre-flash triggers the slave, the meter cuts the flash off quickly and the flashgun has enough energy left to fire a second time when the real flash comes along. With the head set to bounce, much more light is wasted and the slave flash has no energy left to fire a second time.

Yes you do need to buy a fully compatible flash.

[MJS]

Your flash takes longer to recharge when tilted because it needs more power to light the area, longer distance from head to cieling or wall and back, more power needed. straight on flash, less distance, less power.

[mongoose]

Aha! You're right, setting the camera flash to manual makes it work correctly now. The flash goes off in sync with the shutter. This will save me some money from buying a new flash.

[another view]

Your flash takes longer to recharge when tilted because it needs more power to light the area, longer distance from head to cieling or wall and back, more power needed. straight on flash, less distance, less power.

Yup - I think the problems that you're having are related to the technique known as "bounce flash", where you bounce the light off the ceiling. Light levels decrease at the inverse square to the distance so, for example, something 4' away takes four times as much light for the same exposure as something 2' away (to keep the math simple). It's only twice the distance, but that means that you need four times the light. If your subject is 10' in front of you, direct lighting means a distance of 10'. If you bounce the light off of a 12' ceiling, then you probably have at least 15-18' of distance that the light travels.

And that doesn't take into account how reflective the ceiling is - even if it looks like its pure white you're still losing a good 20%, and it goes down from there...

This is why the flash is taking 30 seconds to work again - you're probably making the thing put out 100% of it's output, and it needs that much more time to recycle. Not sure why the ready light is on... Really, it's not a problem of the flash - but if it's a big problem for you, look into external battery packs for the flash. Quantum is standard equipment for a lot of wedding photographers that shoot a ton of flash pictures; Sunpak might have something too.

[mongoose]

One of the reasons I'm playing around with this flash is that I rarely do flash photography. I'm mainly an outdoors photographer. I've only used a flash a handful of times in the past 5 years. Using this slave flash is giving me some creative ideas though, like lighting up someone in the distance in a scenic shot. Fill flash is something I need to learn more about. Maybe once I get better at using this flash, I'll know more about what I want and get a more compatible flash unit.