Sunpak pz 4000af for minolta

If you're asking about the trigger voltage then yes, you may use the PZ4000AF with your D5100 with no harm. If you want to know about something else, please ask the question.

Yes.

Hi

you need to replace batteries

yes

The Sunpak PZ 4000 and 5000 were made for film cameras. I have one for my EOS film cameras. It works just fine. I know this series of flashes was not made for the digital cameras. It likely will not harm your camera if the flash is designed for your camera brand. But some functions will not work.
For example, do not use a flash for Minolta on a Nikon.
You risk damaging your cameras electronics or frying the flash.
Get their PZ 20, PZ 30, PZ40 or PZ 42X for your digital camera.

The Sunpak PZ 4000 and 5000 were made for film cameras. I have one for my EOS film cameras. It works just fine. I know this series of flashes was not made for the digital cameras. It likely will not harm your camera if the flash is designed for your camera brand. But some functions will not work.
For example, do not use a flash for Minolta on a Nikon.
You risk damaging your cameras electronics or frying the flash.
Get their PZ 20, PZ 30, PZ40 or PZ 42X for your digital camera.

Regarding using the Sunpak 4000AF flash with my Canon EOS Digital Rebel, I can't get the flash to fire. There seems to be no combinations of settings that works to make the flash work. Could a weak battery in the Canon cause this? Does it require some other wire connector between the flash and the camera?

I know this is old technology now, I have a pocket digital for most of my uses, but I'd like to try bounce flash again on my old Rebel digital, and so I've gotten out my old camera and the flash I had bought for it. I had bought the Sunpak flash years ago and I honestly don't remember if I got it to work back then or not.

Thanks for any advice.

Yes, you can use Ni-mAh re-chargeable batteries with Sunpak Pz 4000

Canon digital uses E-TTL metering for best flash results, the older Sunpak unit isn't compatible with this, so it is not fully compatible. It may work in manual mode - but won't be as good as a more modern compatible digital flash like the Canon or Metz (eg 58AF1 Canon) versions.

probably in MANUAL mode only.... my Nikon and Canon's work with the pz4000 (at a save trip voltage I may add) but in a manual mode as mentioned above.....