Macro shots using ring flash
 

I recently decided to delve into taking macro shots. My photography is just a hobby as likely it is for most here. I'm shooting with a Pentax K-7 using a Sigma 50mm macro and sigma em-140 DG ring flash. I've riddled both the manual for the flash and my camera and I can not get consistently developed shots with them. The lens by itself takes great shots but when I use the flash, I can take two photos with the first being visible and at the right exposure and the next being completely underdeveloped, just blackness. The flash ignites both times and I don't touch the settings (I always shoot on manual). Please help, any more information needed I'll provide. Thanks!

My guess would be that it's an issue of recycle time, these flashes will fire a second time even if not fully recycled but in this situation they will fire at a reduced power... This would give the results you're seeing. Have a look and see what the recycle time is for the flash and then try and work with that, be warned the recycle time will get longer as the batteries lose charge, fresh batteries will allow the flash to work at it's best, so a few sets of good rechargeables will be a good investment.

I've been searching but can't find the recycle time for your flash... Hopefully it's listed in the instructions.

I did find it, thank you. Ended up being 6 seconds. I'm feeling sheepish as I'm about to divulge my baseline solution in solving this...batteries. I had them in my other flash, only used it for 4 photos before I put them in my ring flash but apparently either that was enough to virtually drain them or they were faulty out of the pack. Thanks again

It’s good to have high milliamp Ni-Mh Battery, I use 2500mAh and they can refresh the flash very fast, another thing that helps is to turn the power down on the flash if you can you don’t need full power when your doing macro work.

Bear in mind too that most rechargable batteries loose significant amounts of charge while standing idle. Newer low self discharge types are MUCH better for intermittant use. NiMH batteries can often loose over 10% of their charge in a month, whilst doing nothing.

Thanks for the heads up on the LSD NiMH batteries Mike, this is the first time I have heard of them.