Ok thank you. And thank you to everyone else- glad to be getting away with the cost of eneloops and a single flash for less than the 200 odd I thought I would be spending! :) I will probably add another flash at some point but I'm already spending more than I have. Budget = 0, final spend = 135... T...

Thank you Lou.
It looks like the external power cable is for a high capacity external battery pack. Looks like batteries are the way...
This has been an expensive weekend.

Nice :) So is it that when using flash where there is a delay, if you use say 1/125th of a second, the actual pulse of light caught by the exposure is much shorter because the image is dominated by the bright flash just before the second shutter close? Obviously you can't use a shutter speed faster ...

OK I'm with you now.
Thank you to all of you for your help.
I'm going to order some eneloops and a battery charger because it looks like externally powering them is a custom job.

So when you use a radio signal to use the flashes, is there some compensating calculation in the camera and between the flashes that allows the two to synch to each other, or do you have to use longer exposures? I only have experience using flashes with a Canon 700D and an Mt24 ex. I think there was...

Sorry, when you said it has an Rf controller, I wasn't sure what that meant. I presume you mean it can control the settings of other flash modules? But was unsure if that means that in optical sensor mode, one flash module is set off by the camera flash, and the other is controlled by the signals of...

Does that mean that two can't be set off by my camera flash optically? Or that each flash has to be manually operated?

OK I just checked. The only options are flash, rear synch or front synch (or wireless, but it's greyed out). All three are full flash. Maybe I should get the controller. Oh and I have looked it up, but I'm not quite sure if what I'm seeing is right or not: are there external power packs for the flas...

I just ordered a 560 iii which says it has a receiver built in too :) have I missed something crucial though? I've not order the controller with the possible hope that the camera will trigger it. Of not I'll get one ordered. And I did notice the serial wasn't 28 to begin with, but I might go for it-...

http://www.ebay.co.uk/itm/Vivitar-100mm ... SwZG9WksbB
How about this?

Are you serious? Currently all it takes to use the flash on my a6000 is to pop the flash out. Would that really work?!

OK so eff 30 odd sounds a little less awful with 135mm I imagine there are other factors not included as you are alluding to with the other details!

Well that is fantastic news! Thank you Pau and Charles. So for those wireless adapters in the first link, is that for use with flashes that don't have it inbuilt? In which case I'll purchase 2 of the 560 iii modules with that hotshoe controller :D seeing as I was already considering having to spend ...

My God that's a large f number! Will that not just leave a blurry mess? And should I be a lot more picky about what tube lens I use then?

Ha ha, I can imagine the temptation to tinker :) I always want to do it with my stuff but I am too much of an infant to be trusted with it. I think I'm going to go for the Yungnuo 560 iii because it seems they are a little cheaper. I wonder if any of you might be able to clear up what each of these ...