TR3 battery pack for Pentax flash


Link Posted 20/06/2008 - 17:39
Dear Matt

- my K10 is always on M or Av - i actually don't use other modes... but my question is another one.
Isn't P-ttl mode on the flash going to use all the power necessary? And not the minimum necessary to illuminate the scene?

Is the P-ttl recognising the ISO setting of the camera, therefore reducing the flashoutput if the ISo is higher?

Wouldn't it be better to set the flash on A or M in case of fast shooting (event indoors where the flash is anyway bounced off a ceiling or wall?)

Obviously for this type of event photography all is needed is a fast shutter (not lower than say 1/45) and nothing else matters. What would happen if the camera was in Tv, and what would be the best setting for the flash then?

Thank you so much for all this. I have read the P-ttl sticky guide, and I usually use this mode. This is why I am curious about the other modes on the flash.

'Between the lights there is always a shadow' & PPG


Link Posted 20/06/2008 - 18:33
Timely, has a blog about Speedlights using battery packs and getting full power recycle times under a second. With that a warning about overheating, but it would be nice to get faster then six second recycle when needed.

Oddly, if I set the camera in manual mode, and set the flash in manual mode using the trick of turning the flash on first... it seems the flash is still getting some sort of information from the camera and changing its power output.

If I shoot a light area, I get two to three shots (as fast as the camera can go) before recharge is necessary.
If I shoot a dark area (still within the camera's ability to shoot full speed), I get only one flash and the next two frames are dark as the flash recharges.

I guess I will need to play with this more, but I am stumped by why the flash behavior would change under these conditions.


Link Posted 22/06/2008 - 22:11
Isn't P-ttl mode on the flash going to use all the power necessary? And not the minimum necessary to illuminate the scene?

Absolutely not. It will only use the complete flash power if the ambient light is so low in relation to the aperture/ISO/shutter speed.

The advantage of "M" mode on the camera is that you can still measure the ambient lighting. The Av mode will try and balance everything for you. When you use "M", and adjust the shutter speed so that it shows around 1 stop under exposure, then the flash has little to do and will only expend a small amount of energy

In fact, if you are doing this inside and out (such as at a wedding), then set the AF540/360 to "HS" mode and you will be able to select higher shutter speeds for outdoors - still the same rule applies - meter for about 1 stop underexposure and the flash will do the rest.

Maybe it sounds counter-intuitive, but it works a treat!

Yes, you can use "M" and "A" on the flash gun - but the P-TTL mode should give you more accurate results... unless the situation is absolutely constant (like studio setups). As I said, if you are doing portraiture, then everything manual is by far the easiest and most consistent.

If you give me a bit more info about what you are shooting, and what you want to achieve, then I could give some more ideas!
(For gallery, tips and links)


Link Posted 03/08/2016 - 05:34
For Aussies, the TR3 is currently $130 shipped from CR Kennedy (Pentax Australia). I just bought one.
SF7, SFX, Z-10, PZ-1, *istD, K100D, K-7, K-5, and Q (obviously a sick man)


Link Posted 03/08/2016 - 15:02
not sure what type of function you are shooting, but I occasionally do need to overpower the ambient light and get some DOF in the shots, on those occasions I will use my studio strobes with radio transmitters for the room, and attach one radio slaved "fill light" on a flash bracket... no ttl, manual settings.. perfect solution? nope, but it does get the job done... most often these days I just up the ISO, to get the ambient exposure about a 1/4 to 1 stop under exposed (depends on the look I want, high or low key) and gel the flash to colour correct where needed and fire away.
btw.. p-ttl annoys me anyways too many people blink on the preflash...
Last Edited by D0n on 03/08/2016 - 15:04
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