If I open the aperture all the way it just gets more over exposed. I haven't seen the reversal effect you mentioned. When I get the time I'll sit down with it for a day and try every combination I can think of and write down the results. This will hopefully give me a system I can use with a minimum of messing about.
Thanks for your help (and Paul's). Leon On 30 April 2011 19:48, AlunFoto <alunf...@gmail.com> wrote: > I agree the P-TTL doesn't seem to do much. But that could still mean > you're having trouble from being outside the metering range of the > preflash. What happens if you open the aperture all the way? If that > makes the preflash register with the camera, you should get > underexposure. :-) > > lørdag 30. april 2011 skrev Leon Altoff <leon.alt...@gmail.com> følgende: >> Close, you may have missed my message to Paul about the change in >> behavior if I actually feed in a focal length for the set up. This >> now stops it firing at full power, but does not get the exposure >> correct. >> >> I can now dial in an exposure adjustment on the camera camera and have >> it affect the output, but then opening the aperture 2 stop results in >> a 2 stop variation in exposure (brighter) rather than the P-TTL >> adjusting for it. Closing the aperture makes it dimmer. It seems >> that the P-TTL is just not doing much of anything. >> >> Using 2 differently powered flashes can only lead to trouble (unless >> you want 2 different power outputs of course). >> >> Leon >> >> On 29 April 2011 23:55, AlunFoto <alunf...@gmail.com> wrote: >>> Leon, >>> Combining the info from this thread and another, you have a setup with >>> two AF-360FGZ flashes, a 30mm (or thereabouts) lens on bellows with up >>> to 25mm extension. The lens is stopped down to f/16, and the >>> flash-to-subject distance is about 10 cm for both flashes. I assume >>> both flashes are in the same mode, "green" P-TTL. >>> >>> My guess is that the extension and stopped-down aperture combined >>> makes the preflash too weak for the camera to gauge the right >>> exposure. It then assumes that the motif is at least 70 cm away and >>> just about pitch dark, blasting it with all flash power available. If >>> this is a correct guess, I believe you will continue to see >>> overexposures as you decrease extension, until you reach a point where >>> the preflash registers with the camera's light meter. I'm curious to >>> see what happens then. Judging from my experience with the 540 earlier >>> today, you should drop very rapidly into underexposure. Assuming >>> constant flash to subject distance for all exposures. >>> >>> It might be a good idea to try one flash at a time too, just to rule >>> out that the dual flash setup mess up anything. I'm very confused by >>> my own dual flash setup, but I suspect that's down to different power >>> rating (GN 54 vs GN 16), so it might not apply to you at all. :-) >>> >>> >>> Jostein >>> >>> 2011/4/24 Leon Altoff <leon.alt...@gmail.com>: >>>> I need to find out more about this, because it doesn't work for me. >>>> At least, not with the lens I use. >>>> >>>> I'll admit it's not your normal A lens, but this set up worked on the >>>> MZ-S and the *istD and I'd love to have it work on the K7 (or the next >>>> camera upgrade). I have added A contacts to a set of bellows. With >>>> the camera set to fully open aperture (f2 in this case), and the lens >>>> on the bellows closed down when the prefire happens, the camera >>>> calculates the correct exposure and the flash fires correctly - using >>>> the *istD and 2 AF360 flashes. The K10D and K7 fire the flash at full >>>> output. >>>> >>>> Both the newer cameras behave as if there is an A lens connected to >>>> the camera. The camera recognises the aperture range I set the mount >>>> to and I can select the aperture accordingly. It even meters >>>> correctly for changes in the aperture set on the camera in P mode. >>>> Everything except the flash output. >>>> >>>> If someone has a simple A lens (maximum of 6 contacts on the lens), a >>>> K7 and an AF360 flash can you conduct an experiment to see if you get >>>> correct P-TTL exposure out of the setup? That will at least let me >>>> know if it's just me or a design issue. I'll have to try high speed >>>> sync mode to see if that makes a difference since it works for Paul. >>>> >>>> Leon >>>> >>>> On 18 April 2011 23:26, Paul Stenquist <pnstenqu...@comcast.net> wrote: >>>>> >>>>> On Apr 18, 2011, at 9:12 AM, Thibouille wrote: >>>>> >>>>>> AFAIK the A lenses do PTTL with K7. >>>>> >>>>> And with the K5 as well. I frequently use it with my A400/5.6 in >>>>> high-speed synch mode. >>>>> Paul >>>>> >>>>> >>>>>> >>>>>> 2011/4/18 Leon Altoff <leon.alt...@gmail.com>: >>>>>>> Hi Tim, >>>>>>> >>>>>>> I've considered this same thing, though Pentax normally do manage to >>>>>>> make a nice improvement between models. Personally I've decided to >>>>>>> upgrade every second major upgrade - bought a K10D, skipped the K20D, >>>>>>> bought the K7, skipped the K5, buy the K3?. >>>>>>> >>>>>>> I'll admit I'd like the improved low light capability of the K5 over >>>>>>> the K7, but as I'm expecting the K3 (for want of a better model number >>>>>>> to apply) to be improved I can wait. For a while. If it's not >>>>>>> improved then I will probably go out and buy a K5 simply to keep the >>>>>>> control layou-- -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
