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 layout on the back the same between the K5 and the K7 (because >>>>> I do use 2 bodies). >>>>> >>>>> I'm hanging out for some rumors of what the next model holds, but >>>>> there is nothing. And I'm watching other's buying K5's. >>>>> >>>>> What should they be working on? I don't know. I would like to see >>>>> them bring back P-TTL flash working on A lenses like the *istD had. I >>>>> use that. >>>>> -- 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.
