V6 II not triggering early enough on Pentax 645Z
I've just upgraded to 1.1.009 from 1.1.006 and have noticed what appears to be an issue with the timing of the flash signal. On the 645Z the very bottom of the frame is slightly darker, which suggests that the flash may have fired just after the second curtain started its travel.
I've verified this with an off-camera speedlight (Shanny SN600FGZ) and a studio strobe connected to the Rx via a sync cable, all whilst keeping the shutter speed to X-sync (1/125). Using a V6 receiver instead of a V6 II seems to help just a tiny amount (still using the V6 II as a Tx), and also taking a sync cable out of the V6 II Tx to the studio strobe also helps a bit, but neither solution is perfect and still leaves a slight darkening at the bottom of the frame.
If I put the Shanny on the camera and remove the triggers from the equation then the illumination is even across the frame.
So it looks like the V6 II Tx isn't getting the 'fire' signal out quite quickly enough on this camera.
I also tried the TYPE1 option, which didn't appear to make any difference at all.
I've verified this with an off-camera speedlight (Shanny SN600FGZ) and a studio strobe connected to the Rx via a sync cable, all whilst keeping the shutter speed to X-sync (1/125). Using a V6 receiver instead of a V6 II seems to help just a tiny amount (still using the V6 II as a Tx), and also taking a sync cable out of the V6 II Tx to the studio strobe also helps a bit, but neither solution is perfect and still leaves a slight darkening at the bottom of the frame.
If I put the Shanny on the camera and remove the triggers from the equation then the illumination is even across the frame.
So it looks like the V6 II Tx isn't getting the 'fire' signal out quite quickly enough on this camera.
I also tried the TYPE1 option, which didn't appear to make any difference at all.
Comments
So, in answer to your question, I haven't tried it with a solely 1.1.006 environment. I just applied the update last night to both units, took some test shots of a plain wall and came away disappointed.
With older firmwares, I haven't seen any black bars with my K100D, K-5II, and K-1. Don't have a 645Z.
I'm pretty sure you shouldn't be seeing any black bars and that
a) a complete V1.1.006 setup may fix things for you, and
b) Cactus will most likely keep tweaking V1.1.009 until all Pentax issues have been addressed.
We don't have the 645Z, need to borrow it from our friend's studio again to verify, probably some time next week. Hope that's alright!
Cheers!
Brand Manager
I'm hearing rumours of a Pentax beta firmware. Does this include any 645Z fixes? I'm really wanting to be able to use my pack outside and I have to be able to at least get up to X-sync speed, if not above. The 1/125 X-sync speed is already lousy without having to go below that at the moment.
(Ignore the left to right; I only set this up quickly with a single head so it's not massively even across the width of the frame.)
This is with firmware 1.1.006 on both Tx and Rx. It's as bad with 1.1.009.
I need a hand from you in trying to tune the sync timings on your 645Z.
Who else has a 645Z here on the forum?
In the meantime I will send you a PM.
Cheers!
Brand Manager
Happy to help. At 1/90 with the Broncolor gear it's producing fantastic results. If we can just get this working at 1/125 as well then I think we'll also be set for HSS since the banding is no worse when you exceed the shutter speed all the way up to 1/4000. At that point I'll be able to really take advantage of this pack outside.
Paul
Brand Manager
I would think because the triggers are canon version it should work. The only thing that I can think of it the strobes have different sync technology. The Profoto uses one long pulse v's several pulses on the eVOLV 200.
Brand Manager
At X-sync speed (1/125s) I have banding. Below X-sync speed (1/90s) I don't have banding. And I can't realistically use 1/90s outside with any reasonable size lens on. The standard X-sync speed of 1/125s is already slow enough as it is.
The issue I raised isn't about HSS timing, which is what the release notes for 1.1.010 claim to have fixed. It's about shutter timing at the camera's actual X-sync speed, which clearly isn't right.
Brand Manager
Good news:
The Shanny SN600FGZ is evenly lit at X-sync (1/125) and 1/90.
My Broncolor Grafit studio packs are evenly lit at X-sync (1/125) and 1/90.
Bad news:
My Broncolor Mobil pack is still giving uneven illumination at X-sync and even illumination at 1/90.
So it looks like the triggers are right on the cusp of acceptability for triggering, and this is being highlighted by the Broncolor Mobil pack, whereas the much shorter durations of the bigger studio packs make it a non-issue.
It's a shame that it's the Mobil that exhibits the problem, because that's the pack I want to use outside to overpower the sun and need the shortest shutter speed possible.
Brand Manager
The Mobil back actually has a long flash duration, as it isn't an IGBT-controlled flash. The band you see at the bottom of the image at 1/125 doesn't get any worse all the way up to 1/4000, so the flash duration is certainly long enough for HSS. The problem is that the flash isn't getting told to fire until too late, so this in combination with its own latency in triggering the strobe means it's not actually occurring until after the second curtain has already started to move.
The fact that the size of the band seems to be consistent at any shutter speed from 1/125 makes me wonder if this isn't inadvertently getting synced to the second curtain rather than the first curtain on the 645Z.
I have my shutter speed set in half-stop increments, so 1/90 is my next slowest shutter speed below 1/125. As you surmise, this is the fastest shutter speed I can use on this particular pack without seeing the banding.
Now that you have a 645Z back in the shop, are you able to see if you can do anything to improve the latency on triggering so I might have a chance of using my Mobil pack for HSS?
Brand Manager
Brand Manager
Sorry, I shouldn't have used slang. Unfortunately it's still not working unless I drop below x-sync.
If the engineers haven't found any further optimizations they can do for the 645Z in the multi-system firmware then I guess I'm going to have to hope that the Pentax X-TTL one helps things. It's annoying because the banding doesn't get any worse from 1/125 up to 1/4000, which suggests it would work well in HSS if only the latency wasn't an issue.
Brand Manager
Keeping my fingers crossed for the X-TTL firmware.
Brand Manager
Brand Manager
Yeah, some radio triggers are not fast enough to sync at 1/125th with Pentax 645D and Z. I have to use 1/100 to be sure. Or HSS.