- Jan 14, 2018
I agree!Very interesting discussion.
I wonder if the "Lightning Mode" of the MIOPs trigger could work in lieu of the Arduino?
Is there any interest in the old school flash cubes? Demand for them for this kind of thing? The company I used to work for still had a bunch in inventory (if they didn't get tossed when they moved to the new warehouse back in May)
Another post in the Lighting forum here mentioned at the very high speeds while in Electronic or Silent shutter mode, the E-M1 Mark II has an X-sync of 1/50 second up to ISO 8000, and then it goes even slower to 1/20 second. I accidentally found that out when I was switching the Godox from HSS to non-HSS sync while at the 1/32,000 camera speed which dropped way down to 1/50 second.
That said, today I got a bunch of FP-26B flashbulbs to play with. They have a much longer burn time as they were made for old focal-plane cameras that had X-sync on them. Oddly, the Olympus is using an even slower digital scan sync (i.e. 1/50 to 1/20 sec. @ 1/32,000 sec.) than the old 1/60 second film cameras did.
However, my first few FP-26B bulbs are showing a lot more promise than the M3B bulbs that have a shorter burn time. The M3B's can be put in a middle of the 1/32,000 second shutter speeds sensor scan, but they vignette on the top on bottom. Top is the sensor scan blocking, bottom is the fade of the bulb having the shorter duration. I think I may be able to sync the FP-26B to be a perfect fit at 1/32,000 second even with a high ISO 25,600 (Where I think the scan will drop to 1/20 second). The FP-26B appears to burn around 70ms at a t0.5 average, or 1/14 second, which is slower than the Olympus high-speed sensor scan so it should cover for a perfect X-sync if initial bulb triggering time is accurate. That I need to play with.
My understanding of the flash cubes is they were built on the AG1 flashbulb. The Magicubes were made with a percussion trigger (No voltage supplied via the camera, just a hammer pin that popped up and ignited the bulb.). The other FlashCubes did take a voltage. However, I think both are too fast though for a coverage of the digital sensor's slow X-sync scan. More of a job for older FP-type bulbs (FP stood for "Flat Burn" tops, not "Focal Plane" according to Wiki.).
Below is my first try with the FP-26B bulb.
Scope showing (in yellow) the FP-26B flat burn duration of ~70ms. I'm calling it a t0.5 for the effective exposure output:
Digital SG ColorChecker chart from above firing with a hold-off delay of 35ms in the Arduino (Fwiw, There's some other delays going on other than the red trigger (me) pushing the shutter button on the Arduino that feeds into the camera's remote shutter release jack. It looks like ~65ms from red trigger to bulb in scope's image, but software's internal shutter open to bulb firing timing is 35ms.). I need to change it back to maybe 31ms as the top's darkness is part of the sensor scan going dark. Bottom is still lit well enough by the bulb so I suspect an ignition timing issue. Lowering the time seems to raise the burn's brightness in the image:
Above: ISO 25,600 at 1/32,000 sec. f/4.5. FP-26B bulb was 10' so a Guide Number is 45. Color of flashbulbs always seemed better for me on skin tones, but they are a bit warmer than electronic flash and more of a flatter spectrum going up towards the infrared end. Electronic does the opposite (unfiltered) and fades down from the higher bluish UV end with less at the warmer IR end, and it just seems more cold (bluish) imho.
For the curious, my intent is to use a Noct type of lens (<f/0.95) which would also lower the ISO and use the flash bulb as a fill in bright sun at 1/32,000 sec., <f/0.95, and lowest ISO of maybe 200. No ND filter! Just a fun theoretical idea to see if it will work. I think it should, but dunno as I need to settle on which fast m43 Noct lens to get.
Bulbs may need to be resurrected.
This AM I changed sync delay timing to 29ms:
Now where's the Noct lens to try this thing out?
Outside in bright sun to play.
No Noct yet (ordered a f/0.8), but had a test with the slow Olympus 45mm f/1.2 Pro in sunlight at 1/32,000 sec. I used the M3B flashbulb since I have more of them than the FP-26B although it is weaker in output and a shorter burn time too.
Below. One without the bulb, and second fill-one with the M3B bulb. I also need to aim the flash holder better as it's tough to not get glare off the x-rite Digital SG card as it is sort of glossy.
No flash. E-M1 Mark II at 1/32,000 sec., f/1.2, ISO 500:
With M3B flashbulb as a fill. E-M1 Mark II at 1/32,000 sec., f/1.2, ISO 500: