(no this is not a tailsync shot – but it is pretty cool 🙂 1/160th f/22 ISO 32 – Brian Sanger. Read on for wide apertures, high shutter speeds and blurry clouds 🙂
Ok so following on from the tests I did earlier with the Safari II and the Yongnuo YN622 radio triggers we did some tests outside against a very bright sunny sky to see if it was actually usable in the field. If you did read the previous post, you’ll know it’s not an ideal light for tail sync: it just performs too well as a normal, x-sync flash – it gets all of the light out pretty quickly which is great for normal sync speed territory outside – you can go right up to the 1/250th of a second and still get all of the light out of the flash. For tail-sync though this is not ideal as the aim of the game is make the light last for the entire shutter travel time. Now, I’m not going to go into the operation of the shutter again, but suffice to say that the shutter speed is not the shutter travel time. The shutter “speed” that we set on our cameras is the time between the first curtain edge and the second curtain edge passing the same spot on the sensor. The shutter travel time is the total time it takes for for both curtain edges to traverse the whole of the sensor. This is a lot longer and the light from most flashes doesn’t last that long. Tail sync causes the flash to fire early, so the peak flash power has come and gone by the time the shutter operates. It uses the tail off of the light to illuminate the subject. Of course, this means just like with high speed sync, you lose most of the light, but it does work with bigger, regular voltage regulated studio heads.
Of course those heads won’t work in the middle of a field – unless you also lug something like the Godox LP800 out there too. The Safari has a smaller, lighter battery so it would be great I could use it like this.
Ok, so we had already been testing some regular x-sync flash with the standard reflector and a long-throw reflector at 1/160th and f/22 at ISO 64. I left the long-throw on and opened up the aperture by 7 stops to f/2. So, 7 more stops on the shutter gives well, it gives 1/20480 which the shutter won’t do 🙂 Luckily the some clouds arrived and the ambient light reduced quite a bit. We started the tail-sync tests at 1/8000th of a second, f/2.0 and ISO64.
I fully expected to need full power at that speed and so in we went, with the YN622 attached to the Safari II’s legacy PC-Sync socket via a cable, I dialled in a tail-sync adjustment value of 1.0 (determined on the studio test session), and… we gave Brian a flash tan. Way too much light! We ended up down at 1/32nd power. This is a combination of the efficiency of the long throw reflector and the D810’s shutter – the gap between first and second curtain is actually quite wide, even with only 1/8000th of a second between them.
We do see the second curtain down at the bottom of the shot – just as we did in the studio tests. We could adjust it out completely, but the trade off is that we shift the exposure to a later point in the flash curve and the light falls off even more towards the top.
Now – there’s nothing at the top of the shot for the flash to light up – it won’t light the sky. So it would be nice if the shutter blades travelled top to bottom instead right? Well , we can make that happen quite easily, by turning the camera upside down. Now, not only do we not see a rear curtain shadow, but the light now falls off down the frame which looks more natural.
Last, we took some vertical with the rear curtain now coming in on the right hand side. Leave a gap there and you don’t see it. Shoot tighter though, and we now see it on Brian’s jacket on the right. As long as you are aware of where the shutter will come in, and how the light falls off, you can place the sweet spot over the part you need to light and get usable results. If I can, I will lug the LP800X AC power pack and some shonky ol’ Coreflash CFD-300’s that have flash duration measured on a calendar to the location, but for a quick shallow DOF portrait, the Safari II is more than capable. I carry a sync cable in the front pocket of the Safari’s bag just in case 🙂