Getting shutter-curtain cutting into frame with studio strobes?

Messages
56
Edit My Images
No
This is new and I can't put my finger on it.

Canon EOS 5D MK4, as you know, this has a flash sync shutter speed of 1/200th, which is what I had it set to the other day while doing a small studio product shot.

Camera was vertical (portrait) and I noticed that about 20% of the image on the right hand edge was totally dark. I thought it was my background light not reaching across that far, but then it looked suspiciously like the focal plane shutter was encroaching into the image i.e. shutter speed set faster than the cameras maximum flash duration, in the case of my camera, 1/200th of a second.

The strobes I was using was a combination of Bowens GM500R (with remote receiver cards in the heads and using Bowens Pulsar remote trigger on hot shoe of camera) and Bowens GM500 heads, the latter using the photo cell built into the GM500 heads. I was using Canon EOS utility with camera tethered to MacBook Air.

I fixed the issue by changing the shutter speed to 1/160th of a second, then the shutter curtain did not come into frame anymore.

But the camera has a flash duration shutter speed up to 1/200th of a second so I can't understand why I'm getting this shutter curtain issue.

If I pop my Canon Speedlight 600 EX onto the camera's hotshoe and fire off shots at 1/200th second, there is no problem. I only get this issue with the above Bowens combination.

I must admit, the Bowen's Pulsar trigger, on camera, is twitchy, at best, it works about 8 shots out of 10, the other two the transmitter does not send a signal, though I doubt this has anything to do with the shutter curtain black-out issue on part of the frame.

I was also thinking that the photocel technology on the GM500 head might have something to do with it as I'm triggering the strobes from the Bowens pulsar trigger on camera, which triggers the three GM500R heads (which have reciever card built in) and then when those heads fire they trigger the two GM500 heads photo cells, so perhaps the latter heads are firing off a trifle late due to the daisy-chaining way in which they are the last to receive the signal. A possibility?

Any ideas or suggestions?
 
1/200th is the maximum possible and assumes that everything is working as it should.

It seems to me likely that either the batteries in the Pulsar are past their best or that there's a poor contact somewhere (transmitter on camera or receiver on flash). It doesn't take much to reduce maximum possible performance.
 
What Garry said.
1/200 is for a shoe mounted flash, everything beyond that offers a potential delay.
If its kit that’s been perfect before, it’s likely the transmitter batteries, if not that, you’ll just need to lower your expectation. Not that it matters in the studio generally.
 
Thanks, buys. Pulsar batteries are fine. Ok, so a guy from a photographic shop said if I buy a different radio trigger system – Neewer, Godox, Yongnuo – then the issue will go away and I'll be able to do high-speed flash sync. I can't get my head around how this could possibly work. But, any suggestions how I could shoot using my Bowens GM500R and GM500 heads at shutter speeds above 1/160th of a second, ideally closer to 1/500th second?
 
I’m no expert but surely the flash will need to be HSS compatible, and coupled with a suitable trigger. I have no experience of the flash you have but I’d be very surprised if just buying a trigger will work. Maybe take the flash head and camera to the shop and try it out if it’s local.
 
Thanks, buys. Pulsar batteries are fine. Ok, so a guy from a photographic shop said if I buy a different radio trigger system – Neewer, Godox, Yongnuo – then the issue will go away and I'll be able to do high-speed flash sync. I can't get my head around how this could possibly work. But, any suggestions how I could shoot using my Bowens GM500R and GM500 heads at shutter speeds above 1/160th of a second, ideally closer to 1/500th second?
There are two types of "High speed flash"
Only an IGBT flash can do HSS (high speed sync) which needs IGBT technology to create a large number of low powered flashes so close to each other that it forms, in effect, a low powered continuous light. Neither of your flash heads have that technology.

The other theortical option is tail end synch, now a bit out of fashion. This requires a flash that has a pretty long discharge time, so that the flash lasts long enough for your shutter to traverse the sensor. The GM500 may or may not be capable of this (a lot depends on the speed of your camera shutter) but, according to the claims made by Bowens, the GM500R won't do it. Maybe you need to talk to a different guy:)

But it begs the question, which would you want to shoot at high shutter speeds in the studio anyway?
 
Garry, the reason I need to shoot at higher shutter speeds is thus: With my Bowens strobes set to the lowest possible power output, with softbox on them, close to the subject (a small product shot for example) with the Canon set to 1/1200th of a second shutter speed, if I want f2.8 or f3.5 for example for depth of field control i.e. throw the background out of focus, I can't achieve this. The Bowens heads, at their lowest power output are giving me flash meter readings of around f6.3 and if I lower the shutter speed on camera to 1/160th to avoid shutter curtain encroaching I'm at f9. Odd, I know. I don't want to have to start sticking ND filters on the lens.
 
All that a shorter flash duration would achieve would be to reduce the impact of the ambient light and modelling lamps, which shouldn't be any kind of problem in a still life studio (I accept that some portrait photographers may like to have a nice bright environment to make the place look cheerful, but that doesn't apply to your situation).

If your camera did work with either HSS or tail end sync then the power would be greatly reduced, helping you in your situation, but it won't work so that option is out.

There are a number of solutions that work.

1. Get at tilt / shift lens - expensive, but this is the tool that controls apparent dof really well (it actually shifts the plane of sharp focus and doesn't create greater or less dof but it's the results that count).

2. Replace your flashes with modern IGBT flashes. Most produce less power, all have a far greater range of power adjustment, which will allow them to be set to extremely low power. Most can also be used in HSS, although personally I regard that as more of a marketing point than a real benefit.

3. Use a good quality ND filter on your lens. I don't like using filters, but a 0.9 one will effectively reduce the power by 3 stops and solve your problem. ND filters are OK in the studio, provided that they're scrupulously clean and that you use a really good lens hood.

4. Use ND gels over your lights, a bit messing around and time consuming but again, if you use 0.9 density then your problem will be solved, and at minimal cost.
 
Thanks, Gerry, I'm aware of tilt/shift lenses, but not for me in this instance and seems like a weired workaround and not a road I want to go down. I'd rather spend that money on Godox AD600Pro heads.

What's IGBT?

I'll look at a high-quality ND filter of 0.9, good suggestion there.

Yeah, I thought of NG gels, but, like you said, messy.

In the meantime I've decided the Bowens Pulsar transmitter and reciever cards are pants as they are totally unreliable and twitchy at best. I get about 6 or 7 shots out of 10, the rest of the time they don't fire so I've just ordered these so I can take the cards out of the heads and use this instead, hopefully this Godox trigger/receiver system will prove better than the unreliable Bowens Pulsar. I don't expect it to fix the sync issue though as that's another issue.

https://www.amazon.co.uk/gp/product/B015SRLIAU/
 
IGBT is the acronym for insulated-gate bipolar transistor.

Many modern flash heads use it, and the technology comes from hotshoe flashguns. Basically, on your current flash heads when you reduce the power setting, less voltage reaches the flash tube, so it produces less flash energy and it also takes longer for the flash energy to be discharged and the flash colour becomes warmer.

With IGBT, regardless of the power setting chosen, it will always fire at full power. If you set it to 1/2 power then it will only fire for 1/2 as long and will store the unused power in its capacitors, and if you set it to 1/128th power then it will only fire for 1/128th as long and you'll still have 1/127th of the power stored for the next shot:)

One of the benefits is extremely short flash duration (when used at low power settings) and another is extremely rapid recycling, again at low power settings. Yet another is that the colour temperature is (can be) far more consistent, both shot to shot and when the power setting is changed. Please see https://www.lencarta.com/studio-lighting-blog/immovable-object-irresistible-force/#.VkHkaL8l-hE Given the strain that the rope was under, only an extremely short flash duration could freeze the action, and given the fact that we didn't know exactly when the rope would break, we needed extremely fast duration - from memory I was shooting at 14 frames per second, which was fine because the flash could manage 20 FPS.

The triggers you linked to are very basic but will work fine with your existing flashes, but if you do decide to go with modern IGBT flashes you will find that most of them have a built in receiver that will need a much more sophisticated transmitter. These transmitters also act as remote control, and offer many advantages.
 
Thanks for detailed reply, Garry. Watched the rope-snap video, will read rest of article shortly.

In the meantime, yes, the trigger/receivers I've just ordered are basic, but I'm confident they will prove more reliable than the Bowens Pulsar, i.e. they should trigger the flash heads every time I take a photo, not just 6 or 7 times out of ten like the Pulsar does.

If I get a Godox AD600Pro head I'll get a Godox ST4 trigger to go with it.
 
Thanks, buys. Pulsar batteries are fine. Ok, so a guy from a photographic shop said if I buy a different radio trigger system – Neewer, Godox, Yongnuo – then the issue will go away and I'll be able to do high-speed flash sync. I can't get my head around how this could possibly work. But, any suggestions how I could shoot using my Bowens GM500R and GM500 heads at shutter speeds above 1/160th of a second, ideally closer to 1/500th second?
Why?
Sorry I see you answered that now.

I think the simple solution is nd filter (I’d filter the lens as it’s easier).
 
Last edited:
Yup, I agree, Phil. I'll just make sure I buy a quality ND filter. I figured if I spend £100 on a decent one it should not interfere with the L series Canon glass.
 
If you have a decent polarising filter it may be worth trying that as a weak ND filter before buying anything.
 
If you have a decent polarising filter it may be worth trying that as a weak ND filter before buying anything.
The OP is doing product photography, which often involves placing the lighting as close as it can possibly be, which means that with the older flash heads that don't have a massive range of adjustment, there is simply too much light for the lens apertures at which he sometimes wishes to shoot. This, combined with the fact that his flash heads are quite powerful, is the cause of his problem.

One good solution is to use an ND filter, as explained above. He is right to be concerned about the inevitable reduction in image quality that will occur when using any filter (2 additional glass to air surfaces and the potential for lens flare) but a good quality one shouldn't cause problems, except possibly when the subject is strongly backlit. Trying it out with a polarising screen won't establish proof of concept and won't help in any way, but I can see why you might think that it would.
 
Trying it out with a polarising screen won't establish proof of concept and won't help in any way, but I can see why you might think that it would.
Most CPL's eat about 1 stop of light, that's all... I would say if you already have one and ~1 stop is enough then it's worth trying.
 
Good points Garry. I was thinking of buying five 125 or 250 heads to fix the issue.
Excess power is a factor, but the choice of the replacement heads is about far more than just power. What really matters here is the range of power adjustment.

You could get the Godox AD400 Pro - 400 W/s and it adjusts right down to 1/256th of full power, but it's pricey. https://www.lencarta.com/godox/godox-ad400-pro-studio-flash-strobe-ac-mains-power

The Godox QT400 is a bit less sophisticated but much better value, it adjusts down to 1/128th https://www.lencarta.com/godox/godox-qt400ii-m-flash-head-fla042

Both of these are IGBT (and of course there are other makes too) and it's IGBT that you need, because not only does IGBT typically have a much wider range of power adjustment, it also produces consistent power at low power settings, which old technology flashes can't do because the input voltage at low power settings is too low. Also - and vitally important for critical colour product photography - IGBT flashes can produce stable and consistent colour temperature even at low power settings, which old technology ones can't.

I'm just a photographer and no expert on equipment. You may want to speak to either Alex or Mike at Lencarta, both know far more about the new equipment than I do and both understand product photography, so you'll be speaking the same language.
 
Good points Garry. I was thinking of buying five 125 or 250 heads to fix the issue.
Long term, if it's going to be a recurring issue I think smaller IGBT heads with greater range of control are the way to go. Something like the Godox GS or SK 300/400 with built in wireless control... hell, an SK300II doesn't cost any more than a 1/2 decent ND filter (but it doesn't have a big range either).
Edit, cross posted w/ Garry's response.
 
Last edited:
Thanks Garry and sk, good points, will look in that direction. I was thinking that £100 on an ND filter could go towards the correct strobes.
 
Thanks Garry and sk, good points, will look in that direction. I was thinking that £100 on an ND filter could go towards the correct strobes.
I use a variable ND, but it cost a bit more than £100. Having ND's isn't a bad thing and can be a better choice than using HSS. But IME they always degrade max IQ slightly (usually not enough to matter), and contribute a color cast (usually fixable well enough). If £100 is 25-50% of getting better/more appropriate lights, then getting the ND now might not be the best use of funds (or maybe it is).
 
Back
Top