Monolight power output/shutter speed/aperture, etc.

[epicwelshman]

Hey guys, I picked up a set of Dynalight Uni400jr monolights with reflectors, grids, softboxes, etc.

I was playing around with them last night, triggered by radio receivers with my D90.

I had a single monolight with a softbox at 1/8 power (the lowest it can go) and I found that I couldn't shoot faster than 1/160 at f10 or so - at 1/200 (the D90's sync speed) I'd get that black edge on the photo from the shutter (presumably from the slight radio delay?)

I'd really like to use these lights at a higher aperture and higher shutter speed - any idea how?

I know the D90 has the AutoFP sync function, but I haven't tried that yet. How exactly does that work?

 

[djbahdow01]

Hey guys, I picked up a set of Dynalight Uni400jr monolights with reflectors, grids, softboxes, etc.

I was playing around with them last night, triggered by radio receivers with my D90.

I had a single monolight with a softbox at 1/8 power (the lowest it can go) and I found that I couldn't shoot faster than 1/160 at f10 or so - at 1/200 (the D90's sync speed) I'd get that black edge on the photo from the shutter (presumably from the slight radio delay?)

I'd really like to use these lights at a higher aperture and higher shutter speed - any idea how?

I know the D90 has the AutoFP sync function, but I haven't tried that yet. How exactly does that work?

The aperture should have nothing to do with with the sync speed the only things that should cause issues with the strobe sync would be the Camera sync and the sync of the radio receivers. You don't mention what kind of trigger/receiver you are using but the EBAY triggers have always had issues syncing with strobes.


You should be able to shoot at 1/200th f2.8 with the strobes, as for the AutoFP that will not work with the off camera strobes that is only meant for the Nikon speedlight system, which fires off a different system.

I would suggest trying PocketWizards, or if your on a budget the Paul Buff cyber syncs. I believe the radio trigger to be the issue.

Although if you want to go higher than the sync speed you will want to use Speedlights or an older electronic shutter camera.

Another thing I am assuming since you want to go with a faster shutter speed you are planning on doing some sort of stop action with the strobes. When strobing the shutter does not stop the action it is the flash duration of the strobes which with the UniJrs is very very slow. They are not meant for stop action more for a mobile studio setting.

If for sports I would recommend the Elinchrom 300RX's or 600RX's really great duration for sports, as well Alienbees (Paul Buff) is coming out with a new strobe meant for action photographers that seems really interesting. Would love to test them out to see how they work in real life.

 

[jampat]

Hey guys, I picked up a set of Dynalight Uni400jr monolights with reflectors, grids, softboxes, etc.

I was playing around with them last night, triggered by radio receivers with my D90.

I had a single monolight with a softbox at 1/8 power (the lowest it can go) and I found that I couldn't shoot faster than 1/160 at f10 or so - at 1/200 (the D90's sync speed) I'd get that black edge on the photo from the shutter (presumably from the slight radio delay?)

I'd really like to use these lights at a higher aperture and higher shutter speed - any idea how?

I know the D90 has the AutoFP sync function, but I haven't tried that yet. How exactly does that work?

Higher (smaller) aperture is easy, just turn up the flash power (or move the light back, or increase the ISO) and you can use a smaller aperture.

When I have needed to shoot faster than the sync speed on the camera, I just compose so that I can crop off the dark edge. It's not ideal but it can work.

Are you shooting first or second curtain sync? If you are shooting second curtain, try to change to first and see if that makes things better, the delay would be less detrimental if it happens after the first curtain.

You should also try a PC cable and see if that fixes things for you, much easier and cheaper to isolate the wireless that way than by trying different systems. No point spending money on a new wireless system until you know that's the source of your problems.

 

[firestarter]

Why do you want to use a faster shutter speed?

Generally with studio strobes, you shoot at the sync speed of your camera (1/200th, or maybe a bit less if there are some timing issues - so 1/160).

You then control exposure by varying flash power, aperture or ISO.

You don't need a higher shutter speed (for handholding etc.) as the length of the flash pulse is generally quite short (1/1000th or less) and that acts as an 'effective' shutter speed.

The only time you would need to change your shutter speed from 1/160 would be if you're trying to balance flash and ambient light.

 

[toxic]

as firestarter said, why do you need a faster shutter?

if you want less light so you can use a wider aperture, you can lower ISO, move the light farther away (at the cost of changing light quality), or use ND filters.

high-speed sync (FP mode) cannot be used with manual flash.

the 1/160 max sync for you is due to the slight delay and the small error margin "built-in" to the shutter. in other words, the X-sync speed that your camera is rated at is very close to the actual one - in some cameras, the "actual" X-sync is slightly faster (e.g. 1/300 but rated at 1/250), so you will still be able to use the same shutter sync speed.

 

[epicwelshman]

Thanks for all the quick replies.

I don't think I was explaining myself properly.

My problem (with my limited one evening's worth of experience) is that the flash power is too high. To get a decent exposure I had the monolight at 1/8, and the camera at 1/160, f10 and ISO 200.

I'd like to take advantage of my fast glass and be able to use f2.8 sometimes, but it seems that this would blow my image completely white.

Basically, how can I dial down the power to allow me to open up the aperture?

 

[toxic]

I'd like to take advantage of my fast glass and be able to use f2.8 sometimes, but it seems that this would blow my image completely white.

Basically, how can I dial down the power to allow me to open up the aperture?

ND filters, on your lens or the strobe.

in general, there is no reason to use wide apertures in a studio. working distances are usually short (10ft at most), and you control the background to subject distance.

 

[epicwelshman]

ND filters, on your lens or the strobe.

in general, there is no reason to use wide apertures in a studio. working distances are usually short (10ft at most), and you control the background to subject distance.

So, to put it simply, my strobes are so flat out powerful that without using ND filters I'm relegated to never having shallow DoF again?

 

[firestarter]

So, to put it simply, my strobes are so flat out powerful that without using ND filters I'm relegated to never having shallow DoF again?

Yes.

I disagree with the 'no reason to use wide DOF in the studio'... I also love shallow DOF effects.

The strobes I bought for myself were lower power (down to 8w) and being a Canon user I have ISO 100 which helps me to get the exposure down.

When I use other people's studios, I have an 8x ND filter (3 stop), so that allows me to drop from (say) f/8 to f/2.8.

So your options are:
- Move the light back away from the subject (although you'd need a larger soft box or brolly to maintain the same light softness
- Put an ND Gel over the light (I do this also - I have two 2x Elinchrom Gels)
- Put and ND Gel over the lens
- Change ISO
- Change light modifier (a shoot through brolly is less efficient than an silver reflector, and can cut some light).

 

[compuwar]

I had a single monolight with a softbox at 1/8 power (the lowest it can go) and I found that I couldn't shoot faster than 1/160 at f10 or so - at 1/200 (the D90's sync speed) I'd get that black edge on the photo from the shutter (presumably from the slight radio delay?)

Can you still return them? I don't usually shoot wider than f/4 when I'm using strobes, but if you'd gotten AB400's, you'd be able to go down to 1/32nd- that'd get you down just under f/4. Add another scrim to the softbox and you might be where you'd want to be, but you'd definitely be in ND filter territory.

Backing off the lights makes them a point source- meaning harsher light, for me that's usually not a good option- resizing the modifier means needing very high ceilings to get a good angle.

 

[chrfr]

Generally, radio slaves have an upper limit to shutter speed which may not be as high as the camera's sync speed. Also, studio strobe flash duration can be surprisingly long- I wouldn't personally go above 1/60 to be sure. The flash duration is what determines your ability to stop action anyway, so there's not often much need to use the max. sync speed in studio.

 

[Consultant]

<snip>
I'd like to take advantage of my fast glass and be able to use f2.8 sometimes, but it seems that this would blow my image completely white.

Basically, how can I dial down the power to allow me to open up the aperture?

A) People don't typically shoot f2.8 with flash. If you want to shoot f2.8, try having modeling light at 100% and higher ISO. Then you can just use the modeling light. Or as mentioned get ND filter.

B) Move flash away from subject. But then you need a larger diffuser.

 

[epicwelshman]

Yes.

I disagree with the 'no reason to use wide DOF in the studio'... I also love shallow DOF effects.

The strobes I bought for myself were lower power (down to 8w) and being a Canon user I have ISO 100 which helps me to get the exposure down.

When I use other people's studios, I have an 8x ND filter (3 stop), so that allows me to drop from (say) f/8 to f/2.8.

An ND filter may be an upcoming purchase then. Though, buying a 77mm filter and an 82mm filter for my two fastest lenses isn't a fun idea!

Can you still return them? I don't usually shoot wider than f/4 when I'm using strobes, but if you'd gotten AB400's, you'd be able to go down to 1/32nd- that'd get you down just under f/4. Add another scrim to the softbox and you might be where you'd want to be, but you'd definitely be in ND filter territory.

Backing off the lights makes them a point source- meaning harsher light, for me that's usually not a good option- resizing the modifier means needing very high ceilings to get a good angle.

I bought them from a friend for a great price, barely used. However, after playing with them a little more this evening I got down to 5.6 at times.

f2.8 was an example... I should have worded myself better. I was just a little worried about being stuck with f10 and smaller for the foreseeable future, but I think much of my worries came from, frankly, not being familiar with studio strobes. Give me a couple weeks

A) People don't typically shoot f2.8 with flash. If you want to shoot f2.8, try having modeling light at 100% and higher ISO. Then you can just use the modeling light. Or as mentioned get ND filter.

B) Move flash away from subject. But then you need a larger diffuser.

F2.8 was an example, but actually, that's not a bad idea, utilizing the modeling light at times.

 

[toxic]

An ND filter may be an upcoming purchase then. Though, buying a 77mm filter and an 82mm filter for my two fastest lenses isn't a fun idea!

you can buy ND gels in sheets to cover the strobe. Lee Filters sells some, can't remember any others off the top of my head.

 

[jampat]

you can buy ND gels in sheets to cover the strobe. Lee Filters sells some, can't remember any others off the top of my head.

Rosco also sells gels.

To the OP, just buy 82mm ND filters and a step down ring. Much cheaper than two sets of ND filters. A filter that's too big doesn't normally hurt (it may interfere with a hood depending on the lens).

 

[epicwelshman]

you can buy ND gels in sheets to cover the strobe. Lee Filters sells some, can't remember any others off the top of my head.

Rosco also sells gels.

To the OP, just buy 82mm ND filters and a step down ring. Much cheaper than two sets of ND filters. A filter that's too big doesn't normally hurt (it may interfere with a hood depending on the lens).

I think the sheets of ND gels may be the better option, according to what I've read online. I rarely have a need for an ND filter on my lens, so if I bought the sheets of gels they'd be substantially cheaper, and would give me more flexibility when handling the light. Plus, I'd be able to see what I was doing in the viewfinder, which is a huge help!