LF shutter flash question...

[Jehu]

I'm going to try to shoot a cheetah at full run with my 4x5. No kidding... I'm going to try it. Anyway... I will have two speedlights on remote near the track with the sun behind and left of the subject. That makes a great kicker with the dust he kicks up. My question... Can I use the faster shutter speeds (1/500) without a sync problem? I've thought about how the shutter works and I don't see how it would be a problem but I could use some reassurance.

[IanG]

Should be no problem at all except having enough power.

Ian

[Dan Fromm]

Leaf shutter, yes. I routinely use a Copal #1 (top speed, 1/400) with electronic flash for macro work out-of-doors. The flash stops motion, overpowers ambient. And I have full control of the lighting.

That said, make sure that your flashes give short enough flash duration at full power. I mention this because I have a nice portable Agfa 643CS whose duration at full power is 1/200.

[Jehu]

Full power for Nikon Speedlights is about 1/1000. My fastest shutter speed is 1/500 on one lens and 1/250 on another. That leaves plenty of open time. Thanks for the reassurance guys.

[IanG]

You need to check out the guide no's and the combination using 2 flashes, that relates to distance and f-stop, your shutter speed is irrelavant except for balancing daylight & flash.

Ian

[Jehu]

The cheetah run was canceled due to weather. I'll get another chance in a couple weeks I hope. At least that gives me time to plan it a little better.

[swmcl]

Well done for being different and taking on a difficult assignment!

I started out buying Nikon Speedlights for a studio setup to take photos of my kids. I now have 3 bowens 1500WS flashes and 2 Bowens 1000WS flashes.

I measured a Speedlight at around 70WS I think...

I wholeheartedly wish you good luck in your quest.

[Jim Jones]

The cheetah run was canceled due to weather. I'll get another chance in a couple weeks I hope. At least that gives me time to plan it a little better.

Don't just plan; test! Theory doesn't always apply to actuality. If flash sync is off a millisecond or two at the highest shutter speeds, it will have a big effect on the results. Better to have a motorcycle as a stand-in for the cheetah until technical problems are solved than to schedule a reshoot. In theory, at 60mph the cheetah would move about 1/4 inch at 1/400 second with a perfectly efficient shutter. However, the blur will be greater due to the opening and closing time required by the shutter. Strong ambient back lighting may have an undesired effect on legs moving much faster than 60mph.

[Jehu]

All very true Jim. I was hoping to get an angle on the Cheetah just after a turn. He'll be down to about 30 mph or so at that point. I'll also be in front of him so the motion won't be that noticeable.

Steve, that's a pretty good idea. I was going to use a dog at the park but he won't be moving quite fast enough. I like your motorcycle idea.

[argos33]

Curious - how are you timing the shutter release? Will it be a fairly wide shot and done by hand? Seems like you could rig up a little infrared trip system if you want to try a tighter crop. But I suppose cropping a normal/wide shot would be a lot easier...

Sounds like a fun project! Post some photos for us once you get some!

[Jehu]

Good question Argos. I've been mulling that over. I searched for a pocket wizard style trigger but couldn't find one. Any suggestions?

My longest lens is a 240 Sironar-S. I'm pretty sure that I'll only be able to get as close as about 75 to 100 feet. The 240 is roughly 2:1 on a 4x5. That would give me about a 50' wide scene at 100'. I'm hoping for a closer blind to shoot from.

If the next run is on schedule, I have two weeks to get this right.

[Doug Herta]

I have to ask: Do you have "the running of the cheetahs" on a regular basis in Reno (weather permitting)? If he sees his shadow do you have 8 more weeks of fall? What is the context behind the cheetah run?

[Rain Dance]

I tried taking pictures too in the cheetah run here in San Diego. But I was using 35mm and no strobes. And they're really fast. I pressed the shutter when the bait was almost out of the frame and all I got was some of the hindi legs and tail.

[Leigh]

I searched for a pocket wizard style trigger but couldn't find one.
Be aware that any wireless remote will introduce a time delay in the actual strobe fire from the shutter release.

It may be short, but it's not zero for any type of remote trigger.

You might want to set up a test shoot along a street with a friend driving a car at about the same speed as the cheetah (I don't know how fast they run).

- Leigh

[Jehu]

I have to ask: Do you have "the running of the cheetahs" on a regular basis in Reno (weather permitting)? If he sees his shadow do you have 8 more weeks of fall? What is the context behind the cheetah run?

http://www.animalark.org

The founders, Aaron and Dianne, are long time friends of our family so I am sort of privileged when it comes to the practice runs. Aaron told me that cheetahs need to run regularly to keep healthy. This isn't just a fundraiser or tourist attraction. It's the best way to keep the animals in good health so it's a weekly or, at least, bi-weekly event. It's open to the public about once a month or so.

[Two23]

Be aware that any wireless remote will introduce a time delay in the actual strobe fire from the shutter release.

It may be short, but it's not zero for any type of remote trigger.





With my CyberSync triggers it is VERY short. I routinely photo trains at night with flash. Some of the trains go 70 mph, which is a bit faster than a cheetah. My preferred exposure for night/flash shots is ISO 800 & f5.6 This is with WL X3200 monolights full power 1340ws from about 50 ft. With Nikon SB-28 flash I get ISO 800 f2.8 from about 30 ft. Keep in mind I shoot in total darkness. The ultimate set up for this project would be CyberSync triggers and two Einstein monolights. They have a VERY fast discharge and each has the power of x10 of your tiny little Nikon flash. Does 1/13,500s flash discharge sound interesting to you? :)
http://www.paulcbuff.com/e640.php


Kent in SD

[Jehu]

I'm actually working on an air-gap flash that has a duration of about 1/2,000,000 second. It uses a 24kv, 0.03mf capacitor. I'm kind of scared of it.

I did this with a few Nikon SB800 Speedlights:
http://farm3.static.flickr.com/2423/3970010336_b86d03ddda_b.jpg

At 1/128 power, the Speedlights have a duration of about 1/40,000 second. Unfortunately, my friends and I have to pool our resources to get enough lights. Even then they need to be within a couple of feet.

I'm pretty sure that Speedlights at full power (1/1000 second duration) within 30' of a running cheetah would allow a fast shutter.