Thanks for responding. Do you think leaving the autofocus on (inadvertently) could have caused the problem?
Yes the tripod was on solid ground and I did have the center column extended because I am 6'4". Yes it's possible I inadvertently pulled on the cable release or touched the tripod. Most of my shots had some sort of wigglr though.
About the cable release.
You said: "Press the button once to raise the mirror and then again to release the shutter."
The cable release has two modes. In Mode 1 you press the button.
In mode 2 you slide the button into a locked position.
So is this correct: In mode 1 you press the button once to initiate mirror up. Then you press the button and keep it depressed for the duration of the desired exposure and then remove your finger to end the exposure.
In mode 2 you also press the button once to initiate mirror up. Then you press and slide the button into a locked position. When you want to end the exposure you 'unslide' the button.
Steve, I believe the problem is camera shake. I think both mirror slap vibration and extended center column played a role. I strongly believe that a tripod with a fully extended center column is no longer a tripod - it has now become a monopod sitting on top of a tripod - not very stable.
The duration of the burst as shown in your picture is only fractions of a second - short enough for the camera shake to play a major factor. Even though your entire exposure was 5 seconds the burst is very short. This shot was probably worse than others because I'm guessing you pressed the release the same instant as the burst of the firework. Others will have less shake because you pressed the release prior to the firework explosion and the camera hadmamchance to settle down a bit before the burst.
Next time I would set the camera to manual focus. Use mirror lock-up. To use mirror lock-up with a release: press the release once to lock up the mirror, then press a second time to take the picture - doesn't matter on the second press if you hold the button the entire time or use the sliding lock to hold the button. The important thing is that you don't pull on the release which may cause the camera to move.
Don't extend the center column of your tripod. I sit in a chair while watching and shooting fireworks so my tripod is never very high at all.
>Thanks for responding. Do you think leaving the autofocus on >(inadvertently) could have caused the problem?
>Yes the tripod was on solid ground and I did have the center >column extended because I am 6'4". Yes it's possible I >inadvertently pulled on the cable release or touched the >tripod. Most of my shots had some sort of wigglr though.
Having the center column extended is like placing a monopod on top of your tripod. This decreases stability and vibration dampening and is likely the largest contibuting factor to your problem.
>So is this correct: >In mode 1 you press the button once to initiate mirror up. >Then you press the button and keep it depressed for the >duration of the desired exposure and then remove your finger >to end the exposure.
>In mode 2 you also press the button once to initiate mirror >up. Then you press and slide the button into a locked >position. When you want to end the exposure you 'unslide' the >button.
Perhaps there is nothing wrong with your use of the cable as I believe that with a 5 second exposure the wiggles are a result of the falling and turning of the fireworks media. Had you used a shorter exposure time I don't believe you'd see the wiggles. Just a thought.
Nobody should seek his own good, but the good of others. <><
Sat 06-Jul-13 12:23 PM | edited Sat 06-Jul-13 12:24 PM by billD80
The "wiggles" aren't due to mirror slap, or the AF, or the fireworks themselves. They're a vibration most likely from the tripod itself being bumped. Or the platform on which its placed vibrating due to people walking, or some other reason inducing low frequency vibration.
I never bother with mirror up, and in the posted picture, it wouldn't have mattered.
What you CAN do is use the self-timer mode, set at 2-secs. GENTLY press and release the shutter button, and go from there.
I use that approach all the time, under circumstances much more demanding than night/long exposure shots (which tend to be very forgiving of small vibration).
I don't think it was vibration from the ground because the tripod was on brick. Possibly I touched the tripod because I was pretty close. I have a remote so maybe I'll use that next time. Here is one that came out a little better.
I would say that it's more likely the tripod, lens or vibration than mirror slap. Mirror slap is not nearly that exaggerated and will normally show up as a lack of sharpness on long exposures. Here's a demo video.
Larry - the tripod tap-test video is an excellent reference. Perhaps the guys over at the tripod forum would like to see it.
It makes three points to me: - never use the center column if you can help it (I removed the column from my Gitzo 2541 to avoid temptation) - proper technique to stabilize the tripod through weighting it AND AVOIDING KNOCKING IT can help - there is a difference between tripods which is measurable
Think about the shape and period of the wave form. Remember, each of those trails is a time trace of the glowing payload. In order to produce this image, your camera would have to have been oscillating in a substantial arc around the axis of the center post of the tripod. You certainly would have noticed such a 'Rosemarie's Baby' incident. I vote VR.
VR was definitely off. I remembered to do that and I checked it afterward. That was when I saw that the AF was on. I had also set AF Off initially at home but switched it on at the beginning of the shoot when I was setting up but never switched it back off.
Sun 07-Jul-13 11:37 AM | edited Sun 07-Jul-13 11:39 AM by billD80
>VR was definitely off. I remembered to do that and I checked >it afterward. That was when I saw that the AF was on. I had >also set AF Off initially at home but switched it on at the >beginning of the shoot when I was setting up but never >switched it back off.
My vote is, big explosions, use of long tele, and tripod (while perhaps good) not up the combination of the first two factors.
Try this... As suggested earlier, set your gear up, with the same zoom setting (no VR). Focus on a point of light, and while looking through the lens (or perhaps with LiveView), just tap the front of the lens barrel, and see how much wobble you get. It should settle VERY quickly (a second).
Shooting at 150mm and up will really exaggerate any motion (I usually shoot fireworks at 8 to 12 mm).
Also, big booms can send reverberation through the air and the ground... This would explain the larger wiggles in the latter part of the first image.
On reflection, the explanation you offer is the simplest. What is striking is the persistence of the wiggles with little evidence of damping if the middle of the waveforms are not taken into account. But freakish timing of several explosions could set up an oscillation in the tripod and keep it refreshed over the length of the exposure. A rogue wave, if you will. The oscillation doesn't need to be isolated to the center column, either. It's likely that an inch up or down might very well have changed the resonance of the tripod/camera system sufficiently to partially (or mostly?) eliminate the effect.