It’s called an anti-rotation pin. This pin interfaces with most cine (motion picture) cameras. Cinematographic camera applications often involve panning the camera. Such activities can result in the camera slipping on its mount. An anti-rotation pin locks the camera and prevents unwanted gyrations. Additionally, on a film cine camera, to reload a fresh roll ...
A tripod can be unstable by:
Having cheap leg fasteners / too heavy a load for the legs
My first tripod ever was a hand-me-down Velbon that had seen some abuse. Even sporting just a 20D and 70-200 f/4 (~3.2lbs) if left alone, the legs would begin to collapse. Slowly, sure, but enough to not want to walk away or be able to do a long exposure.
The mountain and the valley obviously are static -- even more from that distance. The clouds, however, move. If you chose a low ISO value, e.g., in the range of 50 to 100, the exposure time might be enough to get washy/faded/blurred clouds.
If I calculated it correctly, an ISO value of 100 with the other settings (exluding shutter speed) staying the same ...
I haven't seen any camera that has a hole that the peg would fit into.
Let me fix that for you. Here is the base of an old video camera of mine:
The little hole is where the peg goes. If you don't have a camera base with a hole, you don't need the peg. If you do, you do. It stops the camera from rotating relative to the plate you clip to the tripod.
There are a number of good reasons for a center column. The first, and most obvious is that even if you've chosen a tripod that's sized for comfortable eye-level use without the center column extended, every once in a while you'll want some additional height, and on those occasions, the extra height may be worth the penalty you'll pay in stability. In this ...
Along with weighing down the tripod, using a cable to release the shutter will help reduce camera movement.
Also, if you want to guarantee no mirror shake happens during the exposure, hold a black object in front of the lens while triggering the shot, then pull it away for the duration of your exposure.
There is a rule in photography: If you can use a tripod, do it.
OK, I just made it up but let me tell you why it is a good idea:
Stability: No matter how fast your shutter-speed is going to be, a good tripod can do better. There is a rule-of-thumb that says you need a certain shutter-speed (1/focal-length) get a sharp enough image but it does not guarantee ...
Looks like it's related to image stabilization as Tetsujin suggested. Managed to replicate the issue. Switched off the IS and the Ghosting went away. It is a new IS lens (Latest Sigma 105mm macro IS). Guess I just need to remember to switch it off in these circumstances.
For those who are interested, here is the final shot
Mirror slap is an issue in "medium" long exposures - from 1/30 or so til about a second or two.
Tripod shake is issue in "long" long exposures - from about a second upwards.
For shooting stars you can safely forget about the mirror slap. It will last about a second of the four hours exposure. Nothing of importance will be captured in such a short time.
I have a nice heavy tripod and a cheap, light aluminum tripod. I hear a lot of people talking about wind and vibration, etc, and I think you're right - the environment makes a big difference. Landscapes with little to no wind are very forgiving. However, even little wind can go a long way and cause vibration and the type of vibration we're talking about ...
Sigma's product manual says:
Please do not use Optical Stabilization in the following situations.
When the lens is mounted on a tripod
Bulb (long time exposure)
As I understand it, the problem is as follows. Stabilization works by having some lens elements move around to correct for the the movement of the whole assembly. As Isaac Newton ...
I'd like preface my answer with a note that a tripod is not only useful in conjunction with ND filters — it also improves the results from image stacking as well. By fixing the position of the camera, the tripod eliminates changes in perspective, which can occur through minor motion while hand-held shooting a sequence for image stacking.
Aside from fixing ...
The only options are:
Buy a better tripod/head with significant over-provisioning. (i.e.
if your camera were to weigh 2kg, don't get a head for say up to 3kg
but up to 10kg.)
Shield the camera from the wind. (Anything that keeps the wind
from hiting the camera - something along the lines of the "tents"
people use at beaches.)
Use a weight below the tripod - ...
Both of your tripod selections look good to me. If you can live within their limitations, they should work fine for you.
However, both of them are large and heavy enough that they cannot be called "convenient." They're not the small but highly limited sort of tripod you can tuck into the corner of a camera bag.
I find this sort of middle ground ...
Mirror slap will last some fraction of a second. This is completely irrelevant in a multi hour exposure.
Weighing down your tripod is a good idea nonetheless, since movement from wind will be a bigger risk.
May I ask how a tripod can be unstable?
Unstable might be the wrong word to describe the major problem with tripods; unsteady might be a better choice. Tripods are quite stable in the sense that, absent a really strong wind or careless photographer, all three feet will generally stay on the ground. They don't rock like a four-legged table on uneven ground.
I can't think of any technical reason for this to be the case. Even assuming that he used the lens at 105mm, if he was more than 387 ft from the closest object in the frame, he could have focused at 750 feet and had everything in focus even at f/5.6, so f/22 was completely unnecessary unless intending to get the shutter speed longer. A faster shutter speed ...
For most people it is just a personal preference. Some say the flip locks are more bulky and can get snagged on objects. Some will tell you that one or the other is faster to set up and take down.
I have both types(Manfrotto flip locks and Benro twist locks) and have no preference. I find them equally fast to set up and take down, and have never had a flip ...
Well, with regards to your (1)... You could carry a light tripod (or beanbag or any other way of stabilizing a camera) and use only a single ND filter instead of several stacked filters.
With regard to (2), yes you could do that, but stacking a sequence of discrete single images will give you a result that contains several discrete non- or less-blurred ...
Others have addressed your question well, but I wanted to address one other thing:
If it is so unstable, as it is described in many websites/forums, then why do manufacturers add it to tripods?
Stability is relative. A tripod with its legs and center column fully extended is still steadier than you, handholding the camera.
Think about it in terms of "...
There's always the old Hat Trick:
Take your hat (or anything blocking light, a piece of cardboard, the dew cap of your lens etc.). Hold it in front of the lens to prevent light to reach your film.
With the hat still in place, release your camera's shutter. Wait until mirror slap and tripod shake have faded.
Remove the hat without disturbing the camera.
A big reason is that it just makes getting the shot sequence consistent and accurate. In general, you're looking to keep the vertical plane level through the whole sequence and move along the horizontal plane in smooth, even, steps. A panoramic head is simply going to make that easier to do with less effort and risk of a muffed shot at all kinds of focal ...
It is a tool to adjust the tension on the locks for each leg section. The six-sided socket fits over the head of the nut to the upper left in the picture below. If the leg still moves under load when 'locked', then release the leg lock and tighten the nut with the tool. Don't tighten it too much though, or you won't be able to push the lock tab back down.
I've taken pictures of documents recently. While in my case there was no requirement to have high quality pictures, I decided to try to aim for the most detailed and noise free pictures possible. To get the most detail, you should use the largest focal length available and take pictures from as close as possible, but such that you can still focus on the ...
The following method worked for me to stiffen up a generic fakey-pod (i.e., meaningless name / brand gorillapod clone). This may or may not work for your version.
I only had problems with a few joints. These lacked stiffness when being bent and would not hold position. The joints push together – ball-end into socket. They dismantle by being ...
You need something like this:
Or maybe this one, for a lot less money:
There are lots of other models. Some, like the top one shown here, provide a hot shoe so that you can trigger the flash using a ...
It depends the weight of the lens. How much exactly depends on the camera.
Your examples are quite light telephotos and those are no problem at all.
In general when the lens is too heavy, it comes with a tripod mount to attach it.
An equatorial mount and a computer controlled mount are two different things. A mount can also be both.
A equatorial mount has one axis aligned with the spin of the earth (pointed towards Polaris for those north of the equator.)
A computer controlled mount is a mount that knows where the objects in the sky are. You can say, "point at Jupiter" and it will ...