wooden camera and large expousure times?

[C. D. Keth]

Pity you can't use the same trick when taking star trails pictures. Even a short airplane flight through the field of view makes them interrupted, when you cover the lens for that time. On the other hand, when you use a guided camera, you can use the trick - but then you don't get trails...

You could convince people that stars follow the dotted lines

[GPS]

Not difficult, as the whole thing looks like a giant rotor...

[John Powers]

You probably will have a greater problem of having the film move within the film holder during the exposure than having the camera move. I try to remember to give the holder a good tap before inserting it into the camera. Forgot to do this recently with a 30 minute exposure -- the neg slide down in the holder during the exposure and I got a doubled image (8x10 film)...oh well, I can return and try to get that image another day.

This has happened to me way too often that I need to be wary of it.

Another source of movement is the tripod settling during the exposure -- especially if one sets up on leaf litter...one might need to dig out to more solid ground.

Vaughn

Vaughn,

Thank you. Hadn't thought of either problem. The settling possibility would be a good argument for hanging a weight or bag of rocks from the tripod hook.

John

[Vaughn]

Vaughn,

Thank you. Hadn't thought of either problem. The settling possibility would be a good argument for hanging a weight or bag of rocks from the tripod hook.

John

Tripod legs with spikes might also help. This is less of a problem with my gear -- I do have spikes on a 15+ lb tripod with 20 lb of camera/lens/holder. The weight of the set up and the time it takes to set up will usually ensure the camera and pod have settled.

I will often check the composition on the GG after I have taken a shot -- just to make sure nothing has significantly moved -- since I pay lots of attention to the edges of my image (I always print full-frame), it is usually easy to tell if something has shifted (usually caused by me not tightening down a knob!) This way I can expose another negative if I feel it has moved...just a little insurance.

Vaughn

[primoz]

hello
thank you to everyone for your help.
I was worry abaut camera caracteristic(wood) because of temperature change, humidity during night photography.
with film holders and film muvment I also had som bed experience...I read somthing abaut special film holders. normaly they use them for scentific use when critical focus (flatnes) is needed. some experience?
thank you very much and sorry for my english
primoz