spinning 35mm adaptor question

emotepix

emotepix

Well-known member
Hello there

Some simple questions for anybody who has made or is making a spinning CD style 35mm adaptor:

a) suppose you're using a 3v micromotor - what's the formula for calculating the correct variable resistor / speed controller's resistance and power capacity?

b) where can you get a click-style potentiometer of the correct values in a)?

c) if you've got an HDV camera with a 72mm front end, and your optics are set for a focal length of around 4.5"/110mm to the ground glass, will you need a 72mm macro and doublet? Or, since you've presumably zoomed in anyway, will 52mm opticals suffice?

Or is the 72mm glass used to get around edge CA and vignetting issues?


Thanks!
Cheers
Chris
 
A. Im using a 12 v motor but i underpowered it with just 3 AA batteries. using 2 and the rings would show. using 4 and my rig vibrates.

C. 52mm, in my experience, vignettes. a 65mm with step down rings is what ive used. You need the equivalent of a +10 to get clear passed the vignette.
 
teddy bear, what camera do you use yours on?

i wanna make one for my dvx but i wanst sure with the macro, you use a 65 with a 65-72mm stepup?

what about straight using a 72mm +10?
 
zipper, I used it both for DVX and HD100. I had a hard time lukin for a 72mm macro so i edned up with 65. if you got 72mm macros, thats perfect.
 
i know you have to adjust eh adapter so the length between the lense and the gg is proper, once you adjust that, can you put any lense on it? i would assume so, or do you need to re adjust per lense your using?

would u recomend using the 3 +3 macros or 1 +10?
 
the distance between lens and adapter, known as flange depth, is fixed. Thats why a diy adapter must first take into consideration what type of lens you will use, (a nikon, canon or in my case mid format mamiya 645s) in my case the flange depth is 63mm. You can tell a certain camera's flange depth by looking for a circle with a line thru it somewhere on the camera body. That symbol aligns with the film plane in film cameras or the ccd in digital cameras. THAT is also your reference where your GG will be.

Ted
 
I suggest you minimize stacking and go with single +10 as per my experience, stacking also increases CA. A better option is to use an achromat.
 
drummer07 said:
anybody know where i can find the frosted cd? I have looked everywhere...
Click to expand...


in the diy it says the maxell cd-r comes with one that frosted....

is that true or not anymore...
 
Im not sure, i use to get those with swpindle purchases of 25 and 50's.

What I did last time was went to a CD DVD retailer and asked for the frosted ones! The sales guy smiled. Told him i'd buy some discs if he can throw in those blank dummy frosted cds.
 
ive bought many different kinds of cds/dvds and none had frosted. I guess ill look in the phone for a retailer or dupliation of some sort.
 
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