russell_fill

Thanks all for all the info.

I have gone around and around with adapter rings and second party lens etc etc etc...

What I am up to now is to think of a way to open the lens and put some sort of a control

arm/ring through a port so it could be controlled from the out side manually. And

hopefully with the resolution I need for my work. That is why I have purchused a old

28-70 3.5-4.5 lens to tear apart to see what might be able to be done. This is why Im

asking how the iris part of the lens works. Magnets activated by a current or small motors

controlled by a driver or computer on the camera or what?

Does anybody know of a lens builder/repair or customizer.

Im also in the process of using a photocromatic transition lens to see if it will handle the

change from day to nite, maybe 3 stops...maybe. Here is the reason for the 1/64th or even

higher resolution. When I say shoot a sunset from full sun to stars coming out I need

about 6 to 8 stops to keep correct exposure and this would be approx. 300 to 1000

frames/photos. In say 30 to 60 images that represents about 2 seconds of a clip in TV

time. If you say make a 1/3rd stop change each frame if you had that many stops, you

will notice a gradual change. If you have say 1/3rd of a stop every 4 or say 8 frames you

will have large changes of exposure in the clip as the frames are all run continuously at 24

to 30 frames per second. With extreme over exposing and having the light go to extreme

under exposure I can correct for about 2 to 3 stops on each end of that clip using post

adjustments, photoshop/After Effects. After that the noise starts to get un useable for the

start of the clip and the last part of the clip. My hope is to be able to connect a stepper

motor with a gear drive and a light sensitive sensor to control the amount of movement

with the iris over the change in light from sunset to dark or when a large cloud goes by or

for any light change..

Still hoping for some way to get about 5 stops more from my clips.

I am using Canon EOS 1dsM2 and other Canon EOS cameras to photograph time lapes sequences and

work them up in to movies. Im trying to control the f/stop of the lens in smaller movements than 1/3 of

a stop. Any ideas would be welcome. Im tring to find out how the eletronic apetrure is controled or how

to contol it manually. What I need is to be able to control it in as small amounts as possible. Maybe

1/64th of a stop at a time or smaller still.

How do the apetures work?

And is there any one out there who knows if it is possible to run a external control through the contacts of

the lens to control the apeture in smaller amounts than 1/3rd of a stop.

Thanks for any info

Russ Fill