stopping down canon lens on CCD?

[Astroblagger]

Hello i plan to use a canon 200mm F2.8 lens on my Atik 314L+, how do you stop down the lens from F2.8 when the lens isnt on a camera to control it?

[Thalestris24]

Hi

I don't think you can - but why would you want to anyway?

Louise

[Photosbykev]

You can stop the lens down, which will improve star profile in the image corners, BUT you first need to put it on a body with a Depth of Field preview button. Select the aperture required, press the DoF preview button and while pressing the DoF button release the lens from the camera body. This will leave the lens at the selected aperture until it is reconnected to the DSLR body. The alternative is to use a front aperture mask which most people consider to be a better solution.

[Alien 13]

Hi

I don't think you can - but why would you want to anyway?

Louise

I was thinking this too with a small sensor you wouldnt see any edge artifacts on the chip.

Alan

[jnc71106]

the 200mm at f2.8 will be fine with the atik 314 i've used that exact setup in some of my pics

if you want to step it down without connecting it to a dslr body just make an aperture mask for it and pop it in the hood job done

[Astroblagger]

What size micro focuser do I need for the canon 200mm F2.8 lens I see there are 3 different sizes?

[jnc71106]

The smallest one works fine I believe it's 75mm