Auto Iris jumping ?

Hello,

I have just received my BMPCC with newest firmware installed. So far, I am extremely impressed (used hacked 5DmIII before but needed a more pocketable solution with more "dept of field" in available light situations + it is so much easier to handle (even the raw files:-) ).

When using the auto iris button (especially if the light situation changes drastically), the camera jumps through different aperture settings, usually closing down aperture and opening up in steps, as if it had to evaluate each setting before "deciding" whether to "stay there" or to "try another"...

Is this a general behaviour or do I have a "problem" with my camera ?

Thank you!

Best,
T

The Auto Iris only works on electronic MFT lenses. Pressing the Iris button adjusts the Iris to balance the exposure. This process is different in each mode.

In Video mode it takes an overall reading from the scene and exposes it pretty much central. So you extreme highlights will get clipped in this mode.

In Film mode it adjusts the exposure so that nothing in the scene clips.

Generally it closes the iris down and then opens up until it gets to to the desired iris setting. On most lenses this is a very quick process, almost instant.

The camera does not continue to adjust the iris once this adjustment has been made.

Thank you for your answer, Adam. Impressive website, by the way

I forgot to mention, that I currently use the 14mm 2.5 Panasonic lens, 12-35mm 2.8 will arrive tomorrow.

Concluding from your answer, the behavior seems to be normal. I was a little bit confused that "finding the right aperture" needs (in some cases) three or more steps...

If the light situation does not change massively, it is a quick process after pushing the iris button, indeed.

But going from a f2.5 situation to a f16 situation usually pushes the aperture setting to f22 stepping down to f16, which sometimes may take up to estimated 1,5 seconds. Not a problem for me, though - just thought this might be unusual.

Thank you!

Best,
T