Aperture flickering problem

Tomtkt · 12-07-2014, 04:13 PM

Hi,

I god a new K-3 with the 15-55mm kit lens and im testing it now with timelapses. I find it a good buy but i got some problems when it comes to flickering now in one of my test takes.

I read that you could twist the objective to freeze the aperture, but that dont work with the kit lens..
So i am wondering if there is any suggestions or smart settings i should turn on/off to help avoiding the flickering?

A manual lens would for sure do the trick, but i would like to be able to use the kit lens for timelapse as well...

Any help from a Pentax timelapser would be appreciated

**southlander** · 12-07-2014, 08:48 PM

The exposure levels are potentially changing between images as the auto-exposure is reading changing lighting in slightly different ways from frame to frame, and not giving even illumination to each frame. You really need to use M for manual mode and set the exposure levels manually so as to keep exposures constant. (both aperture and exposure time). Googling around for good time lapse tutorial articles should provide more guidance. If a loooong time lapse, changes to settings might be needed somewhere through the capture. But if Manual, this can be controlled so as to be a subtle progression. Also, in post processing, a known series of frames around the intervention can be processed to better sequence the change of lighting, before the rendering to a time lapse video. Unless circumstances dictate otherwise, I would vary shutter speed rather than aperture as you will get an unplanned change in depth of field/control of aberations if varyingly aperture significantly to respond to changes in light.

Tomtkt · 12-08-2014, 01:54 AM

Originally posted by southlander

The exposure levels are potentially changing between images as the auto-exposure is reading changing lighting in slightly different ways from frame to frame, and not giving even illumination to each frame. You really need to use M for manual mode and set the exposure levels manually so as to keep exposures constant. (both aperture and exposure time). Googling around for good time lapse tutorial articles should provide more guidance. If a loooong time lapse, changes to settings might be needed somewhere through the capture. But if Manual, this can be controlled so as to be a subtle progression. Also, in post processing, a known series of frames around the intervention can be processed to better sequence the change of lighting, before the rendering to a time lapse video. Unless circumstances dictate otherwise, I would vary shutter speed rather than aperture as you will get an unplanned change in depth of field/control of aberations if varyingly aperture significantly to respond to changes in light.

I forgot to mention but i have taken some timelapses before with other cameras and i use M when i shoot. I dont vary the aperture, the problem is called aperture flickering and when my camera takes a picture the aperture doesnt always go to the exact same opening, the result is flickering since one image is ligheter than the other.

So my question is if this could be caused by something else in the K-3. Some settings that i should turn of perhaps?

If not the solution is to make my lens think its a manual one, but the twist trick dont work with the pentax as far as i tested. Maybe manual aperture lenses is the only solution for this then.

12-07-2014, 04:13 PM	#1
Tomtkt New Member Join Date: Dec 2014 Posts: 5	Aperture flickering problem Hi, I god a new K-3 with the 15-55mm kit lens and im testing it now with timelapses. I find it a good buy but i got some problems when it comes to flickering now in one of my test takes. I read that you could twist the objective to freeze the aperture, but that dont work with the kit lens.. So i am wondering if there is any suggestions or smart settings i should turn on/off to help avoiding the flickering? A manual lens would for sure do the trick, but i would like to be able to use the kit lens for timelapse as well... Any help from a Pentax timelapser would be appreciated

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12-07-2014, 08:48 PM	#2
southlander Site Supporter Join Date: May 2012 Location: Adelaide Photos: Gallery \| Albums Posts: 1,364	The exposure levels are potentially changing between images as the auto-exposure is reading changing lighting in slightly different ways from frame to frame, and not giving even illumination to each frame. You really need to use M for manual mode and set the exposure levels manually so as to keep exposures constant. (both aperture and exposure time). Googling around for good time lapse tutorial articles should provide more guidance. If a loooong time lapse, changes to settings might be needed somewhere through the capture. But if Manual, this can be controlled so as to be a subtle progression. Also, in post processing, a known series of frames around the intervention can be processed to better sequence the change of lighting, before the rendering to a time lapse video. Unless circumstances dictate otherwise, I would vary shutter speed rather than aperture as you will get an unplanned change in depth of field/control of aberations if varyingly aperture significantly to respond to changes in light.

12-08-2014, 01:54 AM	#3
Tomtkt New Member Join Date: Dec 2014 Posts: 5 Original Poster	Originally posted by southlander The exposure levels are potentially changing between images as the auto-exposure is reading changing lighting in slightly different ways from frame to frame, and not giving even illumination to each frame. You really need to use M for manual mode and set the exposure levels manually so as to keep exposures constant. (both aperture and exposure time). Googling around for good time lapse tutorial articles should provide more guidance. If a loooong time lapse, changes to settings might be needed somewhere through the capture. But if Manual, this can be controlled so as to be a subtle progression. Also, in post processing, a known series of frames around the intervention can be processed to better sequence the change of lighting, before the rendering to a time lapse video. Unless circumstances dictate otherwise, I would vary shutter speed rather than aperture as you will get an unplanned change in depth of field/control of aberations if varyingly aperture significantly to respond to changes in light. I forgot to mention but i have taken some timelapses before with other cameras and i use M when i shoot. I dont vary the aperture, the problem is called aperture flickering and when my camera takes a picture the aperture doesnt always go to the exact same opening, the result is flickering since one image is ligheter than the other. So my question is if this could be caused by something else in the K-3. Some settings that i should turn of perhaps? If not the solution is to make my lens think its a manual one, but the twist trick dont work with the pentax as far as i tested. Maybe manual aperture lenses is the only solution for this then.