Aankondiging

**paly** · 14 oktober 2010, 07:44

Re: Sneel sluitertijden via flitsen

http://www.flickr.com/photos/fotoopa_hs/sets/72157604620957208/

To take insects in flight you need a very fast system. The biggest problem with a digital camera is the shutterdelay. Shutterdelay is the time between the command to take a picture and the real execution. Digital cameras need a minimum delay to prepare the internal capture and to move the shutter from closed to full open. Older mechanical shutters d'nt have this problem to prepare the internal sensors for a new picture. Most of the best old shutters have a short openingstime into the range from a few msec to 10 msec. Digital cameras have mostly more then 50 msec, only a few highend professional cameras have a shutterdelay lower then 40 msec. Insects in flight as macro have a very high relatieve speed compared to the cameraframe. The displacement in a few msec is great so the insects are out of the framepicture at the moment the camera take it. To archieve good records the shutterdelay must be lower then 10 msec and even 5 msec or lower are need. The frame for the macro picture is small for the little bees and flies. I use for this insects a pictureframe of max 60mm x 40mm. The distance from this capture frame to the backside of the camera is about 450mm in this case, but the free distance from the front of the shutter to the focuspoint is only 210mm this for the AF105/2.8D micro lens. Insects in flight are detected by 2 crossed laserbeams. The distance from the laser to the detector is 360mm, so the central cross and focuspoint for the camera is 180mm from the lasers. If an insect passe to this central crosspoint the system is activated to take a picture. From this point how faster how more change to get the insect into your pictureframe and in focus. because the macro short distance, the DOF for a picture is small, a little deviation out of this point from the insect give you a picture out focus. I use a old mechanical compur1 shutter from the years 1955-1960. This old shutter go full open into lower then 5 msec. To activate this shutter you need now an superfast electro magnet instead of your finger push from the old days. Once the shutter is open you may drive the flashes. To freeze the flight action you need a very short flashtime. Flashes must set manual at minimum power to reach this short timing. But low power give you low light. The environment light is not useful as the minimum flash sync periode is mostly near 1/250 sec, much to long for this work. So you need to set the camera to avoid this environment light by setting the ISO value low and the Fvalue high. But this imply more light from the flashes. So this stay a compromise. I use mostly F22, ISO100 and as flashpower 1/64. To realise sufficient light 2 or 3 flashes are used. The camera must stay in bulb mode, so the camera record first only black picture ( and some noise if this time is to long). The newer cameras are better for lownoise for long exposure. Especially the D200 give very low noise even for multiple minutes records of black pictures. Before you can start an record, you need to start the camera with the compurshutter closed. No light enter into the camera so only very little noise over a long period can be created. Once the insects now comme and pass through the crosslaserpoints the compur1 shutter is activated and 5 msec later the flashes. After this action the camera may be stopped. If the camera record black picture over a periode longer then 1 min before an insects is detected, I stop the camera to change over to to a next picture to limit the longterm noise of the camera. Results: www.flickr.com/photos/fotoopa_hs/sets/72157604178299415/ I've build a new setup 2009 to capture insects in-flight. See the description: www.flickr.com/photos/fotoopa_hs/sets/72157611107153997/ For the new setup version 2010-2011 seethis link: www.flickr.com/photos/fotoopa_hs/sets/72157625073020642/ The new results 2011 in-fligh insects: www.flickr.com/photos/fotoopa_hs/sets/72157625642148065/

**Den_Dove** · 14 oktober 2010, 08:18

Re: Sneel sluitertijden via flitsen

Sick >.<
Maar de resultaten mogen er inderdaad wel zijn...

**hjanssen** · 14 oktober 2010, 08:59

Re: Sneel sluitertijden via flitsen

Ooit eens en rtikel gelezen van in het Nikon Pro magazin, die uitrekende hoe kort de flitsen waren bij 1/x kracht en dat dan gebruikte om de insecten te bevriezen. Ik zal later eens kijken of ik het nummer van de uitgave nog kan vinden.

Aankondiging

Sneel sluitertijden via flitsen

Sneel sluitertijden via flitsen

Comment

Comment

Comment