High-speed laser camera 29425 fotoopa
Update 3 july 2014:
For the current 2D version see: www.flickr.com/photos/fotoopa_hs/12537231674
For the current 3D version see: www.flickr.com/photos/fotoopa_hs/6760414583
Finally the high-speed laser camera is ready.
What's new in this version?
- I currently use one of the fastest shutters available. The shutter-lag is only 3.3 msec. This is the time from the command to the moment the picture is taken. The internal Nikon D300 shutter-lag is normal arround 52 msec, a lot to slow for in-flight insects at closeup distance.
The used external shutter is the Uniblitz VS14 shutter. I used the naked body shutter, so the housing is a DIY version. The external shutter is now between the camera and the lens. This DIY housing is only 30mm wide. Because this shutter work as a macro ring, the infinit focus range is limited. But in my case the usable range goes from 17mm to 82 mm frame picture. This range is super ideal for small insects in-flight.
I use now 3 flashes, 2 x SB-80-DX and one ringflash the SB-29-S. This must result into better lighting. The ringflash is not connected to the macrolens but via a new DIY adapter to the frame. This results into a fix position as the macrolens lenght change with the macro setting. If this ringflash stay on the lens, the laser detection optics have not enough free to see the reflected IR signals.
In this version the lasers are a lot more accessible to adjust them correct at the ideal focuspoint of the camera. The results of this is a very high sensivity of the detector system, even at very closeup and high speed movements of the insects. The laser detection time is now 2x 60 usec or 120 usec, the shutter-lag is 3.3 msec, so I have set the flash delay at 3.5 msec to have a small save intervall.
The used photo detector diode is now the BPW41N. The detector have a integrated narrow filter. This filter is used together with IR lasers at 980 nm. The result is insensitive to the sunlight, one of the bigggest problem previous years. The new IR lasers are now very fast switching lasers and the power is a little higher, this results also into a higher reflected signal for the photodiode. results are smaller insects can be detected at higher speed.
The electronics are total reworked. The basic module is again the Terasic CPLD board (MAX II). The high voltage driver for the external shutter is adjusted to this new timings and extra signal are now avaible to open the external shutter during the adjusting procedure of the camera. The diafragma are now set manual on the AF105/2.8Dmicro lens because the camera c'nt drive this as the external shutter is now between lens and camera.
A lot of extra switches are now avaible for new functions. One of this function are the TTL power drive of the flashes via an external 6 position switch on the frame. A second switch set the ballans between the left and the right side into 6 positions. All this information is displayed on the LCD display.
All connection are now a lot reliable. The hole frame contains the electronic prints and all the connection cables. Extra highpower leds are avaible to work at night. This leds are powered via 4 external AA batterys so they give no extra load to the central power batterys (6xAA) for the hole controller.
Total weight is now 7.2 kg. The ringflash have added here an extra load but I exect significant improvement for closeup shots where the distance from object to the front of the macro lens is only 105mm for a macro setting of 2.2:1 (17mm real live picture projection on the sensor).
This setup is really complex but I have chosen for optimum speed and performance. This Uniblitz VS14 shutter is one of the fastest version on the market that supports this integration.
There are a lot of details not to seen on the pictures like how the macrolens focus ring can be locked. Even on manual position, the lens can move slow out focus in long time. So I have loked the focus ring once the calibration is finish.
The hit rate of this camera system is near 100%. Only correct pictures are taken in full flight. This 3.5 msec shutter-lag guarantees a short movement of the insects between detection and the time that the picture are taken. The relative speed at closeup distance of fast moving insects are extreeme high. A normal camera show always a insects out the frame with the internal shutter-lag.
I have worked near 4 months on this design. The total cost is high. I have to buy a lot of new tools for the lathe and the miller machine. New lasers, tested multiple photodiodes, find the necessary aluminum parts, a lot of electronic components etc.. But now I'm ready to capture the beautiful insects once they commeback in spring.
How it's works:
- Shutter integration:
- Camera and external shutter:
Overview of the setup:
Final the results so far for 2011 insects in-flight:
Results for moths 2011: