Stop-Ac4on Photography

Transcription

1 Image Gary Cook

2 Stop-Ac4on Photography High Speed photography - Exposure 4me is very short How short? Short enough to freeze any movement Depends on what you are photographing Big birds.. 1/200 1/2,000 second Small birds... 1/2,000 1/8,000 second Tiny birds... 1/4000 1/20,000 second BB guns... 1/10,000 1/50,000 second Bullets... 1/50,000 1/2,000,000 second

3 Stop-Ac4on Photography What equipment do I need? Camera (obviously!) Flash(s) Remote trigger Lasers Microphones Guns and ammuni4on Birds Eggs or fruit... But not all at once!

4 TWO shu_er curtains Curtains move sequen4ally DSLR Shu_er Ac4on

5 DSLR Shu_er Ac4on For shu_er speeds SLOWER than 1/250 sec, shu_er opens completely: This is because it takes each curtain 1/250 sec to cross the sensor

6 DSLR Shu_er Ac4on For shu_er speeds FASTER than 1/250 sec, the second curtain begins to move before the first curtain has cleared the sensor: This creates a slot that moves across the sensor

7 DSLR Shu_er Ac4on The faster the shu_er speed, the narrower the slot : 1/1000 sec

8 DSLR Shu_er Ac4on The faster the shu_er speed, the narrower the slot : 1/8000 sec

9 Flash So, if a pulse of light from a flash or strobe is shorter in dura4on than 1/250 second, you MUST make sure the camera shu_er speed is 1/250 second or slower. This ensures the sensor is fully exposed when the flash fires If you use a high speed flash with a fast shu_er speed, the flash may only illuminate part of the slot mo4on while it crosses the sensor. This is why most DSLR flash sync speed is around 1/250 sec Sync speed is faster for small sensors, slower for larger sensors: Micro 4/3: 1/320; Crop sensor: 1/250; full frame: 1/200

10 Flash ETTL flash Through the lens REAL TIME control of the flash output Flash is automa4cally turned off when the camera has captured enough light

11 Flash ETTL flash exposure control Exposure depends on the graph area: Intensity Time Maximum flash Reduced flash Minimum flash

12 Flash ETTL flash dura4on therefore depends on the exposure i. e. the flash dura4on varies from shot to shot For high speed photography, the flash dura4on is IMPORTANT So DO NOT USE ETTL flash!!! Use MANUAL flash or High Speed Sync flash High Speed Sync flash...?

13 High Speed Sync Flash High Speed Sync flash Electronically s-t-r-e-t-c-h-e-s the dura4on of the flash to greater than 1/250 sec Guarantees the flash is on regardless of the actual shu_er speed Not available on all cameras and also requires a flash that is compa4ble with this feature. Drains ba_eries very quickly. (Flash is effec4vely always on full power ) Longer total dura4on cools the flash discharge, so color balance can become a li_le warm Useful for bird photography for shu_er speeds of 1/4000 1/8000

14 High Speed Flash Manual Flash allows exposures MUCH faster than 1/8000 sec Remember how the flash dura4on varies with ETTL flash? Maximum flash Reduced flash Minimum flash Manually seing the flash output to minimum guarantees the shortest possible pulse of light. It also minimizes the total amount of light, so need to place the flash close to the subject and/or use mul4ple flash units

15 Manual Flash How short? (on manual seing) [1 μs = 1/1,000,000 sec] Se2ng Canon 600 EX- RT Yongnuo YN 600 EX-RT Canon 430 EX II Contax TLA20 Maximum 1310 μs 1530 μs 1020 μs 480 μs 1/2 905 μs 1180 μs 996 μs - 1/4 408 μs 546 μs 440 μs - 1/8 212 μs 273 μs 185 μs - 1/ μs 152 μs 108 μs - 1/32 73 μs 91 μs 71 μs - 1/64 48 μs 60 μs 49 μs - 1/ μs 41 μs - - Minimum 32 μs 41 μs 49 μs 18 μs

16 Small Birds Simple cable release Op4onal flash or mul4ple flashes Image Gary Cook

17 Small Birds Small birds are WAY too fast for autofocus, so.. Use manual focus Set focus point to be where you expect the birds to pass Use manual exosure Stop the lens down to f/11 Set shuter speed to 1/4000 sec or faster Set ISO to Auto Recommend using High Speed Sync flash Watch for approaching birds and try to fire the camera shu_er a frac4on of a second before the bird reaches the pre-focused spot. Why a frac4on of a second before? Shu_er lag! It takes around 1/20 second for the shu_er to ac4vate. Image Gary Cook

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22 Small Birds You can do this! Just need a remote cable release and something to a_ract the birds Very low cost Flash recommended, but op4onal if it s a nice sunny day But you need pa4ence... Lots of pa4ence... If you don t have the paience to sit there for hours trying to capture the right shot (day aver day), there is another way...

23 Trigger Trap: $40 Accessories are extra 5 ms response 4me (1/200 sec) Uses cell phone app as sensor Triggers: Sound, vibra4on, mo4on, faces Camera or flash Also does 4melapse Rather insensi4ve Need to use your phone

24 Vello FreeWave Stryker:$ μs response 4me (1/10,000 sec) Triggers camera or flash using mo4on or lightning Works well, but limited use and not adaptable

25 Miops Trigger: $230 Accessories are extra 300 μs response 4me (approx.. 1/3500 sec) Mo4on trigger Op4cal trigger Sound trigger Lightning trigger Also does 4melapse Response 4me is not great

26 Ubertronics Strike Finder Touch: $350 Comes with some sensors 1 ms response 4me (1/1000 sec) Mo4on trigger Op4cal trigger Sound trigger Lightning trigger Also does 4melapse Response 4me too slow for ballis4cs

27 StopShot: $350 with beam-break sensor kit Addi4onal sensors and sensor kits extra ($29 - $399) 50 μs response Gme (1/20,000 sec) Maximum versaglity HIGHLY RECOMMENDED THIS IS THE DEVICE I USE Image Cognisys Inc. reproduced with permission Mo4on trigger Op4cal trigger Sound trigger Vibra4on trigger Lightning trigger Sequen4al trigger Ballis4cs trigger Also does 4melapse Mul4ple devices

28 A note about response 4me: Much is made about the response 4me by the manufacturers But it makes almost NO DIFFERENCE if you will only be using the device to trigger your camera.. Camera shu_er lag is usually greater than 50 ms (1/20 sec) Resonse 4me DOES MATTER for accurate 4ming when using the device to trigger FLASH for fast moving objects (crossbow, bullets, burs4ng balloons, etc.)

29 The StopShot Controller Three outputs can fire mul4ple flashes or more than one camera All together, or in sequence Image Cognisys Inc. reproduced with permission

30 Trigger inputs sensors: Microphone Vibra4on sensor Passive infra red* Infra red beam break* Laser beam break* LIDAR sensor (the new Sabre )* * - these can be used individually or in pairs Images Cognisys Inc. reproduced with permission

31 Trigger modes: Simple trigger trigger all channels independently Sequen4al trigger triggers all channels in series Condi4onal trigger used with two sensors ( A and B ): A or B either sensor triggers the system A then B only triggers if A triggers before B B then A same as above, but in reverse A and B system only triggers if BOTH sensors are tripped Used for cross-beam sensors Ballis4cs mode special mode for capturing bullets, etc. Image Cognisys Inc. reproduced with permission

32 Also has: Shu_er lag measurement: System triggers a camera + flash and measures the 4me between ac4va4ng the camera and the flash firing This is SO useful! Water drop photography: System controls the release of water drops from a mario_e syphon and 4mes the flash exposure perfectly Capable of genera4ng mul4ple drops for drop collision photography Image Cognisys Inc. reproduced with permission

33 Shu_er lag measurement: Some surprises... My Canon 5D mk III: On wake (shu_er bu_on ½ pressed before release): 63 ms (about 1/16 s) With mirror lock-up: 86 ms (about 1/12 s) slower!! Not awake simple shu_er press: 580 ms (about ½ s) Image Cognisys Inc. reproduced with permission

34 On wake gives fastest camera response StopShot system has a special 3-posi4on switched cable: Off disconnects the camera from the system Sleep allows the camera to sleep Wake CONTINUOUSLY acts like a ½ press of the camera bu_on Image Cognisys Inc. reproduced with permission

35 One sensor simple microphone Images Cognisys Inc. reproduced with permission

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41 One sensor simple beam break Infra red Laser Image Cognisys Inc. reproduced with permission

42 Two sensors cross beam Pin-point triggering accuracy Image Cognisys Inc. reproduced with permission

43 Cross beam sensors (lasers) in use Image Gary Cook

44 Cross beam sensors (lasers) in use Image Gary Cook

45 Cross beam sensors (lasers) in use Image Gary Cook

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54 Two sensors sequen4al Direc&onal triggering Image Cognisys Inc. reproduced with permission

55 Two sensors sequen4al Direc&onal triggering Image Cognisys Inc. reproduced with permission

56 Two sensors sequen4al Either triggering Image Cognisys Inc. reproduced with permission

57 Two sensors sequen4al Ballis&cs triggering Image Cognisys Inc. reproduced with permission

58 Ballis4cs mode S Mul4ple of S Don t need to know the speed of the projec4le! Place camera a mul4ple of the sensor separa4on: e.g. 6 between sensors, camera placed 18 aver last sensor Set StopShot ballis4cs delay to a factor of 3 (18 divided by 6 ) Shoot! Image Cognisys Inc. reproduced with permission

59 Image Gary Cook Infra red sensors

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77 Range IR Sensor Ac4ve infra red sensor Range is adjustable Triggers when an object enters a pre-determined maximum range Can be used individually, or in pairs (sequen4al, cross beam, etc.) Single sensor can be used stand-alone without StopShot Image Cognisys Inc. reproduced with permission

78 Range IR Sensor(s) Stand alone With StopShot Cross-beam, sequen4al, etc. Images Cognisys Inc. reproduced with permission

79 Two Range IR sensors in use

80 Sabre Sensor LIDAR technology (light detec4on and ranging) 500 ns diode laser pulses with &me of flight measurements Super accuracy (1 typical) with range ga&ng trigger only when an object appears between two user defined distances e.g. only trigger between 5 and 6 feet from the sensor Image Cognisys Inc. reproduced with permission

81 Can be used individually, or in pairs (sequen4al, cross beam, etc.) Sensor can be used stand-alone or with StopShot Wi-Fi enabled with computer control and smart-phone control (iphone and Android) Image Cognisys Inc. reproduced with permission

82 Sabre WiFi App Op4ons... Lots!

83 Acknowledgements Special thanks to Paul and Jen DeZeeuw at Cognisys, Inc., for their kind support and for permission to use Cognisys product images as part of this presenta4on. h_ps:// Ques4ons?