Making my own HDR but need to wait 5 seconds between photos to change exposure?

[quitmeyer]

Hi! im trying to take my own bracketed HDR photos. I have a little loop where i take photos at different exposure settings. but for some reason for the settings to take effect, i need to do a time.sleep(5) between each photo or else the change doesn't seem to take effect.

Now caveat, Im that guy using a arducam 64 on a pi4 and understand im apparently pushing the limits of what these things can do, but im just checking if im doing something wrong and there's a faster way to just change the exposure settings:

here's the meat of the code im doing

    print("About to take HDR photo:  ",timestamp)

    ''''''
    if camera_settings:
        picam2.set_controls(camera_settings)
    else:
        print("can't set controls")
    ''''''
    min_exp, max_exp, default_exp = picam2.camera_controls["ExposureTime"]
    print(min_exp,"   ", max_exp,"   ", default_exp)


    #important note, to actually 100% lock down an AWB you need to set ColourGains! (0,0) works well for plain white LEDS
    #gains = 0,0
   
#     gains =  9, 0
#     picam2.set_controls({"ColourGains": gains})
#     
    middleexposure = camera_settings["ExposureTime"]
    exposure_times = list_exposuretimes(middleexposure, num_photos,exposuretime_width)
    print(exposure_times)
    
    time.sleep(5)
    picam2.start()
        
    time.sleep(5)

    start = time.time()
    
    exposureset_delay=5
    #request =[num_photos]
    #HDR loop
    for i in range(num_photos):
        #middleexposure = camera_settings["ExposureTime"]
        
        picam2.set_controls({"ExposureTime":exposure_times[i] })
        print("exp  ",exposure_times[i],"  ",i)
        time.sleep(exposureset_delay)#need some time for the settings to sink into the camera)
        flashOn()

        request = picam2.capture_request(flush=True)
        #picam2.capture_array("raw")
        
        if not onlyflash:
            flashOff()

        
        flashtime=time.time()-start

        print("picture take time: "+str(flashtime))
        
        folderPath= "/home/pi/Desktop/Mothbox/photos/" #can't use relative directories with cron
        filepath = folderPath+"ManFocus_"+computerName+"_"+timestamp+"_HDR"+str(i)+".jpg"

        request.save("main", filepath)
        print("Image saved to "+filepath)
        request.release()

[quitmeyer]

and to clarify i got it working, and luckily moths don't move THAT much, but something like 1 or 2 seconds between exposures would be much more ideal

[quitmeyer]

I think i fixed it by making the camera STOP each iteration and restart. Otherwise it seems you have to wait a couple frames (and for this slow camera 2 frames is about 5 seconds!)

this gives me about 1-2 seconds between pics

  exposureset_delay=.5 #values less than 5 don't seem to work! (unless you restart the cam!)
    #HDR loop
    for i in range(num_photos):
        #middleexposure = camera_settings["ExposureTime"]
        
        picam2.set_controls({"ExposureTime":exposure_times[i] })
        print("exp  ",exposure_times[i],"  ",i)
        picam2.start() #need to restart camera or wait a couple frames for settings to change

        time.sleep(exposureset_delay)#need some time for the settings to sink into the camera)
        
        flashOn()
        request = picam2.capture_request(flush=True)
        #picam2.capture_array("raw")
        
        if not onlyflash:
            flashOff()

        picam2.stop()

        
        flashtime=time.time()-start

        print("picture take time: "+str(flashtime))
        
        folderPath= "/home/pi/Desktop/Mothbox/photos/" #can't use relative directories with cron
        filepath = folderPath+"ManFocus_"+computerName+"_"+timestamp+"_HDR"+str(i)+".jpg"

        request.save("main", filepath)
        print("Image saved to "+filepath)
        request.release()

figuring out how to save the files later instead of in the loop would be a good next step

[quitmeyer]

Made a script that at least for me and my slow camera can take a HDR series as fast as possible, and save the files later and save some exif data with them: (Still wonky, but works!)
https://github.com/Digital-Naturalism-Laboratories/Mothbox/blob/main/Software/TakePhoto.py