tmx3 Posted March 30, 2018 Author Share Posted March 30, 2018 8 minutes ago, StringJunky said: The camera's sensor, which is writing line-by-line, and the bulb, which I have just found out is flashing at twice the line frequency; 120Hz. Here's a video of that happening: But look at the second photo... There are no bars. Only when I went near the bat were there bars... so it does have to do with the bat, not the lamplight... Link to comment Share on other sites More sharing options...
Strange Posted March 30, 2018 Share Posted March 30, 2018 1 minute ago, tmx3 said: How does ultrasound travel through an iPhone’s lens to disturb the filament? Hold on ... The filament is in the bulb. Light bulb filaments are very fragile (knock a bulb while it is on and it is likely to break the filament) and so potentially sensitive to vibration. This now seems more plausible than the vibrations affecting the relatively solid camera. Quote Disturbed the filament? Then shouldn’t there be a crackly image instead of straight bars??? The bats ultrasound will be a periodic signal. The light flickers at a (different) periodic rate. The camera scans the image at (yet another) steady frequency. Some or all of these could interact and I would expect the result to be regular rather than "crackly". You will often see a similar (but moving) set of bars if you try and video an old-style CRT TV screen. 1 Link to comment Share on other sites More sharing options...
StringJunky Posted March 30, 2018 Share Posted March 30, 2018 1 minute ago, tmx3 said: But look at the second photo... There are no bars. Only when I went near the bat were there bars... so it does have to do with the bat, not the lamplight... You need to be close to the subject as well to get the effect I described. Strange's proposal is feasible as well. Try taking pictures in the same conditions and scene but without the bat near. 1 Link to comment Share on other sites More sharing options...
tmx3 Posted March 30, 2018 Author Share Posted March 30, 2018 Okay, thank you all for your help! Link to comment Share on other sites More sharing options...
Strange Posted March 30, 2018 Share Posted March 30, 2018 (edited) 10 minutes ago, tmx3 said: But look at the second photo... There are no bars. Only when I went near the bat were there bars... so it does have to do with the bat, not the lamplight... One would have to try a set of controlled experiments to work out what is going on. Same pictures with and without the bat, with different types of light sources, different types/makes of camera, etc. Edited March 30, 2018 by Strange Link to comment Share on other sites More sharing options...
StringJunky Posted March 30, 2018 Share Posted March 30, 2018 3 minutes ago, tmx3 said: Okay, thank you all for your help! Keep popping back as someone versed in this subject may be able to give a clear, definitive answer. Link to comment Share on other sites More sharing options...
tmx3 Posted March 30, 2018 Author Share Posted March 30, 2018 3 minutes ago, Strange said: One would have to try a set of controlled experiments to work out what is going on. Same pictures with and without the bat, with different types of light sources, different types/makes of camera, etc. Yeah I mean I kind of did that... I noticed the bars in the photo, and so I tried to take a photo of the bat from far away and the picture was fine. But when I moved closer, I’d have to say I was within a foot or even closer of the bat, the photo started coming out strange. I guess I could have tried a different kind of lamp, but honestly I just wanted a photo of the bat, that’s all. Everything else was just unnecessarily confusing that night. To this day I still don’t understand how he even came into my house. Anyway, thanks again 6 minutes ago, StringJunky said: Keep popping back as someone versed in this subject may be able to give a clear, definitive answer. Well, is there some specific thread or user you have in mind? I could just private message them or tag them... What are the odds of a biologist who studies bats and their effects on light here. Haha Link to comment Share on other sites More sharing options...
StringJunky Posted March 30, 2018 Share Posted March 30, 2018 (edited) 10 minutes ago, tmx3 said: What are the odds of a biologist who studies bats and their effects on light here. Haha Biology expert CharonY might chime in and he's nutty about photography.Did the bat freak you out? I've had two flying in my living room in the past. The first one nearly stopped my heart. Edited March 30, 2018 by StringJunky 1 Link to comment Share on other sites More sharing options...
CharonY Posted March 31, 2018 Share Posted March 31, 2018 6 hours ago, StringJunky said: Biology expert CharonY might chime in and he's nutty about photography.Did the bat freak you out? I've had two flying in my living room in the past. The first one nearly stopped my heart. Oi, who are you calling nutty? I have not followed the thread so some it may already have been discussed, The image in OP looks like banding. The reason is that light sources in your home usually have pulsing characteristics due to the 60 HZ AC voltage being used. For cameras that only have electronic shutters (such as phones) the common readout characteristics of the sensors will result in areas of varying intensities, i.e. banding. In this case it is vertical as the image is read out from the sensor in columns (either starting left or right). So why is there less or no banding in some situations? The reason is the exposure time. If your exposure time is a multiple of the utility frequency, you integrate over the whole wave(s) (again, the brightness of the light sources fluctuates with the AC waveform). Thus the image appears homogeneous in brightness. However, if you get close to an object you are likely to change available light and thus change the exposure time. If the corner is dark for instance, it may slow the shutter to a degree where banding becomes very noticeable (I suspect that most phones will use software tricks to make sure that banding or similar common issue are minimized). If you can, I'd try to take photos (or better, videos) with varying shutter speeds at the same light and look at the results. It may be difficult as phones have a significant layer of software that may alter them. And not, it is not the bat. If they had some sensor shattering powers, the folks in the department who document them clearly would have noticed and published something high-ranked with it. Also I hope that you made sure that in you area bats do not carry rabies or similar diseases and, if hurt, find someone who can take a look at it. 3 Link to comment Share on other sites More sharing options...
StringJunky Posted March 31, 2018 Share Posted March 31, 2018 11 minutes ago, CharonY said: Oi, who are you calling nutty? Enthusiastic then. Link to comment Share on other sites More sharing options...
Sensei Posted March 31, 2018 Share Posted March 31, 2018 (edited) 1) make more photos.. 10+... Various angles.. various distances. 2) make videos... move slowly during making them. 3) try different smartphone and/or regular camera to see whether effect is appearing with them or not. 4) does it appear in preview on screen? On photo there is visible paper box, and center of image in nearly at the corner of this box, and bars looks like interference pattern. On this video you can see how sound can affect water: https://www.youtube.com/watch?v=tI6S5CS-6JI Edited March 31, 2018 by Sensei 1 Link to comment Share on other sites More sharing options...
tmx3 Posted March 31, 2018 Author Share Posted March 31, 2018 9 hours ago, CharonY said: Oi, who are you calling nutty? I have not followed the thread so some it may already have been discussed, The image in OP looks like banding. The reason is that light sources in your home usually have pulsing characteristics due to the 60 HZ AC voltage being used. For cameras that only have electronic shutters (such as phones) the common readout characteristics of the sensors will result in areas of varying intensities, i.e. banding. In this case it is vertical as the image is read out from the sensor in columns (either starting left or right). So why is there less or no banding in some situations? The reason is the exposure time. If your exposure time is a multiple of the utility frequency, you integrate over the whole wave(s) (again, the brightness of the light sources fluctuates with the AC waveform). Thus the image appears homogeneous in brightness. However, if you get close to an object you are likely to change available light and thus change the exposure time. If the corner is dark for instance, it may slow the shutter to a degree where banding becomes very noticeable (I suspect that most phones will use software tricks to make sure that banding or similar common issue are minimized). If you can, I'd try to take photos (or better, videos) with varying shutter speeds at the same light and look at the results. It may be difficult as phones have a significant layer of software that may alter them. And not, it is not the bat. If they had some sensor shattering powers, the folks in the department who document them clearly would have noticed and published something high-ranked with it. Also I hope that you made sure that in you area bats do not carry rabies or similar diseases and, if hurt, find someone who can take a look at it. Hey, thanks for your response! I see what you’re saying... The thing is though (I have to look through my camera to see if I can find the other photos I had to show this) the only time the banding happened was when I was near the bat. Otherwise that’s never happened... I guess I’ll check my camera to see how it’s taking shots now. I did before and there was no issue but I don’t know Link to comment Share on other sites More sharing options...
tmx3 Posted March 31, 2018 Author Share Posted March 31, 2018 14 hours ago, Sensei said: 1) make more photos.. 10+... Various angles.. various distances. 2) make videos... move slowly during making them. 3) try different smartphone and/or regular camera to see whether effect is appearing with them or not. 4) does it appear in preview on screen? On photo there is visible paper box, and center of image in nearly at the corner of this box, and bars looks like interference pattern. On this video you can see how sound can affect water: https://www.youtube.com/watch?v=tI6S5CS-6JI I just saw this, thank you. It seems though as if everyone’s set on the fact that it’s the camera...but that didn’t happen when I was further away from the bat. Only when I was near... That’s why I held the thought in my mind like a conviction that the bat must be emitting something that was causing my camera to take unclear photos... I’ll try anything at this point though. Thanks for the suggestions Link to comment Share on other sites More sharing options...
StringJunky Posted March 31, 2018 Share Posted March 31, 2018 18 minutes ago, tmx3 said: .. That’s why I held the thought in my mind like a conviction... It is good to see you have the insight to see when you are holding a conviction. 1 Link to comment Share on other sites More sharing options...
Bender Posted March 31, 2018 Share Posted March 31, 2018 I think there is no point persuing the bat thing. CharonY gave you the answer. Just Google "banding camera" and you will see plenty of pictures exactly like yours. Sometimes a coincidence is just a coincidence. Link to comment Share on other sites More sharing options...
koti Posted March 31, 2018 Share Posted March 31, 2018 (edited) I don’t know if this helps but lots of camera lenses use ultrasonic motors. Theorerically it might be possible that a bat might interfere with the lens operation giving artifacts in photos. But CharonY’s banding explanation seems a lot more plausible. I photographed a bunch of bats in Haiti once with my 70-200 f4 L IS which has ultrasonic motors and never saw any artifacts. Hundreds of them were flying in close proximity to me. Edit: It was on a coast of Angola not in Haiti. Edited March 31, 2018 by koti Link to comment Share on other sites More sharing options...
CharonY Posted March 31, 2018 Share Posted March 31, 2018 5 minutes ago, koti said: I don’t know if this helps but lots of camera lenses use ultrasonic motors. Theorerically it might be possible that a bat might interfere with the lens operation giving artifacts in photos. Cell phones do not have lens motors. Also, if you mess with it, you will affect focus, not light transmission. Again, shutter speed is the culprit. The reproducibility is issue is based on the fact that most cell phones do not allow fine controls of shutter speed, nor is it often clear what they used. I assume you could check exif data to see whether it changed between banding and non-banding images. However, there is also software trickery that tries to circumvent it so that it only shows up (or becomes more visible) in certain situations. This includes e.g. closeup with little light, where shutter speed are non-ideal and iso is high. A very simple experiment, which does not require you to get an actual camera with controls is to take a picture in horizontal mode. The banding should also become horizontal as it is related to the sequential readout from CMOS sensors (i.e. the integration issues that you see column by column, will should row-by-row). Unless, of course there is some weird technology in cell phones not seen in cameras (which I doubt). 1 Link to comment Share on other sites More sharing options...
tmx3 Posted March 31, 2018 Author Share Posted March 31, 2018 29 minutes ago, StringJunky said: It is good to see you have the insight to see when you are holding a conviction. Thanks! Yeah I mean without having that little bit of insight I’d be incredibly bull-headed for no reason. I resent that quality—would hate to be unreasonably stubborn. 30 minutes ago, Bender said: I think there is no point persuing the bat thing. CharonY gave you the answer. Just Google "banding camera" and you will see plenty of pictures exactly like yours. Sometimes a coincidence is just a coincidence. I’ll definitely look it up. Yeah, after reading CharonY’s first post about twenty times it made more sense to me that that was most probably it. Kind of ruined that magic I felt about the bat. Sigh. 30 minutes ago, koti said: I don’t know if this helps but lots of camera lenses use ultrasonic motors. Theorerically it might be possible that a bat might interfere with the lens operation giving artifacts in photos. But CharonY’s banding explanation seems a lot more plausible. I photographed a bunch of bats in Haiti once with my 70-200 f4 L IS which has ultrasonic motors and never saw any artifacts. Hundreds of them were flying in close proximity to me. Edit: It was on a coast of Angola not in Haiti. I see... Thanks for this post! I’m a little confused again though so I’ll definitely read your post a few more times and compare it to previous ones... First, it could have been the light in my room, emitting heat that could have interrupted the way my camera processed a photograph... But then, it could have been the bat’s effect on the lamplight and ultimately the way the photograph was captured... Yet, the bat had little to nothing to do with it, and so it had to be the camera itself with the way it takes photos... But it could also be— so much regret for not taking more photos. I’ve yet to look back on them and find them. 15 minutes ago, CharonY said: Cell phones do not have lens motors. Also, if you mess with it, you will affect focus, not light transmission. Again, shutter speed is the culprit. The reproducibility is issue is based on the fact that most cell phones do not allow fine controls of shutter speed, nor is it often clear what they used. I assume you could check exif data to see whether it changed between banding and non-banding images. However, there is also software trickery that tries to circumvent it so that it only shows up (or becomes more visible) in certain situations. This includes e.g. closeup with little light, where shutter speed are non-ideal and iso is high. A very simple experiment, which does not require you to get an actual camera with controls is to take a picture in horizontal mode. The banding should also become horizontal as it is related to the sequential readout from CMOS sensors (i.e. the integration issues that you see column by column, will should row-by-row). Unless, of course there is some weird technology in cell phones not seen in cameras (which I doubt). From this, I got shutter speed... Thanks again CharonY, I’ll definitely try this. Exif data? I’ll be in touch Link to comment Share on other sites More sharing options...
koti Posted March 31, 2018 Share Posted March 31, 2018 17 minutes ago, tmx3 said: Thanks! Yeah I mean without having that little bit of insight I’d be incredibly bull-headed for no reason. I resent that quality—would hate to be unreasonably stubborn. I’ll definitely look it up. Yeah, after reading CharonY’s first post about twenty times it made more sense to me that that was most probably it. Kind of ruined that magic I felt about the bat. Sigh. I see... Thanks for this post! I’m a little confused again though so I’ll definitely read your post a few more times and compare it to previous ones... First, it could have been the light in my room, emitting heat that could have interrupted the way my camera processed a photograph... But then, it could have been the bat’s effect on the lamplight and ultimately the way the photograph was captured... Yet, the bat had little to nothing to do with it, and so it had to be the camera itself with the way it takes photos... But it could also be— so much regret for not taking more photos. I’ve yet to look back on them and find them. From this, I got shutter speed... Thanks again CharonY, I’ll definitely try this. Exif data? I’ll be in touch Don’t bother too much with my post, its irrelevant to your case - I didn’t catch that the photo was taken with a phone, there aren’t any camera phones with ultrasonic motors, only lenses for SLR/DSLR cameras have these (the big pro lenses for the big pro cameras) Read CharonY’s post again instead, the explanation is there. Link to comment Share on other sites More sharing options...
tmx3 Posted March 31, 2018 Author Share Posted March 31, 2018 6 minutes ago, koti said: Don’t bother too much with my post, its irrelevant to your case - I didn’t catch that the photo was taken with a phone, there aren’t any camera phones with ultrasonic motors, only lenses for SLR/DSLR cameras have these (the big pro lenses for the big pro cameras) Read CharonY’s post again instead, the explanation is there. I just caught this, too!—which is why I tend to read posts a good few times before responding. Big oops! Link to comment Share on other sites More sharing options...
Bender Posted April 1, 2018 Share Posted April 1, 2018 7 hours ago, tmx3 said: From this, I got shutter speed... Thanks again CharonY, I’ll definitely try this. I think some photography apps allow shutter speed control on phones. 7 hours ago, tmx3 said: Kind of ruined that magic I felt about the bat. But it brought you the magic of how technology can interact in curious and interesting ways. When it comes to wonder, science easily beats magic 7 hours ago, koti said: I don’t know if this helps but lots of camera lenses use ultrasonic motors. Theorerically it might be possible that a bat might interfere with the lens operation giving artifacts in photos. Since ultrasonic motors don't use ultrasound, this is extremely unlikely. 1 Link to comment Share on other sites More sharing options...
Strange Posted April 1, 2018 Share Posted April 1, 2018 2 hours ago, Bender said: I think some photography apps allow shutter speed control on phones. I suspect that is a software simulation of shutter speed as there isn't actually a shutter! 2 hours ago, Bender said: Since ultrasonic motors don't use ultrasound, this is extremely unlikely. But it might make them more sensitive to ultrasound at a similar frequency. Link to comment Share on other sites More sharing options...
Bender Posted April 1, 2018 Share Posted April 1, 2018 6 hours ago, Strange said: I suspect that is a software simulation of shutter speed as there isn't actually a shutter! If you can set the virtual shutter speed or scanning frequency, that's what you need to start experimenting. With any luck they even allow to turn off anti-banding algorithms. 6 hours ago, Strange said: But it might make them more sensitive to ultrasound at a similar frequency. That's almost like affecting a stepper motor by singing at it. I guess if the amplitude is high enough, but I doubt a bat could produce enough volume. Link to comment Share on other sites More sharing options...
CharonY Posted April 2, 2018 Share Posted April 2, 2018 (edited) On 4/1/2018 at 8:22 AM, Bender said: If you can set the virtual shutter speed or scanning frequency, that's what you need to start experimenting. With any luck they even allow to turn off anti-banding algorithms. On 4/1/2018 at 2:15 AM, Strange said: I suspect that is a software simulation of shutter speed as there isn't actually a shutter! It is often called an electronic shutter, which is actually the reason why banding occurs. A physical shutter eliminates the problem as it cuts off exposure . But assuming no other software tricks adjusting it should increase/decrease banding depending on exposure time (and adjusting iso would also be helpful). Of course, just borrowing a regular camera could also be an option (using it in modes that use electronic shutters). In fact, the larger sensor (relative to cell phones) could make the effect more pronounced. On 4/1/2018 at 2:15 AM, Strange said: But it might make them more sensitive to ultrasound at a similar frequency. But why would you expect brightness differences if the focus motor is distorted? Edited April 2, 2018 by CharonY Link to comment Share on other sites More sharing options...
Strange Posted April 2, 2018 Share Posted April 2, 2018 1 hour ago, CharonY said: But why would you expect brightness differences if the focus motor is distorted? Um, well, uh, because ... mumble ... 1 Link to comment Share on other sites More sharing options...
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