Chaotic Mike Posted September 30, 2015 Share Posted September 30, 2015 Hi all, Can anyone explain the source of the distortion seen in this picture? I've got lots just like it... Mike Link to comment Share on other sites More sharing options...
Séan Pádraig Posted September 30, 2015 Share Posted September 30, 2015 I believe that with some optics you get either Barrel distortion or Pincushion distortion.... That looks like pincushion to me... Link to comment Share on other sites More sharing options...
ErikB Posted September 30, 2015 Share Posted September 30, 2015 Something went wrong with transferring the photo files, I think. The resolution horizontal X vertical is different than when the photo was made by the camera. Link to comment Share on other sites More sharing options...
JasonC Posted September 30, 2015 Share Posted September 30, 2015 Looks like it might be shutter distortion. http://m43photo.blogspot.co.uk/2012/12/gh3-electronic-shutter.html Regards, J. 2 Link to comment Share on other sites More sharing options...
Chaotic Mike Posted September 30, 2015 Author Share Posted September 30, 2015 Looks like it might be shutter distortion. http://m43photo.blogspot.co.uk/2012/12/gh3-electronic-shutter.html Regards, J. Bingo! I use a Panasonic micro 4/3 camera, and indeed that is a picture of a moving target taken with a long lens. I am now going to read the article carefully, and be *extremely* ticked off if one of the key use cases I bought it for cannot be performed. Mike Link to comment Share on other sites More sharing options...
Chaotic Mike Posted September 30, 2015 Author Share Posted September 30, 2015 Aha... one RTFM later, and the electronic shutter is disabled. Now I just have to wait for the next air show season... Mike 1 Link to comment Share on other sites More sharing options...
Grayson Posted September 30, 2015 Share Posted September 30, 2015 It's to do with shutter speed. Your camera -digital I presume- lays data in pixels .... One after another. The propeller is rotating and the pixel map is laid down, it's chasing the rotating parts and creates a curve of data. Simple. Look at a TV advert of a car passing lampposts at speed and you'll see curved lampposts if you pause it. Evens the professional guys struggle to resolve this. It's had to solve the shutter speed lag. Link to comment Share on other sites More sharing options...
bhouse Posted October 1, 2015 Share Posted October 1, 2015 As others have said, it's the way your camera's shutter works. The distortion you're seeing is called rolling shutter effect, and many bits of video editing/sfx software have tools for removing it that can also be applied to stills. Another (cheaper) way of avoiding it is to pan with the subject. You'll still have rse on the background, but that can actually look quite good. While panning is essentially simple (keep the camera pointing at the moving subject as you take the photo) doing it well is surprisingly trick. There are lots of online tutorials about panning so probably worth a search. Link to comment Share on other sites More sharing options...
Chaotic Mike Posted October 1, 2015 Author Share Posted October 1, 2015 Thanks all. I *thought* I was quite experienced as a photographer (having been an SLR wet film user for about 15 years before a hiatus with Canon superzoom), so I'm reasonably up on f-stops, shutter speeds, EV readings, panning, tripods, flashes... you get the picture! (more than I did, latterly!) Armed now with new information, and having disabled the electronic shutter, I am agog with anticipation for working with moving subjects once more. New weird artefact as technology makes things better! I wouldn't go back to wet film, but this is an interesting problem to be aware of. Mike Link to comment Share on other sites More sharing options...
chaddy Posted October 1, 2015 Share Posted October 1, 2015 Of course the other thing to take into consideration is the fact that most photographers prefer not to "freeze" the props. Therefore careful consideration in the choice of shutter speed is required. Link to comment Share on other sites More sharing options...
bhouse Posted October 1, 2015 Share Posted October 1, 2015 You actually get a similar effect with cameras that use s focal plane shutter. In those, the sheer takes about 1/25 sec to travel from the top of the image to the bottom so a moving subject looks add if it is leaning forwards (or backwards, depending on direction of travel). Again, panning usually dealt with the problem.You actually get a similar effect with cameras that use s focal plane shutter. In those, the sheer takes about 1/25 sec to travel from the top of the image to the bottom so a moving subject looks add if it is leaning forwards (or backwards, depending on direction of travel). Again, panning usually dealt with the problem. Edited to add a link to a great photo showing focal plane distortion- I thnk in this case the distortion makes a great photo even better: http://discussions.mnhs.org/collections/wp-content/imagescaler/16637c7aa9879c231fe74deb195edd2b.jpg Link to comment Share on other sites More sharing options...
Chaotic Mike Posted October 1, 2015 Author Share Posted October 1, 2015 Of course the other thing to take into consideration is the fact that most photographers prefer not to "freeze" the props. Therefore careful consideration in the choice of shutter speed is required. Yes, I had a previous question about that, that didn't get answered (sniff!). What does the collective think? 1/60"? Could be a real battle between OIS, long lens, long shutter speed, assumed small aperture, desired ISO setting, etc. Here's a funny thing. In wet film days, you calculated your exposure against the amount of light, and your film speed's ISO or DIN rating, i.e. a fixed parameter, and adjusted shutter speed and aperture accordingly. Nowadays, ISO is just something you treat as another variable, anything from 25 ISO to 3200 ISO on my camera, so how are you supposed to know which is 'right'? There is a tradeoff between increasing sensitivity (i.e. ISO rating) and introducing digital noise, but I am sort of surprised that Panasonic don't, for example, suggest you use ISO 200 (or whatever) as default. Any views or opinions out there? Mike 1 Link to comment Share on other sites More sharing options...
cmatthewbacon Posted October 1, 2015 Share Posted October 1, 2015 Aha... one RTFM later, and the electronic shutter is disabled. Now I just have to wait for the next air show season... Mike What's an "electronic shutter"? Does a Panasonic have some kind of "shutter effect" implemented in software? Both my Canon point and shoot and my Canon DSLR seem to have real, physical shutters, and I've certainly not got the effect you're showing up there in any of my air show or classic motor racing pictures, either on fixed viewpoint or panning shots... And when I screw it up, the "motion blur" is the same from top to bottom! I don't understand what exactly it is that you've disabled... Feeling stupid... bestest, M. Link to comment Share on other sites More sharing options...
Chaotic Mike Posted October 1, 2015 Author Share Posted October 1, 2015 The following is conjecture; I haven't googled it for truth or accuracy! I think the camera has both an electronic shutter and a physical one. Because (unlike a wet film camera) the sensor can be permanently exposed to light (it has to if you want to have an electronic viewfinder, or shoot video) it can be persuaded to simply dump its state to file on demand, which must equate to recording the state of the sensor - I don't know if this is done serially, pixel by pixel, or in bunches. Doesn't really matter. Having said all that, I now can't see why you need a physical shutter at all. Time to research, I think! Mike Link to comment Share on other sites More sharing options...
cmatthewbacon Posted October 1, 2015 Share Posted October 1, 2015 (edited) It looks like that the reason you have a mechanical shutter is precisely to avoid the "rolling shutter distortion" that your opening shot demonstrates. At least that what Nikon USA says... bestest, M. Edited October 1, 2015 by cmatthewbacon Link to comment Share on other sites More sharing options...
John.R Posted October 1, 2015 Share Posted October 1, 2015 Yes, I had a previous question about that, that didn't get answered (sniff!). What does the collective think? 1/60"? Could be a real battle between OIS, long lens, long shutter speed, assumed small aperture, desired ISO setting, etc. Mike Hi Mike, I'm nowhere near as qualified as some to answer this but here's my 2p.. With 1/60" shutter speed you would need a very steady hand while panning even with IS/OS/OIS etc, the way it was explained to me many years ago was if using for instance a 70-300mm lens, than if shooting at 300mm then the lowest you should theoretically go to is 1/320" and to try not to go below the focal length your shooting at. I personally find unless its something like the CV-22 Osprey, Chinook, Huey etc that 1/400" will get you great results on both propellor aircraft and helicopters. Hope this helps Link to comment Share on other sites More sharing options...
Radleigh Posted October 1, 2015 Share Posted October 1, 2015 (edited) Yes, I had a previous question about that, that didn't get answered (sniff!). What does the collective think? 1/60"? Could be a real battle between OIS, long lens, long shutter speed, assumed small aperture, desired ISO setting, etc. Here's a funny thing. In wet film days, you calculated your exposure against the amount of light, and your film speed's ISO or DIN rating, i.e. a fixed parameter, and adjusted shutter speed and aperture accordingly. Nowadays, ISO is just something you treat as another variable, anything from 25 ISO to 3200 ISO on my camera, so how are you supposed to know which is 'right'? There is a tradeoff between increasing sensitivity (i.e. ISO rating) and introducing digital noise, but I am sort of surprised that Panasonic don't, for example, suggest you use ISO 200 (or whatever) as default. Any views or opinions out there? Mike I came from film too and was lucky enough to get a Pentax MZ50 for my 12th Birthday and had use of dad's T-90s before that... I can't remember how I used to do it, sadly my memory isn't great which is worrying at the age of 31! Anyway I used to have ISO400 film mostly as it was cheaper, but when using dads I had the good old Kodachrome 64 or something as good... But now with ISO capabilities in modern cameras, it's great as the high ISO doesn't really bother me much with being able to shoot in RAW and using Lightroom to edit the image. For example, 20,000iso, If you had the chance to shoot this high in 35mm film format, the print would have a very rough texture to it UR-CKM An-12BP, Birmingham Airport by Radleigh Bushell, on Flickr In answer to your question, I guess companies can only go so far as to what they put in a manual. They're just selling the product, not teaching the buyer how to use it to it's full extent, but manuals to give a good break down on the actual camera gimmicks, buttons, etc. If in doubt stick it in Auto Edited October 2, 2015 by Radleigh Link to comment Share on other sites More sharing options...
John Laidlaw Posted October 2, 2015 Share Posted October 2, 2015 Practice taking photos of cars travelling in the distance, if you can find a good spot to do it safely. If you can also vary the distance of the shot by moving closer to/further away from the road, that should help you get a better feel for controlling a longer lens with a slower shutter speed. I know (most) cars don't have props... but they do have wheels, a lot of which have spokes, which will blur nicely at the right shutter speed. At least it's better than waiting until next year . Link to comment Share on other sites More sharing options...
TheBaron Posted May 22, 2016 Share Posted May 22, 2016 I stumbled across this just now. This would certainly seem to be a case of 'rolling shutter' as others have pointed out (something US filmmaker refer to as the 'jello' problem). It causes no end of issues in film and video post-production and is usually only caused by cameras with a CMOS sensor. Unlike CCD cameras, a CMOS camera doesn't read off the whole image in one go - it reads incrementally from top to bottom of the frame, hence the lateral distortion to images with something passing quickly across the field of view. If you take a lot of dynamic subjects, don't buy CMOS... Tony Link to comment Share on other sites More sharing options...
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