topic Re: Flash synchronization issue in Point & Shoot Digital Cameras

Flash synchronization issue

gogo1 — Wed, 30 Oct 2019 00:52:57 GMT

PowerShot sx730 hs

It looks the flash speed is not synchronized.

If someone moves during the shooting, he gets smashed head or body. The woman and the man on the right.

This is the first camera from more than 10, which has such issue. Is it adjustable or I need to send it for repair?

Attached original and fixed head.

Re: Flash synchronization issue

MikeSowsun — Wed, 30 Oct 2019 02:31:18 GMT

Please explain “smashed head”.

Re: Flash synchronization issue

kvbarkley — Wed, 30 Oct 2019 13:49:53 GMT

I am guessing it is a long shutter speed with flash with a lot of ambient light. Somone moved after the flash and caused a double exposure looking like a "smashed head".

Re: Flash synchronization issue

MikeSowsun — Wed, 30 Oct 2019 14:23:00 GMT

That was my thoughts too, but the first photo doesn't appear to show "smashed head" or any other type of movement. The second photo is the same as the first, but it has been edited by cropping out the the man and child, and adding brightness.

I am still confused.

Re: Flash synchronization issue

MikeSowsun — Wed, 30 Oct 2019 14:16:14 GMT

If the problem is movement during slow sync flash, the solution is to simply disable "Slow Synchro" in the flash menu by changing it back to "Auto" or "On" instead.

Re: Flash synchronization issue

gogo1 — Thu, 31 Oct 2019 00:23:01 GMT

Thank you for the replies. I checked the flash mode, but unfortunately it is not the problem , because it was on "on" , not slow sync mode.
I found difficulties to upload *.psd file on Canon and Imagebam (surprised). Please , download it from the link to see the face and then click on layer 1 to see how supposed to look really the face. The terrifying fact is that this happens to any picture with flash, when someone moves.

press on 3 dots > download

link

and EXIF file

Re: Flash synchronization issue

BurnUnit — Thu, 31 Oct 2019 01:10:50 GMT

From the nearly square format of the first picture it appears to have been heavily cropped on the left side. Also the light fall-off from the flash seems to only affect the right side of the image. The two women and the young girl are pretty well lit and focused and I don't see anything that resembles a flash synch problem, no "ghosting" or motion blur.

The poor fellow on the right does appear to have his head squashed a bit though. But this shot was taken at the absolute widest end of the zoom and being nearly out of the frame it's not surprising that he's picked up some distortion. He's also under exposed, likely because the on-camera flash isn't designed to light up such a wide field of view.

If you were able to shoot this scene again try zooming in slightly so the flash can do a better job of lighting the narrower field of view. If you were shooting a larger group of people and needed to zoom out wider that might be the time to try the "slow-synch" flash setting and increase the ISO a bit if the camera will allow it.

Re: Flash synchronization issue

gogo1 — Thu, 31 Oct 2019 02:09:12 GMT

I would agree with you for the man, if the whole right part of the image was distorted, but it is only his head. His arm and leg, child’s hand look realistically.

Did you check the *. Psd file? You will see the difference, because the woman on right doesn’t have ugly Halloween face, like on the original picture, but it has to be as on the edited one.

Re: Flash synchronization issue

Mark35mmF2 — Thu, 31 Oct 2019 04:50:12 GMT

Hi gogo1,

Is this a consistent problem with other images in other situations or did it only happen in this situation? This looks to me like as others have said, this could be a matter of lens distortion at the widest angle, especially since the man's head is in the far corner of the image where it would show the most.

Re: Flash synchronization issue

BurnUnit — Fri, 01 Nov 2019 13:19:53 GMT

I also forgot to mention that when shooting in situations like this, by slightly zooming-in you will also reduce the most noticeable wide-angle distortion at the outer edges of the frame. It's the same reason why "portrait" lenses tend to be of a short telephoto focal length. If you do a web search for "wide angle lens distortion" you'll find plenty of information about the effect and how to control it.

I didn't download your PSD file as I don't have a Dropbox account. But it might still be helpful if you post a sample of the original, uncropped image. Even downsized to something around 1600 x 1200 would be okay. Actually, I think I found a copy of the full-size image on your profile page. And I see why you chose to do the heavy cropping.

It also looks like the camera could have been a bit off level. I didn't see any great amount of distortion on your subjects in the center of the frame but I don't really have any way to make a valid comparison. In general I think a big improvement could have been made simply by zooming in slightly and framing your subjects differently to avoid some of the background clutter.

The more you shoot and experiment and learn what works and what doesn't, the better your images will become.

Re: Flash synchronization issue

gogo1 — Fri, 01 Nov 2019 00:24:48 GMT

Like I mentioned, it is not the problem with the wide-angle lens in this case. I resolved it with cropping the picture. The problems are the faces in the center. I have several pictures distorted like that. The annoying thing is it happens regularly and for me this is when one of the people turn his head at the time of shooting and his had gets smashed.

When I started shooting 40 years ago, there was no automatic adjustment and it was hard to determine proper shooter speed and exposure. I was extremely happy, when I used flash, because everything was frozen. But not with this camera.

I agree with Mike, who suggested to check flash mode sync.

If it was not a wrong mode it might be some other issue.

Re: Flash synchronization issue

MikeSowsun — Fri, 01 Nov 2019 01:24:13 GMT

@gogo1 wrote:
Like I mentioned, it is not the problem with the wide-angle lens in this case. I resolved it with cropping the picture. The problems are the faces in the center. I have several pictures distorted like that. The annoying thing is it happens regularly and for me this is when one of the people turn his head at the time of shooting and his had gets smashed.

When I started shooting 40 years ago, there was no automatic adjustment and it was hard to determine proper shooter speed and exposure. I was extremely happy, when I used flash, because everything was frozen. But not with this camera.

I agree with Mike, who suggested to check flash mode sync.
If it was not a wrong mode it might be some other issue.

I cropped your photos and compared them both. I see you did some editing to the face on the lady on the right, but I think it looked fine before the edit.

I see no problem with the photos.What problem do you see?

Re: Flash synchronization issue

gogo1 — Fri, 01 Nov 2019 01:54:00 GMT

BurnUnit, the suggestions you are giving are correct to avoid the distortion at the end of the frame.

I uploaded PSD to Dropbox because I didn’t know they have changed their policy and banned sharing links with public, but only through email.

To see the difference, switching the layers is necessary. If these people were unknown, like for you guys, you will barely notice this.

Re: Flash synchronization issue

gogo1 — Fri, 01 Nov 2019 02:02:21 GMT

Thank you Mike for the GIF! That is another option for demostration, but I never did gif-animation.

Re: Flash synchronization issue

gogo1 — Thu, 07 Nov 2019 01:38:03 GMT

Could you tell me how to send this GIF to Canon expert for explanation?

Re: Flash synchronization issue

MikeSowsun — Thu, 07 Nov 2019 01:45:44 GMT

Save the gif to your computer and then attach it to an email. Just like a photo attachment to any email.

Re: Flash synchronization issue

gogo1 — Thu, 07 Nov 2019 02:21:24 GMT

And to send it to who? Any email, please.

Re: Flash synchronization issue

MikeSowsun — Thu, 07 Nov 2019 02:26:24 GMT

I don’t know who to send it to. Call Canon and talk to some one about it, and maybe they could tell you.