Stabilizer problem: Canon HFM40

**Audidude** · 02-19-2012, 08:25 AM

Newbie here so please bear with me.

Have just upgraded my old Panasonic SD tape DV camera to the Canon HFM40 HD camera which uses SD storage.

My specific use is as an in-car video recorder in my race car - used predominantly in tarmac rally events, so not smooth circuit racing.
The Panasonic did an excellent job of stabilizing the images, and I expected the Canon (they invented image stabilizing I thought??) to be at least as good, but probably better.

My results to date are appalling - so much so that I am considering using the old Panasonic!!

I'll try to be brief:
The camera is mounted on a Manfrotto professional quality clamp and fitted to the roll cage.
First clips were on Programmed AE mode and were so blurry in all stabilized modes as to be unwatchable. I then twigged to setting the shutter speed (doh, I'm not just a newbie to the forum!

) so then set out to film trial clips at both 1/500 and 1/1000.

This solved the frame blurring nicely, but there is still considerable camera shake without stabilizer (as expected) but when I put the stabilizers on every clip has this kind of wavy appearance like the surface of the sea. Reviewing frame by frame shows there is considerable distortion of the image which is causing this wavyness - imagine a the image is overlaid over a cloth waving like a flag in a gentle breeze and you can get the feeling of what's happening.

I am importing unmodified clips into Final Cut Pro X on a Macbook Pro. I have produced a couple of optimized clips and run it through the stabilizer analysis in FCP to no effect.

I have run multiple clips with various combinations of:
MXP and FXP
50i and PF25
Standard stabilizer, Dynamic Stabilizer, Powered stabilizer
1/500, 1/1000

None of the clips give a result that I'd be prepared to upload to YouTube (unlike my old clips of which there are plenty on YouTube - search for "intgrr").

Am I missing something here or is this camera simply not up to the job? I know it's a demanding task for the camera, but plenty of cameras seem capable of it.

Maybe I should have just gone for a GoPro HD after all

Thanks in advance for your help.

Cheers
Audidude
New Zealand

**TimStannard** · 02-20-2012, 07:09 AM

Originally Posted by Audidude

This solved the frame blurring nicely, but there is still considerable camera shake without stabilizer (as expected) but when I put the stabilizers on every clip has this kind of wavy appearance like the surface of the sea. Reviewing frame by frame shows there is considerable distortion of the image which is causing this wavyness - imagine a the image is overlaid over a cloth waving like a flag in a gentle breeze and you can get the feeling of what's happening.

I'm no expert on the format, but what you describe sounds to me like the downside of CMOS sensors with a single shutter-a phenomenom known as "shutter roll". Basically, the image through the lens moves (as it would in fast moving scenes) between the shutter exposing the top part of the image and the lower part. NewBlueFX have a plug in as part of one of the Video Essential packs (I think) which might improve the situation.

Of course, my speculative diagnosis may be entirely incorrect.

**Audidude** · 02-21-2012, 07:48 AM

Originally Posted by TimStannard

I'm no expert on the format, but what you describe sounds to me like the downside of CMOS sensors with a single shutter-a phenomenom known as "shutter roll". Basically, the image through the lens moves (as it would in fast moving scenes) between the shutter exposing the top part of the image and the lower part. NewBlueFX have a plug in as part of one of the Video Essential packs (I think) which might improve the situation.

Of course, my speculative diagnosis may be entirely incorrect.

Thanks for the advice Tim. I will explore this issue further. NewBlueFX video Essentials are not compatible with FCP X yet - I will email them and find out when they anticipate this to be in place.
Cheers

**Audidude** · 02-21-2012, 08:10 AM

Update:

I have found a description on this link which describes exactly what is happening:

CMOS Rolling Shutter

And the example here is identical to the footage I have been shooting (except for subject of course!)

http://www.ssontech.com/content/skool.mov

So it appears to a problem unique to CMOS cameras with a rolling shutter and it is called wobble!
And apparently there is no cure. So what that means is that the camera I have bought is not suitable for the application I have bought it for :(

Now, I told the shop assisstant what I intended using the camera for, and I am certain that shop assisstant will have never heard of CMOS wobble, but we have a consumer protection law in our country that allows for full refund if the product is unfit for the purpose for which it was bought. But I suspect they'll really try and squirm out of this one! Not sure if I can be bothered - might just try selling 2nd hand and wear the loss :(

**TimStannard** · 02-22-2012, 06:13 PM

I'm obviously sorry to learn you've been sold the wrong thing, but I'm gald I was able to point you in the right direction.
The rolling shutter problem is well known and the shot assistant certainly should know about it or have checked - even if you bought it from Tesco, if you asked teh question then the law will be on your side.

The bad news is nearly all cameras are CMOS nowadays rather than CCDs (which have different problems - as described in the article you linked to)