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-   -   IS the CMOS sensor causing the jittery look? (https://www.dvinfo.net/forum/canon-eos-crop-sensor-hd/471647-cmos-sensor-causing-jittery-look.html)

Marty Hudzik January 25th, 2010 10:24 AM

IS the CMOS sensor causing the jittery look?
 
I have had the 7d for about 4 days and I only have a 50mm 1.8 Canon lens at the moment. I anticipated handheld shots not looking particularly stable, but so many of my shots look jittery. Almost a wee bit jumpy. I am not talking about the motion of the people or subjects but more like the overall frame feels like it is shifting a pixel left or right very suddenly. It looks odd. I realize I need to lock down on a tripod but I have never experienced this anomalie with video cameras with no image stabilization.

With this in mind, I have my Eye on a tamron 17-55 2.8 with VC (vibration compensation) and I am hoping this will "ease" the jumpiness of the frame. Anyone actually tried IS on these lenses? DO they work the way video lens IS works?

David Chapman January 25th, 2010 10:51 AM

Hey Marty,

I have the 50mm f/1.4 and yes, any non-IS lens will look like that (more vibration on the telephoto side). You may not see as much on a 14mm or 20mm, but 50mm (actually 80mm) will show a lot of movement. It's because the pivot point on the camera in your hands is so narrow.

Try an IS lens and you will be very happy with the results handheld. I have a Canon EF-S 17-55 f/2.8 and love it.

Marty Hudzik January 25th, 2010 12:57 PM

David,
Thanks for the reply. Is that lens you mentioned a constant aperture lens?

Jon Fairhurst January 25th, 2010 01:32 PM

Consider a shoulder rig.

Justin Baglo January 25th, 2010 02:50 PM

Everything David said up there is right on the money. I also use and love the Canon EFS 17-55, but even with the IS on, I can't get away with shooting handheld at the long end. Perhaps if I had a shoulder rig or drank less coffee...

edit: Yes, that's a constant aperture 2.8

Marty Hudzik January 25th, 2010 02:57 PM

I have shot handheld with non IS lenses with my video rig which is CCD and while it looked a little unsteady it did not have this jumpy jerky look. I just rewatched a clip and the motion of the hands of the person in the scene look fluent but the overall frame is a bit twitchy. This is probably a combination of the poor ergonomics of the 7d for video and the CMOS sensor reacting to motion differently than a CCD. RIght?

It almost looks like a defective image stabilition scheme. As long as this is normal I guess I can learn to work around it until I invest in shoulder mount and viewfinder....not to mention IS lenses!

Thanks.

David Chapman January 25th, 2010 03:36 PM

Marty, it's a lot to do with both: ergonomics + rolling shutter. When I mount my 7D on my shoulder rig, I get much steadier shots than in my hands. It changes the pivot point from my hands to a larger region around my shoulder, putting the camera a good 16" away. Then you are just left with rolling shutter "jello" if you aren't carful. I really wouldn't want a non-IS lens longer than my 50mm. It would definitely be tripod-only for me if I did.

A.J. Aguirre January 25th, 2010 03:42 PM

im actually selling a lightly used tamron 17-50 VC

Tamron AF 17-50mm F/2.8 SP XR Di II VC for Canon - eBay (item 400098535456 end time Jan-26-10 21:36:56 PST)

dont know if your interested but, i have not filed for the warranty yet and it i do have the original reciept, bought it in december, and yes this lens is awesome, i did some tests with the VC on and off and you will notice it for sure

Lance Watts January 28th, 2010 11:01 PM

Yes, the "jitter" is present because the 7D has no internal stabilization. The problem is magnified by the awkward form factor of the DSLR and the fact that you are shooting with a 50mm lens doesn't help either.

The "jitter" can be considerably diminished by doing the following:

1. Using a lens with internal stabilization
2. Using some sort of additional support. A shoulder or gunstock rig would be helpful. Even the Zacuto Z-finder (which is a tremendous focusing aid) can add considerable stability to your handheld shots.
3. Shoot with wider lenses. If you need a fast prime, check out the Sigma 30mm 1.4 or the Canon 24mm 1.4.


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