sensors - cmos vs. ccd (1 Viewer)

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manbehindthemask

Active member

• Dec 22, 2011

• #1

I recently bought a canon compact with a cmos sensor to use for digiscoping. However the video (through the scope) has an annoying wobble effect. This isn't apparent when using the camera on its own, so must be an effect which is accentuated when under high magnification. I recently read that wobble is something common to cmos sensors. My old samsung had a ccd sensor and that never displayed any wobble. Should I avoid cmos sensors from now on for videoing through scope? Are there any that dont wobble? thanks

 

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ericbowles

Well-known member

• Dec 28, 2011

• #2

Whether you have a CMOS or CCD sensor will have no impact on "wobble". The more current technology is CMOS. You might have had some sort of image stabilization in your old camera. In any event, high magnification is difficult under the best of circumstances. I'd try to focus on your technique - use a tripod and keep a weight or hand on top of the scope to reduce vibration.

 

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manbehindthemask

Active member

• Jan 2, 2012

• #3

i found the following after a google search:

Smear, Skew, Wobble, and Partial Exposure
There are four main characteristics sensors may exhibit. CCDs can suffer
from vertical smearing on bright light sources, while CMOS sensors are
immune to that artifact. But CMOS sensors (equipped with "rolling shutters")
can exhibit skew, wobble, and partial exposure; CCD sensors are immune to
those effects.

my previous cameras which had ccd sensors never showed any wobble, my new camera with a cmos sensor does, and it's very annoying. My old cameras didn't have image stabilizing but my new one does. Even with a proper adaptor to attach it to the scope I dont think I would be able to escape the effect completely

 

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ericbowles

Well-known member

• Jan 2, 2012

• #4

While you may have one of the senor issues found in your search, more likely it is something else. I can't speak to the issue of video. All major manufacturers have moved to CMOS sensors because they improve performance. Wobble is not an issue that comes up with the Nikon cameras I use that also have CMOS sensors.

Image stabilization is not a cure-all. There are situations where it can help, but it does nothing to help with subject motion. It also has limited value in reducing the impact of camera movement at long distances - it helps - but possibly not enough. Image stabilization can appear to cause a "chatter" when it is activated. Also auto focus can be a contributing factor. You could even get some wobble caused by tripod vibration or panning with some gear.

I'd look for another potential cause. Try shooting from a tripod with and without image stabilization.

 

Last edited: Jan 2, 2012

Wildmoreway

Well-known member

• Jan 2, 2012

• #5

From experience of doing long exposure night shots using a camera with built in is on the sensor, I alwways switch the is off when taking these kind of shots. Whilst not into digiscoping, the is is not designed for the range of magifications invloved in digiscoping and I would (if the option is available) switch the is off..

 

Bird_Bill

Well-known member

• Jan 2, 2012

• #6

Heres two shots,both off of tripod mounted system taken seconds apart as demo....
1st(left)...tripod mounted,shake reduction or image stabilization on (enabled)
2nd(right)...tripod mounted,shake reduction or image stabilization off (disabled)

If we have SR or IS on(enabled),firmware will try to "steady" the sensor
introducing blur when in reality sensor is stationary ie. tripod mounted,
resulting in blurred image.We're part of the "control loop",we're telling
the camera there's shake and camera not "knowing" any better try's
to correct,causing blur.

Panning is another time its probably a good ideal to turn off or disable
SR or IS as we're trying to move with subject and with system on or enabled
control system is trying to hold sensor steady.

 

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Last edited: Jan 2, 2012

mooreorless

Well-known member

• Jan 2, 2012

• #7

Hi Bill, Thanks for posting this, I think we all forget this.

 

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ericbowles

Well-known member

• Jan 2, 2012

• #8

For others who may be reading this, some of the VR information is specific to Canon cameras with stabilization in the camera body.

I use Nikon DSLR cameras and VR is in the lens. Many lenses have a tripod mode that supports the use of VR on a tripod.

Panning can be a situation where VR is particularly helpful. If you want to follow a subject at a slower than normal shutter speed in order to blur the background, VR can be used in Active mode to limit vertical motion instead of regular VR mode where both vertical and horizontal motion is controlled.

 

Bird_Bill

Well-known member

• Jan 2, 2012

• #9

Great point Eric,I tried to be generic in app.Every manufactuer has proprietary functions that might add or detract from performance.One of my bodies moves sensor for up to 6 minutes sync'd to earths rotation to track astro objects without trailing.No good for panning though.Read manuals,and experiment.Best thing about any digital camera is that delete button,from a guy that still shoots alot of film.