4

Many lenses today have image stabilization (IS) in the lens. At least Canon and Nikon do this.

The Canon and Nikon systems allow one to use lenses intended for full frame cameras in their crop sensor cameras.

Now, if I have a full frame lens and crop sensor camera, does the crop of the sensor:

  • Improve how image stabilization works?
  • Negatively affect how image stabilization works?
  • Leave the image stabilization unaffected?

I was thinking that if the lens has a significantly larger image circle than the sensor, the image stabilization system could perhaps have more room to work with, thus allowing correcting larger amplitude vibrations.

On the other hand, it may be the case that the lens designers did not anticipate potential use in crop sensor cameras, and therefore, don't fully utilize the benefits of the large image circle.

It also might be the case that an optimal crop sensor stabilizer should be optimized for smaller vibrations due to the small sensor size, at a given physical focal length, and therefore, a full frame stabilizer may not be as accurate and pixel-perfect, leaving very small blur at the pixel level.

1

Not really, but still kind of.

Image stabilization as implemented in lenses and cameras usually give you a relative (and not absolute) improvement over exposures done without image stabilization. Since the susceptibility to vibration or motion blur depends on the lens' angle of view, which again depends on the sensor size, and the absolute capabilities achievable with image stabilization depends on what you could achieve without image stabilization, sensor size is something you may have to consider.

I am not even sure if I understood my own explanation, so I'll try to give an example.

A common rule of thumb for hand-held photography is that you should use shutter speeds shorter than the reciprocity of the (35mm equivalent) focal length of your lens. E.g. when shooting with a 400mm tele lens, you should use shutter speeds 1/400s and shorter. This of course varies a lot from person to person, but it is at least a rule of thumb to start with. If this lens had image stabilization with an improvement of two stops, you would now be able to shoot hand-held at 1/100s.

If you use the same lens on a camera with an APS-C sensor with a crop factor of about 1.5, the lens' angle of view would be narrower, more precisely equivalent to a 600mm lens on a full frame camera. This also means, that you without image stabilization would have to use a short exposure time of 1/600s to avoid problems with vibrations. Even if the image stabilization still gives you a two stop improvement, with image stabilization you would have to shoot at 1/150s or less.

So yes, the sensor size is relevant. It does not have direct impact on the image stabilization itself, but changes the 'base line' of what you have to work with before considering the improvements gained by image stabilization.

1

Assuming one is viewing all images at the same display size, images from smaller sensors must be enlarged more to get the to same display size as images from larger sensors.

This means that the same amount of blur, as it is projected onto the sensor, is easier to see in the image from the APS-C camera than it would be in an image from a FF camera.

The difference has nothing to do with the lens: it will perform the same regardless of the kind of camera to which it is attached. The difference has to do with enlargement for different sized sensors to view images at a specific size.

  • The effect you are describing here, increased susceptibility to motion blur due to a larger magnification factor when viewing the image, will in reality be nullified by the opposite effect when making the exposure. If you expose the same field of view onto a smaller sensor, the radius of any motion or vibration blur will be smaller than if you expose the same image under the same conditions onto a larger sensor. – jarnbjo Jul 1 at 14:03
  • @jarnbjo The question does not ask about using a different focal length to get the same field of view. It specifically asks about using the same lens to get a cropped field of view. But even in the scenario you describe, the radius of motion will not be smaller. If the FoV is the same and the display size is the same, the radius of motion will be the same. – Michael C Jul 1 at 14:46
  • Which display size are you talking about? – jarnbjo Jul 1 at 14:51
  • @jarnbjo It doesn't matter as long as both the full frame image and the APS-C image are being compared at the same display size, then the ratio between the two enlargement factors will always be the same. – Michael C Jul 1 at 14:57

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.