Old 11-09-2016, 02:55 PM
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Lognic04 (Logan)
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Question Image stabilization (DSLR) and tracking

I have always thought my images were quite fuzzy compared to others. E.G. the attached m8/20 pic. I know focus is perfect but my pics have always been slightly blurry. It also isn't stacking because they look the same before.
Then i realized.
I had image stabilization on the entire time.
But.. I dont actually know if it is image stabilization. I think it may be trying to counteract tracking or something but who knows.
Any ideas or is it IS?

http://imgur.com/gallery/B8ADw (attaching didn't work)
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Old 11-09-2016, 04:11 PM
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Atmos (Colin)
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Image stabilisation should always be turned off when on a tripod as it will soften your image, whether you're shooting the sky or terrestrial. I've learned that out the hard way as I also had soft images until I realised that I'd forgotten to turn it off.
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Old 11-09-2016, 05:48 PM
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Lognic04 (Logan)
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ok thanks i will test as it seems to be a clear night.
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Old 15-09-2016, 07:36 AM
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sil (Steve)
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1. Image stabilisation should always be turned off unless you are shooting hand held. Always. Pretty sure this is in most (or all) camera/lens manuals. When its turned on its always trying to work out what movements are occuring to counteract and that process will result in softened images slightly.

2. Also aperture will soften an image. Each individual lens has a sweet spot where its sharpest and its NEVER at its widest aperture (smallest f-stop number). If you shot at widest aperture you wont get the sharpest images. Not ever. You should stop down a couple of steps and try that.

3. I also highly doubt focus is perfect as you claim, if you are relying on the camera to tell you it is. It could be front or back focusing slightly at that distance. This is why better camera have micro focus adjustments you can make which will sharpen things up at a given distance (to the expense of all other distances). Look into Lens Align.

4. If you have a UV filter on your lens that can also soften it up. Each layer of glass you add will detract image quality. Especially if its cheaper one or you've cleaned it as you can't completely remove streaks. Point lights like stars are a high contrast scenario where even slight quality loss is noticably.

5. Exposure time could also be a factor, I wont go into.

Breeze and vibrations through your tripod too, doesn't take much to wobble it enough to effect images.

Basically you have a lot of testing to do to pin down the contributing factors and sort them out.
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Old 15-09-2016, 07:49 AM
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There is nothing fundamentally wrong with your image IMO, focus is as good as it can be for the lens used (can you tell us what gear you were using?).

I think the dim star images are not the same shape in centre and corners of the images, maybe the lens suffers from astigmatism (which shouldn't be a surprise as it is obviously a multipurpose camera lens (it has IS)).

Maybe you should try non-IS lens, perhaps some prime focus lens (they are generally better than zooms)
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