Tokina 11-16mm Milky Way Test

[Grimbles]

Hi Everyone,

I recently purchased a 2nd hand Tokina 11-16mm 2.8 lens for my unmodded 500D and managed to get a 30min clear spell about 4 days ago to test it out on the milky way from my back garden. It was just before full astro dark and I was fighting with a quite a bit of light pollution from nextdoors two 500w floodlights positioned directly behind me but it was bit bit late to start texting them to turn them off (they are usually very good if they get advanced notice).

I took about 40 images at 11mm f2.8 iso 1600 20sec on a fixed tripod

I had a real problem with DSS in that the corners of the stacked images were very blurred. The only way I could find to get around this was to do a lens correction in Lightroom on a limited number of consecutive images (5) and then stack the tiff's. I assume this problem was due to the lens distortion at the image edges and rotation (using fixed tripod).

I also had to use DBE in an old version of PI LE as I could not do much with the light pollution in photoshop, Google Nik tool was used for noise reduction.

Overall i am very pleased with the lens and looking forward to getting out in with some darker skies and try some night landscape photography.

Any thoughts on overcoming the stacking issues would be appreciated, I know tracking would improve things greatly.

[RichM63]

I have the 10-17 Tokina fisheye version. You might try stopping it down a little. This should sharpen the edges.

Rich

[Grimbles]

7 minutes ago, RichM63 said:

I have the 10-17 Tokina fisheye version. You might try stopping it down a little. This should sharpen the edges.

Rich

Thanks Rich I was going to try various iso and f stop cominations to compare results but did not have enough time before the clouds rolled in, but will definitely try this next time.

Martin

[happy-kat]

I like the mw cloud you've captured.

I think 20 seconds should easy have been OK and probably lens curvature might have been more of an issue then lack of tracking, theoretically you might have been OK up to 36 seconds so 20 is easy inside star trailing. Do you know of Tokina do a lens profile for the lens you have?

[Grimbles]

Just now, happy-kat said:

I like the mw cloud you've captured.

I think 20 seconds should easy have been OK and probably lens curvature might have been more of an issue then lack of tracking, theoretically you might have been OK up to 36 seconds so 20 is easy inside star trailing. Do you know of Tokina do a lens profile for the lens you have?

Hi

Yes I used the specific lens profile in Lightroom which helped on individual frames, I think stopping down as Rich suggested earlier will help significantly, then as you say I still have a little leeway to increase exposure times.  The tracking issue is not a problem in itself, but I have a feeling that DSS is struggling to cope with the combination of Lens curvature and field rotation at the edges, as the centre of the image is fine.

Overall it is probably not a problem, it's more about finding the best way to expose and  process images from this camera /lens combination.

Martin

 

 

[happy-kat]

Did you also focus where one of the thirds intersect rather than the centre?

I was thinking of a lens profile you could load into the camera. One of my canon lenses has a lens profile loaded into the camera via a eos utility.

 

[Grimbles]

3 hours ago, happy-kat said:

Did you also focus where one of the thirds intersect rather than the centre?

I was thinking of a lens profile you could load into the camera. One of my canon lenses has a lens profile loaded into the camera via a eos utility.

 

Hi

I did not focus at any of 1/3 but will add that to my list of things to try wrt to getting the best out of this lens.

As for loading a Lens profile into the camera, I don't know if you missed it in the origninal post but I am using an older APSC 500D and unless I have missed something, which I may have done, I don't believe that is possible with this camera.  I have looked at , but not tried, the lens correction in Canon's DPP but apparently the profile for this lens is not that great, the Lightroom profile seems to give a significant improvement.

[planetman83]

The corners were blurred because you were about 18 minutes on a fixed tripod while the sky is moving..

[Leveye]

25 seconds at ISO 2500 wide open and your golden with that lens.