IC1396 - first with a Canon 200mm + ASI1600

[Adreneline]

Hi Everyone,

This is my first image using my ASI1600MM-Pro with my Canon 200mm f2.8.

Conditions were not ideal and I only captured 12 x 120s of Ha, OIII and SII. I was really interested in comparing the result with my Samyang 135mm in terms of star shapes, especially at the extremities of the image. This is 5h5s+3h7o+o : RGB all processed in PI with no noise reduction - just ABE and HT. I've also included the Ha.

All C&C welcomed.

Thanks for looking.

Adrian

[alan potts]

That came out pretty much the same colours as mine did with a Canon, except on a longer F/L scope, I like the B&W version very much, lovely delicate detail in there. Great work especially with a DLSR, often considered second best to CCD's and the like.

Alan

[Adreneline]

1 minute ago, alan potts said:

Great work especially with a DLSR

Hi Alan.

Just to clarify this was taken with a Canon lens but not a Canon camera - I used my ZWO ASI1600MM-Pro - a CMOS but not a dslr.

Adrian

[alan potts]

I misunderstood, never mind still a superb shot.

Alan

[Guest]

Very nice images, both !! 

[Rico]

Very nice image. Are running the 200mm wide open at f/2.8 or have you stepped down?

[Adreneline]

5 hours ago, Rico said:

Very nice image. Are running the 200mm wide open at f/2.8 or have you stepped down?

Thank you. I am using the 200mm at f2.8. It is very new to me (hardly used since I bought it three weeks ago) and to be honest I have no idea how to step it down - there is no aperture control on the lens - I assumed it was fixed at f2.8 but I would be happy to be told otherwise.

Adrian

[Rico]

You can buy step down adapter rings that screw into the filter thread at the front of the lens. I got a few from: https://www.crookedimaging.co.uk/products/kood-stepping-step-down-ring-lens-adapter?variant=31154001289

They reduce the f ratio as follows: 

72mm->67mm (f/2.8 ->f/3)

72mm->62mm (f/2.8 -> f/3.2)

72mm->58mm (f/2.8 -> f/3.4)

72mm->52mm (f/2.8 -> f/3.8)

The 200mm lens is amazing and I shoot wide open all the time. But I think if you step down a bit, you can improve the shape of stars at the corner of the images even more. I haven't used the rings yet, so I can't first hand tell you that this is true, but I'll be testing it soon. The positive of using a step down ring is that you avoid the diffraction spikes from the aperture blades. 

Looking forward to more of your images!!

Edited September 26, 2019 by Rico

[Adreneline]

1 hour ago, Rico said:

I haven't used the rings yet, so I can't first hand tell you that this is true, but I'll be testing it soon.

I look forward to hearing/seeing how you get on with the rings.

1 hour ago, Rico said:

The positive of using a step down ring is that you avoid the diffraction spikes from the aperture blades.

A problem I experience all the time when using the Samyang 135mm but not (IMHO) as distracting as those from a reflector imaging system - although I fully appreciate and accept that many feel the diffraction spikes enhance the image.

1 hour ago, Rico said:

Looking forward to more of your images!!

Thank you! - so am I if only the clouds would go away

Adrian

[Space Oddities]

18 hours ago, Rico said:

You can buy step down adapter rings that screw into the filter thread at the front of the lens. I got a few from: https://www.crookedimaging.co.uk/products/kood-stepping-step-down-ring-lens-adapter?variant=31154001289

They reduce the f ratio as follows: 

72mm->67mm (f/2.8 ->f/3)

72mm->62mm (f/2.8 -> f/3.2)

72mm->58mm (f/2.8 -> f/3.4)

72mm->52mm (f/2.8 -> f/3.8)

The 200mm lens is amazing and I shoot wide open all the time. But I think if you step down a bit, you can improve the shape of stars at the corner of the images even more. I haven't used the rings yet, so I can't first hand tell you that this is true, but I'll be testing it soon. The positive of using a step down ring is that you avoid the diffraction spikes from the aperture blades. 

Looking forward to more of your images!!

I'd love to see some test shots as well, if you have time!  

 

Edit: just found this post on CN:

Quote

For my Canon 200mm f/2.8 lens (which also has a 72mm filter thread), I bought this set of rings.  I found that stopping it down to f/3.5 (58mm ring) improved the tightness of my stars.  They were a little sharper at f/3.9 (52mm ring), but not significantly so.  Accordingly, I use that lens with the 58mm ring.

 

Edited September 26, 2019 by Space Oddities

[gorann]

For full freedom of f valiues, you can also buy sets of filter adapters (=step down rings) on ebay and Amazon and use them on various lenses. Here is an example:

https://www.amazon.co.uk/Concept-Stepping-Adapter-Step-Up-Step-Down/dp/B00JL4HGAI/ref=sr_1_3?crid=Q3AIGLBA47RW&keywords=filter+ring+adapter+62-+52&qid=1569568796&sprefix=filter+ring%2Caps%2C193&sr=8-3