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Do lenses vary by brand or is not just f-stop and focal length?


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Hello. I am relatively new to astro photography and I am using a astromodded Canon 60D couple to my existing zoom lenses and have a drop in Astronomik CCD-CLS filter.

 

I get good results with the Canon 70-200 f/2.8 L when using it at f/4-5.6 at 200mm, however when I swap to my Sigma 150-600 at f/6.3 I don’t seem to see as much colour in the resulting pictures - they are really disappointing.

 

From a photography exposure perspective I have increased the exposure length to offset the slightly slower lens, however I am perplexed by the large differences seen.

 

Is it possible that some camera lenses just don’t work well witth Astro?

 

tracked photos using a HEQ5 Pro.  My stars come out fine, just the colours are disappointing.

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Hi Keith. I have edited the colour of the text as it wasn’t showing up with the forum dark theme. It is a known bug in the software and only affects the occasional first post.

 

To answer your question yes in general camera lenses don’t really work well for astro especially zoom lenses due to the amount of glass they have in them. The best conventional lenses are prime lenses that are fixed focal lengths. There are a few like the Canon f1.8 50mm EF and the f2 Samyang 135 which are excellent the latter being really expensive now though. Both of these have different fields of view and the 50mm one is only really suitable for large structures or milky way shots. The Samyang on the other hand is great for larger nebulae.

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  • 2 weeks later...

When I was imaging using a modded DSLR (Canon 450D) I was using old pentax lenses - I had a 50mm for wide field & a 135mm.

Which I used to capture some excellent images with. 

The key to success though isn't lenses or your camera, its tracking. 

Tracking will enable you to take longer exposures producing better images ultimately. 

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