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Tests of 9 Different Chromatic Aberration Filters

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#1 Charlie Hein

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Posted 21 September 2013 - 07:02 AM

Tests of 9 Different Chromatic Aberration Filters

By Gary Poliquin

#2 jgraham

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Posted 21 September 2013 - 08:29 AM

It was very interesting reading the comparisons of such a range of filters used by a single observer. I've also used the Orion Minus Violet, Baader Fringe Killer, and Baader Semi-Apo with similar results. The Semi-Apo filter lives in the star diagonal of my 6" f/8 achro. I observe from a red zone and the light pollution supression of this filter is a bonus.

Thanks for taking the time to post this review!

#3 eklf

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Posted 21 September 2013 - 09:36 AM

Many thanks for a timely and comprehensive round-up of the common filters.

Based on my reading, I have been led to understand that CA is spread across the entire surface, thus other than presenting edge fringing, also reduces overall contrast over the entire surface of moon.

Would you please comment if these filters noticably improved contrast also?

I wonder if anyone else has compared any of these filters with #11.

Many Thanks again for a very nice review.

#4 Messyone

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Posted 21 September 2013 - 05:14 PM

Good write up. I'll have to agree the semi-apo is the best in my f8.
The Fringe Killer, a WO minus V and a #8 are all much the same, too yellow and too little purple suppression to bother with.
Matt

#5 highfnum

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Posted 21 September 2013 - 08:44 PM

nice job
I agree with what you said
I got same set in addition I also have MV-1 as well as MV-20
MV-1 imparts yellow cast MV-20 more balanced

#6 Kon Dealer

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Posted 23 September 2013 - 04:35 PM

Thanks for this.
have to disagree with you on the Semi-APO.
Makes hardly any difference to CA to my eye and spectrographic measurements back this up- only a little bit of violet removed (along with all yellow wavebands).
The#8 light yellow does a very good job of removing all violet bands, leaving longer wavelength blue and only imparts a slight yellow tinge and less dimming than the Semi-Apo.
I'm selling my Semi-APO and keeping the #8- which cost less than a fifth of the Semi-Apo in the first place.

#7 *skyguy*

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Posted 24 September 2013 - 12:30 PM

Check out this German site that shows comparison tests ... both spectroscopic data and daytime photos ... between several of the filters mentioned in Gary Poliquin's article:

Filter Test

Very interesting results ....

#8 Rachal

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Posted 24 September 2013 - 03:54 PM

In the German article, do you have any idea what he was referring to as the Contrast Booster or which filter is similar in Gary's article?

#9 highfnum

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Posted 24 September 2013 - 06:08 PM

contrast booster not listed in his list
I have one - its like MV-1
cuts a lot but give yellow tone

#10 russell23

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Posted 27 September 2013 - 10:27 PM

Check out this German site that shows comparison tests ... both spectroscopic data and daytime photos ... between several of the filters mentioned in Gary Poliquin's article:

Filter Test

Very interesting results ....


It can be seen with both the flowers and the following picture on that thread that the fringe killer reduces the fringing more than the semi apo filter. And the semi-apo achieves a color neutral appearance by completely removing the yellow light. I will stick with the fringe killer.

Dave

#11 KevinS

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Posted 28 September 2013 - 06:10 AM

I was very happy with the Semi Apo...until seeing the German photos and spectra graphs. It seems the Fringe Killer is worth investigating for visual and full spectrum photography.

#12 azure1961p

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Posted 28 September 2013 - 10:20 AM

The semi-apo filter is little more than a combination fringe killer and neodymium. I get the same effec virtually by stacking them and knew that would be the case prior to purchase. I simply don't want a fringe killer component when I want the NEO advantage in my reflector . Essentially all that's happening in the semi apo filter is the neodymium component is blocking the yellow cast . The fringe killer component at a reviewed 10% better in the semi apo config isn't worth having if a person has reflectors and cats as well as full apos. All in one isn't best for my needs.

Pete

#13 azure1961p

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Posted 28 September 2013 - 10:25 AM

Check out this German site that shows comparison tests ... both spectroscopic data and daytime photos ... between several of the filters mentioned in Gary Poliquin's article:

Filter Test

Very interesting results ....


Spectra shows the semi apo passing more blue violet than the fringe killer!
Photos would seem to prove the fringe killer over the semi apo and in every example. Seems opposite the articles finds. Nice link!



Pete

#14 orion61

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Posted 28 September 2013 - 07:42 PM

I have the Orion V-Block and it kind of bugged me with the Yellow hue.
I resolved it completely, by screwing a Wratten 82A very light Blue color filter on the V-Block.
The color changed back to the Natural Hue, the Moon was Grey again, the false CA is gone.
Thanks for the great article.
Larry

#15 highfnum

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Posted 29 September 2013 - 08:43 PM

82A very light Blue
nice tip will try that

#16 russell23

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Posted 30 September 2013 - 07:24 AM

I just ordered a 2" lumicon #8 light yellow filter and a 2" Baader 495 long pass filter. I'm going to compare these with he Fringe Killer not only for lunar/planetary, but also for deep sky observations. I have found the Finge Killer sharpens views or deep sky and makes it easier to find sharp focus above 50x. The long pass should suppress the CA but I am interested in how much it may dim the views as compared to the Fringe Killer.

Dave






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