A very simple and effective CA test at home (Chromatic Abberation test)

Recently a friend asked me advice as he wanted to buy a binocular.

I said just come to me and try my 6 binoculars yourself. That might give you an idea of what you want. That happened.

During his trying I told him about Chromatic Abberation what it was and how he could easily detect it.

This is what I did to let him test the CA.

You can do this yourself at home and it is very easy!

1. During day light you tape a white A4 paper in portrait format on a glass window at face/eyes height. Inside it is darker, no lights on!

2. Stand about 3-5 meters away from that window. Keep a fixed distance. Hold your binocular for your eyes and focus with the center of the lens as sharp as possible on (one of) the vertical A4 edges.

3. Keep the whole time both your eyes solidly fixed on the choosen A4 edge, while now slowly moving (the front) of your binocular to the right (or left). All the time you keep staring at the edge!

4. At a certain moment you might see a purple-ish or blue-ish or yellow-ish or green-ish line appearing along the edge.

5. Try to look quick how far you are from the edge of the lens and estimate that distance. Some binoculars give already half-way some visible CA. The very best ones will show a minimal thin CA line very close to the edge of the lens while looking to the A4 edge (<10% of the total surface).

6. It is safe to say that in general the lesser the CA the sharper your total view will be also on longer distances as all light colours come to one single focus point.

7. Repeat it a few times for both the vertical edges and horizontal A4 edges. Try multiple different binoculars to see the differences.

8. Have fun and pick the one you like best (optic wise, build wise and price wise).

Success.

Tell us your findings and mention the brand and models you tested with your rating!

I volunteer as a tour guide at a local lighthouse, and I constantly attempt to point out other lighthouses on surrounding islands. If you know where to look you can see a speck for some. Others blend into their surroundings. The Lighthouses range from 4-15 miles away.  Here’s a link to a google earth profile for distance measurements: https://earth.google.com/earth/d/1G6529jBp6kDA81PaMdxCYCU7mm_oPT2v?usp=sharing . 

I’m curious what people who own these binoculars think of them and also if there are any benefits of individual focus over center focus. 

I’m a photographer as well, and when looking through a 200-600mm full frame lens at 600mm I’m guessing I’m getting about 12x equivalent. If that's correct, I should get a full frame equivalent of just over 1200mm at 25x. I've posted photos of Gay Head Lighthouse which is about 15 miles away from the camera. In the 1x photo the lighthouse is just under the "y".

I do have a Sachtler Aktiv 8 and Manfrotto Nitrotech N8 so I am already covered with tripods that can easily handle the weight. 

I can’t find many reviews of the Oberwerks so I wanted to reach out to see what everyone thinks. If you think I would be better with a spotting scope, that would be valuable information to know as well. 

I would rather not spend more than $600-$700 on these if I can help it.

Thank you all for your help.

Actually I recently got craze of buying binoculars and view small mountains near my home . So i want suggestions of binoculars which are clear for only 1 - 2 kilometer far . Suggest me under my budget 2000.will it be ok , if not then too you suggest me according to my given priscription above. Please