Resolution Test Chart.

[SpikeG]

Not strictly a review but more of a useful tool for optics testing.

In the photography field reviewers use test charts for testing the accuracy and resolution of lenses to give a standardised result, so why not do the same for scopes.

The following is the chart I now use.

Printed out on A4 at the highest resolution your printer will allow (quality paper is good to) and then laminated, set the chart at 25yds then you can compare optical clarity and resolution of your scopes.
This also applies to light conditions as well, for example how far down you scope will resolve in twilight conditions etc.
It may sound obvious but compare scopes at the same magnification level

As a quick example my cheapo Richter optic will resolve to 38 at 25yds on 32X equally as well as a Nikko (the picture was a little more 'washed out'), but reducing the magnification to 14X showed up it's poorer optics being 3-4 points behind the Nikko.

Hope it's of some use anyway.

Rapidshare link

Direct imageshack link

Note Image is ~2.5MB

[lexus]

Could you please do a follow up post to explain how you use this chart to get the results.

Regards

Nigel

[PESCA]

Thanks, SpikeG, that's an extremely handy chart for checking out scope and NV resolution.

Cheers.
George

[sidesy]

thanks, Gary

[SpikeG]

Could you please do a follow up post to explain how you use this chart to get the results.

Regards

Nigel

No problem Nigel.

It's probably most useful to use as a comparison sheet to a known scope.

For arguments sake lets assume you have a 10-50 x 60 Nikko (or equally a JSR/Leapers/S&B etc it matters not) and you use that as your base scope. Set the test chart out at 25 yards and with the scope set at 10x see how far down you can discern the individual lines. (The numbered lines are all the same so 14 on the circles are the same spacing as the curved lines etc) This will give you your base reading.
Then do the same with your scope of unknown quality and see how far you can resolve to with that. This then gives you a quantitative image clarity for that scope (in comparison to your 'base scope'.)

It also means that any review that uses this chart will have a way to compare to the scope you use. Obviously eyesight is a factor so wear glasses if you need them when using it

Obviously the chart should be used at the same magnification settings and distance when comparing scopes and again in the same light conditions. (There is no reason why the chart cant be used in all light levels)

One of the shooters at the club has also noticed it is useful for setting up the eye bell focus on his scope. After setting it in the normal way (pointing to a clear sky) he found that it was a little way out when pointed at the chart and a little tweak improved resolution no end.

HTH.

[lexus]

Hi Ian

thank you for the follow up, that made it so much clearer

Regards

Nigel

[SpikeG]

Interesting results Mike.
I'm surprised how low the Mamba scored

[Parabuteo]

Hi Mike,Spike.

Interesting chart, I use something similar at work for focus checking, but I am not quite sure what this achieves unless the same person does the test as all of our eyes are slightly different.

As a comparison though it makes sense, for the individual concerned.

Sadly, I can only get 15yds in the garden, but I was sure I was seeing clear stripes at 40 with the lite I picked up...am I seeing, or is it what I think I am seeing?

When I get 5 I will take all of the mamba's down the range and try again Mike.

Interesting exercise...oh hell my cocker is trying to nest in one of my shooting jackets