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

[rick]

I am going to try using for parallax marks.

Whats your opinion about having the scope optically centre before trying it.

[SpikeG]

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.

Very true, my eyesight is becoming worse with middle age rapidly approaching.
As long as it's compared against a baseline scope that you have tried then it will give a quality reference for you.

Good point about what you 'think' you can see as well. I would normally expect a Leup/S&B etc to be miles ahead of a Richter etc but would that inevitably prejudice my results, in thinking I can see more than I really could? (I think it would if I'm honest)

I am going to try using for parallax marks.

Whats your opinion about having the scope optically centre before trying it.

In theory, centring the scope should minimize any aberrations and fringing etc so I always start with a centred scope if possible. Once again the chart could show problems with a scope at the ends of adjustment? Maybe?

[Gloop]

That's well interesting. I will have to give that a go in a week when I can round up a few buddies and we can compare scopes. Should be able to compare 7 or 8 scopes. Mate works in a gunshop so when he's not looking I will try to grab as many scopes as possible and see what results I get. This may take a week or so.

I feel a challenge coming up.

[Gloop]

I have just printed this off. Got me thinking.

I wonder how well this will work with nightvision? Don't see any reason why not. 25 yards may be 2 far out as most NV is no more than 5 mag as far as I am aware. I am a NV novice. So might have to set it to 10 yards.

However as long as you are constant you should get similar results and as there is a big NV meet coming up in November then this could be a really good time to try it.

Comments?

[SpikeG]

I wonder how well this will work with nightvision? Don't see any reason why not. 25 yards may be 2 far out as most NV is no more than 5 mag as far as I am aware. I am a NV novice. So might have to set it to 10 yards.

However as long as you are constant you should get similar results

Yup, as long all the variables are fixed beforehand (distance/magnification/Gen1/2/3/Digital) then comparing like for like will be a doddle.

I would suggest for any test if a number of people are comparing scopes or NV then a quick bit of maths and find the average score to iron the variances of eyesight out would be advantageous (not necessary if only 1 person is doing a comparison)

[Hurricane]

I thought I'd use this chart to give some 'figures' to the differance in quality between my 4-16x50 MTC Taipan and 3-9x50 Hawke Reflex scopes. As it was raining I put chart in my open fronted wood shed (slightly dark) and stood in kitchen with riffles, approx 25yds. First I set Taipan to 9x (same as max on Hawke) and looked at chart, I had great difficulty working out just how fine a resolution I could see, but then I'm not good at that sort of thing, so I then looked throu the Hawke, but I could not get any reliable differance in figures than the Taipan, why?, well with the Hawke I couldn't even read the figures! I tried various distances at various mags, but at any hunting ranges I could not read the figures, so all I can say is the Taipan is vastly superior to the Hawke, but to what figure I don't know, but it certainly makes me think the extra cost was well worth it.

[Gloop]

Boy did I have some fun today.
I got to try an MTC Taipan, Various Hawke scopes, Bushnell,Simmons, Millet, who? Optalens, another who? Nikko Sterling, Vortex, Zeiss and Schmitt Bender.

I set the test to 15 yards, best I could do inside. Light was kept constant. Expensive scopes I couldn't get a good focus on due to the short distance involved. To be fair not unexpected.

Long story short, I was playing with scopes from £70 to £400. Generally they were all similiar between 19 to 21. The MTC Taipan and the Nikko Sterling Diamond were 22. But head and shoulders above them all was a AGS Elite which came out at 26. This is the old AGS not the newer ones.

I then did a low light test with those 3 again. Again the AGS kicked ass. I bought it on the spot.

Good times!!!