Daydream on test card for binoculars (1 Viewer)

rozinante · Feb 28, 2007

While attempting comparisons of different binoculars I often focus through my window on a particular area of peeling paint on the eaves of the building opposite. It has an "organic" pattern of varying areas of top coat, undercoat and corroded metal within an area of about 6" x 4".

I find the consistency of the target makes for quite a revealing quick assessment of an unknown pair of bins against a known standard.

This led me to wonder if anyone has ever devised or heard of such a thing as a test card for binoculars.

mooreorless · Mar 1, 2007

rozinante said:
While attempting comparisons of different binoculars I often focus through my window on a particular area of peeling paint on the eaves of the building opposite. It has an "organic" pattern of varying areas of top coat, undercoat and corroded metal within an area of about 6" x 4".

I find the consistency of the target makes for quite a revealing quick assessment of an unknown pair of bins against a known standard.

This led me to wonder if anyone has ever devised or heard of such a thing as a test card for binoculars.

Hello,That could be the 1951 USAF test target [resolution chart].It uses smaller and smaller lines verticle and horizontal to test for resolution.Edmund's Optics site has these,but this is in the U.S. There is one that goes for about $18 that I have and it has a bunch of these test targets in black,yellow,blue and red in a criscross pattern mounted on heavy paper .
Regards,Steve

Regards,Steve

Sancho · Mar 1, 2007

rozinante said:
While attempting comparisons of different binoculars I often focus through my window on a particular area of peeling paint on the eaves of the building opposite. It has an "organic" pattern of varying areas of top coat, undercoat and corroded metal within an area of about 6" x 4".

I find the consistency of the target makes for quite a revealing quick assessment of an unknown pair of bins against a known standard.

This led me to wonder if anyone has ever devised or heard of such a thing as a test card for binoculars.

I think I remember seeing a review of Avian binoculars some years ago (great bins, incidentally..) in which they mentioned a "phone book" test. Anyway, I sometimes try it with other bins. Put the phone book at the end of the garden, open and propped up, and do with it exactly as you mention with your patch of peeling paint, etc. I think your peeling paint-patch test has a much more existential feel to it, though, than the phone-book test.... |;| (P.S. - why "z" instead of "c"?)

rozinante · Mar 1, 2007

Thanks for that Steve. Here it is in all its glory and available as a high res download:-

http://en.wikipedia.org/wiki/Image:1951usaf_test_target.jpg

Phone book sounds good too.

My paint patch does reveal the ability to distinguish subtle and small areas of differing tone though. I think I should pin up a random warbler pic and see if I can detect distinguishing marks.

Sancho said:
(P.S. - why "z" instead of "c"?)

I think perhaps it's the anglicised form.

Whatever it should be, unlike your namesake with his donkey, my master does not loose me.

AlanFrench · Mar 1, 2007

The best way to test optics would be to measure resolution as a function of contrast.

Here is one source for such a target...
http://preview.tinyurl.com/2qj5kx

Clear skies, Alan

elkcub · Mar 1, 2007

The only test that really works for me is a live bird, but so far I haven't trained one up to pose for binocular comparisons.

Seriously, I don't think test charts can be used to evaluate complex perceptions, since the gestalt is more than the sum of its parts. As for rozinante's dream, well, peeling paint may have more value than he recognizes.

Ed

Sancho · Mar 1, 2007

rozinante said:
I think perhaps it's the anglicised form.

Whatever it should be, unlike your namesake with his donkey, my master does not loose me.

Mind you, if my Mistress (and de facto accounts manager) sees me doing anymore optics tests, or finds me daydreaming about new bins, it´ll be time I lost myself in some inhospitable wilderness

.

mooreorless · Mar 1, 2007

Hi Alan,I asked Henry Link about this USAF Contrast Resolution Target and he didn't think it would work very good.I don't remember his reasons why.I have the USAF Resolving Power Chart that is 36 inch by 24 inch,well what is left of it after cutting out some of the black targets to give to friends etc.

Regards,Steve

mooreorless · Mar 1, 2007

Roz,The trouble with printing off that test target from your link is to get the size right.I tried 3 inch by 3 inch and seemed good,but I didn't try to check the size as compared to my test target that is supposed to be the right size.Also it is in negative and would be better in positive [white with black lines],BT I guess this is cheaper than the alternative and could be used for your own testing.

Steve

henry link · Mar 2, 2007

The problem with the Edmund chart in Alan's link is the poor printing quality. Something you find out after you've bought it. The darkest targets are so dense that the black spills out into areas that should be white and the palest targets are so pale that the smaller groups aren't printed at all. The Edmund glass slide is much better. It has a perfectly sharp vapor deposited target all the way down to the end of group 7 (228 lp/mm). Contrast can be varied to some extent with it by controlling the amount light or varying the darkness of the material of whatever surface is placed behind the slide.

mooreorless · Mar 2, 2007

Hi Henry,Thanks for the update on that,I'm glad I never ordered one of those.My target the group 2 & 3 are not usable ,I just have to set target out farther.I ended up just cutting out one of the black test targets and mounting it on a box Some day I will get one of the glass slide targets.
Regards,Steve

rozinante · Mar 2, 2007

mooreorless said:
Also it is in negative and would be better in positive [white with black lines],BT I guess this is cheaper than the alternative and could be used for your own testing.
Steve

Hello Steve, you should be able to reverse the image either in a graphics program or maybe your printer prefs. It might also be possible to tighten the image up by converting to vector graphics or by effects in photoshop or similar.

What the mono targets lack from our point of "view"

is subtle shades of colour.

Obviously, as has been said the only truly relevant test is in the field but I think these sorts of targets can give some useful feedback.

elkcub · Mar 2, 2007

rozinante said:
Hello Steve, you should be able to reverse the image either in a graphics program or maybe your printer prefs. It might also be possible to tighten the image up by converting to vector graphics or by effects in photoshop or similar.

What the mono targets lack from our point of "view" is subtle shades of colour.

Obviously, as has been said the only truly relevant test is in the field but I think these sorts of targets can give some useful feedback.

You nailed it "...subtle shades of colour." :t:

Ed

AlanFrench · Mar 2, 2007

henry link said:
The problem with the Edmund chart in Alan's link is the poor printing quality. Something you find out after you've bought it. The darkest targets are so dense that the black spills out into areas that should be white and the palest targets are so pale that the smaller groups aren't printed at all. The Edmund glass slide is much better. It has a perfectly sharp vapor deposited target all the way down to the end of group 7 (228 lp/mm). Contrast can be varied to some extent with it by controlling the amount light or varying the darkness of the material of whatever surface is placed behind the slide.

Henry,

Thanks. I didn't know that. For the price, it should be absolutely perfect, and I am disappointed to hear otherwise. I'm glad I never mailed that check!

Clear skies, Alan

Tvc15_2000 · Mar 14, 2007

Frank recommended this one to me.
Its $3 and I found it usefull for fast comparisons of resolution, contrast and brightness. While a bigger chart would provide more details - its not much use if you don't have it with you! This one is small enough to fit in your wallet.

http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=1852

Daydream on test card for binoculars (1 Viewer)

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