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How do you test binoculars??? (1 Viewer)

smallblueplanet

Well-known member
Hi everyone

thanks to all who have answered my questions before......well, here's another obvious one - how do you test bins?

After reading all the threads (and totally ignoring the "try before you buy" ones, cos nowhere had these bins) I decided to buy a pair of Pentax 8x32 DCF SP. Arrived today after a long wait, so........they seem nice enough, but how do I test/compare them with my old bins/other bins???

My old bins are a pair of 2nd-hand Tokina 8x30, fov 143m @ 1000m, multi-coated bak4 prisms, water resistant, lightweight (670g) - cost me £65 about 8/9 years ago.

Well the Tokina are pretty good bins and they have a good depth of field; so then I tried the Pentax they seem a bit brighter, a different shape to hold, but less depth of field, in all nice enough - but are they worth c.£275. Yes I know that its subjective, but how do I test them "properly" to help me decide whether to keep them?? [Or send 'em back and splash out more (or less for the Nikon Sporters!)]

I guess I expected a much bigger difference........help pleeze. :)
 
Hi Manda

what I do is use the bins and see what I think. I would say you should test on days with poor weather conditions since they will test the bins. On a good day in good light you'll find the differences to be much smaller. I recently looked through a top scope but it was a glorious day and I could see only a small improvement and certainly not £700 of improvement.

Another thing to bear in mind is that bins are subject to the law of diminishing returns. Buying top end gear you're trying to eek out that last few % of improvement and you may find you don't need it.

You need to get your hands on some bins and compare the Tokina's and pentaxes to them.
 
smallblueplanet said:
Hi everyone

thanks to all who have answered my questions before......well, here's another obvious one - how do you test bins?

That's a good question. The mechanics are easy to test. Just try 'em and see if you like 'em. As for the optics, others may be more up on this than me, but here's a few thoughts.

Resolution: use a resolution chart or a bank note, and work out at what distance you can just about read some text, or see some feature.

Brightness: Look into deep shade. Differences in brightness become obvious. An even better test is to use them at dusk and find out what you can see when.

Contrast: That's a tricky one. A low contrast image looks flat, or milky, and a high contrast one looks 'lively' and natural. Not very scientific, but that's my approach.

Colour cast: Most binoculars have some colour cast e.g. slight yellow. I find this hard to judge, unless it is blatant, though side by side comparison will reveal a difference in cast between two instruments.

Field curvature. If you cannot keep both field centre and field edges in focus at the same time, then you have field curvature. If your eyes adjust easily you will see less field curvature. Older people are more sensitive to field curvature.

Distortion: Do straight lines bow outwards/inwards at the field edges? Note that distortion is not necessarily a defect, but rather can be a design feature.

Edge softness: Is the image soft at the edges no matter how much you fiddle with the focus?

Vignetting: Look at an evenly illuninated image such as blue sky. Is the field centre brighter than the field edges?

Chromatic aberration: Look at a dark bird in flight against a bright sky, or a white swan on a lake on a sunny day. Is the bird surrounded by objectionable colour fringing? Often the colour fringing gets quite severe as you look further away fromthe field centre.

Ghosting: Look at a bright object. (NEVER look at the sun. You risk your eyesight.) Do you see ghost images?

Flare: Look towards a bright object. Do you see a reduction in image contrast due to scattered light? For example, at dusk, look at the junction between some dark tree tops and a bright sky. Does the light from the sky spill over into the tree tops preventing you from seeing detail in the tree tops?
 
Humm.....it didn't take long for the one-liners!! I realised after posting the opening I'd left!! Ta Tero! ;-)

Hi Pete - sorry we never made the Minsmere do - but I saw the photos!! I mean, as Leif has described, how to test each pair. But the diminishing returns thing is exactly why I want to know what to look for and how.

As an example why - we all went to Fingringhoe Wick and were in the hide looking over the pool, and there's a stick/branch sticking up where a Kingfisher was sitting (about 100m?? away).....our mate says where is it? so we describe the branch and the bird! but no they still can't find it. Well this bird is sun-bathing and just hanging around and we don't want our mate to miss it, so we're pointing and describing the area to look but to no avail. And then we swop bins - our mate spots it, and very pretty it was too! she thought we'd been lieing to her, but no it was her cheap bins they couldn't differentiate the bird/branch from the background!! Well swopping bins saved our friendship and was an interesting lesson in bin quality (but hers were v. cheap)........

Thanks Leif - I'll print that list off and practise checking things optically - especially the ones affected by age!!

Think I'm gonna have to find some Nikons SE's to test.
 
Edge softness is a good way to test. It is very obvious in cheap binoculars, also possible to see in fairly good porros, medium price, as well.

I focus on an object in the middle, then move so it near the edge.
 
Leif, i think your testing method is excellent!
I also find that if you dont exactly optimise the inter-occular distance, align your eyes perfectly, adjust the dioptre perfectly, and optimise the focus for each of the bins you are comparing perfectly, you can get a false result. Sometimes pair 'X' looks better than 'Y', and sometimes its the reverse. I wonder how the reviewers in publications take care of those issues in limited time? Perhaps this is why you sometimes get such diverse opinions about the same bin (not to mention people's physical differences and conscious and subconcious biases).
I also feel that too little mention is made of how stable the image is for different bins of the same magnification. Weight and comfort are fairly crucial, but even if they are poor, some bins just seem more stable than others in my hands.
 
I am increasingly of the opinion that comfort factor is often undervalued, possibly because its hard to quantify. Weight is easy but balance less so, it may vary according to the users hands. No use in having a razor sharp image if you can't hold it still for long. Also some eyecups don't seem to fit me at all. Focus -ability ie how easy it is to change from near to far. Good depth of field helps a lot. If you just test binoculars for a short time the importance of these factors may not be immediately apparent, but they can have a considerable effect on how tiring the binos are to use during a long day in the field. It's these factors that do not appear on data sheets that make the "try before you buy" rule important
 
graham_t said:
I am increasingly of the opinion that comfort factor is often undervalued, possibly because its hard to quantify. Weight is easy but balance less so, it may vary according to the users hands. No use in having a razor sharp image if you can't hold it still for long. Also some eyecups don't seem to fit me at all. Focus -ability ie how easy it is to change from near to far. Good depth of field helps a lot. If you just test binoculars for a short time the importance of these factors may not be immediately apparent, but they can have a considerable effect on how tiring the binos are to use during a long day in the field. It's these factors that do not appear on data sheets that make the "try before you buy" rule important

I agree with this assessment.

Having looked at a number of so-called high-end binoculars recently, there isn't a lot between them optically. Okay, so there is some variation in FOV, DOF and so on, but they all give very good views.

What really sets binoculars apart, in my view, is their handling, which is very much a personal choice. By handling, I mean weight, balcnce, feel in the hand, eyecups, focus knob position, size and smoothness of focus and fast and slow focus. waht suits one won't necessarily suit another.
 
graham_t said:
I am increasingly of the opinion that comfort factor is often undervalued, possibly because its hard to quantify. .....

Absolutely. People get really hung up on what are very minor differences. I don't care what you buy, a careful look will reveal some "problems." I have yet to see a pair that does not lose some sharpness at the edge of the field, or does not have some lateral color. To me, comfort in the hand and a smooth and fast focus were very important.

Clear skies, Alan
 
AlanFrench said:
People get really hung up on what are very minor differences. I don't care what you buy, a careful look will reveal some "problems." I have yet to see a pair that does not lose some sharpness at the edge of the field, or does not have some lateral color.

Allan,

you should try the Nikon SE:s! We are not then talking about "very minor differences" then and you would have to look very carefully to find the "problems" you describe.

Cheers, Jens.
 
I have looked at the Nikon SEs, and pretty much all of the high end binoculars. Yes, high end binoculars are pretty good at the edge of the field, but none of them are perfect. And the "major differences" I found among the various quality binoculars were not in the optics, but in the fit and feel, which, of course, is a very personal choice.

Clear skies, Alan
 
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