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Old Sunday 8th July 2018, 21:06   #1
chris6
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Join Date: Feb 2006
Location: Hants uk
Posts: 207
Finding out what you like - What matters?

What do I know? but at least I think I know more than when I started to buy binoculars to try to find what suited best...

Ideally one could go to a shop to decide what to buy but there is no shop which can stock them all, and then here is the question of availability, whether in UK, EU, or USA. The most regular and consistent members on this forum give very useful pointers to star quality in individual examples, which I have found to be a great help, so one of those recommendations would be a great place to start.

However there remained a degree of mystification concerning factors which are less likely to be a problem with current binoculars, as follows.

1. 'Eye relief' is needed to be able to use binoculars when wearing glasses and for me around 15 or 16mm seems to be the limit. It is probably worth mentioning that ER of '15mm' suits me better than say '20mm', because I don't then need to wind the eyepieces out to a position which they may not retain in active use...especially since some binoculars do not have reliable intermediate stops.

2. The most out-dated is probably 'clarity' which I take to mean the mistiness which used to be common, but you would have to try much harder now to find that clarity is significantly lacking. For most casual users 'flare' and 'veiling glare' probably fall into the same category.

3. The next is perhaps 'sweet spot' which I believe not to matter so much when you are mainly looking at the centre of the view i.e. I find it hard to understand why a user would need to 'let the eye wander' to look at something on the edge of the field when simply moving the binoculars would be the normal response. However I believe that over time the average Sweet Spot has grown in size, perhaps to the extent that it is also no longer likely to be a problem.

4. The reverse seems to have happened to claimed 'Field of View'. Over 4 or 5 years the fashion seems to have bounced back but I have found that anything more than 7 degrees at 8x magnification, or 6 degrees at 10x magnification, is perfectly adequate.

The excellent low cost Nikon Action Extreme EX 7x35 still has a relatively small sweet spot and could be a good starting point. It is rightly popular and on the one hand it might demonstrate that its small sweet spot does not matter much to you, while on the other its huge FOV 9.3 degrees might be unnecessary.

5. Chromatic aberration ('CA') used to be common and was said potentially to limit sharpness (see 9.). It is still often mentioned as something which can be present at the periphery of the view but it has become unusual at the centre and, if so, it's not clear why it should now matter so much (as in 3.)

6. Brightness, mainly important to give a few extra minutes of use at dusk. This depends upon the optical glass, lens coatings, and mainly the size of the objective lenses. The higher range of prism glass according to the 'Bak4' standard is now the norm, while the terms 'ED' and 'Dielectric coatings' are no more specific and cover a range of possible other relatively marginal improvements.

7. Ease of use: some prefer 'open bridge/dual hinge' over the traditional single hinge because you can grasp each barrel individually, and this can help, along with greater weight to hold the binoculars steady, so to that extent the bigger the better. However the weight might only really matter if you are out all day, when a harness could be the solution. A larger Exit Pupil (objective size divided by magnification) can also help by making it easier to line up the binoculars to get the best view, and 4mm seems to be the tipping point for this if it is critical for you e.g. for small size and low weight, 8x32 is often preferred.

8. Colour. This might appear to be a complicated issue which can only be understood by looking at transmission charts for the range of frequencies of light which the human eye can see. However it seems to boil down to 'RGB', as for the controls on a TV: if red does not look red then there is something wrong (suitable test subjects being red berries?), and when green does not look green there is something wrong (leaves/trees/grass) and when blue does not look blue there is something wrong (the sky). For me the main thing here is still the tendency for the colours to appear too muted, as with B&W TV when you might want to turn up the colour control, and 'contrast' is related in a similar way.

9. Sharpness. To make comparisons it is probably enough to look at the same bit of text in the same light at the same distance. Imo, in combination with Colour this is what can really make all the difference in the enjoyment to be had from a particular pair of binoculars.

10. Quality Control/ Warranties. Obviously QC is likely to be more reliable at higher prices, but if they are new you can always return them. My own experience has been that the warranties on Vortex, Opticron, and Meopta were solid.

Last edited by chris6 : Sunday 8th July 2018 at 21:40.
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