Kowa YF 8x30 Binoculars Review

Whilst roof prism binoculars are all the rage at the moment, they do have their drawbacks and with the Kowa YF Series, it is refreshing to see a highly respected optics manufacturer like Kowa producing some new porro prism binoculars. Porro prism binoculars generally offer a better depth of field, a wider field of view and because the objective lenses are often spaced wider than roof prisms, they often produce a slightly better stereoscopic image. In the cheap to medium price range, porro prism binoculars are also quite often optically superior to roof prism ones because they don't require expensive phase correction and high reflective coatings on the prism glass as you do with the roof prism design.

I recently got the chance to spend a few months with the Kowa YF 8x30 binoculars and below is my full review:

Kowa YF Series Binoculars
Whilst Kowa are probably best known and indeed admired for their high end spotting scopes and binoculars manufactured in Japan, like the Kowa 10x33 Genesis XD Binoculars that won my award for the Best Safari & Travel Binocular in 2011 or the fantastic Kowa Genesis 10.5x44 XD Binoculars that won the Best Binocular Reviews best binocular of the year in 2010, they did not really offer a binocular for the more price conscious customer.

That has now recently changed with the announcement of two new ranges of much more affordable binoculars - the SV roof prism binoculars and the YF line of Porro Prisms. Both lines still come with a whole host of quality features and specs, but cost much less than their top of the range Genesis models. How have Kowa done this? To start with, they reduced costs through simultaneous product development and instead of being made in Japan, these models are manufactured in China.

I know many people may be put off by this and it is true there are some truly awful binoculars on the market that are made in China, but to say that all binoculars made in China are bad is like saying all birds fly! I have often been rather pleasantly surprised by many Chinese manufactured binoculars, especially by ones where the parent company is either European, American or in this case Japanese, where they have a reputation to uphold and where the research and development takes place in the "home" country and only the actual production takes place in China.

Currently there are two porro prism models in the YF series, one with a 6x magnification and this one with it's 8x magnification. So lets see if these Kowa YF 8x30 binoculars have what it takes:

Selected Highlights

• 100% water & Fog Proof
• Fully multi-coated lenses
• Field of View: 396 feet at 1000 yards
• Eye Relief: 16mm
• Good quality wide neck strap
• Compact design can even be used by older children

The Body

Taking them out of the box and holding them for the first time I was struck by just how light and comfortable they were to hold. Their styling and build quality also looked good, making them look and feel far more expensive than their actual price tag, which is always a good thing.

Build Quality
I have not been able to establish exactly what the frame of this YF30-8 is made from, which is a shame as I do wonder what Kowa used to make them so light (see section on weight below). Sometimes a lightweight binocular is only light because it is made of cheap materials and whilst I did not test them to destruction (I have to return them!), they do feel very solid and robust and should handle most of what you throw at them during normal usage.

Like most modern binoculars, the frame has been covered with a rubber armoring and Kowa are quick to point out that the YF binoculars actually have 2 types of rubber armour, but don't go on to explain. Looking and handling them, the different rubber coatings are not obvious and so I can't really comment on the implied benefits of this.

What I can say is that the rubber coating is fairly hard and so is not quite as tactile as some binoculars out there, but will still improve the grip compared to a un-rubberized pair and will protect them from scratches as well as small bumps and knocks. The rubber armour also has another benefits, like making the binoculars less reflective, it will also help dampen down any sounds, if something like your watch or ring strikes against the barrel. These are important features if you want to remain unnoticed when observing timid birds and other wildlife.

On the underside of the body there is a deep wavy depression in the rubber armor on each barrel, which not only adds to the styling, but is placed in such a way as to also help with grip and your thumb placement. This is rather like the thumb indents that you find on many other binoculars and it just encourages you to hold them at the right point to get them nicely balanced.

The objective lenses sit almost 4mm within the body armouring, which is something that I really like as tit gives them plenty of protection. The bridges between the two barrels looks to be made from metal, which is good as poor quality optics often use a hard plastic, which helps to keep the price and weight down, but means they are far less durable.

Waterproof & Fogproof
These Kowa YF Series binoculars are waterproof which not only protects them from moisture, but in dry conditions it also prevents any dust and other small debris from entering them that could lead to your view being spoilt.

During the manufacturing process, the air inside the Kowa 8x30 YF binocular is replaced with dry nitrogen gas which helps prevent internal fogging. This means that you can safely use them in places where there are very low temperatures, high humidity levels or rapid temperature changes without the risk of any condensation forming on the inside the optics. A side benefit of fog proofing is that because there is no internal moisture it also protects the inner workings from corrosion.

The Eye Cups
The eyepiece housing looks to be made from a hard plastic or something similar, as do the twist-up eyecups, which have then been covered in a fairly thick and fairly soft rubber coating. The ocular lens has a diameter of 19mm, whilst the eyecup has an external diameter of 39mm and are fairly comfortable even when pushed quite firmly against your face.

The twist-up (helicoid) mechanism of the eye-cup on these YF binoculars is excellent - it is very smooth and has a very good 4 fixed stops (2 intermediate), meaning that eyeglass wearers have a good amount of flexibility when adjusting the eye-relief to suit their exact needs. The maximum of 16mm of eye-relief is also good and should be enough for most people who wear glasses to be able use these optics without having to remove their glasses and still get the full field of view without any vignetting. Non-eyeglass wearers will just use the eyecups in the fully extended position.

Focusing
The central focussing wheel, looks like it is made from a hard plastic or something similar and is covered in a soft rubber coating with large indents cut out of it to help with grip and adds to the styling. The focussing wheel has a diameter of 35mm which is large enough to make using them even with thick gloves on, no problem at all.

The focusing mechanism is geared so that it only takes about 3/4 of a turn of the wheel to go from infinity to it's minimum focusing distance of 2.1m (6.9 feet). What this means is that focusing from near to far (or vise versa) is very quick and much quicker than a binocular that takes more revolutions of the focussing wheel to go from one end of the focal plane to the other (some take more than 2 full turns). An aggressively geared mechanism like this can sometimes mean that fine tuning your focus to get it exactly right is a little more tricky, but I never had a problem with this. Here the deeper field of view that you often get on a porro prism binocular also helps.

Interpupillary Distance
The distance between the centers of the ocular lenses can be adjusted from a minimum of 5.1cm to a maximum of 7.2cm by opening and closing the central hinges on the bridge. This is usually referred to as the inter-pupillary adjustment and is done to accommodate the differences in the distance between different peoples eyes.

Diopter Adjustment
Like the majority of binoculars, the diopter adjustment ring is located on the right barrel, between the eyecup and the body . The mechanism is not notched or ratcheted and so can be moved accidentally. However, there are markings on the barrel and quite a few on the diopter ring and so if you remember your mark, it is fairly simple to return it to your desired setting. For those who don't know, the diopter setting is used to correctly set up and focus the binoculars to your particular eyesight and only needs to be done once.

Best Binoculars Rating for Body Construction Quality: 7/10

Weight
These Kowa 8x32 binoculars weigh just 475g (16.7oz) which is extremely good and makes them one of the lightest mid-sized binoculars that I have ever reviewed. For comparison and to put this into context, take a look at the weights of other similar sized binoculars below:

• Pentax 10x30 PCF CW: 462g (16.3oz)
• Steiner 8x30 Military-Marine: 510g (18ozs)
• Minox 8x33 BL Binoculars: 649g (22.9oz)
• Nikon EDG 8x32: 655g (23.1oz)
• Kowa Genesis 10x33 XD : 590g (20.8oz)
• Swarovski 8x32 Traveler EL: 610g (21.5oz)
• Barr & Stroud 8x32 Sierra: 595 (21.0ozs)

Weight alone can sometimes be a little misleading because some featherweight binoculars are only light because they have been constructed from cheap, poor quality materials and components that also happen to be light. Whilst these don't have a magnesium frame like some of the top of the range optics listed above, they still feel very robust and definitely don't have that cheap plastic feeling that you sometimes find with binoculars in this price range.

Dimensions
Their most compact dimensions are (Length x Width x Height): 11.8 x 16 x 4.8cm (4.6 x 6.3x 1.9in) - with their eyecups fully extended their length increases to 12.6cm (4.9) and with the inter-pupillary adjustment set to it's minimum, their width is 13.3cm (5.2in). This pretty good and they actually compare very well with most mid-sized roof prism binoculars.

What is interesting is just how comfortable it is to hold onto this design of binocular and the large focusing wheel is easy to reach even with pretty small hands, making these ideal binoculars for women and children.

Balance
Overall I thought that the balance of these Kowa 8x30 binoculars was good and this is where the well placed wavy depression in the rubber armour under each barrel really helped as it just encourages you to get your hands and thumbs into exactly the right position. Compared to large heavy optics, the balance is not as critical on a mid-sized binocular like these, but it can still help you to keep the binoculars nice and steady when looking through them, especially during longer periods of observation.

Best Binoculars Rating for Body Stats: 7/10

Kowa YF30-8 Optics

The Prisms and their coatings
Even at their fairly low price point, these Kowa YF 8x30 binoculars come with some good quality optical components and coatings including the use of BaK-4 glass on the prisms as opposed to the inferior BK-7 prisms found on many lower cost binoculars. This superior optical glass helps to produce sharper and clearer images.

Unlike roof prism binoculars there is no need for expensive phase correction coatings and high reflective coatings on a porro prism. This not only makes it much easier to produce a binocular with a high quality view, but also helps keep the cost down and is one of the biggest advantages of the porro prism design.

Lenses
Fully multi-coated lenses are used on both their YF series binoculars, which means all air-to-glass surfaces have received multiple layers of anti-reflective coatings which increases light transmission to produce a brighter image and therefore better low light performance.

These high reflective coatings on the lenses can make a really big difference on the brightness of the image produced and I have often seen binoculars with smaller objective lenses, but high quality anti-reflection coatings easily outperforming binoculars with much larger objective lenses, but with fewer or no coatings. Beware of these lower quality optics that will often only add multiple anti-reflection coatings to the outer surfaces of the lenses (Multi-Coated) and cheaper still are optics that only have a single layers of anti-reflection coating added to the outer lenses (Coated). The very cheapest optics have no anti-reflective coatings at all and I highly recommend staying well clear of these.

The table below shows Transmittance by type of lens coating:

Best Binoculars Rating for Optical Components Quality: 7/10

Optical Stats

Field Of View
Their field of view is 132m at a distance of 1,000 metres (=396 feet at 1,000 yards = 7.5°), which is excellent and they make it onto my list of wide angle binoculars and is a real highlight on these Kowa binoculars and therefore should be more than wide enough to keep most people happy including most birdwatchers.

Close Focusing Distance
Kowa don't advertise the minimum close focusing distance on these, but I measured it at 6.9 feet (2.1m). I regard anything under 6ft as being very good, so if you are looking for a mid size binocular that is also reasonably good for viewing objects close up, things like butterflies for example, these will hold their own, but may not be ideal if this is your main intended use for them.

Eye-Relief:
Their maximum eye-relief of 16mm is also good and this should be enough for most people who wear glasses.

Best Binoculars Rating for Optical Stats: 8/10

Image Quality

As I do for all my reviews, I compared the view through these Kowa 8x30 YF Series binoculars with that of my control binoculars of a similar size and magnification.

Brightness
I conducted these tests on a fairly overcast morning: In terms of image brightness, these were to my eyes about the same as that of my benchmark 8x32's that have slight larger objective lenses and so overall I would rate them as being very good in this area and easily as good or better than most in this price range.

More about Image Brightness and the 8x30 Configuration
The most common size of objective lens for a mid-sized binocular is 32mm as this tends to strike a good balance between light gathering potential and size of the device, yet these Kowa YF binoculars come with slight smaller 30mm lenses, so whilst this does help keep their weight and size down, does it have a large impact on the image quality and brightness?

Good light gathering ability is important because quite often you will find yourself in situations where the lighting is sub-optimal, especially in thickly wooded or forested areas, early in the morning just before or at sunrise or late afternoon when most birds and other animals are at their most active. Full sized binoculars with larger 42mm objective lenses will have the ability to let in more light, but will obviously also be bigger and heavier and so harder to carry about in the field and put in with your luggage. To explain how this configuration works, all 8x42 binoculars have an Exit Pupil of 5.25 and a Twilight Factor of 18.3 and an 8x32 binocular has an exit pupil of 4 and a twilight factor of 16 which are both in theory better than this 8x30 that has a exit pupil of 3.8mm and a twilight factor of 15.5 and shows that the increased objective lens diameter of a larger binocular has the potential to gather more light and make it possible for the binoculars to transmit more light and thus should in theory work better in low light conditions.

But what these exit pupil and twilight figures do not take into account is the transmittance or quality of the optical system, which is as important, if not even more so in producing a bright and good quality image. This is because the performance of a pair of optics in poor light also depends a lot on the quality of the glass and optical coatings and not just the exit pupil and twilight factor formula. Good coatings on the lenses and the prisms (for roof prism binoculars) can double the amount of light that gets through the binocular, when compared to those that have none or poor quality coatings.

Colour Fringing
There was no obvious signs of color fringing (chromatic aberration) around the edges of objects even when closely observing the edges of light or white coloured objects sitting in front of a dark background. So once again I would say that they perform excellently in this area.

Softening
There was a small amount of softening of the image on the periphery of the view, but not enough to make it noticeable unless you are actually looking for it.

Contrast & Colour Reproduction
Unlike the artificial tints that you sometimes find on cheaper binoculars, the colour reproduction looks and feels natural. I also thought that contrast of the image was also very good and once you have correctly focussed on an object the image is pin sharp.

So tho sum up, I would rate the view through these Kowa's as very good and far better than you would expect to find on a mid-sized binocular in this price bracket.

Best Binoculars Rating for Image Quality: 7/10

8x30 Kowa YF Comparisons

In the table below I have compared some of the main stats and features of these Kowa YF binoculars with that of some similar sized binoculars that I have reviewed in the past:

Whist it may not seem fair to compare these mid priced binoculars with some very top of the range models, it does help to put them into perspective and show that in terms of their main specifications they do compete very well.

Included Extras & Attention to Detail:

Neck Strap
The next strap that comes with the Kowa YF series binoculars is nice and wide and very well padded. It looks to be well made and is of fairly good quality, but is not quite as deluxe as what you get with the Kowa Genesis 10x33 XD Binoculars for example. I like the attention to detail in that the padded section that hangs around your neck is curved to ensure that it hangs more naturally.

Carry Case
The soft carry case is nice and roomy and makes it easy to store the optics with the eyecups fully extended and with the Interpupillary Distance set to maximum. The case does not come with it's own strap, so to carry it on your shoulder, you feed the binocular's neck strap out the sides of the lid when they are in the case. On the back of the case there is a loop which you can thread your belt through to carry it on your waist. The flip up lid is held closed with a strip of Velcro. Unfortunately there are no extra pockets on the outside or inside which are useful for carrying things like lens cleaning cloths, some money, keys or other small personal items.

Lens Covers
The eye-piece cover (rain guard) is made from a very flexible plastic/rubber and fits nicely, if just a little too loosely onto the eye-pieces meaning that it is possible that they could come away accidentally. I like the fact that it has a flexible bridge between the two cups that allow for the different distances between the two eyepieces depending on your inter-pupillary adjustment. This is something that is often overlooked by manufacturers meaning that the eyepiece covers wont fit, unless you store your binoculars fully open, which can be a real pain as you have to adjust them every time you use and replace your binoculars.

The objective lens covers are made from plastic and fit well into to the ends of the barrels of the binocular and should not fall off that easily. Each of them has a loop which can be used to attach them them to the neck strap.

Rather surprising is that these Kowa binoculars did not come with a lens cleaning cloth, but I guess to keep the cost down they have to make sacrifices somewhere.

also included is a fairly comprehensive, but generic YF series instruction booklet that includes details on adjusting the eyecups, how to properly attach the neck strap, the inter-pupillary adjustment, how to properly focus your binoculars, lens care and cleaning, and all the YF binocular specifications.

Kowa Guarantee
Kowa provides a limited lifetime warranty for this binocular.

Best Binoculars Rating for Extras & Attention to Detail: 6/10

Conclusion

Strong Points: Taking into consideration their low price, I was really pleasantly surprised by these Kowa YF Series binoculars. Highlights include their wide field of view, very low weight and compact size. The quality and brightness of the view through them is also well above what you would expect in their class and the build quality and styling make them look far more expensive than they really are.

Weak points? To keep their price down, Kowa have had to make compromises somewhere and as such the quality of the extras like the carry case and lens covers are not quite as luxurious as top of the range binoculars. This is also evident in the fact that little details like the focusing wheel and eye-cup housings are made from a hard plastic whereas Kowa's top of the range Genesis models use metal ones. But having said that, they do the job and I would much rather these compromises to keep the price down than if they were to skimp on the really important stuff like the quality of the optics and coatings which would obviously adversely effect the view through them.

Ideal Uses: Their fairly compact size makes them more than decent travelling or camping binoculars and the 8x magnification, with a wide field of view and good quality bright image also means that they make excellent birdwatching binoculars.

These Kowa 8x30 YF binoculars are great for general wildlife observation and even some types of hunting where size and weight are important and like most mid-sized binoculars these make a good all-round general use binocular.

Once again their nice wide field of view and fairly compact size means that they would be ideal to take to sporting events, like horse racing or motor racing where the wide field of view allows you to see more of the action at once without having to look around and their good depth of view means you will have to change the focus far less often.

Their compact size, nice and small minimum interpupillary distance and the ease of which you can hold onto the barrel and access the large focusing wheel also makes these ideal binoculars for people with small hands so great as a pair of binoculars for women. These features and their low cost makes me also highly recommend them as a great pair of serious binoculars for a child/young adult.

Acknowledgements

I would like to thank Alpha Digital Services Ltd, the UK distributors of Kowa Binoculars for sending this binocular to me to review, but I would also like to point out that all the reviews on this site, including this one are my opinion and are not influenced in any way by manufacturers, distributors or suppliers.