GPO Passion HD 10x42 vs 10x50 Binoculars

In this article and the embedded video below, I test and compare the GPO Passion HD 10x42 Binocular versus its slightly bigger brother, the 10x50 GPO Passion HD to discover which is best under different circumstances and for different uses like birding, wildlife observation, hunting, and travel.

General Info on 10x42 vs 10x50 Binoculars

Whilst I have already made a video and article in my BinoWars Series going over the main differences between 10x42 and 10x50 binoculars (which by-the-way, I do recommend you take a look at as well as this one), but much of what I spoke about in it was somewhat generalist in nature and mostly based on theory and my past experiences. 

So as I currently still have both the 10x42 and the 10x50 samples of the stunning GPO Passion HD that I tested for my reviews of them, I thought this would make the perfect opportunity to put this theory to the test on a perfectly level playing field by comparing a couple of binoculars against each other that use exactly the same materials and level of optics and coatings.

What The Numbers Mean

To begin with, we will take a look at the most obvious differences, being size and weight. But before I start, you need to be sure that you know what I mean when I refer to a 10x42, 10x50, or indeed any other configuration. If you are at all unsure, quickly go and check out my article & video on what the numbers mean on a binocular.

GPO Passion HD 10x50 Binoculars

Size & Weight

So as you can see in the image above, the basic overall body shape is the same between these two instruments, which is what you would expect from two roof prism binoculars within the same series.

However, you can also clearly see that these 10x50mm GPO Passion HD binoculars are somewhat longer than the 10x42 version.

They are also slightly wider and deeper because of their larger 50mm lenses

At 967g, this GPO 10x50 Passion HD binocular is about average for a high-end 50mm binocular using a metal chassis and mostly metal components. 

This is about 120g heavier than the 10x42 version which tipped my scales at 851g.

Depending on your exact needs or perspective, these differences may seem insignificant to some, or quite large to others. 

So for example for many general uses and as an “average” adult, you may not really notice the difference in size (and weight, but if you have smaller hands and/or have to travel or carry the binoculars with limited available space, the relatively small increase in size could be of importance to you. So it just depends on your particular circumstances.

Note: If you do need or want a particularly lightweight, small instrument, then it may be worth considering a smaller mid-size instrument, so something like a 10x32 or even a full compact (a 10x26 for example). 

Shape & Design

Another small, but potentially important difference between these two binoculars that comes about as a direct result of them using different sized objective lenses is that in order for the 10x50 to accommodate the larger lenses 50mm objective lenses the barrels obviously need to have a large diameter as well. 

In terms of ergonomics, for me, and my “average” adult-sized hands this extra 8mm or so in diameter is not noticeable and I did not feel any real, notable difference in feel or balance between the two when using them. 

However, when it comes to attaching them to a tripod, the reduced gap in between the barrels of the 10x50 when compared to the 10x42 makes it quite a bit more tricky to remove the dust cap and then screw in a tripod adapter. 

Whilst this is in no way for me a deal-breaker, I can say I much preferred mounting the 10x42 passion HD onto my tripod and so my advice would be if you do need to buy a tripod adapter, just make sure that the one you choose has a thin leg design that will allow it to fit in between the barrels as I have used some more bulky/robust adapters in the past that would not fit these or indeed most 10x50 binoculars. 

Close focus Distance

The 10x50 Passion HD binoculars have an advertised minimum focus distance of 9.2ft (2.8m), which in my experience is good for a full-sized binocular with a 10x power but not quite excellent

On the other hand, you can get a little closer to your subjects with the 10x42 version as it has a slightly nearer advertised close focus distance of 6.5ft (2 meters) which is very near to what I would describe as being excellent for this class of binocular.

As you can see in the video above, I tested both to see how near I could get to this tulip before I could no longer focus on it and then measured the distance. This is something I do for all my reviews, although I usually just do it in front of a wall, but thought this would look better. 

As is usually the case, I found that the measurements supplied by GPO in the official specifications to be very much on the safe side as I was actually able to achieve a sharp view of the tulip at only  2.5 meters (8.2ft) with the 10x50 and even closer at just 1.8meters (5.9ft) away with the 10x42.

Either way and for most normal uses, I would say either instrument will be just fine as it is rare that you would want to focus on an object at less than these distances. However, if one of your passions is to view butterflies, other insects, or flowers from a very close range, then this is another small difference between the two to keep in mind.

Comparing Objective lenses on the GPO Passion HD 10x50 Binoculars and GPO Passion HD 10x42 Binoculars

Image Quality

As well as spending a lot of time using them in varying conditions out in the field, I also very carefully made side-by-side comparisons of the view between these 10x50 and  10x42 GPO Passion HDs, and a selection of my relevant benchmark binoculars at different times of the day and in different light conditions and these a some of my thoughts and observations: 

Also please note that whilst I have included some footage that I shot with my camera through these binoculars, this should be just considered for illustration purposes only as in my experience the view you see with your eyes through binoculars is far better than that which a camera is able to capture. This is especially true in low light conditions, where the limitations of the camera’s aperture really do come into play, but it also does highlight to me just how impressive the design of our eyes and vision is.

Colors & Contrast
In terms of the colors and contrast, both these GPO binoculars look to me to be equal, and whilst they both deliver what I would describe as a bright image, it is not at all washed out as they still manage to produce vibrant, yet realistic-looking colors with what I feel is an excellent variation between dark and light areas that gives the image a lovely sense of depth.

Image Brightness & Low Light Performance

50mm vs 42mm lenses, whilst a difference of 8mm may not seem, or indeed look like that much, in certain light conditions, it can make a noticeable difference to the image brightness. 

So just like the windows in your house, where large ones let in more light than small ones, there is the potential for more light to get “collected” and pass through larger objective lenses than smaller ones.

Here the quality of the glass the expertise and precision in making the optical system, and the exact coatings that are used throughout the entire optical pathway also play an important role, which is why I often find that a high-end binocular with quality components and coatings will optically outperform a low-quality binocular that has larger lenses.

However, this is what makes this particular comparison so interesting as we are comparing these two instruments that are from the same series and from the same brand, so we can be pretty certain in the assumption that the glass,  coatings, and expertise used are the same. So the only factor that we need to consider when looking through these two GPO Passion HD 10x50 and 10x42 binoculars is the physical variations and what effect this has on the view and in particular image brightness.

Ocular Lenses on the GPO Passion HD 10x50 and 10x42 Binoculars showing the different size exit pupils

Exit Pupil Size – 10x50 vs 10x42 Configurations

As well as the quality of the optics, the image brightness that you perceive when looking through binoculars is greatly affected by the ambient light conditions and whether your eyes in those particular conditions are receiving enough light.

This can be explained by the relationship between the size of the pupils in your eyes and the size of the shafts of light exiting the ocular lenses known as the exit pupils. 

I have an in-depth article on everything you need to know about this relationship between your pupil size, the exit pupils, and prevailing light conditions – see the Complete Guide to the exit-pupil, which I highly recommend you look at, but in brief,  the exit pupil size comes as a result of dividing the aperture or in this case the objective lens size by the magnification. 

Therefore a 10x42 binocular produces exit pupils that are 4.2mm in diameter, whilst a 10x50 configuration produces slightly larger 5mm exit pupils.

So in my experience, when the ambient light conditions are good, average, or even fairly poor, a 4.2mm exit pupil combined with good quality optics are sufficient to supply your eyes with enough light for your see a bright, good quality image. 

This is because in these light conditions the pupils in your eyes are going to be less than 4.2mm in diameter and thus even though the 10x50 is delivering a larger 5mm shaft of light to your eyes, it is not taken in by them and thus the image brightness will look to be the same or extremely close between a 10x42 and a 10x50 in these conditions. 

So as suspected by the theory and past experience, when I compared these two in good light conditions on a cloudless morning, I found that the GPO Passion HD 10x42 binoculars looked to my eyes to be equally as bright as that of the 10x50 GPO Passion HD, which as you can see by the comparisons is reflected when I captured this footage through them with my camera.

Indeed even in fairly dull overcast conditions when I compared them later, I found the same to be true once again and they look to be equal in terms of the image brightness.

However, In very low light when the sun had dropped below the horizon and the pupils in my eyes were dilated, this was where the larger 50mm lenses and the resulting larger exit pupil began to make a difference and whilst the difference was fairly subtle to my eyes, the 10x50 GPO Passion HD looked to me to produce a  brighter image.

As you can see, this difference also showed up when using my camera to take video through the binoculars and indeed it became almost impossible to create an image using the 10x42 at one point. However, here I must stress once again that the limitations of my camera versus my eyes are on full display as the image brightness that I perceived with my eyes is much brighter than that which is captured on film. 

So as I expected, these 10x50 binoculars make for a better choice in low light than a 10x42 Indeed I would put them almost on par with a similar quality 8x42 binocular. So if you are often bird watching over longer distances (like at a lake or the coast) or view wildlife over longer distances and go out early morning or as the sunsets or in bad weather, these would make a great option.

Other Areas
In terms of the level of Color Fringing, Image Definition, Distortions & Blurring around the periphery of the view, I once again found both these models to be very similar and so will not go through it in this video, rather I urge you to take a look at the full reviews on the BBR website where I go through these and many other aspects in much more detail. 

Field of View

The GPO Passion HD 10x42 is advertised as having a field of view that is 336ft wide/high at a distance of 1000 yards away (or to convert to metric is roughly 112meters wide/high at a distance of 1000meters), 

In my experience, and comparing them against some recent full-sized 10x binoculars that I have tested and reviewed, this is a relatively very wide FOV for a 10x binocular and places them near the top of the table in this magnification class.

What is interesting and perhaps to some a somewhat surprising difference considering that they both have a 10x magnification is that at  309ft at 1,000 yards (103m at 1,000 meters), the 10x50 GPO passion HD has a slightly narrower view of the world.

For a 10x binocular this is still perfectly within the bounds of what I would call normal, and for most uses, this relatively small difference between the two will probably not be that important and indeed unless you are actually looking for it and comparing the view back and forth, as I have, it is actually quite hard to notice. 

However, if you especially want or need a 10x binocular with a wider FOV, like if you view fast and erratic moving birds, then this should be something to keep in mind. Also just as a note, if you do need a wide view, then unless you also really need detail at distance, I find it is often better to drop the magnification and go with something like an 8x42 or even a 7x50. 


So in most ways, the way these two GPO binoculars performed and compared against each other were pretty much as I expected, but there were a few aspects that surprised me and so this was certainly for me a useful, fun, and interesting exercise and I hope it has been the same for you

But just a final reminder, for the full reviews of both these binoculars where I go into way more detail on all aspects as well as comparison tables to other similar binoculars, where to buy to get the best deals, and a whole bunch more, please be sure to check the links below:

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