Best Marine Binoculars: 7×30 vs 7×50 Specs

Ever wondered what professional sailors choose?

Embarking on a sailing journey demands the right gear…

And having a pair of reliable marine binoculars tops the list.

Whether you’re scanning the horizon for distant landmarks or observing marine wildlife, choosing between the 7×30 and 7×50 models can significantly impact your experience.

Let’s delve into the technical aspects and discover which marine binoculars are best suited for your nautical adventures.

Both models commonly use a Porro prism system… a favorite in marine binoculars for its distinct advantages over the more typical Schmidt Pechan Roof prism.

Named after Italian physicist Ignazio Porro, Porro prisms excel in a marine setting thanks to their unique design.

They were used for everything, but in more recent years, their use has become more targeted towards marine binoculars.

One of the Porro’s primary purposes is low-light observation and these kinds of binoculars are used by European hunters who hunt in low-light situations.

Porro prisms thrive in marine binoculars with their low-light capabilities and reliable performance on the water.

The construction of Porro prism binoculars enables them to have a focusing system for both eyes and they continue to be favoured for the marine binoculars market because of their better waterproofness.

Individual focusing for each eye ensures precise adjustments, especially beneficial in low-light conditions, allowing for seamless viewing without second-guessing the focus.

You set the focusing individually for each eye once, and then you focus with your eyes through the binoculars…

But the main disadvantage is the close focusing distance, which is around 10 m, 15 m, and even 20 m with some models.

On the 7×30 and 7×50 configurations, I believe the individual focusing for each eye is a function of the waterproofing and is the main reason.

They typically have a single bridge design and the majority of the housing is made out of plastic materials supported by rubberized armour that can withstand saltwater and the sun’s rays… because these binoculars get exposed to the sun a lot on ships, boats, and the marine environment… they are excellent marine binoculars.

The most affordable binoculars in this market are not cheap and if you see cheap then they’re probably of questionable quality. The most expensive models that have integrated compasses do not want to be lost or damaged… you’ll be crying for days.   

Why choose 7×30 or 7×50?

The 7x magnification is probably the highest magnification you can use on sailboats or any ships and not suffer from sea sickness.

So should you go with the 7×30 or 7×50 model?

In terms of field of view, they are really similar. All of them have a field of view between 120 m (for the more affordable models), all the way to 150 m (for the best models on the market).

For low-light capabilities, 7×50 wins hands down.

It is twice as bright as 7×30… but because you use it at sea and most often in Summer light, it does not shine in additional value as much because it is not used in low light as much.

Turning to the comfort of use, the 7×50 is better because it has better eye relief and the 7×30 is a bit more sensitive to your eye position. So in this respect, the 7×50 is more comfortable to use.

However, when you are wearing them around your neck for a long period of time, then the 7×30 is far more comfortable.

That’s because Porro prisms cannot be constructed as compactly as Schmidt–Pechan Roof prisms so they can be heavy and if you also have a compartment for a compass, that usually adds 150 g of weight.

For use with glasses, 7×50 is usually a bit better because it has a longer eye relief. The best models usually have around 22 mm or 23 mm of eye relief which is a lot.

In terms of price, the price difference between the two models is not outrageous.

Which Size Marine Binoculars is Best?

The 7×30 is probably best for amateur use, whereas the 7×50 models are more for professional use… and are at least aimed at that audience. The 7×30 is a better choice for kids because it’s lighter and less bulky.

So… if you are an amateur user or have kids on board or you are more into compact binoculars and will not be using them as frequently, then go for the 7×30 version… especially because during daytime use… you will not notice much difference if you don’t wear glasses… but you will notice the difference in size and weight.

When will you go for 7×50 marine binoculars?

If you are a professional sailor, or at least sailing frequently and you want to benefit from dusk use, and if you wear glasses.

Which model of marine binoculars suits your sailing style? Share your thoughts in the comments below!