7x50 vs 10x50 7X50 vs 10X50 binoculars?

[Victor Boesen]

Hi! I was supposed to get the 10X50 version of These for christmas, but i just saw that the 7X50 version is 25£ cheaper than it used to be, so my question is, would they be worse or better than the 10X50 version if i want to use them for looking at for example m31, m33, m13, m42, m81 and m82. It would mean a lot if you replied with you opinion and experiences of with a 7X50 binocular or even both. I am going to hold them in hand in the beginning until i get a tripod adapter (which i will get soon after i get the binoculars).

Feel free to ask me anything regarding your response!
Thank you!!

Victor Boesen

[kev100]

Hiya,

I have the 10x50 model, and can heartily recommend them (in fact, I wrote the review on FLO's website ...). They are a little on the heavy side, but using a monopod (which I'd recommend over a tripod) makes using them much easier (and steadier). Great views of M31, and I have seen M33 with them, though it's a very low surface brightness object, and so isn't really what I'd call a 'binocular object'. I've just about seen M81 and 82, though again, at nearly 13 million light years away, these are very small at 10x mag, and require averted vision and good skies to see clearly. As for M13, I have seen it with these, but it appears as a very small, fuzzy 'star', so, again, isn't really a binocular object if you want to see individual stars/detail.

The 10x50s are best on large objects (the moon, pleiades, hyades, M31, etc), so I'd say the 7x version is more so (having less magnification means less detail in distant objects) ...

Kev

[Victor Boesen]

8 minutes ago, kev100 said:

 

The 10x50s are best on large objects (the moon, pleiades, hyades, M31, etc), so I'd say the 7x version is more so (having less magnification means less detail in distant objects) ...

Thank you for the great review! What confuses me is that on flow if you scroll down, there's a fov illustration of both versions and it seems like they're the same even tho the 10X50 have 3x more magnification? Do you know anything about that?

[Putaendo Patrick]

How old are you? As the human eye ages, the pupil's ability to dilate decreases. Once you reach your 30s, the benefits of 7x50 binoculars tend to be reduced. As I understand this in simple terms, more light is coming through the binoculars than the pupil can absorb so, while these binoculars are still perfectly usable, they begin to loose the advantages they have for younger viewers. There's an interesting short article here:  www.cloudynights.com/documents/binoexit.pdf

[kev100]

3 hours ago, Victor Boesen said:

Thank you for the great review! What confuses me is that on flow if you scroll down, there's a fov illustration of both versions and it seems like they're the same even tho the 10X50 have 3x more magnification? Do you know anything about that?

I have to confess I can't comment on the fov being the same. I know there's a way of calculating binocular fov, but can't remember it just now. However, I do know that 'by rights' 10x50s should have a smaller fov, having as they do greater magnification than the 7x but with the same objective diameter. The Helios 10x50 design, though is described as 'WA', meaning wide angle, and the design of these binoculars has about 6 degrees fov (wider than many 10x50s, and thus taking their for into the smaller magnification territory of the 7xs ...

Sorry if that's a bit vague, but I can say that the fov of the 10x bins is very wide. I can easily fit in the whole of the Hyades 'V' and the three stars of Orion's belt, something I can't do in the fov of my 20x80 Celestrons, for example ...

Kev

[Victor Boesen]

3 hours ago, Putaendo Patrick said:

How old are you? As the human eye ages, the pupil's ability to dilate decreases. Once you reach your 30s, the benefits of 7x50 binoculars tend to be reduced. As I understand this in simple terms, more light is coming through the binoculars than the pupil can absorb so, while these binoculars are still perfectly usable, they begin to loose the advantages they have for younger viewers. There's an interesting short article here:  www.cloudynights.com/documents/binoexit.pdf

I am 14 years old, so I am hopefully still having a good 6,5mm of pupil left.

 

47 minutes ago, kev100 said:

I have to confess I can't comment on the fov being the same. I know there's a way of calculating binocular fov, but can't remember it just now. However, I do know that 'by rights' 10x50s should have a smaller fov, having as they do greater magnification than the 7x but with the same objective diameter. The Helios 10x50 design, though is described as 'WA', meaning wide angle, and the design of these binoculars has about 6 degrees fov (wider than many 10x50s, and thus taking their for into the smaller magnification territory of the 7xs ...

Yeah, but what the difference will be is not easy to figure out.

[Alien 13]

Its strange but when I was a lad the 10 x 50 was frowned upon by Sir P an many others as having no place in Astronomy.

Alan

[Ruud]

From these two I would choose the 10x50.

The 10x50 has a 5 mm exit pupil, which gives a darker sky background than the 7x50, with its exit pupil of 7mm.

Often, 7x50's show a wider true field than 10x50s, but not in this case, both have a 6.5° tfov.

At 6.5° tfov, the apparent field of view in the 10x50 will be a spacious 65°, and in the 7x50 it will be a claustrophobic 46°.

For astronomy, get at monopod as well. Sit on a chair and rest the monopod on the ground, or stand by a chair and rest the monopod on the chair. Both ways the binoculars will be high enough over your head for you to look up without getting really tired arms.

[Victor Boesen]

49 minutes ago, Ruud said:

From these two I would choose the 10x50.

The 10x50 has a 5 mm exit pupil, which gives a darker sky background than the 7x50, with its exit pupil of 7mm.

Often, 7x50's show a wider true field than 10x50s, but not in this case, both have a 6.5° tfov.

At 6.5° tfov, the apparent field of view in the 10x50 will be a spacious 65°, and in the 7x50 it will be a claustrophobic 46°.

For astronomy, get at monopod as well. Sit on a chair and rest the monopod on the ground, or stand by a chair and rest the monopod on the chair. Both ways the binoculars will be high enough over your head for you to look up without getting really tired arms.

Thank you so much for your help. This made me stick to the 10X50 WA.

Victor Boesen

[ollypenrice]

I really don't think that individual object detail is what you're after in a binocular. That is telescope territory. The advantage of the lower magnification is that the image appears more stable when hand held. Now let's assume that birding enthusiasts and astronomers have, on average, the same steadiness of hand and let's also assume (or at least suspect) that the birding community are more expert on hand held binoculars than we are, since we tend to like standing behind vast instruments pumping 300x magnification and mounted on things that look like dockside cranes. The birders are great advocates of the 8x binocular. Like Sir PM they tend to be sceptical about hand holding 10X.

Try an honest self test. Take bins of 7x, (or 8x, you will never tell the difference) 10x and 15x and hand hold them while trying to read text at the limit of resolution some distance away. This will tell you whether or not the magnification really works hand held. I'm not going to try to tell what you will find, I just recommend the excercise. You may be surprised.

Olly

[Victor Boesen]

2 minutes ago, ollypenrice said:

I really don't think that individual object detail is what you're after in a binocular. That is telescope territory. The advantage of the lower magnification is that the image appears more stable when hand held. Now let's assume that birding enthusiasts and astronomers have, on average, the same steadiness of hand and let's also assume (or at least suspect) that the birding community are more expert on hand held binoculars than we are, since we tend to like standing behind vast instruments pumping 300x magnification and mounted on things that look like dockside cranes. The birders are great advocates of the 8x binocular. Like Sir PM they tend to be sceptical about hand holding 10X.

Try an honest self test. Take bins of 7x, (or 8x, you will never tell the difference) 10x and 15x and hand hold them while trying to read text at the limit of resolution some distance away. This will tell you whether or not the magnification really works hand held. I'm not going to try to tell what you will find, I just recommend the excercise. You may be surprised.

Olly

thanks for the help! i will give it a go!

[Stub Mandrel]

I bought some Celestron Nature 8x42s recently.

I must admit I struggle with binoculars, but I saw M31,32 and even a hint of m33 despite some light pollution. Mars was a glowing orange spot with no surface detail, I convince myself there was a hint of nebulosity around the Plieades and areas of rich starfields (like the Hyades, Perseus and Cassiopeia) looked great.

Unfortunately I have trouble keeping looking for long enough to get into the detail :-( heavier than 8x42 would be a complete waste of time for me.

 

[Ben the Ignorant]

I have compared 7x50's and 10x50's side by side several times, the 7x's always had an excessively bright background. The 10x's always showed deep sky objects better because they look larger against a darker surrounding. The steadiness problem has a solution: first become aware of the permanent body motion by standing with closed eyes, and focus on your balance. You'll notice your hips are constantly oscillating.

You can make the motion visible by holding a laser against your hip if you own one. It's impossible to stop the movement but you can limit it. The trick (also used by accuracy shooters) is to restrict the motion to the left and right. After some practice you can keep the binoc or the gun parallel to the line of sight.

Then it no longer matters if you move because standing somewhere or a couple millimeters to the side changes nothing in stargazing or shooting. The projectile would hit two millimeters to the side even if the target is at 50 meters, that's negligible. However if you let your body oscillate, even a very small angle between your line of sight and the target will translate into a large miss when you shoot, or a distracting wobble when you stargaze.

Focusing on balance also makes body motion slower. This is how some people can handle 16x or even 20x binocs, or send bullets accurately, offhand, at distances that boggle the mind of those who don't know the tip. You might consider a 12x50 after you practice this magician's trick. There's a show about debunking all the magicians' tricks on YouTube, I watched all the episodes .

[BinocularSky]

Olly is absolutely correct that 7x50 is much easier to hold steadily than 10x50. However, I still find 10x50 preferable for astronomy - simply because I find it easier to see things with it. As Olly says, you are not after detail with a hand-held astro binocular so, while you don't want the image jumping around like a puppy on amphetamines, you don't need it rock steady either. This is where we differ from birders.

Just a few observations (pun intended, of course! ) :

The navy prefers 7x50 mainly because they are easier to use on a heaving deck.

There are a few large, low surface brightness objects that can be easier in 7x50 : NGC7000 and M33 lurch to what I nowadays try to pass off as a mind.

[Charic]

I own the 8x50 Wide Angle version of the Helios Naturesport.
My  telescope provides the power, my binoculars provide the field of view, at  just over 8°.  It's  why I grab these binoculars first and foremost.
The 10x50s should be slightly different, 3x extra mag.
The higher magnification gets you closer, may reduce the field of view, enhances contrast between sky and target.............  but will you see and feel the difference?..........if your eyes can detect the subtle changes, maybe you opt for the 10x50s ?
I compared  Strathspey 10x50 with Strathspey 7x50 and although they were both very good, the SP7x50s did not appear to be any better than my  Helios 8x40s and I much prefer the wider field of view. I even mount the 8x40s,  the views are stunning when the optics are rock steady.

I have mentioned many times my lack of appeal for my Revelation 15x70s from my present observatory, possibly its just the optics themselves, or my own eye sight, so just recently  I bought some premium quality optics to compare against, however a recent change to where I can view from, less than 500 feet away?  completely free of street lighting! makes for a better situation, so in all cases where astronomy is concerned, the less man made light pollution there is,  the better the conditions for visual observation.

[Alfian]

Here's a  link to an interesting article about exit pupil  and binoculars which might help with your choice.

http://www.cloudynights.com/documents/binoexit.pdf