• BirdForum is the net's largest birding community dedicated to wild birds and birding, and is absolutely FREE!

    Register for an account to take part in lively discussions in the forum, post your pictures in the gallery and more.

Meostar B1 7x50 is here (1 Viewer)

galazie1

Well-known member
It gets interesting now

I was disappointed with it optically. I think its optics performs at 65% the level of my SLC 7x50

But I love SO MUCH its ergonomics. It works so lovely in my hands, more than any binos i've known.

So i keeps reaching for it instead of the SLC these days
 

Attachments

  • Screenshot_2019-11-26-20-38-10-58.jpg
    Screenshot_2019-11-26-20-38-10-58.jpg
    25 KB · Views: 110

John A Roberts

Well-known member
Australia
Hi Galazie,

When you say that the B1 only performs at 65% of the SLC, are you referring to the brightness of the image, or to other qualities?


John
 

Canip

Well-known member
galazie,

65% is a fairly specific value. Are you sure it‘s not 70%? ;)

Meaning: I wonder like John which performance parameters you might have been referring to.

Canip
 

galazie1

Well-known member
When i first get the meopta, without the slc to compare, i thought it was about 85%.

When i compared the two side by side. I thought of 65%

The difference is obvious. Definitely not 80%. I am not sure if it could be 70%. So i put it at 65% :)

Some examples:

- clarity: the slc is crystal clear. The meopta is more hazy. The meopta shows a somewhat more "grainy" image
- sharpness: the slc is obviously sharper. The meopta is not a sharp binoculars. It is less sharp than many chinese binos (although the image is still much better than most chinese binos because it is smooth and quality was consistent across the fov)
- edge sharpness: decrease at 80-90% in the slc and maybe 70% in the meopta
- depth of field: huge difference. Slc much better. The slc is very very good in this aspect. The meopta is quite ordinary in this
- colour: both very good

That's what in my mind right now
 

Attachments

  • Screenshot_2019-11-27-19-34-58-55.jpg
    Screenshot_2019-11-27-19-34-58-55.jpg
    46.1 KB · Views: 123
Last edited:

galazie1

Well-known member
Advantages of the meopta:

- rubber skin appears to be high quality. The surface is grainy. The material was very easy to grip. It is a great grip. Just like it sticks to your hand and you don't feel like you will drop it. The slc rubber is glossy and you feel like you havebto care more about holding
- the focus wheel on the meopta is very slow and smooth. I personally prefer the slow focus as to me slow focusing makes the act of focusing more leisure.
- the meopta is clearly lighter, together with the great grip mentioned above, it makes the meopta feels so easy and carefree in your hands
 

galazie1

Well-known member
One poor thing about ergonomics: because the meopta is not sharp, it is difficult to find the exact focus point. I often go pass and back a couple of times until finding the right focus
 

galazie1

Well-known member
So for roughly the same money ($800-900), one can get a good used SLC as the primary binoculars. But if for any reason the Meopta is choosen, the owner will surely be happy enough. It is acceptable optics with the ergonomics that may melt your heart.

That said, when i gave the meopta to a friend (who has an EL SV 10x50). He found the optics OK but was not as impressed as me by the ergonomics
 

henry link

Well-known member
The Meopta 7x50 is almost certainly defective. True DOF in afocal instruments like binoculars is a function of magnification only, but the impression of narrow DOF is a common illusion in binoculars with abnormally high aberrations because the combination of defocus and high aberrations looks worse (more out of focus) than defocus combined with a "normal" level of aberrations. Unfortunately, just what is wrong can't be determined by even the most accurate subjective description of the image. That requires a high magnification star test.
 

galazie1

Well-known member
The Meopta 7x50 is almost certainly defective. True DOF in afocal instruments like binoculars is a function of magnification only, but the impression of narrow DOF is a common illusion in binoculars with abnormally high aberrations because the combination of defocus and high aberrations looks worse (more out of focus) than defocus combined with a "normal" level of aberrations. Unfortunately, just what is wrong can't be determined by even the most accurate subjective description of the image. That requires a high magnification star test.

Do you mean all 7x binoculars should be the same in terms of DOF?

My visual experience is that it differs, examples with other 7x that I have, in terms of DOF:

- nikon sp 7x50 is best, slc 7x50 is close

- nikon edg 7x42, slc 7x42, and kowa 6.5x32 one step behind

- meostar 7x50 is another step behind

(This doesn't mean the kowa is better than the meopta. The kowa is much poorer in other respects)

If DOF is technically a function of magnification only, then maybe this is related to other factors that I wrongly take as DOF. E.g sharpness, clarity

And when mentioning DOF, I mean the distances of kilometers. Like the buildings that first apear and those at the horizon. For short distances like in a park or a forest, the difference is not that clear
 

Attachments

  • Screenshot_2019-11-28-06-25-59-16.jpg
    Screenshot_2019-11-28-06-25-59-16.jpg
    26.5 KB · Views: 67

typo

Well-known member
Galazie,

I'm not a particular fan of 7x50s but I have tried the Meostar 10x50, the SLC 7x56 and most of the 7x42s at different times. I can't say I noticed any deficiency in on-axis resolution in the more expensive ones, but I wouldn't expect to with a 7x models. The would be a difference in colour rendition, but how much would depend on when the Meostar in particular was made (the first two digits of the serial number). A different colour balance can alter colour contrast and perceived sharpness in different light conditions.

Henry is right of course. In principle, depth of field is dependant on just magnification, but there are conditions attached. It only applies to single points in the field of view (usually the centre).not comparing centre with edge. Just as the dof of a camera varies with aperture, a binocular dof varies with the diameter of the pupil of your eye. A cloud passing over will change the apparent dof.

You are right that a very bad binocular can alter the dof. The Meostar isn't a bad binocular. In fact the effective resolution of the 12x50 HD I tested was really exceptionally good. Your sample could have been damaged, in which case Henry's star test should help diagnose the problem.

Optical engineers come up with quite a lot of variation in field curvature and edge aberrations (like astigmatism), in the models you mention. There is consequences for the size of the apparent sweetspot and depth perception, but the differences generally mean they suit one field situation better than another. I'm sure you have a preference, but whether it is better or not is a different argument.;)

Using distant targets, particularly in a city, adds the complication of haze and the binocular transmission spectrum of course. I often find the models that are better at cutting through the haze, do not have the colour fidelity I prefer for birdwatching. I'm afraid I don't remember enough detail about the Meostar 7x50 I tried to comment, but the 12x50 HD I reviewed was very good on colour fidelity.

David
 

Canip

Well-known member
Do you mean all 7x binoculars should be the same in terms of DOF?

.....
.....
.....

Not all 7x binoculars, but principally all 7x50 binoculars if they have the same effective exit pupils.

Why is that so?

Field of depth (in a visual instrument, like binoculars) is primarily determined by two main factors and one less important one.

The main factors are:
magnification, and accommodation capacity of the eye (i.e. also age dependent!).

The secondary factor, which contributes less, is the size of the effective exit pupil.

I am no expert, but that's what experts say (see detailed explanation in: Holger Merlitz, Handferngläser, 2nd ed., pp. 155ss, esp. 157).

fwiw Canip
 

typo

Well-known member
Catnip,

For the purposes of this discussion Galazie's focal accommodation is essentially a constant so not a consideration here. The difference between a 1.8mm pupil and a 5mm pupil equates to a 7 fold decrease in depth of field by the usual formula, but the perceptive change may be a less depending on the drop in visual acuity across this light range. When testing binoculars, I've seen a small passing cloud change the apparent depth of field 2.5 fold in less than a second.

I have seen an English draft of that chapter of Holger's book and sent him some suggestions. FWIW ;)

David
 
Last edited:

galazie1

Well-known member
Given i just have the binos and no magnification booster, is there anything of a star test i can do?

When i defocus a bright star to both ends (far and near) of the focus range, the images of the light disc (the defocused star) appeared to be very similar in the Meopta and the Swaro slc, at each end, both when opening both eyes and each individual eye.
 

galazie1

Well-known member
The Meopta has serial number 17xxxx. I guess it was made in 2017

The SLC is 1998 (serial number 68xxxxxxx
 

Canip

Well-known member
.....
.....
.....
I have seen an English draft of that chapter of Holger's book and sent him some suggestions......

.....

Tks, David.
I sent Holger a number of suggestions over the years - but I am still not an expert, he is ... ;)
 

henry link

Well-known member
Given i just have the binos and no magnification booster, is there anything of a star test i can do?

When i defocus a bright star to both ends (far and near) of the focus range, the images of the light disc (the defocused star) appeared to be very similar in the Meopta and the Swaro slc, at each end, both when opening both eyes and each individual eye.


7x is useless for a this kind of star-test, but you probably do have "magnification boosters" in the form of other binoculars. A 7-10x binocular would boost the magnification of a 7x50 to 49-70x, just about right for a proper star-test of a 50mm lens. Obviously the 7x50 needs to be mounted. The binocular behind it can be handheld in a pinch, but naturally mounting it and aligning it well with eyepiece of the 7x50 is better. Don't defocus beyond about 5 diffraction rings in each direction.

As far as DOF goes, don't forget that eye and binocular combination is very different to a camera. It's only the eye's DOF (as modified by the binocular's magnification) that determines the final size of the out-of-focus diffraction discs in front or behind best focus. The focal ratio of the binocular objective is always irrelevant and the exit pupil size of the binocular is irrelevant unless it is smaller than the pupil of the eye. Then the exit pupil acts as an aperture stop in front of the lens of the eye (which does act like a camera lens) and that changes the focal ratio of the eye, which increases the DOF just like in a camera lens.
 
Last edited:

Users who are viewing this thread

Top