10X32, Leica vs Nikon vs Zeiss

[Lewie]

I am considering buying a 10X32. I already have a Nikon Premier LxL 8X32 and a Pentax DCF SP 10X50. I am happy with both. I thought that with a 10x32 I would have a pair of binoculars with 10 power and a lighter weight and wider FOV.

Currently I am leaning toward the Zeiss.

I know that some persons believe that the Nikons have more CA. CA is irrelevant to me. I have never seen any CA, even when using inexpensive binoculars. I am beginning to think that CA is all an urban legend. But to be honest I am one of those persons who can not see the numbers in those pictures of little colored circles.

Any comments?

[Tero]

lighter weight and wider FOV?

The 10x32 would weigh about the same as 8x32
the 10x50 you have is of course heavier, or should be

[Lewie]

lighter weight and wider FOV?

The 10x32 would weigh about the same as 8x32
the 10x50 you have is of course heavier, or should be

I meant that I would have a 10-power with lighter weight and wider FOV than my 10x50. I thought I might get the best of both worlds. What I was worried about was how the smaller exit pupil might affect the ease of use.

[Sailcat]

I meant that I would have a 10-power with lighter weight and wider FOV than my 10x50. I thought I might get the best of both worlds. What I was worried about was how the smaller exit pupil might affect the ease of use.

Eye position will be somewhat more critical in the 10x32 binoculars, but not uncomfortably so, in my extremely humble opinion. The difference in weight between the 10x50 and 10x32 will be more significant, however.

[chartwell99]

[QUOTE=Lewie]I am considering buying a 10X32. I already have a Nikon Premier LxL 8X32 and a Pentax DCF SP 10X50. I am happy with both. I thought that with a 10x32 I would have a pair of binoculars with 10 power and a lighter weight and wider FOV.

Currently I am leaning toward the Zeiss.

I own the 10 x 32 Leica BA and love it for travel chiefly for the reasons you suggest. It also has a remarkable close focusing ability, but depth of field is extremely shallow in comparison to a 10 x 42 or 10 x 50, necessitating constant re-focusing in certain situations. I have tried the Nikon HG 10 x 32, and while not as compact as the Leica BA, it is noticeably brighter and sharper than the Leica. Whatever brand you choose, I suspect that you will not be disappointed by the 10 x 32 configuation.

[FrankD]

Eye position will be somewhat more critical in the 10x32 binoculars, but not uncomfortably so, in my extremely humble opinion. The difference in weight between the 10x50 and 10x32 will be more significant, however.

I tend to agree.

In reference to the bins in question I would think that since you haven't ruled it out we would also have to look at the price comparison. To the best of my knowledge the Nikon is the least expensive of the group while still providing one of the best overall images.

[iporali]

Currently I am leaning toward the Zeiss.
...
Any comments?
If I were buying binoculars now, I might as well choose the Zeiss (I own the Nikons). However, if you don't see CA and don't consider the Nikons heavy, why not going with familiar optics & ergonomics. The shallow dof makes focusing of the 10x32s even more (over)sensitive than with the 8x32, but the image is beautifully bright, contrasty and sharp "to the edges".

Ilkka

[elkcub]

I am considering buying a 10X32. I already have a Nikon Premier LxL 8X32 and a Pentax DCF SP 10X50. I am happy with both. I thought that with a 10x32 I would have a pair of binoculars with 10 power and a lighter weight and wider FOV.

Currently I am leaning toward the Zeiss.

I own the 10 x 32 Leica BA and love it for travel chiefly for the reasons you suggest. It also has a remarkable close focusing ability, but depth of field is extremely shallow in comparison to a 10 x 42 or 10 x 50, necessitating constant re-focusing in certain situations. I have tried the Nikon HG 10 x 32, and while not as compact as the Leica BA, it is noticeably brighter and sharper than the Leica. Whatever brand you choose, I suspect that you will not be disappointed by the 10 x 32 configuation.

I don't own a 10x32, but do find myself having to question why a 10x32 would have a shallower DOF than an 10x42 or 10x50? I recall Henry Link mentioning several times that the only variable determining DOF is magnification. Maybe I misunderstood, and he meant with fixed objective size. Maybe not. :stuck:

Anyway, I will say that my 10x25 SLC seems to be shallower than my 10x42 SLC, and that in turn seems shallower than my Swift 10x50 Kestrel — but they have increasing FOVs as well, and the Kestrel is a porro with more 3-D effect. Things are not always what they seem it would seem.

This is not intended as a rhetorical question, and it might even be relevant to the thread, i.e., selecting the 10x32 format.

Ed

[iporali]

I don't own a 10x32, but do find myself having to question why a 10x32 would have a shallower DOF than an 10x42 or 10x50? I recall Henry Link mentioning several times that the only variable determining DOF is magnification.
Ed,

I think you are right, but if I remember correctly, the stopped-down iris increases the objective's f-number & DOF and reduces aberrations - the more the larger is the objective.

Anyway, the 10x32s have a very shallow DOF and especially with high-geared focusing (like in the Nikon HGs) the perception of shallow DOF is very strong.

Ilkka

[elkcub]

Ed,

I think you are right, but if I remember correctly, the stopped-down iris increases the objective's f-number & DOF and reduces aberrations - the more the larger is the objective.

Anyway, the 10x32s have a very shallow DOF and especially with high-geared focusing (like in the Nikon HGs) the perception of shallow DOF is very strong.

Ilkka


Hi Ilkka,

I must be getting something wrong, but this never quite made sense to me.

Assuming we're dealing with objectives of the same focal length, isn't the f-number determined by dividing focal length by the effective aperture? According to Ed Z on CN, the effective aperture should be determined the iris' pupil diameter, if it's smaller than the exit pupil of the binocular. Hence, under these conditions, for a fixed iris pupil size the f-number would be independent of the diameter of the objective, and constant — and DOF would be constant too.

Of course, if the eye were to open to match or exceed the exit pupil of a larger objective binocular (of constant power), then the f-number would become smaller and one might experience that DOF would decrease as objective size increased.

Again, as I said, I may well be making a mistake somewhere. I'm in learning mode. :stuck:

Ed :stuck:

[iporali]

According to Ed Z on CN, the effective aperture should be determined the iris' pupil diameter, if it's smaller than the exit pupil of the binocular. Hence, under these conditions, for a fixed iris pupil size the f-number would be independent of the diameter of the objective, and constant — and DOF would be constant too.
Ed,

I feel very uncomfortable trying to explain this, but my understanding is that if you have a pair of large binoculars, say 10x50, and stop them down by aperture masks (eg. 42, 32 and 25 mm), the DOF should increase due to increasing f-number (=smaller aperture). So, a 2.5 mm iris "transforms" your 10x50s into long focal length 10x25s. Then why do the compact 10x25s seem to have shallow DOF? I think they use short focal length objective and ocular, which makes their f-number smaller (relatively larger aperture) than that of the 10x25s which are stopped-down from the 10x50.

Does that make any sense? I hope so. Henry, Alan... Help! ;)

Ilkka


EDIT: When I talk about focal lengths and f-numbers I mean the objective of the binoculars. It creates the aerial image just like the camera lens - and this is what IMO is different in large and small binoculars. Binoculars themselves don't have a focal length (they are afocal).

[chartwell99]

Ed,

I feel very uncomfortable trying to explain this, but my understanding is that if you have a pair of large binoculars, say 10x50, and stop them down by aperture masks (eg. 42, 32 and 25 mm), the DOF should increase due to increasing f-number (=smaller aperture). So, a 2.5 mm iris "transforms" your 10x50s into long focal length 10x25s. Then why do the compact 10x25s seem to have shallow DOF? I think they use short focal length objective and ocular, which makes their f-number smaller (relatively larger aperture) than that of the 10x25s which are stopped-down from the 10x50.

Does that make any sense? I hope so. Henry, Alan... Help! ;)

Ilkka


EDIT: When I talk about focal lengths and f-numbers I mean the objective of the binoculars. It creates the aerial image just like the camera lens - and this is what IMO is different in large and small binoculars. Binoculars themselves don't have a focal length (they are afocal).

My sense of depth of field in photgraphic lenses is the degree of depth of field is more a function of focal length than aperture. For example, in 35 mm film photogrpahy, the depth of field for a 100 mm lens set at f16 will be dramatically shallower than a 25mm lens set at f2.8. While I can't describe the arthrimetic in binocular optics, my consistent experience is, all things being equal, the smaller the objective aperture, the shallower the depth of field.

[henry link]

Check this thread: http://www.birdforum.net/showthread.php?t=41596&highlight=depth+field

Between it and the linked Cloudy Nights thread I think the subject was pretty well exhausted.

[elkcub]

Ilkka/Chartwell/Henry,

Basically my problem is trying to reconcile Henry/Kimmo's hypothesis (a) that DOF is only dependent upon magnification, with (b) Chartwell's hypothesis that DOF improves with objective size — even at a fixed magnification. (I think that's what was said.) I don't follow how (a) and (b) can be true at the same time.

If the focal length of the objectives were different between binoculars (note I assumed they were the same in post #10) then I understand that a particular aperture would produce a different DOF for the objective lenses. However, hypothesis (a) would require that once oculars were added to produce the correct magnification at the eye, the experienced depth of field would equalize. Hence, if (a) were true, (b) would not be true — and visa-versa...

I didn't find the earlier BF or CN threads addressed this, but I may have missed it.

Ed

[zuiko]

I disagree with the bigger objective = better depth of field theory.

A pin hole gives almost infinite DOF for example. An f1.0 lens gives razor thin DOF.

DOF relates to depth of focus which is what one gets at the eye. With a pinhole one has almost all paraxial rays - it acts as a universal lens. Stopping down always increases the DOF.

The more paraxial the focussed rays are the more the depth of field. A narrower objective will by its nature have more paraxial rays compared to a bigger objective all other things being equal.

So a smaller objective will give greater DOF than a larger objective, based on basic optical principles.

Regards.

[iporali]

Ed etc.

I know this has been exhaustively discussed, but I would like to offer an example which illustrates how *I* can think that Ed's options a) and b) can be true at the same time.

Let's take two binoculars with the same power:
1) Large binoculars (10x50):
long focal length objective + long focal length eyepiece + large exit pupil
2) Compact binoculars (10x25):
short focal length objective + short focal length eyepiece + small exit pupil

In case 1) long focal length objective produces an aerial image, which has a short DOF, but this image is "viewed" with a low power magnifying glass, which has a longer DOF.

In case 2) short fl objective produces an aerial image with a long DOF, but this image is viewed with a powerful magnifying glass with correspondingly shorter DOF.

=> same power, same DOF! (a) "Henry/Kimmo")


Now add the eye pupil and bright daylight (typical viewing conditions) in the system.

Case 1) exit pupil is often larger than the eye pupil => the eye is stopping down the objective which increases DOF.

Case 2) exit pupil is as large as or smaller than the eye pupil => no stopping down, no increase in DOF.

=> in bright light large binoculars are perceived to have more DOF! (b) "chartwell99")


Please, feel free to correct if there is some basic misunderstanding.

Best regards,

Ilkka

[zuiko]

A binocular is simply an astronomical telescope design with prisms to invert and flip the image.

The ratio between the focal length of the objective and eyepiece is what determines magnification. So for equal magnification the ratio is going to be the same.

1. If the objective has a 40cm (2.5 D) fl then the eyepiece needs a 4cm (25 D) fl for a mag of 10x.

2. If the objective has a 25cm (4 D) fl then the eyepiece needs a 2.5cm (40 D) fl for a mag of 10x.

In each case the eyepiece is always more powerful than than the objective - so the relationship does not change.

The smaller objective binoculars will not have less DOF. They may be equal to the larger objective pair, but even more likely to be greater DOF.

[iporali]

In each case the eyepiece is always more powerful than than the objective - so the relationship does not change.
I agree with that, but isn't the DOF of the 40D ocular shorter than that of the 25D because it must be brought closer? DOF is directly proportional (well, related) to viewing distance (macro-closeup photos have a very short DOF).

Ilkka (in learning mode...) :t:


EDIT: Inversely -> directly proportional. Short distance - short DOF. Sorry!
BTW, My "DOF" means sometimes "depth of field" and sometimes "depth of focus"... ;)

[zuiko]

I agree with that, but isn't the DOF of the 40D ocular shorter than that of the 25D because it must be brought closer? DOF is inversely proportional (well, related) to viewing distance (macro-closeup photos have a very short DOF).

Ilkka (in learning mode...) :t:


The 40D definitely converges the rays more towards the shorter focal length.

Thus the effective depth of focus (range of acceptable sharpness/resolution) would therefore be smaller compared to a comparable 25D lens with the same diameter. And that's the important part.

The 40D lens in the smaller objective lens binocular also has a narrower exit pupil thus the marginal rays being refracted are more paraxial than in the case for the larger exit pupil.

On balance the DOF is going to be the same or better for the smaller objective. I haven't tested this by an optical analysis but it's a gut feeling based on the geometrical model I have in my mind.


Regards.

[Tero]

Lewie, how is this proceeding? where did you shop for these in Iowa?

Personally, I would almost always go for 10x40 over 10x32. But Zeiss is a big name..what was the size again?

[Lewie]

Lewie, how is this proceeding? where did you shop for these in Iowa?

Personally, I would almost always go for 10x40 over 10x32. But Zeiss is a big name..what was the size again?

Still considering

I called Eagle Optics and talked to someone who said that with the 10X32 there is much loss of light and color transmission when compared to an 8X32.
(I have a Premier LXL 8X32 and was considering a premier or FL 10X32.) I do not want to gain magnification but lose quality. Therefore I am now considering a Premier or FL 10X42. I have the Pentax SP 10X50, which I do like. Very good detail and color, but a narrow FOV, especially when hiking in brushy areas.

Concerning stores, I live in Davenport, Iowa, and there is just one store within 50 miles that carries top bins, and they are very slow to get them in stock. The last time I checked they did not have the Premiers, FLs, or Ultravids(SP) in stock. I usually go through Eagle Optics. I do not need another pair of bins, but.....

I truly appreciate all the ideas, hints, and suggestions.

[elkcub]

Now add the eye pupil and bright daylight (typical viewing conditions) in the system.

Case 1) exit pupil is often larger than the eye pupil => the eye is stopping down the objective which increases DOF.

Case 2) exit pupil is as large as or smaller than the eye pupil => no stopping down, no increase in DOF.

=> in bright light large binoculars are perceived to have more DOF! (b) "chartwell99")

Please, feel free to correct if there is some basic misunderstanding.


Ilkka,

As I understand it, according to Ed Z of CN, the eye stops down the objective lens when the iris' pupil is smaller than the binocular's exit pupil. Essentially, the rays from the outer portion of the objective are eliminated, leaving only those in the center. The implication is that DOF should increase because the rays are more paraxial as zuiko mentioned. When the iris becomes larger, the amount of light is not increased beyond what the exit pupil allows. I don't know if the outer portion of the eye's lens is involved to confuse the issue, but brightness is compromised. There has been some discussion about the quality of the center portion of optical lenses, which might favor a large lens being stopped down rather than a small lens being used to its full extent, but I always thought that must be a minor factor with high quality optics.

Getting back to the enigma, Henry/Kimmo seem to have actually measured depth of field (of binoculars) experimentally, and have come to the conclusion that power is the controlling variable. As mentioned in an earlier post, my own set of 10x binoculars seems to comply with hypothesis (b), but such perception is a tricky matter in light of the other variables not held constant, e.g., FOV, focus control, and so forth. A theoretical explanation would be more satisfying, of course.

Ed

[Curtis Croulet]

Pardon me for my inadequate knowledge of optics and probable misuse of terms...but as I've come to understand it, an image can be truly in focus for only the selected distance. Everything else in front of and in back of the focused object is out-of-focus. Perceived depth-of-field depends upon how much fuzziness you're willing to tolerate. There is no magic point where everything suddenly becomes unsharp. Different brand camera lenses may have depth-of-field scales that disagree, because the designers apply different criteria for what constitutes acceptable sharpness. If you put more power on the scope/binocular, then you're magnifying the focused image and also the fuzziness of everything else that's not in focus. That which was acceptable is no longer acceptable.

[Tero]

Still considering

I called Eagle Optics and talked to someone who said that with the 10X32 there is much loss of light and color transmission when compared to an 8X32.
(I have a Premier LXL 8X32 and was considering a premier or FL 10X32.) I do not want to gain magnification but lose quality. Therefore I am now considering a Premier or FL 10X42. I have the Pentax SP 10X50, which I do like. Very good detail and color, but a narrow FOV, especially when hiking in brushy areas.

I truly appreciate all the ideas, hints, and suggestions.
There is a delicate balance in pleasing the same user with both 8x and 10x. Try to get to the stores to try them, or similar models out. I don't have any of these and rarely see any pentax. But in winter I seem to be happy with brighter 8x porros and summer 10x roof prisms. Not that it will work for someone else.

I used to think that the hand feel was important, but I can now use both porros and roof prisms, though I can still point the roof prisms faster. But the field of view is smaller.

[Bill Atwood]

Concerning stores, I live in Davenport, Iowa, and there is just one store within 50 miles that carries top bins, and they are very slow to get them in stock. The last time I checked they did not have the Premiers, FLs, or Ultravids(SP) in stock. I usually go through Eagle Optics. I do not need another pair of bins, but.....

The Camera Corner in Davenport used to carry a decent selection of bins and scopes.

[elkcub]

Pardon me for my inadequate knowledge of optics and probable misuse of terms...but as I've come to understand it, an image can be truly in focus for only the selected distance. Everything else in front of and in back of the focused object is out-of-focus. Perceived depth-of-field depends upon how much fuzziness you're willing to tolerate. There is no magic point where everything suddenly becomes unsharp. Different brand camera lenses may have depth-of-field scales that disagree, because the designers apply different criteria for what constitutes acceptable sharpness. If you put more power on the scope/binocular, then you're magnifying the focused image and also the fuzziness of everything else that's not in focus. That which was acceptable is no longer acceptable.

For the most part I agree with what you said. However, DOF (depth of field) is one of those properties that is often thought of on a relative (i.e., ordinal) basis, for example, "Binocular A has more DOF than binocular B." Hypothesis (a) mentioned earlier translates into the ordinal statement, lower power binoculars have greater DOF than higher power binoculars independent of objective size. Hypothesis (b) translates into, binoculars with larger objectives have greater DOF than binoculars with smaller objectives independent of power. Note that either statement might be judged to be true or false, on a consensus basis, even though individuals use quite different absolute criteria as to what is "acceptable" focus. If statements (or hypotheses) such as these are found to be universally agreed upon, it is usually followed by an effort (by someone) to prove that it must be so on a theoretical basis. Thus, observation becomes the handmaden of science. I think Henry Link recently coined the name "Binocology" in reference to this emerging field. |;|

Ed