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The Zeiss SFL 8x30 compared with select current 8x30/8x32 roof binoculars (1 Viewer)

According to B&H:
SFL 8x30: 459g
Leica 7x35: 590g
SFL 8x40: 641g

So the 7x35 are much closer to the 8x40.

Length is:
SFL 8x30: 11.9cm
Leica 7x35: 13.2cm
SFL 8x40: 14.5cm

So the 7x35 are exactly in the middle.
A surprising characteristic of the 7x35 Retrovid is its density. It’s an aluminum not a magnesium body, who knows how much that adds to its weight. The feeling holding it in hand is that of a high end bino that’s just full of glass. At first use it is surprisingly heavy for its size.
 
Which makes me wonder. Is there an advantage in a bigger ocular lens diameter? Maybe a more forgiving eyebox?
 
The size re
Which makes me wonder. Is there an advantage in a bigger ocular lens diameter? Maybe a more forgiving eyebox?
The diameter of the ocular's eye lens results from two other specs: eye relief and AFOV, which form a cone with the height equal to the eye relief distance, the angle of the AFOV equal to the vertex angle and the eye lens diameter equal to the diameter of the base.

There are many possible cone shapes that can be formed from the same diameter eye lens, from wide short cones (wide AFOV, short eye relief) to long narrow ones (narrow AFOV, long eye relief). AFOV will shrink at the same time that eye relief lengthens and vice versa. Really, it's more useful to know AFOV and eye relief than it is to know the eye lens diameter since the eye lens diameter can be calculated from the eye relief and AFOV, but the eye relief and AFOV can't be known from the eye lens diameter alone.
 

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According to B&H:
SFL 8x30: 459g
Leica 7x35: 590g
SFL 8x40: 641g

So the 7x35 are much closer to the 8x40.

Length is:
SFL 8x30: 11.9cm
Leica 7x35: 13.2cm
SFL 8x40: 14.5cm

So the 7x35 are exactly in the middle.
I stand corrected without myself actually looking up the starts. But what I do know for a fact is that the retro feels ‘smaller’ than 8x40
 
I stand corrected without myself actually looking up the starts. But what I do know for a fact is that the retro feels ‘smaller’ than 8x40
Indeed. But they are not that far so one can choose to go lighter and smaller with the SFL 8x30 or have a bigger diameter with the 8x40 without too much weight gain.
Or keep the excellent 7x35 of course.
 
The size re

The diameter of the ocular's eye lens results from two other specs: eye relief and AFOV, which form a cone with the height equal to the eye relief distance, the slant height angle equal to half the AFOV angle and the eye lens diameter equal to the base.

There are many possible cone shapes that can be formed from the same diameter eye lens, from wide short cones (wide AFOV, short eye relief) to long narrow ones (narrow AFOV, long eye relief), but AFOV will always shrink at the same time that eye relief lengthens. Really, it's more useful to know AFOV and eye relief than it is to know the eye lens diameter since the eye lens diameter can be calculated from the eye relief and AFOV, but the eye relief and AFOV can't be known from the eye lens diameter alone.
Henry any chance you might be able to sketch this, Please? I sorta get it, but am not sure... I fear any back and forth with words to clarify might make things worse...

Thanks Tom
 
Holger, re this:
Was SFL 40 which has been out for a year (or more?) now less impressive in this regard? I would have expected most to prefer the 40mm.
I have the same question.

As well, was "Merlitz Distortion" used on the SFL40s to?

Thanks

Tom
 
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{{ cont'd }}

The Zeiss SFL 8x30 compared with select current 8x30/8x32 roof binoculars

PART 2: Brief side-by-side comparisons

Comparison 1: Zeiss SFL 8x30 and Leica UV 8x32 HD+

Since Zeiss withdrew the FL 8x32 from the market, and with the NL Pure 8x32 and Victory SF 8x32 clearly larger and heavier, the UV HD+ holds the “top spot” among small, lightweight 8x30 / 8x32 roof binoculars, both in terms of price and “premium prestige”.

It is even smaller than the SFL and not much heavier, has often been named a “design icon” and defends its position with very good mechanical and optical performance. There isn’t much to criticize about it in my view, except the modest usable eye relief which makes its use uncomfortable for spectacle wearers.
The SFL is much better in this respect, its usable eye relief may be perceived as almost “too generous” if you don’t wear glasses; this is a point that has been raised in some early reviews when it was mentioned that you may have to experiment a bit with the right eyecup position. Because of this, in my experience the 8x40 model of the SFL series allows for a better and more natural “ease of view” (Einblickverhalten) than the 8x30. But this is a personal impression which may not be shared by others. The ease of view of the UV should be unproblematic for people not wearing glasses

Both SFL and UV exhibit a pleasant image and comfortable panning behaviour (see post # 1 the “Merlitz Distortion :)), both are non-flatfield binos.

The FOV in the SFL is, and appears, a bit wider than in the UV; the image in the SFL is very slightly cooler than in the UV for my eyes.
Central sharpness and image brightness appear quite similar. On the other hand, contrast – as seen when observing rough structured surfaces such as certain building walls or tree bark – is a bit better in the UV; when you have it side-by side with the SFL, the difference is not huge, but clearly recognizable.

Edge sharpness: better in the SFL than in the UV, even when the wider FOV of the SFL is taken into account. Field curvature is low in the UV and even lower in the SFL.

CA: both the UV and the SFL are not totally color-free (would be surprising in this compact format), but with proper eye placement behind the eyepieces, CA in both is low at the center of the image and moderate further out towards the edge (the SFL 8x40 appeared a tiny bit ahead of the 8x30 model in my experience).

The UV has the typical “dry” Leica focuser with the tiny “click” upon changing focus direction. It is not as smooth as the one of the SFL, but it has been working reliably and precisely for years. The SFL focuser is a bit faster than the one of the UV; in both binos, it is very easy to quickly find sharp focus. The position of the focus wheel is “traditional” on the UV (close to the eyepieces), further towards the front of the bino on the SFL. In my view, preferences in this regard are personal.

A note regarding the excess travel of the focus wheel beyond infinity: both binos have sufficient extra travel, with one caveat for the UV (and valid for most UV HD models): the full range of diopter adjustment and the full extra travel are mutually exclusive, so if you need much of the diopter adjustment because of different vision in your eyes, you may not have much extra travel beyond infinity left on the focus wheel. This is due to the way the diopter and focus mechanism are linked; In the SFL, the mechanisms are completely independent and the mentioned limitation does not apply.

Is the UV worth around 500-600 $ more than the SFL? Your own decision!

My personal verdict of the two binos in a nutshell:

  • UV is smaller, but slightly heavier
  • Ease of view is better in the UV
  • Contrast is better in the UV
  • Usable eye relief much better in the SFL, insufficient for spectacle wearers in the UV
  • FOV is wider in the SFL
  • Central sharpness and image brightness are comparable, as is CA
  • Edge sharpness is better in the SFL

fwiw Canip

{{ to follow next: Nikon MHG, Swarovski CL, etc. }}

IMG_2334.jpeg
 
...................... I would have expected most to prefer the 40mm.
The 30mm comes with such a considerable weight saving and still provides an excellent view that this version is like the proverbial "offer you can't refuse". Even my wife whom I knew she wanted a 10x version opted for the 30mm. The weight reduction was what impressed her sufficiently. Of course, being 80 contributes to the priorities.
 
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The 30mm comes with such a considerable weight saving and still provides an excellent view that this version is like the proverbial "offer you can't refuse". Even my wife whom I knew she wanted a 10x version opted for the 30mm. The weight reduction was what impressed her sufficiently. Of course, being 80 contributes to the priorities.
To me… there is a weight/size that makes a binocular too small in size, too light. Example… the MHG. I am sure the SLF will be in that category. They seem ‘toylike’…

The other end of spectrum is big and heavy. This is why I like the Meostar b1 series or the Leica Ultra or Retro. They fit right in the middle but more on the smaller lighter side… just not so to get in the ‘toy like feel’
 
The diameter of the ocular's eye lens results from two other specs: eye relief and AFOV, which form a cone with the height equal to the eye relief distance, the angle of the AFOV equal to the vertex angle and the eye lens diameter equal to the diameter of the base.

There are many possible cone shapes that can be formed from the same diameter eye lens, from wide short cones (wide AFOV, short eye relief) to long narrow ones (narrow AFOV, long eye relief). AFOV will shrink at the same time that eye relief lengthens and vice versa. Really, it's more useful to know AFOV and eye relief than it is to know the eye lens diameter since the eye lens diameter can be calculated from the eye relief and AFOV, but the eye relief and AFOV can't be known from the eye lens diameter alone.

Thanks for the explanation! Than Swarovksi is doing a great job with the NL Pure 32? Huge AFOV, quite large eye relief and large ocular's eye lens. If I understand it correctly, the NL Pure must have a large lens diameter because of the huge AFOV and the large eye relief?

The AFOV of the NL 8x32 is 65 degrees, of the NL 10x32 it is 69 degrees. The eye relief is the same. So the lens diameter of the NL 10x32 should be bigger than the measured 25mm of the NL 8x32?

A large lens diameter might suggest that the binoculars have either a large AFOV or a large eye relief? Or both large in case of the NL Pure?
 
Holger, re this:

I have the same question.

As well, was "Merlitz Distortion" used on the SFL40s to?

Thanks

Tom

As far as I know, all the SFL models are supposed to have distortion curves which kind of 'follow my prescriptions'. What this means precisely I have no clue, because Zeiss has not shown me their distortion curves and just mentioned it in passing. I have once seen the 8x40 SFL and the panning behavior appeared fine to me, while, at the same time, pincushion distortion was quite low. This is how it should be, but just by looking through the binocular I can only come to a qualitative assessment. I would need precise measurements or a ray-tracing of their design in order to know what they have done. I am trying to contact Zeiss in order to discuss how one might actually find a definition of what makes a 'good panning' binocular, and whatever this will be, it should eventually show up in the spec sheets.

Cheers,
Holger
 
To me… there is a weight/size that makes a binocular too small in size, too light. Example… the MHG. I am sure the SLF will be in that category. They seem ‘toylike’…

The other end of spectrum is big and heavy. This is why I like the Meostar b1 series or the Leica Ultra or Retro. They fit right in the middle but more on the smaller lighter side… just not so to get in the ‘toy like feel’
I think I agree with you. For me, the SFL 40 attracs me more than the SFL 30, because 600-700 gr is light enough and give you a certain grip/stability especially for a 10 power.
However, if bird watching isn't your main activity, heaving just 500 gr on your neck is not bad either. I think it is all about your needs.
 
The format 8x30 is hugely popular as far as I can see on this forum. There must be a reason for it and I think it's the weight. And birdwatchers don't mind a smaller exit pupil that much. But I bet most of the people who are in for the 8x30 have a second bin with a larger diameter as well...
 

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