Zeiss SFL 8x30 black out, kidney bean issue (1 Viewer)

[wildbill85]

I love these little binoculars! However, I can't get them dialed in just right to prevent kidney beaning when looking anywhere but center glass. The glass is sharp to the edges, and with such a wide field of view, it's a shame that I cant appreciate those portions of the glass. When looking center glass, it's beautiful and perfect. Should I try the 8x40 SFL for its larger exit pupils or should I be looking for a different bin altogether?

 

[MiddleRiver]

The 8x40 is definitely less 'finicky'. The form-factor/size is significant tho, and for hiking/travel, I'm still using the 8x30. The 40 is not much heavier but it is considerably larger and that diff sometimes makes a diff to me. What others have said is def true - make sure eye-cups and IPD are very carefully set. I wear glasses and I need the eyecups out a little. I unscrew them then screw them back in till resistance (click stop) begins. I prob should stick a small o-ring in there.
The IPD suprised me as I thought I was adjusted correctly by having the image merge into a circle. I instead measured my IPD carefully then set it with a ruler and it made a huge difference.

 

[wildbill85]

The 8x40 is definitely less 'finicky'. The form-factor/size is significant tho, and for hiking/travel, I'm still using the 8x30. The 40 is not much heavier but it is considerably larger and that diff sometimes makes a diff to me. What others have said is def true - make sure eye-cups and IPD are very carefully set. I wear glasses and I need the eyecups out a little. I unscrew them then screw them back in till resistance (click stop) begins. I prob should stick a small o-ring in there.
The IPD suprised me as I thought I was adjusted correctly by having the image merge into a circle. I instead measured my IPD carefully then set it with a ruler and it made a huge difference.

I suspect it's my deep set eyes, strong brow, and high nose Bridge. I just measured it out for a precise 60mm IPD and it helps a little, but the FOV is significantly worse.

 

[MiddleRiver]

Weeeell... Diff people and diff bins for sure. If the size isn't a deal breaker, I'll say that imho the 8x40's are hard to beat, regardless of $$. And they give (me) an effortless view, with no blackouts or tricky placement. Caveat - as noted earlier, I wear fairly close fitting specs.

 

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I would try the Zeiss SFL 8x40. The bigger exit pupil will definitely help with the kidney beaning. 8x30's unless they fit your eye sockets perfectly can be finicky as a group. 8x40's and above are much less finicky and eye placement is easier and that is a big advantage of the bigger aperture in addition to the better low light performance. I agree with MiddleRiver. The Zeiss SFL 8x40's are hard to beat for a birding binocular regardless of price.

 

[WJC]

I love these little binoculars! However, I can't get them dialed in just right to prevent kidney beaning when looking anywhere but center glass. The glass is sharp to the edges, and with such a wide field of view, it's a shame that I cant appreciate those portions of the glass. When looking center glass, it's beautiful and perfect. Should I try the 8x40 SFL for its larger exit pupils or should I be looking for a different bin altogether?

Kidney beaning has nothing to do with “being dialed in.” it is strictly related to eye placement.

 

[wildbill85]

Kidney beaning has nothing to do with “being dialed in.” it is strictly related to eye placement.

I can see how you misunderstood. I have my IPD and eye cups dialed in for proper eye placement.

 

[WJC]

I can see how you misunderstood. I have my IPD and eye cups dialed in for proper eye placement.

Sorry, I have just never heard of an IPD or eyecup being “dialed in.”

I’m not really OCD. However, there are several phrases used to describe optical performance that have nothing to do with Optical performance in a clinical optical sense.

 

[Maljunulo]

I can see how you misunderstood. I have my IPD and eye cups dialed in for proper eye placement.

Can you tell us exactly how you know they are correctly adjusted?

 

[wildbill85]

Can you tell us exactly how you know they are correctly adjusted?

I have deep set eyes so my cups are at the first stop and sometimes I just keep them all the way down and rest them on my brow with a slight tuck of my chin. I adjust for ipd by squeezing the bin's until I can maximize fov and have no distortion when looking center frame. There's a sharp black circle if it's correctly adjusted, otherwise it's a soft circle with a loss of FOV. I can even pan well with them, but as soon as my eyeballs stray to about 2/3rds away from center glass I get black out and I even get vignetting before that. They're not unusable. In fact, I really like them! I just think if I'm paying all this money for glass I should probably put it towards a pair that works better for my face.

I'm hoping the 8x40 SFL will work better for my face. My thinking is that the extra light will help reduce the black out. I have Monarch 7 8x42 and 10x42 and I get vignetting with them as well, but only blackout when I'm shifting my eyes to the extreme edges.

I'm assuming binoculars exist where you can put your face up to them and scan all the edges of the glass without vignetting and blackout but I don't know...

 

[[email protected]]

I have deep set eyes so my cups are at the first stop and sometimes I just keep them all the way down and rest them on my brow with a slight tuck of my chin. I adjust for ipd by squeezing the bin's until I can maximize fov and have no distortion when looking center frame. There's a sharp black circle if it's correctly adjusted, otherwise it's a soft circle with a loss of FOV. I can even pan well with them, but as soon as my eyeballs stray to about 2/3rds away from center glass I get black out and I even get vignetting before that. They're not unusable. In fact, I really like them! I just think if I'm paying all this money for glass I should probably put it towards a pair that works better for my face.

I'm hoping the 8x40 SFL will work better for my face. My thinking is that the extra light will help reduce the black out. I have Monarch 7 8x42 and 10x42 and I get vignetting with them as well, but only blackout when I'm shifting my eyes to the extreme edges.

I'm assuming binoculars exist where you can put your face up to them and scan all the edges of the glass without vignetting and blackout but I don't know...

You just have to find the binoculars that fit your face and eye sockets. If you stick with an 8x40, 8x42 or 8x56 you will find eye placement will be easier because of the bigger exit pupil, and you have a better chance of finding a binocular that has no blackouts.

 

[Maljunulo]

Put the binocular up to your eyes, focus on a distant object, and while continuing to look through the binocular at the object, slowly move it away from your eyes until it is at least a foot in front of your eyes, and tell me what happens.

 

[wildbill85]

Put the binocular up to your eyes, focus on a distant object, and while continuing to look through the binocular at the object, slowly move it away from your eyes until it is at least a foot in front of your eyes, and tell me what happens.

The fov narrows all the way to just a tiny dot at 1 foot

 

[MiddleRiver]

The fov narrows all the way to just a tiny dot at 1 foot

The exercise is to see whether the two images merge to a circle or overlapping circles.
I'm entering into uncharted territory, but with roofs, I think getting an accurate measurement of IPD and using that, is the best way to get your pupil centered in the eyepieces. That said, unless you can do it from a distance, or have an optician measure your IPD, there's the risk of error.

 

[Maljunulo]

As stated, the point was to see if the two images remain merged into a single field.

Do they?

 

[Maljunulo]

I am not convinced that kidney beans are an attribute of the binocular.

I believe that they they result from misalignment between the optical axes of the binocular and the optical axes of the observer’s eyeballs.

 

[MiddleRiver]

I am not convinced that kidney beans are an attribute of the binocular.

I believe that they they result from misalignment between the optical axes of the binocular and the optical axes of the observer’s eyeballs.

But surely you'll agree that some optical designs are more prone to that misalignment?

Maybe it's semantics were quibbling over.

No doubt that in the ideal world every (proper) design works 'correctly'. But also no doubt that I can snatch my 8x40SFL's without much care, where as the 30's require more careful placement at my eyes and with regard to required adjustments (IPD, eyecup setting, etc.). I don't think anyone is saying it's a 'flaw' in the optical design. But not all designs are created equal!

 

[wildbill85]

As stated, the point was to see if the two images remain merged into a single field.

Do they?

They're merged into one single field yes

 

[wildbill85]

I just spent the day with the 8x30 sfl again. I'm finding myself naturally tilting my head just slightly when I pan or look up and down. It gets rid of the blackout! With a little more time I may be able get some muscle memory down to make them work consistently. With this method, I do notice some ghosting on the opposite edges of where I pan. Ghosting might not be the right term. It's almost like a pale ghosty vignette instead of a black one. Normal?

 

[Maljunulo]

They're merged into one single field yes

Okay, then it appears that your IPD is indeed set correctly.