Is there an optimun exit pupil diameter for daylight conditions? (1 Viewer)

Hello to everyone.

As some of you may have noticed on a previous post, I am in a bit of a quandry regarding a pair of 8x50 Ultravids.


They are certainly great bins (as are my other 2 Leica bins), but I seem to have a great deal of difficulty with blackout in daylight settings, even if the eye cups are extended all the way.

I do not think that I have experienced such problems with bins of small objective sizes, but it could just be my faulty recollection. I will go back to the optics store today for some comparison shopping.

My question is: Is there an optimum EP diameter range for daylight viewing? Will I see just as much blackout with an 8x45 Ultravid as with the 8x50? I have read in other posts that bins with large diameter objectives are prone to blackouts. I have also read that you can learn to properly use the bins and eliminate most of the problem.

Any thoughts would be most appreciated as I have 30 days to return the 8x50s and I will do so if the problem can be eliminated by choosing a bin with a smaller objective.

Rgds,

Steffan

Hi Steffan,

My Leica 8x42BN has very good eye relief and I've never had a blackout problem with them. The same for my Swarovski 8.5x42EL.

I've used a friends Zeiss 7x42 Classic. It has a large exit pupil, very good eye relief and no blackout problem.

I like a 5+ exit pupil for daytime viewing. They are fast getting on a target.

My two biggest concerns with the Leica 8x50:

1. It's heavy, 35+ oz. (the Ultravid)

2. It has a relatively small true field of view for an 8x binocular.
8x50 Ultravid = 345 ft at 1000 yards
8x42 Ultravid = 390 ft at 1000 yards

Rich

I don't think blackout is simply related to pupil diameter, or to much else. I have a Nikon 8x30 E II which, as other people have reported of its 8x32 SE big brother, is somewhat blackout-prone. Neither my 8.5x44 Swift Audubons, 7x42 B&L Discoverys, nor 8x25 Nikon Sportstar IIIs are backout-prone. Until I saw your post I thought it might be related to large apparent fields of view making what should be an automatic process of lining your binoculars up with your eyes less reliable.

I wouldn't like to predict whether or not any particular design would be blackout-prone, but some people don't have problems so you might be able to train yourself or adjust yourself out of it. If I would you I would try raising the eyecups to reduce the eye relief, and get into the habit of moving the binoculars fractionally away from my eyes to recenter them when blackout occurs. I think with practice I have become a little less liable to backout with the E IIs (but to be honest, I use the Swift Audubons as my main binocular because - amongst other reasons - I have never had a blackout problem with them).

Thank you both for your replies.

After reading several posts and doing some research, I have come to the conclusion that the larger objective must have something to do with the blackout problem. Many have told me that there Leica (and others) _x42 bins don't have a blackout problem, and after yesterday, I have to believe them.

I hate to say it, but for me, a solution has been found.

I went back to the optics shop and spent some time with the runner-up in my bin search. The Swaro 8.5x42 ELs are not only the sharpest bin that I tested, but with an eye relief equal to the 8x50 Ultravids (18 mm), I experienced no blackout problems. I do wish that I had a chance to test the 8x42 Ultravids, but the shop was out of stock. Needless to say, the Leicas went back and I bought the ELs.

That was a tough choice. The build quality of the 8x50 Ultravids was absolutely outstanding. They were SPOTLESS, inside and out and the focus was smooth as silk. They were also a pleasure to use in low light. For the record, anyone that owns a pair of Ultravids owns a pair of bins that at least equals the best in the business.

But one of my goals in buying a new pair of bins was ease of use, as my wife (and perhaps others) will be using these as well. I just could not see coaching people on how to hold my bins. For top of the line money, you should receive top of the line performance. I was also able to try the Zeiss FL and the Leica Trinovid. While they also provided excellent performance, the minute I held the ELs up to my eyes, I knew that they were a match for me.

Folks on the forum have said several times that you have to go with what works for you and not for others, and I am happy to say, that is what I did. That is really great advice. Buy what works for you. Your money, your eyes, your satisfaction.

Thanks again for everyone's help in this search. You have all been a terrific help.

Rgds,

Steffan

Well, even if we didn't figure out why they didn't work for you, you managed to get a pair that did work instead. I'd call that a success.

Merely having a big objective wouldn't cause that, there is probably something about the overall design of the optics that did not work with your eyes.

Congratulations, Steffan!

The 8.5 EL is outstanding.

Rich