Sorry to make assumptions, but I had to because your question lacked any detail. Your question of will binos “do the same job” depends on whet the job you need to do is. Will they do the same job of providing more detail than the naked eye? Yes. Will they provide the same level of magnification, detail and light gathering as a large objective zoomable spotter? No.
It’s like asking if a motorcycle will do the same job as a SUV. If the job is to transport yourself 2 miles to work and home and you live in San Diego where it doesn’t rain, then yes it will. If you need to load groceries and take 4 kids to soccer practice 6 days a week and you live in North Dakota, then no they won’t both do the same job.
Do you have a good set of Binos now? Do you use them on a tripod? If not, you might be surprised how much a tripod can help with glassing. If you are wondering which to spend money on, I think it would be wise to get a good set of Binos 1st before a spotter. Lots of guys like to glass with 15x Binos in wide open country for long sessions because they provide a wider field of view and less eye strain using both eyes than a single eye spotter. You can cover more country and it’s more comfortable. Once game is spotted the spotting scope comes out to judge the animal for more detail.
To just judge if a bull is legal. A set of 10s on a tripod aught to do it for most applications.
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