Honestly, the D850 is a beast that really demands top tier glass to shine. Ive been shooting Nikon for over a decade and found that while older primes are light, they sometimes struggle with that 45MP sensor. Im very satisfied with the Sigma 50mm f/1.4 DG HSM Art for Nikon F and its basically my go-to for portraits now.

• Optic quality: The Sigma is designed for high-res sensors. Its way sharper wide open than the Nikon AF-S NIKKOR 50mm f/1.8G.
• Character: It has a much smoother fall-off. The bokeh is less busy, giving you that high-end look you felt was missing from the zoom.
• Alternatives: If you want more compression for outdoor shots, the Nikon AF-S NIKKOR 85mm f/1.8G also works well and I have no complaints about its performance on FX. Youll be happy with the Sigma tho... the weight is the only real trade-off but the images are worth it.

Building on the earlier suggestion, while the 1.8G is a decent budget pick, it really doesnt do the D850 sensor justice when you are shooting wide open for a wedding. Ive tried many primes over the years, and in my experience, if you want that wow factor without the back-breaking weight of the Sigma, you should seriously consider the Tamron SP 85mm f/1.8 Di VC USD.

• Nikon AF-S NIKKOR 85mm f/1.8G: Light and cheap, but i found it has pretty noticeable chromatic aberration on high-contrast edges when paired with high res bodies.
• Sigma 50mm f/1.4 DG HSM Art: Sharpest of the bunch probably, but its basically a total brick to carry around all day at a wedding.
• Tamron SP 85mm f/1.8 Di VC USD: This is the sweet spot. It has vibration compensation which is a lifesaver for late-afternoon shots, and the weather sealing is better for Vermont in the fall. Honestly, dont settle for the older Nikon glass just to save a few bucks if you are rocking a 45MP sensor. Youll see the purple fringing and soft corners immediately. The Tamron fits perfectly in your $800 used budget and gives a way more modern, clean look than the zoom ever could. Ngl, the VC alone makes it worth it for handheld shots when the light starts to drop. Just make sure to check the focus calibration... third party stuff sometimes needs a quick tweak in the D850 menu.

Regarding what #1 said about the D850 being a beast, I saved cash using the Nikon AF-S NIKKOR 85mm f/1.8G. It handles resolution beautifully and avoids the heavy Sigma bulk for weddings!

@Reply #2 - good point! Finding that sweet spot where you aren't carrying a brick but still get the quality is the goal. > Does the older Nikon glass still hold up against the newer third party stuff on a high res FX sensor or is the Sigma actually worth the extra bulk? Honestly, you cant go wrong with any of the pro-grade glass from Sigma. Their build quality has become really impressive over the last few years and they handle high-res sensors perfectly. That said, sticking with native Nikon gear usually gives you that extra bit of peace of mind regarding autofocus reliability, which is huge when things are moving fast. Just get any of the newer pro-level primes from those brands. They are built to last and will definitely outshine the older entry-level stuff on your D850. Reliability is everything when you only get one shot at the ceremony... it just depends on if you prioritize weight or that extra bit of build quality.

To add to the point above: the reality of the D850 is that its incredibly unforgiving. I spent way too long trying to get my kit dialed in for a shoot last year and it was honestly a letdown. Everyone hypes up the sharpness of these primes, but they rarely mention the technical headache of getting them to actually focus where you want on a DSLR sensor this dense. Unfortunately, my journey with used glass on this high-res body wasnt as smooth as expected:

• AF Fine Tune is a massive time sink. I spent an entire weekend with calibration targets and still had issues with focus shifting at different distances.
• Older glass often has some pretty nasty longitudinal chromatic aberration that shows up way more on 45MP than you would think.
• Many third-party options require those proprietary USB docks just for firmware fixes or focus mapping, which is just more clutter and cost to deal with. I really wanted that clean prime look, but the DIY calibration process is basically mandatory if you dont want half your wedding shots to be slightly soft. Its not just about the glass quality, its about the mount communication being a bit of a legacy mess. Honestly, its not as plug-and-play as the zoom you are used to...

Jumping in here because i've seen way too many people get burned by picking up used third-party glass without checking for focus issues first. When youre shooting with a D850, that high-res sensor shows every single tiny flaw. Honestly, those third-party primes are sharp as hell, but I really have to warn you about the autofocus consistency. In my experience, they can be hit or miss on DSLR bodies without doing a lot of manual fine-tuning. I've tried many different setups over the years and i always tell people to be cautious with the older native glass on high-res bodies too. They're reliable, but sometimes they just dont have the resolving power for those 45 megapixels. If you go with a non-native brand, you basically need to factor in the cost and time of using a calibration dock. Ngl, missing focus at a family wedding because the lens and body aren't talking perfectly is a total nightmare you want to avoid. If you want absolute reliability, sticking to native glass is usually the safer play for high-stakes shoots, even if the third-party specs look better on paper.