Honestly, putting a budget lens on a 61-megapixel beast like the A7R V is a huge gamble. That sensor is gonna expose every tiny bit of chromatic aberration and corner softness. You gotta be careful because cheap glass usually means a lot of compromise when you have that much resolution to feed.

• I have used the Tamron 20mm f/2.8 Di III OSD M1:2 and honestly, it is sharp enough for that sensor in the center, but the autofocus is sluggish. It uses a gear-driven motor so it hunts more than I like. Just be warned, it makes a weird clicking noise when focusing.
• Make sure to keep your lens corrections turned on in-camera. This lens has massive barrel distortion that the software fixes. If you dont, your shots are gonna look like they were taken through a literal bowl. It takes up a lot of processing power in post too.
• If you decide to go manual to save cash, I would suggest the Samyang 14mm f/2.8 ED AS IF UMC. It is dirt cheap and sharp, but be warned, the mustache distortion is a nightmare to fix in post... really annoying if you have straight horizons in your Oregon landscapes.
• You might want to consider looking at a used Sony FE 28mm f/2.0. It isnt ultra-wide but the build quality is decent and it handles the high resolution better than most third party budget stuff at that price point. Just dont expect miracles for under 450 bucks on a flagship body. Honestly, I might even suggest renting something like a G-Master for the trip and buying a real lens later. You dont want to get back and realize your high-res shots are all mushy.

TL;DR: Snag the Viltrox 20mm f/2.8 FE AF. Im super happy with mine, zero complaints on resolution. Its way better than going manual for hiking.

I've spent a fair amount of time trying to get high-res results out of budget glass, and honestly, that sensor will punish you if you arent careful. If you can find a used Sony FE 28mm f/2, it is a very capable performer for the price. To get that wider field of view for landscapes, look for the Sony SEL075UWC Ultra Wide Converter. It basically snaps onto the front and gives you a 21mm f/2.8 setup. Its a bit of a DIY solution, but it maintains all your electronic connections and autofocus which is huge when you are out in the field. If you prefer a single prime, the Tokina FiRIN 20mm f/2.0 FE AF is a solid alternative that often flies under the radar. Its built like a tank and the optics were specifically designed to resolve higher pixel counts better than the cheaper plastic primes. You might have to hunt for a used copy to stay under 450, but its worth the effort for the extra sharpness. Manual glass is fine for some, but having AF when you're hiking through Oregon is gonna save you a lot of frustration.

To add to the point above: everyone is spot on about that sensor being a total beast. In my experience, the biggest mistake people make is thinking any E-mount lens will just work fine because it fits the mount. While they technically click in, many budget wide-angles have massive field curvature that becomes a total nightmare on the A7R V. Youll focus the center, but the edges will look like absolute mush even if you stop down to f/8 or f/11. I've tried many cheap glass options over the years and honestly, some of the entry-level stuff has pretty poor weather sealing too. Since youre heading to Oregon, you really gotta watch out for mist and moisture if you go too cheap. That high-res sensor wont just show softness, it'll highlight every bit of sensor dust and internal lens flare that better coatings usually handle. Just be careful with anything too dated or youll end up with 61 megapixels of regret once you actually see the raw files on a big screen... just my two cents after making that mistake myself a few times.

Finally someone says it. Ive been thinking this for a while but wasnt sure.

> Is the Tamron 20mm 2.8 actually sharp or should I go manual? Man, I am literally sitting here in the same spot. Bought the A7R V thinking I was totally set and then my bank account just laughed at me when I started looking at wide glass... its rough when you realize that 61MP sensor is basically a microscope. I had a similar panic before a trip last year where I realized I had no wide glass left and zero cash. The problem is really the pixel density. When you have that many pixels packed onto a full-frame sensor, any tiny flaw in the lens—like spherical aberration or just poor resolving power—gets magnified like crazy. I eventually went with a Sigma 24mm f/3.5 DG DN Contemporary and Ive been really happy with it because it actually holds up under that high resolution. It has that all-metal build which makes it feel safe for hiking and the optics are surprisingly punchy. Its just a weird spot to be in, having a high-end body and trying to find glass that doesnt make the images look like mush when you crop in. Still figuring it out myself tbh.

Yep, this is the way

Gonna try this over the weekend. Will report back if it works!

Honestly, the Samyang AF 24mm F1.8 FE is a sleeper hit for that 61MP sensor. I’ve been very satisfied with the resolution it pushes, and the technical specs are solid for the cost. It uses 11 elements in 8 groups, including extra-low dispersion glass to help with chromatic aberration. The specialized astro-focus mode is actually a really reliable way to lock infinity when youre shooting landscapes at night. If you need something wider, the Samyang AF 18mm F2.8 FE is another strong contender. Its tiny, weighs only 145g, and incorporates three aspherical elements to maintain frame-wide sharpness. I’ve had no complaints with corner performance when stopped down slightly. Either of these works well within your $450 budget and definitely beats fiddling with manual glass on a trip.