You were pointing almost directly in the direction of the Sun. Loon on the ground. The shadows are pointing at you. So, as others have suggested, get a longer lens shield, or I would just move a few more feet around the "circle" you are standing on at the jumper's fence so as not to point so directly at the Syun.

For situations like this in IrfanView, my "go-to" editor, I increase the "contrast" and then add some darkening of the "gamma" control. Try them out until you get what you want. I'm sure other software has controls with almost the same names.

Here is my attempt. --Richard

The time to use a protector (and it should be clear glass, not UV unless you're way up in the mountains) is when photographing in hazardous environments where sand, salt spray, mud, chemicals, metal shavings, food particles, or other flying debris might damage your lens.

A good, securely attached, metal or polycarbonate lens hood will protect the lens as well or better than a filter under normal conditions.

All filters can generate flare under the right conditions... Flare can look like overall fog.

The photo below was made in 1975. I had a UV filter on a lens for which hoods are not available (55mm f/3.5 Micro Nikkor, which has a built-in hood behind the filter ring). Unfortunately, all the filter did for me was to add some flare in the upper left center of the frame... I still debate with myself whether I like it or not. It does add a little creepiness to a graveyard photo of naughty kids trying to figure out how to get that heavy monument back on the pedestal!

This happened to me on a recent shoot when I took the camera out at the location. I had forgotten to leave the AC off or otherwise protect the gear from cooling during the ride. There was a faint fog in the glass that I didn't notice and I was in a panic later that night when I saw that the first 50 were terrifyingly soft. Thankfully it went away as the lens warmed up.

Secondly, if you have a lens hood you shouldn't have this haze unless the sun in the field of view. In that case you are left to post processing dehaze as last resort.

Many things can create this hazy look.

> Dirt, dust, and fingerprints on front or rear or both lens elements — Get some professional lens cleaning tools and be sure your lenses are all spotless before you use the camera. It's amazing how many folks forget to check this. I clean my lenses before any photo or video event.

> Failure to use a lens hood designed for your specific lens — Don't work "against the light" without the correct hood on your clean lens. I always use a lens hood/shade, unless I'm using my short macro lens within two inches of a subject. It hides stray light sources and protects the camera should I drop it.

> Using ANY sort of filter when pointing the camera toward a light source — Avoid filters when possible. Wear the camera around your neck on a good neck strap, or secure a tripod with sandbags and such, and keep the lens hood on, so a fall won't kill your front element. If you must use filters, be sure they are absolutely spotless. Clean them as you would any fine lens, on both surfaces.

> Moving a camera from a cold to warm environment — In humid conditions, atmospheric moisture will condense onto cold surfaces. Allow your gear to stabilize in temperature before removing the lens cap.

> Atmospheric haze — In early morning, or after a rain, there is often fog or haze in the air.

> Air pollution or smoke — At a scout camp, this is common... Near industrial sites, it can happen. In cities plagued by inversion layer topography, it can be a common problem!

> Bad white balance — Are you using a target to set your white balance? A white balance target can get rid of blue tints in shadows, or the tint from an overcast sky, whether you're recording JPEGs baked in camera, or saving raw data files. (It's used with the eyedropper tool in post production of raw files, and used with the custom/manual/pre-set function when recording JPEGs at the camera.) Auto White Balance is not a panacea for JPEG photography, although using it for raw capture isn't wrong if you have a gray balance reference in the scene.

> Bad menu settings for JPEGs, or ignorant processing practices when working in raw editors — Settings matter. You can get great JPEGs at the camera in many situations if you "pre-process" your images by changing the JPEG engine's menu settings. This takes a lot of testing and trial and error, but when you know what to change, your JPEG captures improve dramatically. If you edit raw files, use a freshly calibrated and custom profiled monitor and follow the software maker's guidelines for using their tools.

UV Haze filters really only work for distance scenes taken at high altitudes. They helped a LOT with film, by killing UV, which tends to fog film in a part of the spectrum humans can't see. Modern digital cameras have UV (and IR) filters built into their sensors, so they are mostly immune to UV below about 6000 feet (about 1800 meters). If you're above 6000', MAYBE they'll help, but I doubt they will help at close distances. They often CAUSE flare when photographing into/toward the light source.

I can see from the shadows that you were shooting into the light. Try to avoid this situation as much as possible. If unavoidable, having a long lens hood can help. Have you tried using a haze or warming filter on your lens?
Your last bet would be some post work. If your going that way, then shoot RAW so you'd have more room for adjustments. Jpegs with regards to editing is a little finicky.

A touch of photo filter (warming filter (85) 45-50% density), S-curve & vibrance adjustment in Photoshop will result to something like the below:

What film do you shoot?

Since you last had a roll loaded, there's probably been some changes. Fujifilm Neopan 100 Acros II is "back" as this v II after the film had been dropped a few years ago. Very high contrast, great in full sun.

(color) Kodak Gold 200 has been added in the 120 format.

(color) Fuji Pro 400H had been discontinued in all speeds and formats.

(color) Kodak ProImage 100 is available in the US market.

(color slide) Kodak Ektachrome E100 is back.

(color slide) FUJIFILM Velvia 50 is back.