gofast Loc: Joliet, IL

I was at the dog park, it was bright overcast-great for not too bright, contrasty pics. I was using P mode on a T3i, 75-300 lens, usual skylight filter, ISO 200. The camera pretty much was running 1/800 almost wide open.

The pics look greyish. Certainly not white. The dogs are in good focus. What went wrong?

pesfls Loc: Oregon, USA

Your meter is being overwhelmed by all the snow and trying to turn it to 18% gray. If you go manual and meter just the snow and the open up by about two stops it’ll then turn white.

PixelStan77 Loc: Vermont/Chicago

The high reflectance of the white screws up the metering system in our camera and told it to close down two stops to compensate. So, mind over meter, you need to open up 2 stops.The same you need to do if you are photographing black horses. You need to close down to stops.

Mark Sturtevant Loc: Grand Blanc, MI

You are shooting to freeze motion, and did well on that. But conditions were difficult in this situation since you had extensive areas that are very bright and dark areas (the dogs) that now look too dark. This would challenge a lot of people.
You can correct your issues in post processing, and doing so is no mark of shame. Post processing should be part of your toolkit.

tradio Loc: Oxford, Ohio

Set your ISO to 100. Shoot 1.5 to 2 stops over.

jscorbin Loc: Woodinville, WA

Or, to put it another way, the meter doesn't know that the scene is of snow. The meter is doing exactly what it was designed to do: expose for medium gray.

Mark Sturtevant Loc: Grand Blanc, MI

The OP says it was almost wide open. I think for most lenses going wider would bring in chromatic abberation.

Thomas902 Loc: Washington DC

"...What went wrong?" gofast you are shooting from way too high above the talent in this visual statement... with people, animals etc. you seriously need to have your lens at or slightly below their eye level... Yes this means getting down on the deck... Try it you will be amazed at the drama this breathes into your narratives...

As for exposure? Other posters have alerted you to how "dumb" exposure metering is... a.k.a. it can't see that you are attempting to capture white snow... however it does an awesome job of turning it to neutral gray... lol

Caveat: Before you go down on the deck in a dog park best to carefully canvass the ground for fecal material... far too many thoughtless k-9 owners are not policing after their animals... experience is a brutal teacher....

btw, Jack Russell Terriers can leap vertically over 5 times their height... might consider this breed and post your imagery in the BIF forum... Jack Russell's will gladly greet you midair at your eye level! Believe their vertical height record on a jump is over 6 feet... lol

Hope this helps or is at least food for thought....
I wish you well on your journey gofast...

Revet Loc: Fairview Park, Ohio

Everyone else covered the problem when shooting snow so I will address the composition. I also agree that the shot would have been better from eye level or lower. In addition, the dog on the right creates a lot of tension being so close to the edge of the frame with him/her looking off the edge.

CPR Loc: Nature Coast of Florida

When seeing problems in a shot I like to take it into Photoshop and see what changes can fix the problem. That gives a good idea of the problem.

In this shot just raising the temperature (the Light in Kelvin) fixes the grey.(Or on this laptop screen - fixes the blue.....)
Contrast changes would take out the way the tracks in the snow stand out.
I could set White Balance to the snow or use one of the other techniques mentioned.

Rab-Eye Loc: Indiana

Bingo. Your alternative is two stops of exposure compensation.

John_F Loc: Minneapolis, MN

The lack of shadows suggest heavy cloud overcast w/no direct or reflected sunlight. Such lighting will be rich in the blue end of the spectrum, so your image shows the scene as it was. Depending on your camera's controls & settings plus measures in your PP image editing software, you will be able to alter the imbalance in the incident illumination. Experts with your camera will have prescriptions for you.

In my opinion, capturing scenes 'as they exist' is not "wrong."

camerapapi Loc: Miami, Fl.

The exposure. Exposure meters read 18% gray. If the subject is too bright you have to open at least one stop from the meter reading (open the aperture by one stop) Middle gray is not black nor white but in between.
In general open 2 stops for bright subjects and close 2 stops for black subjects from meter reading. Subjects of middle tonalities (18% gray) are properly exposed by meter reading.

James Van Ells

The sunny 16 suggestions are at ISO 100 shoot at 1/100 @f16. At ISO 200 shoot at 1/200 @f16. This holds true on bright beaches and snow.

rmalarz Loc: Tempe, Arizona

pixelstan and jscorbin pretty much hit the nail on the head.
--Bob