TAv Mode, the GR's Secret Weapon

Now that you understand the exposure triangle, here is the mode that lets you control the two things that matter on the street, depth of field and motion, while the camera handles the third for you. It is called TAv, and it is the reason GR shooters guard the camera so fiercely.

What TAv actually is

TAv stands for Time and Aperture value priority. You set the shutter speed. You set the aperture. The camera sets the ISO automatically to make the exposure correct. It is, in effect, shutter-and-aperture priority with Auto ISO. Most cameras make you give up control of one of the creative variables; TAv lets you lock both and surrender only sensitivity, which on a modern sensor is the variable you care about least.

This mode disappeared from the GR III and its return in the GR IV is genuinely good news. It is the single best mode for daylight street work.

The street recipe

Here is the setting to start from, the one to commit to memory: TAv, f/8, 1/250 to 1/320 of a second, Auto ISO with a cap around 3200, snap focus preset to 2m. Walk into that configuration and you are ready for almost any daytime situation.

Why these numbers? f/8 gives you deep depth of field, so combined with snap focus at 2m almost everything from about a metre to infinity is acceptably sharp. 1/250 to 1/320 is fast enough to freeze ordinary walking and gesture. Auto ISO floats up only as far as the light demands, and the cap stops it climbing into ugly territory without your say-so. You point, you shoot, the picture is sharp and correctly exposed. You spend your attention on seeing, not on dials.

When to reach for other modes

TAv is your daylight default, but it is not the only tool.

Av mode, aperture priority, is the simpler cousin. You set the aperture and ISO and the camera picks the shutter speed. It is fine when light is steady and you mostly care about depth of field, and it is one less thing to think about. Many GR shooters live in Av and are perfectly happy. Use it when TAv feels like too much.

Manual with Auto ISO is the night tool. After dark, light varies wildly from one shopfront to the next. Set a wide aperture, say f/2.8, set a minimum shutter you can hand-hold, and let ISO float. You keep the two creative controls fixed and let the camera chase the changing light.

The thing the IBIS will not do for you

The GR IV's stabilization is excellent, roughly 6 stops, and it will let you hand-hold absurdly slow shutter speeds and still get a sharp building. But read this twice: IBIS fixes your shake, not your subject's motion. A person walking, a passing cyclist, a hand gesturing, all of that blurs at slow shutter speeds no matter how steady the camera is. That is why the street recipe keeps you at 1/250 minimum. When you drop below that, you are choosing to let your subjects blur, and that should always be a choice, never an accident.

Make it yours

Once the street recipe feels natural, experiment. Try f/5.6 for slightly more subject separation. Try 1/500 in bright light to freeze faster action. The recipe is a launch point, not a cage. But on a day when you just want to walk Via Zamboni and make pictures without thinking, TAv at f/8 and 1/250 will not let you down.