Gatorcoach Loc: New Jersey

I've been using BBF on my Nikons for a few years now and can't see myself ever going back to the shutter button focus. I fully understand that one touch locks the focus and holding the button provides continuous focus. My question is how can you lock in the aperture? I've scoured the manual and online resources, asked professionals (and others who think they are!), and have tried everything I can think of but cannot find the answer.

There are numerous times I want to lock the exposure when using "S" or "A" modes and re-composing but cannot currently do it without switching to manual mode.

There's gotta be an easier way.

Walkabout08

I’ll look but I’m thinking you should investigate using the AEL button.

ecobin Loc: Paoli, PA

You cannot lock aperture in Auto mode. What would be the point - just use Aperture priority mode.
I use manual mode with auto ISO and then do exposure compensation as needed. That allows me to lock aperture and shutter speed.

ecobin Loc: Paoli, PA

He’s using that for back button focusing as do I.

Rick from NY Loc: Sarasota FL

Am I missing something? If you want to lock the aperture, use “A” mode. To lock shutter speed, use “S” mode. Why would back button focus affect either unless you are in “auto mode”?

CHG_CANON Loc: the Windy City

You're right, it couldn't be easier. Aperture priority has the aperture 'locked'. Shutter priority has the shutterspeed 'locked'. Focus with the BBF held until the focus location as desired is set. Release the BBF and the focus is 'locked'.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

As others have noted, Aperture Priority uses the aperture you select in A and/or M. Shutter Priority uses the shutter value you select in S or M. And M uses the shutter and aperture value that you select.

You can lock exposure (and if you are in A mode, presumably aperture), by programming the Assign AE-L/AF-L button (F6 on a D810). AE-L has two modes - lock exposure only while pressed, or lock exposure by press and release until unlocked by press and release. You can also use Shutter Speed and Aperture Lock - to lock either one and/or the other - Custom menu setting F7 on a D810.

You can also assign the AE-L/AF-L button to only change the exposure and/or the focus while the button is being pressed.

Different camera versions have different function setting assignments - F1 on one camera may be F7 on another - but both are described using the same language.

TerryVS

On a D850 you set the BBF as you have it and exposure lock as half push of the shutter button.

Terry

jerryc41 Loc: Catskill Mts of NY

Bultaco Loc: Aiken, SC

Manual mode with auto ISO, use the command wheels to select aperture or SS.

Gatorcoach Loc: New Jersey

The D750 does not allow that. The shutter button options are "photos" or "movies" only.

Gatorcoach Loc: New Jersey

Thanks to all who have responded but the question, I thought, was simple and clear. The answers were all over the place and not helpful. Nowhere did I say, or imply, that I use "Auto". I never use it.

I shoot generally on "A" (aperture) and realize that is how I lock the aperture setting. That's easy. I am also aware that in "S" mode I lock the shutter speed. Got that too.

The issue I have - and I didn't articulate that clearly is when there are varying brightness levels - sometimes from very bright to heavy shade. As I move around the scene the aperture stays the same but shutter speed changes to the proper exposure. When I want to expose for the highlights (ex. sky) I have to aim high or the camera may see the dark areas and adjust accordingly. The aperture is locked but I don't know if it is the proper or desired exposure.

A workaround is shoot in Manual and measure and set the aperture and shutter speed individually. I'm looking for a more efficient way of doing this.

I'm very grateful for your help but please keep responses to the questions.

CHG_CANON Loc: the Windy City

Do you move your AF point around within the frame so you're both focusing and metering for the exact location your plan to capture? Consider this adjustment as something easy and effective to the situation you describe. Your Nikon d750 as 51 individually selectable AF points.

Gatorcoach Loc: New Jersey

No. But I will try that. Thanks, Paul

CHG_CANON Loc: the Windy City

It takes practice to get the 'finger feel' of moving the AF points with the camera held to your eye, but that's the purpose and positioning of all the external controls on advanced equipment like the D750. Sometimes, it's also just easier to look at the scene, decide where to focus, move the point there while holding / looking at the camera, then raise the camera to a shooting position and go.