CliffMcKenzie Loc: Lake Athens Texas

I have a bracketing issue with my D850. Simply put, when camera is instructed to bracket 5F 1.0 with following sequence -2, -1, 0, +1, +2 in manual mode with ISO locked down, aperture locked down and shutter priority set to 1000. The anticipated result should be 1/250, 500, 1000, 2000, 4000 and in that order (Bracketing Order is - +). Exposure Step Value =1.

What is happening is 1/1000 -2, 500 -1, 250 0, 125 +1, 60 +2. It is taking the opening value and bracketing downward from there. I have concerns here, but the camera is still following step value instruction (sequence -2, -1, 0, +1, +2) but the end product is linear in one direction.

Please note 5F 1.0 is the setting and not -3F.

Similar results for 3F 1.0 as well.

Now, switch to aperture priority mode with ISO locked down. The camera is setting shutter speed, and all works exactly as expected (sequence -2, -1, 0, +1, +2) and in the correct order (Bracketing Order is - +). I have two underexposed and two over exposed.

Unique to the camera? No, both D850s operate the same way.

So in manual mode with the desire to lock down aperture & ISO and set my opening shutter speed…how do I do it to achieve 2 under and 2 over?

Bill_de Loc: US

Remember we are dealing with fractions!

1/1000 (-2), 1/500 (-1), 1/250 (0), 1/125 (+1), 1/60 (+2)

I may be crazy, [not been proved] but that looks right to me.

1/1000 provides the least light while 1/60 provides the most light with 1/250 as a midpoint.

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CliffMcKenzie Loc: Lake Athens Texas

Bill, you are correct.

If the setting is 1000, then the desired result should be 250 500 1000 2000 4000. In manual it takes the shutter setting and drops it in a comparable manner. In aperture priority mode, it performs correctly.

tcthome Loc: NJ

You are correct.

MJPerini

If it works correctly in AV use that if you are concerned that the shutter speed choices are too slow----and if this is for tomorrow and you are using a long lens you are probably correct.
Again if this is for the eclipse on a tripod you COULD stay in manual and manually change speeds. Not as fast or convenient but you do have some time with the eclipse.
If this is not about the eclipse, a Call to nikon? (but good luck tomorrow, they will be swamped)

Bill_de Loc: US

Problem has been identified. In effect it was nothing but a math misunderstanding.

Reading ... it's "Fundamental"

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User ID

According to your own careful observations, the solution is to fudge it two stops toward your intention. Youve almost exactly said as much yourself, so Im puzzled why you then posted a query that youve already resolved. Regardless, kudos on carefully checking out and double checking your gears odd quirks.

BebuLamar

Since I never used the feature I don't know exaclty how it works. I think I will check it out. Perhaps in manual mode (no auto ISO) it doesn't consider the meter reading at all and start the sequence with the what setting is on the camera.

User ID

Well acoarst ! In manual, the settings are not driven by the meter. The meter is just info for users, not connected to anything. It all makes sense so Im still a bit puzzled by OPs need to post a query. But, he provided a useful heads up for other users to know how fully M-mode robotic bracketiing relates to manual settings.

BebuLamar

So if you want to do a 5 shots bracketing, 1 stop interval, from -2 to +2EV in auto mode you would start with whatever the meter indicates and the camera will do from -2 to +2. If in manual mode it start at whatever setting is and increase exposure from that point so you have to set the initial setting so that it's 2 stop under.

Orphoto Loc: Oregon

Complete non sequitur. You cant be in full manual mode AND have a shutter priority.

My best guess is that you are in manual with an indicated shutter speed of 1/250. The camera is performing as it should. You are messed up by auto iso parameters.

Note, the math on your anticipated values runs backwards.