JohnnyRottenNJ Loc: Northern New Jersey

Hi to all;
Currently I'm shooting with a Nikon D500, using a Tamron DX 17-50f 2.8 lens. In normal lighting conditions, I get razor sharp images. But I'm noticing two things: When using a flash (Godox V850 II for Nikon) and I added MagMod "dome" to evenly disperse the light, often the subject will be out of focus but the surroundings will be sharp??? I have the focus set down to the one dot, and I put the focus box on the subjects face yet the pics still come out bad.
Secondly, I was shooting in low light at a baptism ceremony. I used a NanLite LumiPad 11 so I could set the camera on "coninuous Low." I realize that there are limitations with the Lumipad, but my images came out grainy and unsharp. I had set the ISO to 10,000 and even adjusted the camera to Auto ISO (with no luck) I set the camera to Shutter priority 1/200 of a second. I realize the higher the ISO value the more grain gets introduced, but the results were so wide varying, it is maddening. Some pics were rather sharp, others were very unsharp and muddy "grainy."
Any suggestions? I would likely be using a mirrorless camera by now, but I have seven DX lenses. Going to a full frame camera with a cropped lens makes no sense. While I'm on the subject, are there any Nikon fans out there who could make suggestions for a Nikon mirrorless? I'm hoping to get enough on a trade in of the body and all lenses to offset some of the cost of the new camera. Plus my needs have changed and I'm not likely to need more than two or three lenses. I figure staying with the same make camera would cut down on the learning curve and the Godox for Nikon would likely be OK with the newer model camera. This old dog wants to learn as few new tricks as possible. I welcome all tips and suggestions.
Thank you in advance.

User ID

You can get a DX Z camera plus an FTZ which allows you to use whichever you wish to keep among your present lenses.

Your choice of a pinpoint AF target might be counterproductive in dim light. Try giving the AF system more "opportunity" by using a bit wider target.

If your AF assist beam is enabled, check on whether your flash modifier is blocking it.

Also, if youre not using BBF get with it.

If your unpredictable exposures occur using flash, it may be related to your AF errors cuz the lens informs the flash about distance.

As to "grain", even at a fixed ISO noise is increased by even slight under exposure.

Finally, I get the impression that youve got too much automation engaged. The twofold result of too much automation can be erratic results AND a users inability to sort out the interactions that cause the problems.

CamB Loc: Juneau, Alaska

A bunch of things ring wrong about this to me. You say you are using a flash in some sort of dome AND you are shooting at 10000 ISO. First, 10000 ISO is really extreme. You get noise but you also get a little mush as apposed to crispness in your shots. (I may get a little pushback on this, it's hard to define) Flash and high ISO don't play well together. You use high ISO so you don't have to use flash. Next you say you are using a shutter speed of 200. That is pretty much going to wipe out any ambient light in a dark situation, making everything rely on the flash, which, in turn makes the high ISO pointless.
Thinking about setting up my camera for a Baptism in a dark church I would weigh two choices. Do I want to use flash and if so do I want to use ISO, f-stop and shutter speed to balance a little ambient light in the shots. (Probably) Or do I want to forget the flash and adjust just for ambient light? (My preference) If the later is my choice I would start with an ISO around 1600 and go up from there a little at a time to get the right exposure. Worse case would never get me close to 10000. I would, of course, use fast glass, 1.4 to 2.8. Shooting in low light, narrow depth of field, slower shutter speeds, you shouldn't expect every shot to be sharp. At slow shutter speeds you will get a lot of garbage. Expect it. Over shoot and only show the good ones. Flash is easy but often garish. Ambient is harder to shoot but much cooler in the end.

delder Loc: Maryland

Practice Practice Practice!
I would go back to "Film Days".
The most we had was Tri-X 400 pushed to 800 or 1200 @ the most.
Find a similarly lit location,
[Light Meter] & try bracketing shots.
You might put your camera in manual for this exercise.
Learning the "Golden Triangle" between apature, speed & shutter will help you.

MJPerini

Nothing wrong with your camera or lens. Shooting at ISO 10,000 is your problem.
If you had just used a Tripod you could have shot at 1/60 at Iso 2500 or 1/30 at 1200
You also could have bounced flash and done fine 90% up 10% little kicker card to get catchlights and shadow fill.
Little LED panels are fairly useless in large spaces unless they are very close to the subject.

Also remember, light dim enough to need iso 10,000 is usually pretty unattractive light, pumping iso may get you the exposure you need but it is still ugly light. A bounce flash done well, can fix that..... meaning it can raise ambient levels AND supply some directionality & shadow fill. In situations where flash is prohibited , bring an f/1.4 prime and a tripod.
I have ignored IS/VR or IBIS but both of those can also help.
In a Church, a monopod can be as good as a tripod -Rubber pad on floor, lean against a Pew at mid point and slowly squeeze the shutter.
Good Luck next time

BebuLamar

I estimate with the Nanlite and at 6' distance you can shoot at f/5.6, 1/60, ISO 6400.

imagemeister Loc: mid east Florida

Stronger light on subject, LESS ISO , f4-5.6 for DOF

CamB Loc: Juneau, Alaska

Answering Part two of your question. I have been using a Nikon DX camera for years. Currently a D7500. Two weeks ago I bought a new Nikon, Z611, full frame mirrorless. My two main, fast lenses are full frame so I am good there, but I have a bunch of DX lenses too. They work on the new camera but at a reduced pixel size. My DX wide angle lenses give me the same view as a full frame wide angle but with about half the pixels. Thats OK for now but I will have to pick up a full frame wide angle some time soon.
As far as the controls being in the same place...sort of. It's actually very different and I have put in many hours trying to figure it all out. Some things are good and some not so good. I shot two performances of the Juneau Symphony Orchestra this weekend, one a rehearsal, but for various reasons I was called back to shoot part of the live show. The silent setting for the shutter was wonderful. It doesn't make any sound at all. The people around me while I was shooting didn't even know I was taking pictures, except for the fact that I was holding a camera with a big lens on a monopod and had to move around a little bit during the show. Fortunately, after close to fifty years of shooting theater in Juneau, most people know me and expect me to be there with a camera. I haven't even gotten into all the various focus modes of the new camera. The cruise ships and whales are just starting to show up so it will be an interesting summer.

CHG_CANON Loc: the Windy City

We should see some actual examples of your problematic results, with the images stored and the EXIF complete. What you describe in your technique and then your described results do not match. We probably can see something different in the EXIF than you've described in your technique. We then can give actionable ideas, rather than random guesses.

Orphoto Loc: Oregon

Another thing to consider. If it really is so dark that you need to push iso that high....it may be simply too little light for your autofocus system to operate reliably. When that happens revert to manual focus.

delder Loc: Maryland

Makes sense!

tcthome Loc: NJ

Don't know enough to help with most of your problem but in the D500 menu settings. Is there an option for modeling flash? Built-in AF Assist Illuminator? And if so, Are they set to ON? Helps the camera pull focus & with exposure. It is also possible if your doing a continuous shooting that the flash will not put out the same power of flash not having enough time to recharge fully. Good luck & enjoy your new camera if you purchase.

tcthome Loc: NJ

Include all flash settings/set-up also!

yorkiebyte Loc: Scottsdale, AZ/Bandon by the Sea, OR

.... "actual examples, with EXIF". This.

BebuLamar

The D500 doesn't have a built in flash. Also the OP doesn't use a Nikon flash so I don't know how much control the D500 has on the flash.