Problems with in door photography

[goodguy]

I have a question about a problem which I am struggling with for a long time.
I find in closed spaces with limiting lighting sometimes my camera will give me bad results.
I will try to explain the best way I can, this problem follows me from my D7000 through the D7100 and now the D750 so I am sure its not a gear problem but either lighting issue or my technique.
For an example I shot in my sons graduation, the next day my daughter graduation and few days later in a friends wedding and I was not allowed to use flash.
Results were in many shots the same, reddish picture, not focused and very grainy.
Its not that there wasn't enough lighting, the ISO went from 2800ISO to 10000ISO depends of the area I shot but even at 2800ISO the picture was not focused and very grainy.
I used either my 24-70mm or 70-200mm and it wasn't a camera shake.
My assumption is............
1.Camera struggles to lock focus for some reason
2.Camera locks focus but in camera NR is very aggressive thus the soft images

With the D750 pictures are less grainy but just as soft as it was with the other DX cameras.
Also picture not as red as with the DX cameras but still more red then it should be.
I shoot with AWB and I know I should change it to counter the red issue but the truth is that the red I can correct in post processing and even the gain isn't such a huge deal but the picture softness is killing my shots.
Here is an example

 

[goodguy]

Forgot to mention usually I shoot at f4 and above and I always focus on the eyes.

 

[Derrel]

EXIF sez 0.019999 second, which is 1/50 second...the shot to me looks a bit unsharp due to probably a bit of subject movement, maybe even a bit of camera movement...it just is not "sharp-sharp"...even though it appears to be well-focused...the color's weak nature almost goes with the territory of weak, indoor lighting and high ISO settings; as ISO values go upward, color richness drops wayyyyy down. This shot was done at ISO 6400, which is at a level where color richness is noticeably inferior to that at say, ISO 200.

It's difficult to say exactly what the issue is on this small an image; sometimes you can look at an image like this at full size, and see a faint ghosty-like outline around a mostly sharp subject, and you can determine that, for example, the camera was moving in one direction as the shutter fired. On this, I agree...I think there might be some noise reduction that has reduced detail, maybe even quite a bit; the weird area is the watch face and the man's left shirt sleeve where it has some creases: see how the hands on the watch are visible, and the crease looks sharp? That's how I can tell it is well focused...those areas were IN-FOCUS. But the detail that the shirt creases indicate is not uniformly shown across the image, so that makes me thinks noise reduction is a factor. As well as some kind of movement, since 1/50 second is a very marginal speed for people/events.

 

[goodguy]

EXIF sez 0.019999 second, which is 1/50 second...the shot to me looks a bit unsharp due to probably a bit of subject movement, maybe even a bit of camera movement...it just is not "sharp-sharp"...even though it appears to be well-focused...the color's weak nature almost goes with the territory of weak, indoor lighting and high ISO settings; as ISO values go upward, color richness drops wayyyyy down. This shot was done at ISO 6400, which is at a level where color richness is noticeably inferior to that at say, ISO 200.

It's difficult to say exactly what the issue is on this small an image; sometimes you can look at an image like this at full size, and see a faint ghosty-like outline around a mostly sharp subject, and you can determine that, for example, the camera was moving in one direction as the shutter fired. On this, I agree...I think there might be some noise reduction that has reduced detail, maybe even quite a bit; the weird area is the watch face and the man's left shirt sleeve where it has some creases: see how the hands on the watch are visible, and the crease looks sharp? That's how I can tell it is well focused...those areas were IN-FOCUS. But the detail that the shirt creases indicate is not uniformly shown across the image, so that makes me thinks noise reduction is a factor. As well as some kind of movement, since 1/50 second is a very marginal speed for people/events.

Thank you for the very valuable information, here is another shot, not very bad but not sharp, the really bad shots I deleted but I think it will help to show my case here
6400ISO
f2.8
1/100
55mm

 

[goodguy]

f3.5
4500ISO
1/50
145mm

 

[goodguy]

There is roughly same softness in all shots no matter shutter speed, aperture and ISO
I got MUCH better results when shot outside in dim lighting at 128000ISO, this issue always appear when I shoot indoors.

 

[KmH]

In each of your Nikon user manuals is a page that notes that in a variety of situations AF will have trouble focusing accurately.
In the D750 users manual it's on page 131.

In the last photo you posted of the 2 women the bright and dark areas would be 'sharply contrasting areas of brightness'.

The ISO setting has no affect on AF. The ISO setting only affects exposure.
AF is done with the lens as open as the lens can open, and with stills, AF is done before the shutter opens.

 

[bratkinson]

As Derrel stated above, slow shutter speeds frequently cause subject blurring, even in posed shots. My general rule for shots with living/breathing/moving subjects requires at least 1/160th to freeze humans, faster for automobiles, and really fast for airplanes.

I do a lot of indoor photography, hand held, no flash. I've learned from experience to use 1/160 and faster for human subjects. To compensate, aperture size must be increased (with corresponding reduction of DOF), and/or ISO speed increased (with increased noise). I still shoot as low as 1/10th, but the keeper rate is somewhere in the neighborhood of 1 in 25, maybe worse. At 1/60th, about 1 out of 3/4 are keepers. In short, it's learning tradeoffs of the exposure triangle and coming up with an 'acceptable compromise' (somebody on this site used that term 2+ years ago, and I've stolen it from him/her).

I've also learned to keep my camera in AI Servo (Canon) so it keeps tracking moving subjects once I've locked on. I don't know what Nikon calls it. When I figured that out, the switch from single shot to AI Servo improved my keeper rate significantly.

 

[goodguy]

As Derrel stated above, slow shutter speeds frequently cause subject blurring, even in posed shots. My general rule for shots with living/breathing/moving subjects requires at least 1/160th to freeze humans, faster for automobiles, and really fast for airplanes.

I do a lot of indoor photography, hand held, no flash. I've learned from experience to use 1/160 and faster for human subjects. To compensate, aperture size must be increased (with corresponding reduction of DOF), and/or ISO speed increased (with increased noise). I still shoot as low as 1/10th, but the keeper rate is somewhere in the neighborhood of 1 in 25, maybe worse. At 1/60th, about 1 out of 3/4 are keepers. In short, it's learning tradeoffs of the exposure triangle and coming up with an 'acceptable compromise' (somebody on this site used that term 2+ years ago, and I've stolen it from him/her).

I've also learned to keep my camera in AI Servo (Canon) so it keeps tracking moving subjects once I've locked on. I don't know what Nikon calls it. When I figured that out, the switch from single shot to AI Servo improved my keeper rate significantly.

Thank you for reply, I will try to bump up shutter speed next time, in good lighting I shoot as low as 1/30 on my 24-70mm and 1/60 (with VC ON) on my 70-200mm with sharp results.
I am not sure why it should be different in in door shooting but I will try your suggestion and see.
I always shoot AF-C with back focus button so I am with you on that one

 

[Derrel]

Indoor light and the light from the sun are very different. Molecular Expressions Science Optics and You Light and Color - Sources of Visible Light

 

[PaulWog]

The minimum shutter speed rule really is a "minimum", for a 50% or higher hit ratio with good hand-holding.

Your minimum shutter speed for a consistent 100% hit ratio with not-perfect hand-holding needs to be muuuuch higher.

Even 1/100 can get you shaky images. At 1/50, you'll definitely get lots of shaky images.