Why the noise??

[smd]

I don't understand why there is such a difference in the amount of noise in two photos taken right after each other with the same settings. Zoomed out, the photo looks fine but when you zoom in it looks so flat and noisy. The next photo is in focus and less noisy. Can anyone explain why?

 

[dcbear78]

Missed focus ever so slightly on the first one.

edit: On the bright side you got lovely focus on that leaf

What focusing technique and settings did you use?

 

[smd]

I just set the focus point and use back button focus

85mm
ISO 200
f2.0
1/400sec

 

[dcbear78]

Continuous focus? Af-c or whatever Canon call theirs?

 

[smd]

AF-S

 

[Derrel]

First shot is out of focus, and from far away; second image is in-focus, and shot with the kid larger in the frame. When both images are scaled to have the same head size, the OOF, far-away frame shows more noise because it is 1) under-exposed and 2) shot from farther away and 3) lacks much real detail, so the noise seems to come to the forefront. The second shot is better exposed, and well-focused and so actual scene/subject detail comes to the forefront.

 

[dcbear78]

Try changing it to AF-C. That way the camera will continually adjust focus (while holding the back focus button) in case either you or your subject moves. Ever want to focus and recompose? Then just let go of the focus button. Back button focus like this gives the best of both worlds. Since I changed my technique to this I guess I have about a 90% keeper rate, if not higher. Last weekend I took 400 odd photos at a wedding ceremony and discarded 2 that were out of focus.

 

[KmH]

Yep.
Under exposure makes image noise more visible. The boy in the long shot is under exposed.
What metering mode did you use?
Also, some fill light from a reflector or a lower than full power pop of flash would have solved both the exposure and the 'flat' issue.

As far as the focus, you used a fairly large lens aperture for the long shot. Notice the branch of leaves hanging down are more sharply in focus than the boy is. So tell us what focus area mode the camera was set to.

 

[robbins.photo]

Ok, so as others have mentioned focusing and exposure issues are probably both at fault here. For portraits I prefer to set the camera's AF system to a single focus point, and then put that focus point on the subjects eyes. If you let the camera choose the focus point from a set of 9, or 11, or whatever it will choose the highest contrast point in that set which can lead to unexpected results.

For metering on portraits I prefer center weighted average myself, though in certain lighting situations spot can also be very useful. I don't normally recommend matrix metering for portraits but YMMV.

 

[smd]

Yep.
Under exposure makes image noise more visible. The boy in the long shot is under exposed.
What metering mode did you use?
Also, some fill light from a reflector or a lower than full power pop of flash would have solved both the exposure and the 'flat' issue.

As far as the focus, you used a fairly large lens aperture for the long shot. Notice the branch of leaves hanging down are more sharply in focus than the boy is. So tell us what focus area mode the camera was set to.

I was using spot metering and to be honest I wasn't paying any attention to the focus area mode. What would you suggest I use?

 

[ronlane]

Yep.
Under exposure makes image noise more visible. The boy in the long shot is under exposed.
What metering mode did you use?
Also, some fill light from a reflector or a lower than full power pop of flash would have solved both the exposure and the 'flat' issue.

As far as the focus, you used a fairly large lens aperture for the long shot. Notice the branch of leaves hanging down are more sharply in focus than the boy is. So tell us what focus area mode the camera was set to.

I was using spot metering and to be honest I wasn't paying any attention to the focus area mode. What would you suggest I use?

For a portrait like this I would use the smallest spot focus you have in camera and focus on the eye.

 

[Alexr25]

Spot metering can be very accurate BUT you have to know what you are doing to get good results. The camera always assumes that the area you are metering is a mid tone, if in fact you are metering on light fabric or very light skin tones then you have to dial in some +ve exposure compensation to compensate for the fact, if on the over hand you are metering a dark area then you need -ve exposure compensation to get the proper exposure. I suspect that in the first photo you metered from the boy's shirt or the very light skin tones of his face and that caused the camera to under expose and increase the noise.

 

[Dave442]

I only use Spot Metering in M exposure mode, especially as I am probably taking exposure from one area and focusing on something else.