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Why so grainy?
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Apr 3, 2016 18:24:34   #
Franku Loc: Wallingford, PA and Parrish, Fl
 
I have been playing with self-portraits and most, if not all, of my pix have looked great in the viewer but very grainy when magnified. I am certain that UHH will provide some good analytical advice. I used a Nikon 7100 with a Nikon Nikkor 18 - 300 lens. I did not use Photoshop at all.
I believe all of the other info is indicated in the download. If not, let me know and i will try to provide.
Thanks in advance for your help.


(Download)


(Download)


(Download)

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Apr 3, 2016 18:33:36   #
rook2c4 Loc: Philadelphia, PA USA
 
The ISO 1600 setting possibly.

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Apr 3, 2016 18:45:28   #
big-guy Loc: Peterborough Ontario Canada
 
Agree with the ISO setting but also the use of f22 makes for an over all soft shot. If you're doing a portrait then why would you want absolutely everything in focus? Use an aperture of f2 to f5.6 to keep only the subject in focus and let the background blur. Unless you are photographing a rustic old sea cap'n then choose as low an ISO as you can, preferably 100. Your shot is under exposed as well which doesn't help your cause.

OK, there are three strikes against you but on the bright side you don't have a multi million dollar contract that says you're not allowed to strike out. You do have the option of either redoing the portrait or making the corrections on any following portraits.

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Apr 3, 2016 18:50:41   #
Franku Loc: Wallingford, PA and Parrish, Fl
 
Hey Big Guy,
That's an excellent analysis. i will take your advice and give another try.
Thanks loads.
Franku

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Apr 3, 2016 18:55:34   #
PAR4DCR Loc: A Sunny Place
 
I think that Peter has given you some good advice Frank. Try to keep that ISO as low as possible.

Don

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Apr 3, 2016 18:56:36   #
big-guy Loc: Peterborough Ontario Canada
 
Your welcome.

Franku wrote:
Hey Big Guy,
That's an excellent analysis. i will take your advice and give another try.
Thanks loads.
Franku

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Apr 3, 2016 18:57:33   #
Apaflo Loc: Anchorage, Alaska
 
Franku wrote:
I have been playing with self-portraits and most, if not all, of my pix have looked great in the viewer but very grainy when magnified. I am certain that UHH will provide some good analytical advice. I used a Nikon 7100 with a Nikon Nikkor 18 - 300 lens. I did not use Photoshop at all.
I believe all of the other info is indicated in the download. If not, let me know and i will try to provide.
Thanks in advance for your help.

You are shooting at ISO 1600, but underexposing significantly. Exif data says it was shot in Manual Exposure mode, with a shutter speed of 1/160 and an aperture of f/22.

For essentially noise free images with a D7100, ISO 1600 is the highest you'd want to go, and ISO 800 is much better. But in either case you have to nail the exposure too! Shooting at f/11 would have been okay, but ISO 800 and f/8 even better.

Regardless of that, the processing is not helping at all. I can't tell if you shot that in RAW and processed it, or shot it in JPEG and processed that. In any case the saturation is too high, the brightness is too low, and the contrast is too low. It looks vastly better using a curves tool to remap the tones to have more of them in the higher levels to bring up the brightness of the shirt and the face.

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Apr 3, 2016 19:12:45   #
ggttc Loc: TN
 
Apaflo wrote:
You are shooting at ISO 1600, but underexposing significantly. Exif data says it was shot in Manual Exposure mode, with a shutter speed of 1/160 and an aperture of f/22.

For essentially noise free images with a D7100, ISO 1600 is the highest you'd want to go, and ISO 800 is much better. But in either case you have to nail the exposure too! Shooting at f/11 would have been okay, but ISO 800 and f/8 even better.


I agree...and I shoot a d7100...the exposure is off...and to be honest it almost seems like the focus is soft...the camera will do well at high ISO but I wouldnt bet my life on it. Nothing adds grain like soft focus IMHO.

Its a great camera...keep on shooting and good luck.

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Apr 3, 2016 19:20:20   #
Franku Loc: Wallingford, PA and Parrish, Fl
 
THANK YOU, THANK YOU, THANK YOU ALL!!!

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Apr 3, 2016 19:23:17   #
Franku Loc: Wallingford, PA and Parrish, Fl
 
You guys really made my day and i thank you all.

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Apr 4, 2016 03:06:51   #
R.G. Loc: Scotland
 
The problems with #1 are obvious and have been well commented on. In addition I would add that since they are self-portraits, the camera must have been on a tripod or some such, so to use a lower ISO you could have used a slower shutter speed. Nothing in the frame seems to have been moving, so a slower shutter speed should have been OK.

If you're including #2 and #3 as examples of the graininess that you mention, I think the trouble is that the subject is distant and therefore small within the frame. If you zoom in close on any image you'll see more of the graininess and rough edges. Since you're not under any time pressure with shots like this you could take the time to frame it close to how you want the eventual framing to be.

And if it's that way already, remind yourself that it's normal viewing distance that matters, not what you see when you zoom in close. The fact that the subject is so distant will be encouraging you to zoom in much more than NVD would require.

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Apr 4, 2016 05:33:49   #
lamiaceae Loc: San Luis Obispo County, CA
 
R.G. wrote:
The problems with #1 are obvious and have been well commented on. In addition I would add that since they are self-portraits, the camera must have been on a tripod or some such, so to use a lower ISO you could have used a slower shutter speed. Nothing in the frame seems to have been moving, so a slower shutter speed should have been OK.

If you're including #2 and #3 as examples of the graininess that you mention, I think the trouble is that the subject is distant and therefore small within the frame. If you zoom in close on any image you'll see more of the graininess and rough edges. Since you're not under any time pressure with shots like this you could take the time to frame it close to how you want the eventual framing to be.

And if it's that way already, remind yourself that it's normal viewing distance that matters, not what you see when you zoom in close. The fact that the subject is so distant will be encouraging you to zoom in much more than NVD would require.
The problems with #1 are obvious and have been wel... (show quote)


#1 is obviously under exposed and therefore noisy (grainy). I don't see a lot of noise in the other two unless I pixel peek and even at that those are not all that bad to me. Though I might actually expect more resolution from that model camera.

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Apr 4, 2016 08:32:47   #
Apaflo Loc: Anchorage, Alaska
 
Most of the replies were written before the 2nd and 3rd images where there. They provide some very interesting comparisons. Number 2 is the original full size, number 3 is cropped from 2.

So the real comparison is 1 and 3.

Shutter Aperture ISO Focal Length
------- -------- ---- ------------
Image 1: 1/160 f/22 1600 65mm
Image 3: 1/30 f/4 100 28mm
Difference: +2 +4 -4

The exposure is increased by 6 fstops, and the ISO sensitivity reduced by 4. Hence there is a 2 fstop increase in brightness. That is probably just a little too much! But the difference between over exposing slightly at ISO 100 and under exposing significantly at ISO 1600 is very obvious in the amount of noise. While the first image did not take well to being cropped, with the second image cropping is not so much of a problem.

But the real trick to all of this is not to memorize this as a set of facts that one tries to repeat, and instead it is an example to help learn why each component worked towards the end result. Being able to look at a scene, measure the light, and decide what mix of the various parameters will produce whatever result is desired.

For example, the first image had the advantage of requiring less cropping, and thus getting more pixels on the subject, due to the longer focal length used. Given the lens available, perhaps instead of a 65mm focal length it would have been better to use 130mm or even 200mm. That would provide much higher resolution and lower noise.

Another difference that might be useful would be more Depth of Field in the third image (purely a matter of taste). To do that stopping down to at least f/11 would be better. Along the same lines, the shutter speed of 1/30 of a second works fine for, ahem, elderly gentlemen but if this were the grandkids it might not be fast enough. So the 1/160 of image 1 might not even be fast enough. What it comes down to is realizing that ISO 1600 is in fact usable, but only if the image is not under exposed!

The extra 2 fstops of exposure provided for image 2 is not critical at ISO 100 where the dynamic range of the camera is greater than that of a print by 2 or even 3 fstops. At ISO 1600 the D7100 has a useful dynamic range of about 6.85 fstops, which is probably just about exactly the same as print, and that makes precise exposure very critical.

Using ISO 100 is fine for this particular shot, and the 2 fstops of slop for for expose makes it easy. For other cases with the same light but needing different results... using ISO 1600 may be necessary!

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Apr 4, 2016 08:34:38   #
camerapapi Loc: Miami, Fl.
 
I hope that you understand some basic principles of why pictures show noise. I will make some comments on this.
In the first place, underexposure will show noise. A high ISO setting in general will show noise. When the sensor gets hot and it will, noise will show in the pictures.
In good light nobody needs to shoot at ISO 1600 although at times and under certain circumstances such high ISO is needed. f22 is not a good choice for individual portraits and shooting a group with the subjects spread apart f11 is usually more than enough. Most portraits are shot between f8 and f5.6.
There is a simple remedy to make sure your exposure is right on and it is looking at the histogram after a shot. If there are no clips at the borders of the histogram the exposure is fine meaning there is no under or over exposure. Clipping the left side (shadows) is always more acceptable than clipping the right border where the highlights are.
Your first shot is underexposed and obviously shows noise the others are fine to my eyes.
There are excellent noise reduction softwares available and Nik happens to have one that is free. Download it because having a noise reduction software should be part of your workflow.

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Apr 4, 2016 08:41:51   #
kubota king Loc: NW , Pa.
 
Another reason your photos look better when viewing them with your camera is because the photo size is a lot smaller and that hides a lot of things you can see when you look at them on your much larger monitor . Tommy

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