Halo around background objects

My husband surprised me with a Nikon D7000 for my birthday yesterday. I'd been playing with his for the last few months, and developed quite an interest. Prior to that, I was a point and shoot/camera phone girl, so there is still ALOT I'm figuring out. I'm a bit beside myself with happiness, though .

I was playing with it in the yard today, and I have a question about something I'm finding in a few of my photos. I'm getting a 'halo' effect around background objects when I use larger apertures, and I'm not sure if it's something I'm doing wrong or a normal part of working with the depth of field.

This was shot handheld in RAW format using a 35mm 1.8G lens. Aperture is 4.5, shutter speed 800, ISO 1600. (Feel free to laugh at my high ISO, I was playing with it the night before and forgot to change it, haha. All part of the learning, I suppose.) I've not done any processing except to export it as a smaller jpeg for uploading. The halo I mention is particularly evident on the orange poppy just behind the main yellow one.

I did see this on other photos without that high ISO, just none of them as obvious as this. Any ideas what is causing this and what I can do to avoid it?

Thanks for the help!

Hi and welcome...I think it may be Chromatic Aberration..When you take images with a bright background this effect can happen...Try it from a different position with out the brightness behind...

At 4.5 you should be starting to get a little bokeh. Out of focus areas start to distort and create strange effects and the effect of shapes and lighted areas of the backhround becoming more blurred, And blended as the lens is opened farther with it being most pronounced at 1.8.
The bokeh of that particular lens is loved by some and hated by others, and not known to be as attractive as the 50mm.

Looks perfectly normal to me ...just small depth of field so background is out of focus...
Try using auto ISO set it 400-6400 and min shutter speed say 1/60 if you dont have VR ..work in P mode
If its a new camera the sharpness will be set soft ..go to menu and push it up to +9 and the contrast to -1
No need to use RAW the finest Jpeg with compression set to variable makes life a lot easier in Photoshop etc

Welcome to Nikonites,

The effect you see is called Bokeh and is very normal. Some expensive lenses produce softer Bokeh while some will look "jarred" a little. I guess you'll have to learn how to use it to your advantage.
If you reduce the size of print or view the print from a greater distance, this become less predominant.

Hope this helps.

There are a number of lenses that can produce Halos in bright contrasty conditions at wide open apratures.
However... I see no sign of this effect in this picture. Maybe it shows when enlarged more ?
The graininess is a consequence of using a wide aprature and high ISO. When shooting in RAW at such High ISO you need to Edit the pictures.
Mostly you need to use and apply Noise reduction. This will give the pic a far more pleasing effect and smoothe out the Bokeh.
Bokeh, is the name given to the out of focus areas of the picture.

This is with just a little noise reduction added !
View attachment 12085

Thank you all for the replies, it's very appreciated. I hadn't considered that the high ISO might be doing unpleasant things to the bokeh, and I do notice some difference in your edited photo. I'll have to play with the processing and work on softening that effect.

I think I'll also toss on the other lens and do some comparison shots to see if it's just a normal effect of our particular lens.

Pistnbroke, the camera was straight out of the box and I'm only about a fifth of the way through the manual. I didn't consider there may be settings to play with within the camera. Thanks for the heads up!

There's a touch of purple fringing on a couple of the edges, which is due to longitudinal chromatic aberration. Lots of very fast lenses exhibit this behaviour at wide apertures - my 85mm f/1.8 AF-D does it badly up to about f/4 especially with very high contrast boundaries. It's fairly easy to correct in post process, and becomes less noticeable in smaller image sizes.

You're gonna have to get used to the camera, and get it broke in good. !600 isn't too high an ISO for outdoors. A famous photographer (Jay Maisel) that does pictures for Time Magazine, some pics for National Geographic, and others, says that he shoots all the time at ISO 1600, day and night. Of course, I'm sure some pics need more post processing than others. Here's a pic I did at ISO 1600, f/4.5, that turned out ok............

I can see the halo you are talking about. It is, as gfinlayson stated, chromatic aberration. The issue you are asking about is not the bokeh that exists in the image, as others have stated, but the fringe of discoloration at the edges of the objects; particularly appaernt where there is high contrast. This flaw can not only develop due to camera settings or glass, but also in post-processing if you over sharpen or over saturate an image. You made it clear that you did not post process the image but check to see if your camera's Optimize Image setting is set to Vivd, More vivid, or Saturate.