Glowing Gull Help

[squ1d]

February 19, 2008 at 6:47 pm

Hi, just wondering if anyone can help me with this.
I took this picture today and when I downloaded it to my PC I noticed this glow.
I’ve cropped the image to get in close..
Here’s the exif data.

Tv(Shutter Speed)
1/2000Sec.
Av(Aperture Value)
F1.4
Metering Modes
Centerweighted average metering
Exposure Compensation
0
ISO Speed
100
Lens
EF50mm f/1.4 USM
Focal Length
50.0 mm
Image size
3888 x 2592
Image Quality
RAW
Flash
Off
White Balance
Auto
AF mode
One-Shot AF
Picture Style
Standard
Parameters
Tone Curve : Standard
Sharpness level : –
Pattern Sharpness : –
Contrast : 0
Sharpness : 3
Color saturation : 0
Color tone : 0
Highlight tone priority : No
Color matrix
–
Color Space
sRGB

Any ideas where I’m going wrong?

Thanks…

[DaveP]

February 19, 2008 at 8:28 pm

most probably chromatic abberation. Have a look at this link for a full explanation.

http://en.wikipedia.org/wiki/Chromatic_aberration

[Alan Rossiter]

February 19, 2008 at 8:35 pm

It may be out of focus. You’re shooting a moving object with One-shot AF at f1.4. F1.4 for a start will give a shallow DOF and the autofocus may have been activated at a shorter distance from you to the gull as it is moving away from you. Have a look at the glow in the foliage behind the gull – it’s further exaggerated so the glow on the gull may be the starting of an OOF image. Moving objects should, almost always, be taken in continuous auto focus.

But it could be CA too but I’d expect that at the edge of an image unless this is a particularly poor lens.

Alan

[squ1d]

February 19, 2008 at 9:17 pm

Thanks for the replies and suggestions..

The lens is a brand spanking new Canon EF50mm f/1.4 USM so I hope it’s me and not the lens.

Is there a way I can test the focus suggestion without going back tomorrow and asking the bird to do another flyby?

Thanks!

[randomway]

February 19, 2008 at 9:29 pm

1.4 and fast lenses are prone to show CA when used at bright daylight… they are designed for low-light use. You could try stopping down to f/4-f/8 to get more dof and all around sharpness, and maybe it would help keeping the CA away.. I’m not sure about the latter. Focusing a 1.4 lens can be tricky, so don’t worry, you will need a bit of a time to learn it.

[squ1d]

February 19, 2008 at 9:34 pm

Thanks randomway.. I think you’re right. I only got the Lens yesterday and today was my first day out with it so I’m pretty sure it’s my fault! :-)

[Pitmatic]

February 19, 2008 at 10:05 pm

I have a G3 thats prone to CA when fully wide at F2 but it only really shows where you have white to black transitions such as the bird and its background

I have also done this on a very cold morning and my own breath went over the lens but that was really cold! but its worth being aware of it :)

[Not Pete the bloke]

February 19, 2008 at 10:24 pm

It is Chromatic Abberation due to shooting wide open in bright conditions with your particular lens. For instance, have a look here where Ken Rockwell has used a similar lens at various apertures on a sunny day. Look at the photo taken at f1.4 – there is as much CA as in yours. (Dont pay too much heed to what KR says, just look at the example pictures).

Ross

http://www.kenrockwell.com/nikon/50-comparison/f-stops.htm

[squ1d]

February 21, 2008 at 12:40 pm

Thanks a million to everyone for your help and guidance on this.. Much appreciated..