PDA

View Full Version : Glare on Pics



Icey
07-01-2012, 4:15pm
Hi All,

Should be obvious that I am new here,

I'm playing around with bulb mode and night shots and I seem to get a glare type effect.

http://i43.tinypic.com/hsjm93.jpg

Any ideas on how to reduce it or remove it all together?

If i knew the correct name for it I would just search...

Cheers

Wayne
07-01-2012, 4:17pm
Lens flare is what you have here. By design some lenses flare more than others, and some virtually not at all. Try to position the camera at a slightly different angle, and make sure the front & rear elements are clean.

nardes
07-01-2012, 4:26pm
The flare may also be the result of a user fitted filter, such as a UV filter, screwed on the front of the lens.

If you do have a filter on the lens, take it off and take the shot again to see if the flare reduces/remains.

Cheers

Dennis

jimbob12
07-01-2012, 7:10pm
if you slow down the shutter speed just a fraction it wont be so obvious

Mark L
07-01-2012, 10:35pm
You need to change the copyright year in you camera Ben. :D That won't help the lens flare though.
Welcome to AP.:th3:

FallingHorse
07-01-2012, 11:47pm
if you slow down the shutter speed just a fraction it wont be so obvious
The image was shot in Bulb for 142 seconds. Should it be even longer :eek: :confused013

William W
08-01-2012, 6:06am
Were you using a Canon Kit Zoom lens at FL = 18mm?

As well as other elements mentioned (i.e. remove filter; cleaning lens and lens angle to the lights), you will, in most shooting scenarios, lessen the likelihood of that blue/purple flare you have circled, if you use a smaller aperture (about F/9~F/11 would be a good start) and also use that particular lens at about FL = 24mm(**1).

Generalizations:
In most cases a Prime Lens will be less likely to make that Flare.
In most cases a Longer Lens will be less likely to make that Flare.

If it is the purple/blue Flare which concerns you, it is not that much considering the apparent shooting scenario - it might be best to consider that Post Production should be used, to remove it.


WW


Foot note:


(**1): If it is the Kit Zoom lens you have then (from my memory for all the variants of the EF-S18 to 55) as you zoom, the lens will extend and retract.
If this is so, then if you use the lens at the FL when the zoom is retracted the most (the shortest physical total length) then this will lessen the likelihood of this flare.
I think this Focal Length is about 24mm, when the kit Lens is at its shortest physical length.

William W
08-01-2012, 6:07am
if you slow down the shutter speed just a fraction it wont be so obvious



Why?

WW

Kym
08-01-2012, 9:00am
Shutter speed is fine. It's all about the lens and possibly a useless UV filter (if there).
I'd close down the aperture for this as an alternate attempt. Leave the SS the same.

Your EXIF...

Camera Model: Canon EOS REBEL T2i
Focal Length: 18.0mm
Aperture: f/5.6 <<< try f/11 or f/16
Exposure Time: 142.000 s
ISO equiv: 100
Exposure Bias: none
Metering Mode: Matrix
Exposure Mode: Manual
White Balance: Auto
Flash Fired: No (enforced)
Color Space: sRGB

jimbob12
08-01-2012, 9:31am
ooops :o i meant make the shutter speed shorter not longer :D i find that if i leave the shutter open too long i get a lot of the flare but if i shorten the time its not as bad
sooooorry for confusing you :D

William W
08-01-2012, 10:22am
. . .i meant make the shutter speed shorter not longer . . . i find that if i leave the shutter open too long i get a lot of the flare but if i shorten the time its not as bad . . .

Thanks for answering my question.
That's an interesting result.

What lens(es)? What Camera(s)?

I would expect that reducing the Shutter Speed (and increasing the ISO to accommodate the same exposure), would result in the same amount of Flare for any one aperture setting and any one scene.

However, I would expect that reducing the Shutter Speed and making no adjustment to the ISO or the Aperture would reduce the overall exposure and the Flare would in this case appear less: but the exposure would be less overall, too.

And, I'd expect that reducing the Shutter Speed and opening the Aperture would in most circumstances make the lens prone to more flare, because of the wider aperture.


I was hoping that you had some definitive A/B tests following the lines of Long Exposure Reciprocity for Digital Sensors / Sensor Over-Excitement or a similar possibility.


WW

jimbob12
09-01-2012, 3:22pm
lol sorry no tests available :)
i just find it doesnt matter for night shots to be a bit underexposed as then the sky is darker and you dont get the city lights glow as much. and in pp you can up whatever highlights you want brighter..