Photography 101 - The Purple Fringe· Page 2

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simonrl
51% (Neutral)
Administration

16 years ago

#21

"Vanoord" wrote:
What's interesting is that I've tried it with two 8400s and got broadly the same pattern: it would be interesting to see what the output from any other 8400s is (hint hint! 😉 )

I've got one serviceable 8400, two in bits and one on it's way from Australia!! When that arrives I'll give it and the other working one a quick test and upload the results.

But Vanoord's results with his two confirmed what I always suspected with the 8400 in respect of purple fringing. That it varies between individual cameras, whilst always appearing in the same place.

I shall dig out the most spectacularly awful purple (and yellow/green) fringed photo I every took with mine. If you've got Underground Reflections or downloaded one of the wallpapers it might surprise 😉

my orders are to sit here and watch the world go by

Vanoord
54.4% (Neutral)
Newbie Topic Starter

16 years ago

#22

"rjw" wrote:
Yes, as you surmise there Vanoord, the purple will be in the same position for each make/model of camera. Linky for Nikon D80;

http://www.fotocanada.ca/Articles/D50%20vs%20D80%20amp%20glow%20images/D80%20vs%20D50%20amp%20glow.html

Thank you indeed, rjw - for ten points, can you guess which camera I own other than the Nikon 8400? :lol:

Hello again darkness, my old friend...

simonrl
51% (Neutral)
Administration

16 years ago

#23

Straight off the camera:

🔗Personal-Album-1-Image-31353[linkphoto]Personal-Album-1-Image-31353[/linkphoto][/link]

And that was why this photo was converted to b/w!

🔗Moel-Fferna-Slate-Mine-28-08-2006-Image-011[linkphoto]Moel-Fferna-Slate-Mine-28-08-2006-Image-011[/linkphoto][/link]

Interesting (I suspected as much but wanted to check) the purple fringing on mine was always on the left hand side, whereas Vanoord's and redlion's is on the right. Odd.

my orders are to sit here and watch the world go by

Brakeman
50.2% (Neutral)
Newbie

16 years ago

#24

Out of interest what was the exposure time of this photo Simon?

[photo]Personal-Album-1-Image-31353[/photo]

The management thanks you for your co operation.

simonrl
51% (Neutral)
Administration

16 years ago

#25

2 minutes (just over, 126 seconds)...

Probably explains it!

my orders are to sit here and watch the world go by

Brakeman
50.2% (Neutral)
Newbie

16 years ago

#26

Hmm, It looks like I will have live with rather annoying anomoly & get used to reframing shots to crop out the purple as some of you have suggested.

The management thanks you for your co operation.

Brakeman
50.2% (Neutral)
Newbie

16 years ago

#27

I have been in touch with Nikon over this issue, their reply can be seen here.

http://nikoneurope-en.custhelp.com/app/answers/detail/a_id/1141/kw/dark%20current%20noise/r_id/127673

So not a fault as such but rather annoying just the same.

The article is shown as being for DSLR cameras, but the E series 8400 suffers the same fate according to nikon support.

The management thanks you for your co operation.

Morlock
50.2% (Neutral)
Newbie

16 years ago

#28

I wonder if this is the reason for the different sky colour in some recent lamp test pics?
Taken with a cheap Canon A40, same setting for both pics.
🔗Personal-Album-1695-Image-31667[linkphoto]Personal-Album-1695-Image-31667[/linkphoto][/link]
🔗Personal-Album-1695-Image-31668[linkphoto]Personal-Album-1695-Image-31668[/linkphoto][/link]

simonrl
51% (Neutral)
Administration

16 years ago

#29

I suspect the first shot is a standard Oldham and the second your Q5 conversion? :flowers:

Interesting though, the sky effect is what you get from light pollution like this:

[photo]Llechwedd-Slate-Mine-24-01-2007-Image-006[/photo]

But if you used the same settings and same shutter time on both those shots the sky should have been the same brightness.

Brakeman - thanks for posting that, I guess it also partly explains why it seems to vary from 8400 to 8400. Maybe some generate more heat?

my orders are to sit here and watch the world go by

Morlock
50.2% (Neutral)
Newbie

16 years ago

#30

"simonrl" wrote:
I suspect the first shot is a standard Oldham and the second your Q5 conversion? :flowers:

Interesting though, the sky effect is what you get from light pollution like this:
quote]

Your suspicions are correct. 🙂
The only other possibility is there is a large steelworks about 10 miles away which often lights up the horizon, normally to a much greater degree though.

McKenzie
50.2% (Neutral)
Newbie

16 years ago

#31

I think the problem you are encountering could well be chromatic aberration...there are some photography software programs that can help you remove this i.e Adobe photoshop....there is a lot of available information on chromatic aberration on the web !

Cheers
Steve

simonrl
51% (Neutral)
Administration

16 years ago

#32

I always assumed it was chromatic aberration, which sounds more painful than it actually is, but if there is any with the 6mm (24mm equivalent) lens in the Nikon 8400 it'll be eclipsed by the 'colour bloom' due to electrical component heating mentioned in Brakeman's link http://nikoneurope-en.custhelp.com/app/answers/detail/a_id/1141/kw/dark%20current%20noise/r_id/127673%3Cbr%20/%3E

Vanoord's tests with his 8400 on a long exposure were with the lens cap on.

I tried the same with my EOS on a 5 minute exposure (at which point I gave up) and it didn't show a hint of purple :angel:

my orders are to sit here and watch the world go by

Vanoord
54.4% (Neutral)
Newbie Topic Starter

16 years ago

#33

This one's another Nikon shot, the D80 this time:

🔗Personal-Album-2-Image-41540[linkphoto]Personal-Album-2-Image-41540[/linkphoto][/link]

Exposure time: 19 minutes, 27.7 seconds.

Purple fringing is pretty evident, but relatively localised.

Hello again darkness, my old friend...

Edd
50.2% (Neutral)
Newbie

16 years ago

#34

Not had any problem with the 5400 :tongue:

Also not noticed any problems on the D60 range either

This was a 2 min shot on the D60 at F9 and playing with a Speed Flash

'I started reading it with full intention to read it all and then got bored and went and got beer instead!'

Ben Cooper
50.2% (Neutral)
Newbie

16 years ago

#35

It looks a lot like thermal blooming from the circuit board behind the sensor - my old Minolta 7D used to suffer from this on long exposures. Basically the sensor didn't cope well with being turned on for long periods - it heated up, which caused exactly this effect on the images.

Absolutely nowt you can do about it, apart from try to alter the colours or crop to remove it...

http://www.transientplaces.co.uk

Nikki Scholes
50.2% (Neutral)
Newbie

16 years ago

#36

There is actually a solution to this, the purple corner effect is something called sensor glow or amplifier glow, I had issues with my D80 when doing long night exposures, its easily fixed by turning on noise reduction, D80's and D90's definitely have it, im pretty sure most good DSLR's will too somewhere in menu options. It means the camera takes some extra time to process the image but its worth it to get rid of those nice purple bits 🙂

mountainpenguin
50.2% (Neutral)
Newbie

16 years ago

#37

the noise reduction is (at least for cannons) available on the power shots as well. It is on by default for anything over (iirc) 15 seconds. It is done by taking a dark frame (shutter closed) exposure of the same length as the real exposure. As this is expected to be black anything that isnt can be subtracted from the equivalent pixel on the first image.
If your camera does do it you can take the a picture of the same length with the lens cap on and do the subtraction in software later. Obviously this works better if your shooting in raw.

martymarty
50.2% (Neutral)
Newbie

15 years ago

#38

I happened to buy brakeman's 8400 and had this problem yesterday when i got home and had a look at the pictures, and i thought he was having me over.. anyway after having read this i tried the noise reduction took two 30 sec exposures one with it off one with it on and now the problem is solved, i'll just have do all my pictures again :thumbsup:

nid oes bradwr yn y ty hwn

Barney
50.2% (Neutral)
Newbie

15 years ago

#39

Marty, if you have CS3 or 4 the fringing can be dealt with easily enough in order to save your photo's. A much cheaper option is Paintshop pro x2.