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07-23-2007, 01:44 AM   #1
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Help!

I recently purchased a Tamron 70-300 di Ld lens.
I have been rather happy with it up to date. However, I took the shot added here and the clear purple outline around the subjects (sorry, I dont knowthe technical name) is quite disturbing.
Is this the lens at fault or am I doing something wrong.
I know, it's not the greatest photo but the problem is quite evident.
Thanks for any thoughts or advice


Last edited by Bramela; 10-06-2007 at 04:33 PM.
07-23-2007, 01:59 AM   #2
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Purple Fringeing - common problems with a lot of traditional lenses with particular lighting.

Ways to avoid it - Avoid harsh lighting especially with backlit projection of light; Use Raw format so rid of these fringeing better with PP software; use the lens in overcast weather or dim lit environment; Neutral density filters could be used

Most of FA lenses will have fringeing if you blow the photos to A3 size prints. Otherwise most shots would get by without people noticing ...

For me, I have seen one of the worst fringeing in Fa 135 f2.8 ...
07-23-2007, 02:36 AM   #3
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Thanks for that, Roentarre, I can agree with what you say, now that you explain it.
Actually it was in the middle of the day, when the light was harshest and with the reflection off the water, made it worse.
I usually, try to avoid too much photography at that timeof day. Got caught out in this instance.
So thanks again, will work it out from here, I think ( I hope?)
07-23-2007, 02:46 AM   #4
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You can try stopping down your lens (making the aperture smaller) to get rid of the purple fringing.

07-23-2007, 07:03 AM   #5
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A little PP

Hi Bramela,

I am looking for a lens in this range so I downloaded your photo and did a quick touch up to see if any of the PF is correctable, hope you don't mind. I used RAW Therapee which is a freebee on the net. All I did was push the "Blue-Yellow slider under "color shift" about a plus 11. What do you think?

Last edited by regken; 09-12-2007 at 08:06 PM.
07-23-2007, 08:52 AM   #6
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That's the achilles heel of the Tamron 70-300 unfortunately, which is counterbalanced by it's extreme sharpness.

If you use photoshop, gimp or paintshop, you might want to try this
Chromatic Aberration (purple fringing) removal script - Color Fringe Reducer 5.0 - Shay Stephens Photography
07-23-2007, 01:25 PM   #7
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Purple Fringing.

No I don't mind a bit Regken. I do agree the improvement is quite remarkable. As I said previously, it's not a great photo so well done, you given me something to dabble with.
Thanks for the advice I will checkout the PP sites that you and others have suggested.
Yes I will try the stopping down as well.
I welcome all suggestions (and criticisms) gladly.
Appreciate the imput from you fellow Pentaxians.
Thanks again
07-23-2007, 02:36 PM   #8
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The new, quite expensive, Pentax 12-24mm f/4 suffers from this as well. So much so that I purchased another one to test whether I had a bad copy ... I didn't. This said just to explain "I feel your pain". (I'm also bidding on the lens you have, will probably win given my bid, and now will probably not need it now that I secured a really fast long prime I didn't think I could find but that's another story ).

Anyway, getting to it. The photo posted is a bit on the overexposed side. You'll find that chromatic aberration, while if won't disappear, will reduce with a bit less exposure. At least it did with my lens that suffers this. Additionally, that's also just a function of the lens @ when zoomed/extended. See here, towards the end of this review:
Tamron AF 70-300mm f/4-5.6 LD Di macro (Pentax K) - Photozone Review / Test Report

07-23-2007, 04:39 PM   #9
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this usuallt occurs at hi contrast areas. depending on the software it's pretty easy to fix with a hue/saturation adj.
i adj. the magentas and then the blues in PS.
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