Colour Fringing

[WesGibbon]

I am looking for some suggestions from more experienced Alpha users:

I purchased an Alpha 900 in February, and am very pleased with it. I believe it is giving me sufficient resolution and quality for me to use it in place of my Mamiya 645 Pro outfit, which I am now finding a bit too heavy (age is catching up with me!).

I do have a problem with colour fringing on wide-angle lenses. More specifically, it seems to affect lenses which have the capability to go wider than 35mm. For example, the ‘classic’ 28-135mm and other wideangle zooms show what looks like magenta/cyan fringing at focal lengths at least up to 50mm, while my 35mm and 50mm primes show virtually none. However, the 20mm and 28mm primes do show the same amount of fringing. I have seen posts on this website suggesting that it can be easily removed, but I haven’t discovered how yet. Can anyone suggest the best way to remove it?

I should add that it is only really noticeable at the edges of large prints (particularly the corners) and of course with many subjects it is not really noticeable anyway, but I would like to get rid of it if I can.

My main interest is landscape photography, and my lens line-up looks as though it is going to be:
Minolta 20mm f2.8
Minolta 28mm f2.0
Minolta 35mm f2.0
Minolta 50mm RS f1.4
Minolta 75-300mm (big beercan)
Minolta 100mm f2,8 macro

I have only just acquired the 28mm, but I find that the 35mm and 50mm primes lenses are sharp. I will probably keep the 28-135 for when convenience is more important than ultimate quality.

Are there websites which describe Photoshop techniques which can be used, or is there software that will make a good job of removing fringing? All suggestions will be very much appreciated!

Wes Gibbon

[alphaomega]

I think it would help if you specified what image software you are currently using and/or have available. The obvious answer is Photoshop CS3 or 4 with Adobe Camera Raw but you may not have this and Elements is of no use as ACR will not display Cromatic Aberration removal in that package. If you need to acquire a new package then your budget would also help when it comes to making recommendations as PS is rather expensive if CA removal is your only requirement.

[alphaomega]

I forgot to add that is - in my opinion - a major omission by Sony that they issued IDC version 3 with the A900 and did not include CA reduction in their revised and upgraded RAW converter. I wonder what is in their minds. Perhaps they did not have the knowledge or thought that A900 users would have and use PS anyway.

[Wes Gibbon]

I think it would help if you specified what image software you are currently using and/or have available. The obvious answer is Photoshop CS3 or 4 with Adobe Camera Raw but you may not have this and Elements is of no use as ACR will not display Cromatic Aberration removal in that package. If you need to acquire a new package then your budget would also help when it comes to making recommendations as PS is rather expensive if CA removal is your only requirement.

Thank you for taking an interest, and for your quick response!

I have been using Sony IDC, which as you say does not include CA removal.

I have Photoshop CS3, but that does not include A900 compatibility in ACR. My understanding is that they don't have an update for CS3 for the A900 as they would like you to upgrade to CS4. Presumably there is a PNG converter which would work, but will that do the job?

[bakubo]

I have Photoshop CS3, but that does not include A900 compatibility in ACR. My understanding is that they don't have an update for CS3 for the A900 as they would like you to upgrade to CS4. Presumably there is a PNG converter which would work, but will that do the job?

Check to see if there is a later version of ACR. I know that ACR 5.4 works with PSE 6 so I bet it does for PS CS3 also.

[David Kilpatrick]

You need to download the DNG Converter version 5.x - preferably the latest one - and run that on the raw files, creating new .DNG versions in bulk.

Your old CS3 ACR will then read them properly, and what's more, do a very good job with noise compared to direct ACR processing. It may seem a little clumsy, but the .DNG converter is free, and it converts your files into an open-raw format which an increasing number of applications can read.

David

[bakubo]

I just checked. 5.4 is okay for PSE 6 and 7, but only PS CS4.

http://www.adobe.com/support/downloads/ ... ftpID=4524

"The Camera Raw 5.4 plug-in is not compatible with versions of Photoshop earlier than Photoshop CS4, versions of Photoshop Elements earlier than Photoshop Elements 6.0, or versions of Premiere Elements earlier than 4.0."

[alphaomega]

If you go to http://www.adobe.com/support/downloads/ ... ftpID=4038
you can download ACR you can download Adobe DNG Converter and Camera Raw 4.6 update
This is the latest ACR usable with CS3 and includes A900 support.
On http://www.adobe.com/support/downloads/ ... rm=Windows
you can also pick ACR 4.6 without DNG support. There is a complete instruction as well about how to replace your current ACR with update 4.6.
That should resolve all your fringing problems.

[David Kilpatrick]

Are you sure 4.6 includes A900 support? I guess the A900 is nearly a year old now. It just doesn't seem that old! I think we got CS4 around Dec 2008 so CS3 probably did include the A900 in the very last revision. I am a bit confused by the sheer speed with which Sony roll out new cameras.

If anyone would like a near-mint A380 kit with 18-55mm SAM, I guess I have no further need for the kit I bought to test (though I like it in many ways) and I'll sell it for £100 less than the lowest current UK-warranty price. I now have to acquire yet another Alpha... and I know that will not be the last.

David

[Wes Gibbon]

Thank you for all your help.

I m currently downloading the DNG converter.

On http://www.adobe.com/support/downloads/ ... rm=Windows
you can also pick ACR 4.6 without DNG support. There is a complete instruction as well about how to replace your current ACR with update 4.6.
That should resolve all your fringing problems.

I will look into ACR 4.6 tomorrow.

[alphaomega]

Ref David K's comment above, the Adobe site lists A900 as supported by ACR 4.6

I forgot to mention that there is also the option of removing CA in the CS3 Lens Correction Filter but that solution is less satisfactory than the ACR route.

[Wes Gibbon]

Ref David K's comment above, the Adobe site lists A900 as supported by ACR 4.6

I forgot to mention that there is also the option of removing CA in the CS3 Lens Correction Filter but that solution is less satisfactory than the ACR route.

Thanks for the suggestion. I'll have look at that method too, though having shelled out many spondulicks on an A900 & some quality glass, an inferior method may not make sense for my best work. Still if it is quicker, there is always a place for a 'quick and dirty' solution that saves time in an emergency.

[David Kilpatrick]

If your quality glass is CZ, DxO Optics Pro will offer you automatic CA, vignetting, and geometry correction with the A900 from raw - along with a much better conversion for high ISO.

David

[Wes Gibbon]

If your quality glass is CZ, DxO Optics Pro will offer you automatic CA, vignetting, and geometry correction with the A900 from raw - along with a much better conversion for high ISO.

David

The ‘quality glass’ is all Minolta: 28mm f2.0, (and a not quite so quality 20mm f2., and also a 28-135mm which I sometimes use for convenience in place of prime lenses, (not quite as good, but I'm still reasonably pleased with it, at least in the 28-70 range) so no CZ glass.

I also carry 35mm f2.0, 50mm RS f1.4, 100mm f2.8 macro and a big beercan (75-300), but they show minimal or no fringing. Still, even minimal fringing is worth getting rid of it it can be done easily.

n.b. looking at the preview, a smiley appeared from nowhere! It should read f2.zero.

[David Kilpatrick]

Yes, the point 8 .8 smiley is annoying!

Looks like you, like me, have a load of glass which DxO does not cover. Forced to use other methods...

David