CA on 50d

amtaylor

amtaylor

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Andy
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I have an 85 1.2 and on my 50d has quite noticeable CA but on the 5d it doesn't seem much even wide open. I suppose due to the denser mp count in the crop it would be a bit more but it does seem a little more than I would expect. Any thoughts
 
Checking my 5D and 20D with Siggy 50+85mm f1.4's I found the same thing. It looks like there's less CA with the 5D but having said that it's difficult to get the images to look exactly the same to do an exact comparison.
 
The sensor doesn't create any CA, that's all from the lens.

The 50d might just show it up a little more than the 5d. Possibly due to a less forgiving sensor on the 50d.
 
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I think it's just with it being such an extreme lens in every way. I've sold my 85mm 1.2 now, but it did suffer from CA on highlights. The 50mm 1.2 I still have suffers from it too sometimes but it makes up for it in other ways.

Have you tried using the CA correction in Canon DPP?
 
It's just irritating because I want to use it on the 5d but my 35 stays on that for the time being until I can get another ff body and the shots just look so much better on the 5d and I'm a bit of a perfectionist
 
Do the time honoured pro thing and convert to B&W. ;)
 
CT said:
I think it's just with it being such an extreme lens in every way. I've sold my 85mm 1.2 now, but it did suffer from CA on highlights. The 50mm 1.2 I still have suffers from it too sometimes but it makes up for it in other ways.

Have you tried using the CA correction in Canon DPP?
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I tend to use lightroom as despite what people say it produces a much more detailed cleaner image than dpp. Maybe earlier versions didn't but swapping between programmes is kind of irritating especially when tweaking raw files.
 
CT said:
Do the time honoured pro thing and convert to B&W. ;)
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Its not that bad its just that I know its there and I'm not getting as good an image as on the 5d. But then I knew that was going to happen across the board so I shouldn't be surprised really.
 
Have you had it cutting one edge off round specular highlights yet?
 
The lens throws such a large image circle into the camera that the circle fouls the mirror box - at the bottom I think ,and produces that strange effect. It lessens a lot as you stop down. You should find some examples of it on the web. As I say, it's a very extreme bit of kit! :D
 
I think it's more noticeable on the 50D because the image is effectively enlarged 1.6x, so the CA fringes will be shown 1.6x wider.

Don't the lens corrections in Lightroom get rid of it? If not automatically, using the manual sliders?

Just on this, I think the lens corrections suite in DPP is better than Lightroom's, so I'm thinking of doing the Raw conversion and lens corrections in DPP and then exporting/importing into Lightroom. As a TIFF? Has anyone done this, got any views?

CT said:
Have you had it cutting one edge off round specular highlights yet?
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LOL :)
 
HoppyUK said:
I think it's more noticeable on the 50D because the image is effectively enlarged 1.6x, so the CA fringes will be shown 1.6x wider.

Don't the lens corrections in Lightroom get rid of it? If not automatically, using the manual sliders?

Just on this, I think the lens corrections suite in DPP is better than Lightroom's, so I'm thinking of doing the Raw conversion and lens corrections in DPP and then exporting/importing into Lightroom. As a TIFF? Has anyone done this, got any views?

LOL :)
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Lightroom doesn't sort the CA and even with messing with the manual sliders doesn't get rid of it all. The only problem with the tiff idea is surely you wont have the same degree of play as you would have with a raw and you can duo an awful lot more in lightroom. I wish Adobe would release a better CA removal update
 
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I'd suggest trying DxO instead of lightroom. My Sony 50/1.4 has horrible CA when wide open, but DxO automatically fixes it every time.
 
amtaylor said:
Lightroom doesn't sort the CA and even with messing with the manual sliders doesn't get rid of it all. The only problem with the tiff idea is surely you wont have the same degree of play as you would have with a raw and you can duo an awful lot more in lightroom. I wish Adobe would release a better CA removal update
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It's already been suggested but DPP should eliminate them entirely anyway?

End of problem!
 
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According to Ken Rockwell the 85mm 1.2L doesn't suffer from CA at all unless you've missed focus! :lol:
 
CT said:
According to Ken Rockwell the 85mm 1.2L doesn't suffer from CA at all unless you've missed focus! :lol:
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Not so and anyway what about the CA in areas that are out of focus. I cant get the lens correction in dpp to do anything at all. It says it is but doesn't make a blind bit of difference
 
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LOL I know, but Rockwell is always good for a laugh.
 
amtaylor said:
Not so and anyway what about the CA in areas that are out of focus. I cant get the lens correction in dpp to do anything at all. It says it is but doesn't make a blind bit of difference
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Strange it should do. Does it recognise the lens from the exif? If not try downloading an update.
 
odd jim said:
The sensor doesn't create any CA, that's all from the lens.

The 50d might just show it up a little more than the 5d. Possibly due to a less forgiving sensor on the 50d.
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I don't think that is strictly true for digital sensors, as the microlenses above the photosites play a role. Probably doesn't contribute in this case though, as it is quite a long lens.
 
odd jim said:
Strange it should do. Does it recognise the lens from the exif? If not try downloading an update.
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It does recognise it. If I tick the colour blur box it does remove some but not all. Defringe in lightroom seems better but requires messing about to get it right
 
Technically it is not CA but purple fringing which is why DPP or lightroom can't properly get rid of it. CA are the cyan-magenta / yellow-blue distortions and can be cured very easily.

Fringing is much harder to eliminate, but you can always stop down slightly, avoid very bright highlights and get it all in perfect focus. Failing that you could replace the offending colour in photoshop.
 
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