Nikon 28mm 1.8g Chromatic Aberration

hobodan

hobodan

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Dan
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hi folks, i would like the opinion of those of you experienced in using primes!

i recently purchased the Nikon 28mm 1.8g - whilst doing a few test shot i have noticed some Chromatic Aberration. now i know its unrealistic not to expect zero CA whilst shooting wide open, but i'm unsure if my new lens is showing to much & may possibly have issues?!

here is where i first noticed it with a shot of my son - you can clearly see it in his eyes (shot at f1.8)

http://www.flickr.com/photos/dan-jam/8077413287/in/photostream


so i tried to get a shot to see how i could highlight it at maximum and i took this lovely shot of my big clock!

http://www.flickr.com/photos/dan-jam/8077408806/in/photostream

so, am i being overly critical of my new prime? or is this to be expected shooting wide open in those conditions?

advice very much appreciated
 
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I have read about bad rearward focus shift of the 28G rather than a lot of CA. Are you replicating this on a regular basis and can you correct it easily? It's a lens I was looking at so I'd be interested to hear your views on it and see more sample pics.
 
Can't say for sure, and fast wide-angles like that are prone to a few quirks, but that just doesn't look quite right to me. If it was mine, I'd be wanting to try another sample, if only for peace of mind.
 
Well it is strange, if you look at this picture - you will see that on the writing on the top of this panel which reads (*** - Division of Andel Ltd), you can clearly see that to the left of the focus plane there is a green glow and to the right there is a red glow! this seems to be consistent in most shots that have bright contrast (why i originally thought it was chromatic aberration).
i'm sure i have heard this mentioned before about this lens but it does strike me as being very strong and definitely noticeable without pixel peeping.

i bought the lens from DigitalRev (hong kong based) so im not sure if i should return the lens to them and ask for another sample or send it to nikon?

would you agree that something is not right based on the picture below?

http://www.flickr.com/photos/dan-jam/8079609751/in/photostream




Apart from that everything else about the lens is great. lovely Bokeh, Sharp, Quick focus

Thanks all
 
Looks normal enough to me. At 1.8 I think all primes suffer a little, [I had the old 85mm 1.8D and it was a lot worse wide open than your examples] easily corrected in post. You're looking too close me thinks :) It's not obvious at all on the picture as a whole, only when you pixel peep.
 
hobodan said:
Well it is strange, if you look at this picture - you will see that on the writing on the top of this panel which reads (*** - Division of Andel Ltd), you can clearly see that to the left of the focus plane there is a green glow and to the right there is a red glow! this seems to be consistent in most shots that have bright contrast (why i originally thought it was chromatic aberration).
i'm sure i have heard this mentioned before about this lens but it does strike me as being very strong and definitely noticeable without pixel peeping.

i bought the lens from DigitalRev (hong kong based) so im not sure if i should return the lens to them and ask for another sample or send it to nikon?

would you agree that something is not right based on the picture below?

http://www.flickr.com/photos/dan-jam/8079609751/in/photostream




Apart from that everything else about the lens is great. lovely Bokeh, Sharp, Quick focus

Thanks all
Click to expand...

That's bokeh CA fringing. All fast lenses have a bit of it, and you can improve it in something like Lightroom, but that just looks too much to me.

I'd contact Digital Rv. They have a good rep on here ('Julia' I think posts on here?). Maybe link to this thread and pics and take their advice.

Let us know how you get on.
 
Well that's exactly what I'm trying to ascertain. I haven't used primes a whole lot really so I don't have the previous experience to judge!

You are right that it can be gotten rid of post processing ( although I can't seem to do it using aperture 3 , had to use Nikons View NX)

So yeah, if that is what I would have to except as using a prime then so be it, but if it is a genuine fault of the lens then obviously I would rather have a replacement.
 
Thanks hoppy - I'm just going to email Digitalrev in a second.

If I didn't try another sample I think it would always be on my mind that I may have a bad lens!

Cheers
 
I think what i'm seeing is Axial Chromatic aberration - this test on the 85 1.4 g has somewhat put my mind at ease a little. even this £1200 lens has pretty bad Axial CA wide open. Stoping down or using software is the only way to completely remove it from the image, i'm finding Aperture 3 not so great for removing CA - maybe i'm doing something wrong!

http://www.luminescentphoto.com/blog/2010/09/04/hands-on-with-the-85mm-f1-4-afs-g-nikkor/
 
I think you ar wright to complain. None of my Nikon lenses exhibit this even wide open
 
Your lens is absolutely normal!! Axial CA is common at wide apertures. Shoot in RAW and you can basically just switch it off in Lightroom.

Here's a test of your lens..

http://www.photozone.de/nikon_ff/751-nikkorafs2818ff?start=1

Seems consistent.

Shooting wide open is always going to reveal more CA and more softness in all lenses. If you want perfection at f1.8 forget it. I'm not sure it's CA in the eyes of the little boy. Can you post a link to a RAW file of these shots... or at least a full resolution image somewhere?

It looks pretty normal to me anyway. Seriously.. sending that back is a serious waste of time and money. All lenses will exhibit some CA wide open, especially axial CA in OOF contrast detail.


Your biggest issue with that lens at 1.8 is the vignetting actually... almost 2EV difference across the field. It's a damned sharp lens though, and by the time you reach f4 all that nonsense has gone, and perfection is yours. Shooting wide open is a compromise. Have you seen how bad the aberrations are in the 50 and 55mm 1.2 Nikkors? Coma and CA are atrocious!!... you buy that lens to shoot with fast speeds at lower ISOs in the dark though... not to win a lens test resolution chart competition :)

You have a great lens there.
 
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Thanks for your input pookey - it has reassured me a little.

And yes I wouldn't be shooting wide open in bright daylight often, I suppose I'm guilty of trying to find the imperfections of my new toy! If only to make sure I don't have a faulty one as £500 is certainly not a light purchase for me (especially as i'm only a "hobbyist")

What I first started noticing was reflective objects (metal) showing red fringing around the edges of the parts with intense light spots, that's is the same as the shot of my boy which is showing a reflection of a spotlight in his eye which also has the red glow. I don't think that can be Axial CA though as of that which is in the second shot of the panel, I'm guessing its another type of CA.

Thanks again
 
CA comes in many flavours. I call what you've shown boken CA fringing - out of focus areas picking up the tint which is different to axial CA, better known as purple fringing (in the boy's eyes). That's fairly normal. That clock shot doesn't look right to me though, no reason for that I can see.

Maybe it is normal. But it's not very good if it is.
 
I'd just correct it in LR4 / PS (effectively desaturating the offending colour) and move on. 85 f/1.2L has more blooming than that. If you get the subject in perfect focus and avoid blown highlights this would help to control the issue too.
 
Cagey75 who earlier said said:
Looks normal enough to me. At 1.8 I think all primes suffer a little, [I had the old 85mm 1.8D and it was a lot worse wide open than your examples] easily corrected in post. You're looking too close me thinks :) It's not obvious at all on the picture as a whole, only when you pixel peep.
Click to expand...

Is it 'cause I is Oirish???

:shrug::p:lol:
 
Just an update on this thread.

I did return the lens for a replacment, obviously there is still CA wide open - I have been trying to replicte my original shots to see if it has the same issues; I am satisfied that the issue isnt as prominent as it was in m first copy.

A quick word on DigitalRev - they have been fantastic, no issues on getting a replacement. They have kept me really well informed and posted the replacement lens the same day the old one arrived in Hong Kong.
My only complaint is with Royal mail; they qouted me £75 for 2 day garuenteed delivery or £20 for 4 day garuenteed delivery. I opted for the 4 day option but my parcel was delivered 9 days later.
 
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