Lens gone soft? What would cause this?

[Walter Arnold]

Hey all,

I have a Nikon 50mm 1.4D and have used it for about 4 years now with no issues. Recently on an engagement photoshoot I noticed that everything that I took at 1.4 and 1.8 was super soft and had terrible glowing chromatic aberrations around highlight edges. Now I understand that wide open it is not going to be the sharpest setting however I have not seen this problem until recently. So I took two sets of test shots (link to zip file with JPGs here: https://www.dropbox.com/s/wfss6e3bun...Test%201-2.zip ) labeled the file names as to what Fstop I was using, and you can clearly see in each test that until I get over 2.2, the image quality is horrible and on the second set of shots you can see the horrible ghosting on the highlights of the chrome.

So my questions is, could there be an issue with the lens and if so what can be done? I want to know before I send it to nikon and they sit on it for a month...


Thanks for any input!

Walter Arnold
www.thedigitalmirage.com

[mrchile]

You'd be better off posting images directly here Walter. Sizing them for the web at about 800 pixels on the long side should do.
I could not get into your zip file, and I suspect others will not be able to either.

[mrchile]

OK, I actually was able to get the files.
I've always had that happen at 1.4 with the same lens.
Consider that the DOF is so shallow, that everything out of that plane is going to be out of focus and more or less diffuse depending on the light, especially if you are close to the subject.
To be blunt, I don't see anything I wouldn't have expected to see with this lens at those settings.

[Walter Arnold]

THanks MrChile! It's just strange because I've used it for so long and don't ever recall noticing these issues. Anyway, I guess I'm glad it's not broken, I just don't think I will ever shoot at anything less than 2.2 on this lens. I'd rather have a little iso noise than the softness and glowyness

[Skipper]

I'm not going to download anything and could not see the images by just clicking on the link. But I take your word for it that it's soft. I do think lenses 'go soft', it's happened to me. Hopefully yours can be repaired.* The other possibility is that it has lost calibration with your camera or maybe you are using it on a new camera. Lenses that are tack sharp on one body can be soft on another body. But, yes, wide open it's possibly softer. But..... you said you had great results for a few years with this until recently so I suspect something's going on.

*I have to say I'm pretty angry right now with Nikon repair. Just like you I had a lens that I got great results from, consistently, for a couple of years, a Nikon 24-120 f4. Super sharp. I used it all the time. Then it got really soft on me. I had a thread about this here I think earlier this year. It was so bad I couldn't use it. I sent to Nikon and I got an email invoice for about $350. I called and said 'What's the $350 for exactly and what's wrong with it.' I was told they did not know what was wrong with it but it would cost $350 just to open it up and have a look. I was told that I would be told upon completion of the repair what was wrong with it. If it would cost more I'd be informed and given the option of going ahead with repair. It was all very vague so I hemmed and hawed about approving the 'repair'. I approve it eventually. I got the lens back yesterday. The paperwork says only that the autofocus was adjusted. Period. No indication of what might have been wrong with it. Nothing. I doubt it was ever determined what was wrong with it. The autofocus was adjusted. That's it. For $355.54. What a rip off. A $355.54 adjustment.

So I'd think twice about going to Nikon repair if you decide to have it looked at. I heard of a great Nikon repair business not too long ago but can't think where it was -- if I find out I'll post.

[Walter Arnold]

I think I figured it out Chile... After hunting around a lot I ended up on DxOMark where they tested the lens, and the flat out said that the lens performs great on an APS-C sensor, but only so so on the Full Frame. The reason I never had this problem in the past is I was shooting the 50mm on a Nikon D300s and only recently upgraded to the D800. Who would have figured that a 2x more expensive camera would handle the lens much worse than the cheaper one? Mystery Solved! Here's their quote about the lens:

Nikkor AF 50mm f/1.4D
With its wide-maximum aperture, this lens shows very good light transmission, allowing it to reach its best DxOMark scores fully opened on a full-frame sensor. But this lens has very few advantages over the others on a full-frame body. The others, including the Nikkor 50mm f/1.8D have a better resolution. Moreover, this 1.4D shows pronounced distortion, vignetting, and chromatic aberrations. Just as with the 1.8D, the 1.4D’s sharpest aperture range starts at f/2.8. But even stopped down to f/5.6, the 1.4D’s edges remain much softer than the center.
Although just average on a full-frame sensor, the 50mm f/1.4D performs much better on an APS-C body, reaching a very good DxOMark Score of 18 at f/2.8 and providing very good definition. However, the Sigma 50mm F1.G DG EX HSM is still sharper on this kind of sensor.
In summary:
Average on full-frame, the Nikkor AF 50 mm f/1.4D performs much better on an APS-C body. But the Sigma remains better.

[Walter Arnold]

Thanks Skipper! We posted this at the exact same time lol. And you were right. it was the difference between one body and another. Never would have guessed... I have heard so much bad stuff about nikon. Even some of the big named pros have had major beefs with the repair folks... They also apparently dont want to ever repair any grey market stuff...