Nikon 50mm f/1.4G blurry quality at large apertures: Is this normal?

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Nikon 50mm f/1.4G blurry quality at large apertures: Is this normal?

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chris_weinert

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Hello everyone,

I'm new here, which is because I just switched from Canon 5D Mark II to a D800. I've been reading forums and reviews for weeks now and I know that in this forum alone there's 127 threads on the topic, but I still open a new one, hope that's ok.

I'm currently trying to find lenses that are good enough for the camera, and I'm into getting just a few lenses that are then really good and practical (not really expensive), my targeted setup is the same that I had with the 5D: a Nikkor 17-35 (or 16-35, still not decided), the 85mm 1.8G (bought and kept it) and of course a 50mm/1.4.

I'm currently going through that typical "figuring-out-the-new-equipment" phase, I had the same thing with the 5DII when it was new, I was ranting at the **** quality of some lenses (used a D700 before the Canon a couple times), only to find out later that it was better then it looked on my test chart shots.

Test charts? Yeah, I too do hate shooting those, but it's just the first thing I always do when a new lens arrives: use the Focus Test Chart from http://www.focustestchart.com to check the lens for AF-adjustment, and make sure the focus offset is curable with AF fine adjustment.

Now, to finally get to the point:

I've just tested my 4th copy of the 50mm 1.4G, and am *really* confused: I did now get this focus shift issue sort of under control by fine-tuning AF to be correct at f/2.8. But still what I don't get is how everyone is raving over this lens to be super sharp also at the larger apertures. At 1.4, it's super-blurry, and this goes for all four copies I've tested now. It starts to get acceptable from f/2.8 on, but to me, that's not the idea of a f/1.4 Lens. I'd more expect it to be at least ok at f/1.4 and then good at f/2.8 and pristine at f/5.6 to 8. (The 85mm f/1.8G delivers pretty much exactly that.) All four copies were definitely not like that, and yes they were from different manufacturing batches, which was clear from the different generations of packaging and S/N.

So no, test charts results are no way what makes a lens worth using, but still, I'm just extremely confused over the blurry quality of the 50/1.4 G lens copies compared to what people say about it. Here's my 85mm f/1.8G at 1.8 vs. the 50mm f/1.4 G at 1.8, both from a 100% crop from the area indicated with the red rectangle (both crops are very congruent with the sharpness in the exact center).

50mm f/1.4G @ 1.8:

85mm f/1.8G @ f/1.8:

Just to make sure, the 50mm @ f/8 is perfectly sharp (never mind the focus shift):

Can anyone who's also a 50mm f/1.4 fan tell me if this is normal?

Thanks in advance for any help on this,
Chris

P.S.: On a side note, I'd actually look into more expensive alternatives, too, if they were better, but it appears there aren't really that much. I also tested the Sigma 50mm f/1.4, same results at large apertures as the Nikkor. The Cosina/Zeiss is not even a real Zeiss from the results, plus it's MF (been there, done that, didn't work out). If anyone has a secret hint on an alternative, lemme know.

Posted 7 months ago #
Emceee

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SLR Gear did testing with the 50mm f/1.4 and it seems it is a bit soft at f/1.4 in comparison to other slower stops.

You're never really going to get <b>ultra</b> sharpness at f/1.4 on any lens, the lens is probably fine you're just pixel peeping a bit too much and expect more than the lens is truly capable of.

Posted 7 months ago #
Geoff_K

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Is it remotely possible the 1.4 is backfocusing so badly that at f8 it is sharp at the focus point due to DOF ?

I would be disappointed with the lens also and keep it ONLY if I shot things that required f1.4 in order to have any chance of a capture. Sometimes an iffy shot beats no shot.

Posted 7 months ago #
proudgeek

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I bought a 50mm f/1.4G with very high hopes a year ago and have been underwhelmed with its sharpness wide open. I always assumed it was a DOF issue. In contrast, I'd rented a 50mm f1.4D a few times and found it to be VERY sharp.

Posted 7 months ago #
Eric

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It looks like you are doing everything right. However although it may be my eyes, it looks to me like the left hand side of the image is in better focus than the right. Since it appears that you focus point is off center, I wonder what would happen if you tried with the focus point centered on the chart. I would expect the 50mm to have greater field curvature than the 85, so it may be that you are seeing some of that. It might be interesting to try with the image centered and see what you get.

Posted 7 months ago #
spraynpray

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I don't have a D800, but I do have a D7000/50mm G f1.4, If you think it will help I'll print your sheet and post the result tomorrow?

Posted 7 months ago #
jerl

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It doesn't seem too unusual. Obviously, it is not back/front focused because the chart is not parallel to the sensor (so at least 1 point on it will be in focus). In general, wide-open primes won't be as sharp as when they're stopped down. They just appear to be very sharp because the stuff that's in focus is much sharper than everything else.

Your comparison seems reasonable too: The 85/1.8G is a newer design that performs exceptionally well, even wide open. Also, 1.8 lenses are easier to make sharper than 1.4 ones. Finally, the Nikon 50mm lenses tend to have a reputation for "only" being good, while the 85mm lenses are reputed to be very good.

I don't have the lenses in question, but I might be able to try with the 50/1.8D and 85/1.4G to see how that comparison works (it will probably be closer together than what you are getting).

Also, if it bothers you, you can try exchanging or getting another copy to see if you get the same results.

Posted 7 months ago #
chris_weinert

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Wow, so many answers, thanks guys! I really appreciate it!

@everyone concerned with the alignment of the test chart and sensor: The big picture is just supposed to serve for illustrating the crop area, in fact it's one of the first shots where the alignment is not correct. The images that the crops are taken from of course were taken with everything properly aligned.

Plus, my issue here is not the front or back focus, but the image quality of the sharpest area – wherever that is. The crops show the area with the sharpest content, in the wide-open cases it happens to be around the correct area of the focus chart, in the f/8 case, it's further backwards due to focus shift, but I don't care for now, my issue really is the image quality.

@Jerl: Yeah, this is my 4th (!) copy now, all the same results. If you find the time, yes, your lenses comparison would be very interesting, too!

@spraynpray: Same goes for your suggestion. :-)

@Geoff_K: The focus shift issue is quite a thing, but no it's all controllable and it's clearly visible where the focus sweet spot is at all apertures. THis is really about the quality at the sweet spot, wherever that is.

@proudgeek: Hm, funny, because I also had the impression from the D700 uses a few years ago, that it was tack sharp. Then again, it was at a much lower resolution, so maybe that's why. From the results I see now on the web, it doesn't look like it actually is. At least not when you mount it on a pixelcounter camera like the D800.

@Emcee: Yeah, I know, I thought myself that it's pixelcounting, but this morning I took a test shot out of the window at a friend's place and the blurriness was so bad I could see it slightly zoomed in. That's when it starts to matter, I think.

Thanks for all your answers so far!
Chris

Posted 7 months ago #
Gareth

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it's not sharp till about f2. i never shoot it wide open. (I have a d700)

the 35 1.4g on the other hand is perfectly sharp at 1.4.

Posted 7 months ago #
tcole1983

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I am curious to try this now with some of my lenses to compare.

Posted 7 months ago #
safyre

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Yes, this is pretty much normal. The reason why it seems so pronounced is because you're zooming in on a 36mp picture. I use the 50 1.4 most of the time, mostly at 2.8 and rarely going below that. Just like all lenses, the optimal sharpness is a couple stops lower.

Posted 7 months ago #
Gareth

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here is a comparison. shot wide open with exposure delay mode, on a tripod, manual focus using live view, at near closest focusing distance. I even stretched the 35mm pic so the head was the same size as the 50mm pic.

Posted 7 months ago #
Gabbb

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I had this lens for a while, but sent it back and kept the 50mm 1.8g, i found it to be much sharper and more reliable.

Posted 7 months ago #
chris_weinert

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@safyre: I do know that I can't expect the tack sharp perfomance wide open, of course I'm aware of the limitations, I was just confused because it's such a pronounced blurriness, as opposed to what I read from what people are saying about the lens. But you answered my question :-) so it's not just the copy but the normal way.

@Gareth: Wow! Thanks for the comparison! I simply don't understand why the 35 get's it done, also the 85 (although only the 1.4 would serve for a fair comparison), but the 50 doesn't. I wonder why there's no "expensive version" 50/1.4 lens available that works properly also at the wider aperture... The whole point for me for using a fast prime is using it at or near wide open. The 85/1.8 is such a great lens, as seems to be the 35/1.4, why is there no equivalent in the 50mm range?

Posted 7 months ago #
msmoto

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OK, here is the 50mm f/1.4 D Nikkor wide open, 1/100 sec, ISO 4000 -0.7 ev on a D4.

http://www.flickr.com/photos/fantinesfotos/7997107939/sizes/o/in/photostream/

It looks fairly sharp to me. And this is cropped to about 60% of the full image as I remember. The example given at the beginning of the thread looks almost like there is a flare in the lens. Almost as if something were on the lens element...

Posted 7 months ago #
DavidHarsay

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msmoto said:
OK, here is the 50mm f/1.4 D Nikkor wide open, 1/100 sec, ISO 4000 -0.7 ev on a D4.

That's a different lens, which is what i have. It's sharp on the D700 anyway, not sure what 36MP's look like.
Dave

Posted 7 months ago #
chris_weinert

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msmoto said:
The example given at the beginning of the thread looks almost like there is a flare in the lens. Almost as if something were on the lens element...

There definitely wasn't, and it was like this with all the other 3 copies, too. Plus, Gareth's example pretty much resembles it as well. No?

Posted 7 months ago #
R8R

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I don't know where you read the f/1.4G is sharp wide open. No way. It is slightly less sharp than the f/1.8G, even when both are set to f/1.8.

The payoff with the f/1.4G is that little extra something-something when you need it in very low light. It's also nice for softy/moody portraits.

Sharp? No.

I love the look of it though, especially on my D3. I have one and use it all the time.

If you want sharp(er), get the f/1.8G. It also focuses slightly faster, especially from infinity to close, cause the focus gearing has a shorter throw. Also, slightly better optical formula (1 aspherical element)

If you want the widest aperture to use available light, keep the f/1.4G.

Posted 7 months ago #
jerl

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The initial test of the 50/1.8D and 85/1.4G (both at max aperture) are fairly similar, with maybe a small edge to the 50mm. It's difficult to tell because the 50mm has so much more depth of field, but it seems a bit better. I'll try to do a proper test tomorrow and maybe I'll be able to post the results. My feeling is that 1.8 lenses are easier to get sharper, but of course we want the 1.4 lenses for the 1.4, not necessarily for the best sharpness.

Posted 7 months ago #
TaoTeJared

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chris_weinert said:
@safyre: I do know that I can't expect the tack sharp perfomance wide open, of course I'm aware of the limitations, I was just confused because it's such a pronounced blurriness, as opposed to what I read from what people are saying about the lens. But you answered my question :-) so it's not just the copy but the normal way.

@Gareth: Wow! Thanks for the comparison! I simply don't understand why the 35 get's it done, also the 85 (although only the 1.4 would serve for a fair comparison), but the 50 doesn't. I wonder why there's no "expensive version" 50/1.4 lens available that works properly also at the wider aperture... The whole point for me for using a fast prime is using it at or near wide open. The 85/1.8 is such a great lens, as seems to be the 35/1.4, why is there no equivalent in the 50mm range?

I have the 50g as well, it was severely back focused by -18 (using lens align). I reset the fine tune to 0 and it looked like your results. Aligning it looks much better but I wouldn't call it "tack" sharp. At F2.8, it is though. You might try the extremes of the fine tune to see what happens.

Comparing the 35mm vs. 50mm is a bit problematic as the DOF is larger and, after all, the 35mm is a $2,000 lens. The 50 1.4 is more of a "bokeh" focused (attain a smoother look) just like the 85mm 1.4 rather than the "most technically" sharp. The 1.8s in Nikon's lenses have held that position. The only brand I have ever seen optimized to shoot wide open is Leica. If you plan on always shooting wide open and are willing to send your lens in, I have read of people sending them in to be optimized for wide open use at a particular distance. The "out of box" setting is to allow the best compromise for near to far shooting.

Many of us are waiting for a f1.2 which will be the "high priced" 50mm, but I doubt it will be tack sharp at 1.4.

Posted 7 months ago #
chris_weinert

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Thanks for your replies again!

@R8R: Ok, thanks. I guess I'm just gonna order a 1.8 and see how that works out, then.

@jerl & TaoTeJared: This DOF issue when comparing lenses is actually not what most people always think: Given a specific motive (say, for instance, a headshot from forehead to chin), the DOF of a lens will always be the same at the same aperture but different focal lengths. Meaning: If you take a 35, 50 and 85, always set it to 1.4, and always fill the picture with the headshot, you will have the same DOF for all pictures. To be clear, for this, you will need to take the same picture (i.e. as I said, always fill the frame with the full head), which will result in different distances from the subject for each focal length, and due to that of course produce the typical different looks of the different focal lengths, i.e. the close distance of the 35 will pronounce the nose more, the further away you go, the flatter the head will look. But the DOF, as in how sharp are the ears compared to the nose, is gonna be the same. Again, this goes only for the situation that you're actually moving towards or away from the subject to produce the same frame.

So Jared, this is also what you should do when you take the test shots comparing the 50 and the 85. Always move the camera to adjust for the focal length difference, so that the sheet of paper has the same size in the frame, i.e. touches the top and bottom of the frame or something.

Posted 7 months ago #
chris_weinert

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@TaoTeJared again: Concerning the back focus, it's the same with my 50/1.4G now, I have a value of -18 set in the AF fine adjustment (optimized for f/2.8).

Posted 7 months ago #
spraynpray

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Well, I took a look at my lens and it is similar to yours. In reality I'm not sure how big a deal this is, because you are checking it close to minimum focus which is not a realistic test. I can't say I have seen a problem with it in use. On the bright side, it shows how consistent Nikon's manufacturing is! Of course stopping it down drastically improves things even at that close range.

What bothers me more is that I have had to use the full -20 to correct its back-focusing. As I've printed the sheet out, I may as well carry on and test the other lenses....

Posted 7 months ago #
bossa

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I had a 50/1.4G and got rid of it AFAIC. It was 'just like' what I see in the shots people are posting here and I hated it. I had a Sigma 50/1.4 prior to the 'G' and couldn't get another one fast enough. But I'll probably get the 1.8G as well as I need a lens that's sharp corner to corner which the Sigma isn't.

The best '50' I had up until last week was my Pentax DA*55 F1.4, a killer lens and sharp wide open. I've been selling my Pentax kit to finance my D800E's and lenses but made a mistake selling the FA31 Limited, DA*55 and the FA*300. But I won't be making that mistake again and I'll be keeping my FA77 F1.8 Limited.

You really start to appreciate shorter lenses on the APS-C format when you need to focus closer. My Sigma 85/1.4 has the same close focus as the Nikkors and you just don't get the same result up close as a '50' on APS-C. (unless one buys extension rings and then you can't get back enough.. lol)

Posted 7 months ago #
DJBee49

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I think you should probably just get a f1.8! Mine cost me less than £100, is sharp at f1.8 and very sharp indeed from f2.8 onwards- until it hits diffraction at about f11 or f16. It is only a 'D' but focusses very fast and works fine on the D800 and D700. I use it all the time and love it. I also think that the real advantage of the fraction of a stop wider aperture on the f1.4 is far less significant than it used to be. It was critical in the old days with film but now, the current crop of digital cameras have such amazing performance at high ISOs that for me at least, the f1.8 is perfectly adequate virtually all the time. And it is reliably sharp!

Posted 7 months ago #