Those were taken with the camera mounted on a tripod, f/1.4, ISO 1000. I did this on my kitchen table, so I had whatever light was in the room.
I systematically went through and adjusted the AF Fine Tune in increments of five units. I took at least five shots at each fine tune value, and selected the best one to show on the web page. Focus mode was AF-A, using only the center focus point.
I also took a series of shots with the subject carefully hand focused via extreme zoom in Live View mode.
Each shot was loaded into ACR. I applied a smidge of sharpening, and then saved them out as PSD files. I then loaded them into Illustrator and saved the JPG's as 100% crops. You are seeing a small slice from the center of the image on these samples.
So what I think I am seeing is that this lens cal ALMOST be adjusted into good focus, but not quite. Even at Fine Tune = -20, its still a little off compared to the carefully hand focused shots. If the AF fine tune went to -30, then maybe we would have it.
So, what to do?
Is this the lens? I've not done a test, but I've never had reason to doubt my D7000 before. My 18-200 produces sharper shots than these, under whatever sloppy conditions I happen to find.
Do I just return the lens and try another one? Do I send the lens/body off to Nikon for adjustment?
#2. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 0
I'd consider a couple more bits of testing, having been down a similar road.
First, find a new target. That banana might not be the best target, given the shape, and the contrast between the blue and yellow might not be good enough - especially since the blue label has yellow text and graphics. I could see that throwing the AF system.
For my initial testing, I used a piece of brown cardboard with a flo-orange sticker from the gun range. Very high contrast against a very uniform background.
Secondly, do a Speedlight Assisted Focus test. Basically, run the same test as you have on the new target then toss on a SpeedLight, and use AF-S and have the infrared assist you in locking on.
If you get similar result with this final test, I'd say that you have a problem. Whether that problem is with lens, camera, or a combination is a tougher call.
#3. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 0
-15 looks better than the other, imo, but I go along with Jon's thought since you say the other lens performs well. Why not do the same test, using your other lens, with the same settings and see what is produced? Could you go back to the vendor, explain what is happening and get another lens to compare before settling on a replacement? Good luck.
Nobody should seek his own good, but the good of others. <><
#4. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 0
Looks like your body has back-focus problems. Not all lenses are the same, so even if the auto-focus on the body works perfectly, the variances in the lenses may make for better focus on one lens, and worse focus with another lens - all on the same body.
I have two lenses, the Nikkor 18-200 mm VR and the Sigma 150-500 mm. Both worked perfectly on my D90. When I got the D7000, suddenly I had soft focus with both lenses. I did some trials with a focus chart and even fine-tuning the auto-focus to -20 I was still getting back-focus.
I took the camera and the Nikkor lens to a Nikon repair center and they adjusted the auto-focus. I still had to fine-tune the auto-focus afterwards, but now both lenses focus very well with a -17 auto-focus fine-tune setting. Speaking to the repair tech afterwards he told me as long as one can get good auto-focus within the -20 / +20 fine-tune allowance then the camera is considered to be within specification.
I suggest you take the body with all Nikon lenses to a repair facility and have them fix it. They need the lenses as well in order to calibrate both body and lens together. You can Google and print a focus test chart if you want to run your own trials, but I feel confident from looking at your pictures that a trip to the repair center is indicated. The fact that the focus in your pictures progressively improves the more negative fine-tuning is dialled in proves it to me.
#5. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 3 Thu 31-Jan-13 02:02 PM by Omaha
Thanks for the thoughts, guys.
I ran some basic tests with the 18-200. Similar setup to what I did with the 50 (but I didn't fiddle with the AF fine tune). Didn't need to. Bottom line is the images are sharper than the images produced by the 50. So, other than its "see in the dark" abilities, the 50 is useless to me.
I just checked, and I've only got a few more days on my 30 day return window. Back it goes.
EDIT : Rassie, you and I cross posted.
I'm interested in understanding why you think this is a back-focus issue on the body. My "common sense" view of things is that if it were the body, then I'd see problems with my 18-200 as well. Since I don't, I'm blaming this one on the 50. But I'm also sure you know more about this stuff than I do, so anything you can do to take me to school would be much appreciated.
#6. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 0 Thu 31-Jan-13 04:49 PM by gfinlayson
I wouldn't return your 50mm based on those focus tests. To have so little light that you needed ISO 1000 at f/1.4 isn't giving the AF system much of a chance, and the depth of field at f/1.4 is wafer thin. Your choice of focus target was also far from ideal. The centre cross focusing point is also quite large (larger than you would presume from the focus point indicator) so areas beyond the focus point indicator may be chosen by the AF system. The 18-200 has considerably more depth of field shot wide open than the 50mm, so if it were off a bit, you probably wouldn't notice it.
Get hold of a proper focus test chart, set it up as instructed in good light and try again. Here is a very good reference for focus testing with a downloadable test chart.
I have the 50mm f/1.4 as well - on one of my D7000 bodies it was a little soft in the centre at f/1.4. An adjustment of -3 was needed to get it perfectly sharp, but I carried out the tuning with a properly set-up test chart in good light. There's no other way to do it properly.
#7. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 0
St Petersburg, RU
There is not enough information to conclude that there is or isn't a problem. There are too many less than ideal variable compromises. 1. Focus sensor area is larger than the target so it might just as easily decide that an edge at a different focal plane is what you intended. 2. Way too little light for meaningful AF tests. 3. multiple focal planes within the target focus point with a very narrow depth of field at f/1.4 4. The shots not shown could have easily been the ones closest to the actual preferred choice by the camera AF. 5. The additional images at each adjustment value, if much different shows that the ambiguity of the tests are producing a range of values that prevent any conclusions at any one adjustment that was selected as the the closest.
Try increasing light, use an external flash patterned assist light to aid the AF to be more consistent. Close down the aperture for a base line set ofimages. With deeper depth of field you can determine if the lens can resolve fine detail or there is an optics problem. Create a flat target with distinct edge contrast. Use enough light for a good shutter speed that eliminates tripod shake. Make sure the focal plane and target are parallel. Shoot a series and evaluate them all, and average them
Your 18-200 at its widest aperture has such a deeper DOF that even moderate AF misalignment would be in focus. The f/1.4 50mm wide open is being asked to perform at a much higher level of precision to be in focus. I do not know the distance from camera to target so can't tell you what DOF you should expect. As a test, try taking set with both lenses at the same aperture. The 50 will probably be better even if it runs into softness at 1.4. Good luck... Stan St Petersburg Russia
#8. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 0
You have certainly received a lot more, and better advice than I can offer. But I do have a curiosity question. Does the in-focus green indicator light show it has locked in focus (solid green) when you take the pictures when using auto focus?
#9. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 5
Yes, the body could be part of the issue. If the body has a -5 mis-focus and you use a lens with a -5 mis-focus, you have a combination that is off by -10. However, another lens with a +5 focus error would be perfect with the -5 error body.
#10. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 0
If it's a Sigma or a Tamron, send the lens back immediately. Although both companies have significantly improved quality control, both companies still produce lenses with too much sample variation. Still though, even Nikkor glass exhibits some sample variation that is occasionally extreme enough to produce a bad one. Whatever. I'd say exchange it.
#11. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 10
Excellent help, everyone! This forum rocks!
Its a Nikon. I bought it from Amazon, and just dropped it off at the UPS Store. Mainly I was running out of time for my return window, so I needed to make a decision.
I'm intrigued by this comment:
>I wouldn't return your 50mm based on those focus tests. To >have so little light that you needed ISO 1000 at f/1.4 isn't >giving the AF system much of a chance, and the depth of field >at f/1.4 is wafer thin. Your choice of focus target was also >far from ideal. The centre cross focusing point is also quite >large
What it suggests to me is that my real problem here is one of expectations. I do mainly portrait photography. What I want is to be able to put the focus point on the subject's eye and get a nice, sharp exposure, automatically, with at least a 50% "hit rate".
Maybe that's just not realistic with a 50mm f/1.4?
I get that the combination of my test subject and lighting were sub-optimum, but that was somewhat by design. Real world shots don't occur in idealized conditions. This process started because I noticed I was getting a very high rate of missed focus shots (maybe one in 15 or 20 being acceptable). Most of those were taken in outdoor daylight.
Is it unreasonable to expect to shoot a 50mm f/1.4 AT 1.4 and get consistent AF hits? I realize that the DOF on that lens is going to be razor thin. At the same time, I expect that if I carefully compose the shot, putting the AF target right on the subject's eye, I should get a decent hit rate. Are my expectations way off?
The way I calculate it, at a distance of five feet (at f/1.4 and with my crop sensor D7000), I should have a little over an inch of usable in-focus depth. That should give the camera a bit of margin for error to get the eyes in focus. Is there something wrong with my calculations there? Is that too narrow a DOF window for reliable AF control?
In any case, having returned the 50, I'm thinking of trying something longer (85mm? 105mm?) What I want is something that can totally wash out the backgrounds while getting a sharp hit on the subject. Maybe trying out the 50mm was doomed from the start...
#12. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 8 Thu 31-Jan-13 10:15 PM by Omaha
>Hi Jeff, > >You have certainly received a lot more, and better advice than >I can offer. But I do have a curiosity question. Does the >in-focus green indicator light show it has locked in focus >(solid green) when you take the pictures when using auto >focus?
There was never any hint with this lens, either in the banana tests or in real world shooting, that it was having trouble achieving focus lock. It always snapped right on without hesitation.
#13. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 11 Thu 31-Jan-13 10:59 PM by gfinlayson
Focusing on a subject's eye is a much easier target for the AF system as it usually presents a high contrast area - the centre of the eye is normally much darker than the surrounding skin and in any case has a dark centre surrounded by white. Your banana was a low contrast target and with lighting levels that require ISO 1000 and f/1.4, there is very little contrast variation for the AF system to detect.
I've shot portraits with my 50mm at f/1.4 - f/2.0 and got the eyes bang in focus very easily. Depth of field is so shallow at these settings, that the ears and nose are out of focus, but the 50mm f/1.4 has always got the eyes tack sharp.
For proper AF fine tuning, you need to optimise the focusing conditions for the lens - that means using good light and a high contrast target.
Your banana was shot in low light and was a low contrast target.
#14. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 13
>Focusing on a subject's eye is a much easier target for the >AF system as it usually presents a high contrast area - the >centre of the eye is normally much darker than the surrounding >skin and in any case has a dark centre surrounded by white. >Your banana was a low contrast target and with lighting levels >that require ISO 1000 and f/1.4, there is very little contrast >variation for the AF system to detect. > >I've shot portraits with my 50mm at f/1.4 - f/2.0 and got the >eyes bang in focus very easily. Depth of field is so shallow >at these settings, that the ears and nose are out of focus.
That makes me think this really was about the lens. I took several hundred portrait shots with it and had very few usable results.
I don't think the banana was soft (heh, heh ) because the AF couldn't "see" it. I think it was soft because the AF was off.
#19. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 18
Most of your settings are ideal for the type of shooting you're doing. For portraits at or near wide open on the 50mm f/1.4, I tend to favour AF-C. Others may disagree, but with such a limited depth of field, the slightest movement of your subject after focus has locked with AF-S can produce a soft image.
Your AF may indeed need some fine tuning, but until you ascertain exactly what is required with a properly controlled focus test, returning the lens for another may not improve matters. The point that I tried to make earlier and that Stan reinforced is that the banana was a poor AF test target. It won't enable you to figure out how far your AF fine tune needs to be adjusted, only a proper focus test will do that.
I'd try a properly conducted focus test first - if you can correct the issue within the range of adjustment in the AF fine tune, then I'd do that and accept that your particular lens needs AF tuning with your D7000. If you can't, then there are two options - swap the lens and try again, or send the body and lens to Nikon to check the overall calibration.
Many people never need to worry about AF calibration because there either isn't an issue or the available DOF with kit/consumer grade f/3.5, f/4.5, f/5.6 lenses gives enough depth of field to not notice any misfocus.
When you go up to pro-grade ultra-fast lenses with wafer thin depth of field, AF accuracy is critical and fine-tuning is often required to get the best results. That's why the more serious bodies have the facility to fine-tune.
#20. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 0 Sat 02-Feb-13 02:23 PM by ericbowles
I know the lens has already gone back, but just a few comments for future reference.
The 50 f/1.4 should produce very sharp images, but DOF is very small wide open. That makes it easy to miss focus. But you already know that. The other issue is the 50 f/1.4 is not at it's sharpest wide open. While you should use f/1.4 for fine tuning, it really performs much better at f/2-2.8. So getting sharp images requires a different aperture than fine tuning - and your test images should be a little soft at f/1.4.
In comparison to the 18-200, the zoom has an minimum aperture of f/4 or so at 50mm. That means you are going to have a lot more DOF and many errors will be forgiven. The 18-200 may have issues at the extremes, but at 50mm it is in a focal length where it performs very well compared to any lens including the 24-70.
AF is not perfect. AF accuracy can be viewed as a relative distribution of AF errors over a number of images. If your test equipment is precise, you'll see that every time you focus using AF, the result is a little different. There should be a concentration of AF results at the best the lens can perform, but there will also be a distribution of missed focus that includes some bad misses. There is a thread somewhere here by NatGeo photographer Daniel Cox with a link to his blog. He tested the D4, D800 and D600 AF on a moving dog in great light. With the D600 he only hit focus on 54% of the images - and he thought that was quite good. The D4 hit about 70%. All of the results were better than any prior Nikon camera. http://www.naturalexposures.com/corkboard/testing-the-nikon-d4-d800-d600-in-predictive-auto-focus/
While it did not come up here, the center sensor is the one that performs best on Nikon cameras. The surrounding cross sensors perform slightly less well, and the other sensors less accurately still. This also applies to the amount of light required wide open - the center sensor is the one that focuses at f/5.6 or f/8 and other sensors may only provide focus at f/4.
Phase detect AF is slightly less consistent and less accurate than the contrast detect AF of Live View. Live View will be better and more consistent, but it is slower - and not practical for some images. Still, Live View provides a perspective on what the lens is capable of delivering if properly fine tuned. Think of it as a baseline.
There are a wide range of AF tests for different factors. You can test to fine tune the lens. You can test for performance of phase detect focus on specific AF sensors. LensRentals.com does most of their testing with the center sensor only - other sensors are not going to be as accurate and introduce many other variables.
Stick with the 50 f/1.4 - it really is a very good lens in spite of the copy you received and issue you experienced.
#21. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 0 Sun 03-Feb-13 11:05 AM by Ellis Feibush
I own a 50mm f1.4D and a 50mm f1.8G. Both are tack sharp lenses (for 75mm film focal length), especially for portraits with my D7000. It's the 18-200mm I had problems with and later sold (soft focus issues at infinity and at every focal length, especially at the wide end) and God awful lens creep! Maybe I got a bad copy but not sure. In my experience I have found it hard to buy a DX series walk around zoom lens that does it all, that takes tack sharp images at any focal length. I used it as a so called "travel lens" and it failed miserably. I know that in some circles it has become the "darling" of the so called walk around lenses, but not here with me - IMHO.
#23. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 22
I'm sure you're right Mathew. I guess my copy must have had back focus problems. Used that lens in Istanbul, Turkey and none of the pictures were really sharp. What a disappointment. I'm not in Istanbul too often. Probably should have sent it back to Nikon but if not for the God awful lens creep, I just didn't want to use the lens under any circumstances. I understand the new lens has a lock on it to prevent lens creep. A good friend of mine and certified Canon photographic mechanic, could have checked for back or front focus issues with this lens, but as I said, I was so disappointed I never got it fixed. I have too many other DX zoom lenses that are better. I have since heard of others that have had trouble with their 18-200mm lenses. Must have been a bad batch. But, if you get a good one it becomes the best thing since the discovery of prunes. Enjoy your Nikons and their fine lenses.
#24. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 23
My wife has a copy of the 18-200VRII and there's no question about the lens creep being, well, creepy. ; )
She keeps the camera strap over her shoulder, and if she's not careful the lens will work it's way forward on our hard hikes. As long as she has it locked, though, it never seems to be a problem.
Sorry to hear about your wasted shots in Istanbul, however if it will make you feel any better I ALWAYS wish I'd done things differently, had different equipment with me, approached this subject in a different frame of mind, or different time of day... never seem to get THE shot.
I think, too, that when I do manage to have all those lined up I'll be ready for my dirt nap. Hope it doesn't happen too soon!!!!
Besides, back focus issues with your camera or a faulty lens are precisely the excuse needed to revisit Istanbul. : )
#26. "RE: What to do? Bad lens? Bad D7000 body?" In response to Reply # 11
>>"I get that the combination of my test subject and lighting were sub-optimum, but that was somewhat by design. Real world shots don't occur in idealized conditions."<<
This is one that I have struggled with as well. But, in reality, it is necessary to test the "lens" in an optimal environment to see if it's the "lens" that has the problem. Every time I get a new lens, macro filter, TC, etc. I am surprised by the results.
Once, the lens can be eliminated as the problem, then it is time to discover what you have a right to expect in the conditions in which you are shooting. Then, like you said, you may find that your expectations aren't easily achieveable; with the type of gear you have, and in the environment that you shoot.
Then you need to discover if there is some skillset that you may achieve to help match your expectations. There is bound to be some Nikonian on here that can help with that. Or, you could just explain what you are trying to achieve, and get advice on how best to achieve it.