Nikon 70-200 VR II - inconsistent focus

guitarvirtuosoab

So i purchased a 70-200 II for my d800 a few weeks ago. It appears that in some situations,the lens back focuses tremendously. The weird thing is it's not all the time. Sometimes it focuses dead on, but in the situations that is does back focus, it back focuses every time. I've attached some 100% captures showing the focus points and you can see the problem. It most definitely seems to only be in the longer focal lengths. Should i just return to B&H and exchange for another copy? i still have a few more days to RMA it. I also don't find the autofocus to be all that much quicker to attain (wrong or not) than the 70-300 4.5-5.6. Granted I know these pictures aren't great. They were shot at 2.8 rather than stopping down some, but still focus shouldn't be off that much. I have several more shots of this goose and they shouldn't all be this bad.


Misfocus at 190-200mm





Much Much better focus at 70mm

Msmoto

Camera body?
If focused manually, with focus indicator showing in-focus, does it do the same thing?
Are you simply pushing the release or do you push halfway and allow the lens to focus, then release fully?
Single point focus?
S or C AF?
Does the lens do this on all bodies?

JJ_SO

How's the sound of the Silent Wave Motor? Is it sounding like constantly moving until target or is it more a sticking noise like something mechanical is wrong? Actually one of my lenses gets this SWM changed which was also unreliable in focussing.

I'd guess it's better at 70mm caused by larger DoF.

guitarvirtuosoab

Msmoto: should have added more info. I thought it could be the body, but the lens reacts the same way on my d300. no other lens seems to be reacting the same way , but this is my first big aperture zoom. The 85mm 1.8 needed a +6 AF adjustments. The 50mm 1.8 needed no adjustment.

S AF
Single Point Focus
I half press shutter several times to lock in with each shot i take to try to achieve best focus and ensure VR is fully engaged.
I have not tested the manual with focus indicator.


JJ_SO: It's the only 70-200 i've tried. So it seems to sound fine. Maybe a little louder than I expected. I tend to agree that 70mm would improve based on DOF, but it doesn't seem to be front or back at all in this case, where the 200 is clearly back. The more i look through the 190 to 200mm shots, the more i'm seeing the same problem.

John

No AF system is perfect.
Depending on contrast, lighting,... the focus sensor might miss.
Also note that the area of the AF sensor might not match what's indicated exactly.
In the first image it looks like the camera focused on the background. (probably due to a lack of texture on the duck's neck)
That being said it does look like some backfocus to me.
I have the 70-200 as well and it's tac sharp; even at f2.8.
Do note however that a very shallow DoF often means that you can very well have only a centimeter of less DoF (at f2.8, 200mm, target close by). So, any movement of the subject and/or the photographer will put the subject out of focus.

I would suggest that you give the lens another try on a static target with high contrast and lots of detail while the camera is mounted on a tripod.
That would remove photographer and subject movement from the equation.

Then repeat the same experiment using live view focus.

Msmoto

it is interesting that in some situations the AF will not work on a fine line. It requires more of a rough field of texture or multiple shapes. So, if after testing as John has suggested, on a surface with much texture, it shows back-focus as much as you see in the examples....It may have a problem. The best way to do this is with an actual focus test device such as a Lens Align tool.

http://www.bhphotovideo.com/c/product/747316-REG/LensAlign_LA_LA2_LensAlign_MkII_Focus_Calibration.html

Good luck

guitarvirtuosoab

Here is one more sample. No wind at all that day so the flower wasn't moving. Plenty of texture. Done on a tripod. I have about 7 shots just like this in a row all focusing the same way. To add to this. The 70-300 VR locks right on perfectly from the same POV at any focal length on the same camera.



I'm still tempted to exchange for another sample to rule out the lens since it's still within return timeframe. if the second has same problems.. I'll calibrate based on that. If it were simply always backfocusing, i'd just fine tune, but i don't want to kick the 70 out which appears pretty good in order to fix 200.

Msmoto

OK, one more thought...you are focusing closely. Do you have the "full" range on and are you not closer than the lens will focus?

Fred_B

I did get a bad lens on the first try. The focus was extremely sticky and loud. It still focused sharp.

The replacement I have focuses fast and quiet. It did need a little focus adjustment but most lenses do on my D800. Before I corrected mine it did look better at 70mm but that was because the depth of focus was so much higher. It was back focusing but the pictures looked ok.

I'd use the focus adjustment in the camera. If you have to go out of the range in the camera either send it back or ask Nikon. Personally I'd rather take it in to Nikon service than risk getting another "bad" copy.

John

Based on the flower picture I do think that the lens has an issue. (Assuming that the target was beyond minimum focus distance.)
The 70-200 f2.8 that I use is extremely sharp so you might have a lens with a defect of some kind.

guitarvirtuosoab

Msmoto: it's actually not close focus where the issue lies.. These are small 100% crops. The fence was close focused at 70mm maybe 5 feet away and is very accurate, if not perfect, focus. The goose was probably 35-40 ft. The flower was maybe 8-12 feet. At any rate, none were done with the limiter engaged. I had it on A-M priority and was not touching the manual focus, so the camera won't shoot unless it's registering as being in focus.

Fred_B. I'm not sure if there are any nikon service centers anywhere close to Pgh, PA. Likely not as we have 1, yes 1, retail camera store in Pgh. it's sad. I will try dialing in an adjustment tonight to see what i get, but to me this seems pretty far off, not just slightly like my 85mm was. The funny thing is the cheapest lens we own, 50mm 1.8, doesn't need any adjustment, and the most expensive needs the most adjustment.

Rx4Photo

@ guitarvirtuoso, after seeing those images, especially the last one, I'm thinking this is an issue beyond what you should have to try to adjust with AF-fine tuning. In other words, it looks to be more than a "tweak" would be necessary. In a case like this please don't discount the thought that you just might have to send your D800 in for a focus assessment. I had my D800 for several months and even proudly wrote on a couple of threads here that I didn't have a focus issue. I would rarely get slightly out of focus pictures but those would still annoy me.

After 9 months of owership I finally bit the bullet and sent my D800 in for an assessment along with a new Nikkor 85mm f/1.4G lens which was backfocusing on it. OMG, what a tremendous difference that made. Both are now sharp as needles. My D800 now along with my 70-200mm VR2 and 85mm seems to need no AF-fine tuning although I'm till testing it more or less. The overall IQ has improved because I can easily see what I focused on and the transition to bokeh much better than before.

Definately consider changing that lens but also if you can live without you D800 for a few weeks consider having an official Nikon service done on it before warranty is up. Both of my services were No charge.
*I live in Florida and had to ship them to Melville, NY.

guitarvirtuosoab

I can certainly use the d300 and DX lenses for now. My d800 never gave me the issues many had complained about, although, (exlcuding 70-200 altogether) it has done some hunting and not attaining focus at all in some focus points in instances where it seems like focus should be easily achieved. I didn't think much of it at the time, but maybe it's part of it. Note this is different because in this new case it's actually achieving "focus" rather than just racking back and forth. How do i go about contacting nikon service... just though nikonusa.com? I bought the body in June or July last year so it's still under warranty as well. I haven't filled out any warranty cards though.. I just kept them all

guitarvirtuosoab

I think what i am going to do is exchange the lens and retry another copy since that is still an option. If at that time it's still not improved, i'll send all in for assessment

Rx4Photo

I also just keep all of my Nikon warranty cards but I do log onto the Nikonusa site and have logged each and every Nikon product, serial number, and date/place purchased with them. So when I called Nikonusa to ask what I should do they were able to pull up my information. They confirmed my e-mail address and sent instructions to me for where to send it. Even though there is an official Nikon "repair" shop down in Miami somewhere I felt better knowing I would be sending it to NY to a real center. I bought my body last June as well.

guitarvirtuosoab

unless i can be assured that whatever issues exist with the 70-200 will be corrected by the service center.

Golf007sd

@guitarvirtuosoab: If I was in your shoes and given the steps you have taken in addressing this issue, an exchange is warranted. Get and RAM and have this lens replaced.

guitarvirtuosoab

I've made up my mind.. I'm going exchange. If nothing else it will likely put me with a better copy. If still an issue i still have a couple months of warranty on the D800 to send in for service. I don't want to give in to starting out with a bad copy though.

Msmoto

Good choice from my viewpoint

Golf007sd

Given the OP action, one which I agree, then the topic is now done with would you. Hence, close it.

Rx4Photo

Why close it? I'd like to know how things turned out. Perhaps guitarvirtuosoab can post an update sooner or later.

guitarvirtuosoab

I will certainly respond when things change. I RMA'd it this afternoon and for exchanges/defective products B&H provides a prepaid UPS sticker so i don't even have to eat shipping cost again. For just a return for refund they do not provide prepaid. It's nice that they want to keep their customers as happy as possible. When i get the next copy i'll provide the same shots (at least of the flower) to show comparison. The other shots were over 100 miles away so i don't think i'll make the trip just to take those pics.

Msmoto

This may pop up again for another who needs to get some tips on AF Fine Tune.

guitarvirtuosoab

I was further testing my 85mm 1.8 today and did notice that at closest focus at 1.8, the left most focus point is slightly further backfocused than the middle or the right most, which of course is the dreaded left most focus point problem.. however, it's nearly unnoticeable unless you zoom to about a 5% of the entire image. i'm not really worried about that. but the 50mm and the 85mm were overall sharp across the board aside from the very very slight out-ness of the left points. That 70-200 was clear as day out at several points. It was sent out for return today, so hopefully will get a new copy by wednesday next week as my wife has an engagement shoot!!.. haha.. I guess primes will be in order otherwise. when i get time though i am going to send the d800 and at least one lens for eval of the left point. might as well get it fixed if i can even though it's very minor.

guitarvirtuosoab

ok so i have the new lens as of today.. I quickly mounted it after work, took it outside and fired off a shot at the same flower as fast as i could. No tripod, not even really checking settings. I totally understand that they are by no means perfect shots and they are zoomed to 100% like the original. i just wanted to see if in a pinch needing a quick shot how accurate the new one is. Keep in mind the flower above was on a tripod and these aren't. here are my shots:





HUGE DIFFERENCE IMO!!

Msmoto

Great...glad you were persistent. These appear quite satisfactory in focus.