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Author Topic: D810 + fast primes handheld  (Read 26107 times)

Some Guy

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Re: D810 + fast primes handheld
« Reply #20 on: August 16, 2014, 12:27:12 pm »

It's fine in LV modes, I think, but my understanding is that LV uses a contrast detect autofocus system and the viewfinder uses a phase detect autofocus system. I'm mostly interested in getting this lens fixed for viewfinder use.

In manual focus mode, I'm still using the phase detect system for the focus lock dot, so it makes sense that it would be off there too.

Not exactly.  Set the camera body to Manual and the lens both.  Ignore the AF totally.  Get into Live View and zoom in with the + button and focus manually and fire the camera while on a tripod.  Ignore the AF dot.  All you are doing is setting up to check if the lens is good or not.

If the Manual Live View focus works and is sharp (Passes in the above.), then you can get back into the AF and "try" and tune it.  If you can't, then maybe time for service.

If you have that Reikan FoCal software it will check your focus for one set distance range per test, but it isn't infallible for varying distances.  That is what only Nikon can fix (or Sigma with their tuning dock which Nikon needs to do, imho.).  Plus, it isn't often repeatable as the lens may turn a bit shot-to-shot too (Some hysteresis thing where they may have some +/- 500 count out of maybe 6,000 pulses in the lens rotation stepper. If they set it tight, it will be slow to focus and hunt; if loose, it is faster to focus although misses AF a bit more too.  It's a trade-off.).

I have the Nikon 105mm Macro G and it drifts shot-to-shot and spins a little each time.  FoCal software has a hard time zeroing in on a final tuning number as the lens drifts a bit and you can see it on the final report on all the test shots it takes at a set AF tuning number trying to come up with one valid number.  Even on firing a battery of shots in rapid fire, one will be sharper out of 10 even at the same fixed object.  Maddening really, but this stuff isn't plu-perfect either and can have a lot of slop that "Meets factory tolerance levels."

I have a D800E and was worried about the moire stuff initially.  I don't get it often, nor do I read much of it after Nikon presented it as a "Possible problem vs. the D800."  When I do, it's cause for celebration in that I know the AF locked on the proper point and everything was sharp.  However, it is very rare I get it even if I try.

SG
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trevarthan

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Re: D810 + fast primes handheld
« Reply #21 on: August 16, 2014, 12:30:04 pm »

Not exactly.  Set the camera body to Manual and the lens both.  Ignore the AF totally.  Get into Live View and zoom in with the + button and focus manually and fire the camera while on a tripod.  Ignore the AF dot.  All you are doing is setting up to check if the lens is good or not.

If the Manual Live View focus works and is sharp (Passes in the above.), then you can get back into the AF and "try" and tune it.  If you can't, then maybe time for service.

That was actually the first thing I did. It's sharp manually focused. I'm not convinced that means the lens is good though. I think that just means the optics are fine. I could be wrong. I don't know how extensive the electronics are on these things.
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trevarthan

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Re: D810 + fast primes handheld
« Reply #22 on: August 16, 2014, 01:02:14 pm »

Alright, I redid my tests with the 85mm f1.4g and the d810 in slightly more controlled conditions and with more variation. These are the results:

With the target 6' away, af tune +6 is perfect for f1.4 and f2.8. This also holds for the target 4' away.

With the target 16' away, af tune is +10 at f1.4 and f2.8 is fine there too.

So, I'm not really seeing focus shift for apertures, but distance. Is that still called focus shift?

I intend to redo this test with my D3s too, but it's out in the field this morning so I'll have to wait for it to get back.

The D3S is similar.
Looks good at 6' with +8 for f1.4 and f2.8.
Looks good at 16' with +11 for f1.4 and f2.8.

Does this indicate a problem with the lens, or is this expected behavior from the lens?
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photodan

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Re: D810 + fast primes handheld
« Reply #23 on: August 16, 2014, 02:16:37 pm »

...  However, being a software engineer, I have to wonder if Nikon has settings within the firmware of the camera (or less likely, the lens itself) that they can tweak (and we can't) that compensate for this sort of thing. That would account for some of the lens reviews where people send the lens off and it comes back "perfect".

Funny you should mention that because I feel the the camera makers are able to do that, but haven't done so in the past, to my knowledge. Maybe they will in the future, or perhaps maybe they are doing so in certain cases lately, but that's pure conjecture, and I'd be surprised if they were. Maybe Sigma's new firmware upgrade capability for fine tuning focus by focal length/distance will cause the camera makers to make more of an effort. Or, more likely, when 36mp and higher mp DSLRs become common place in the future then the camera makers will make more of an effort to improve autofocus accuracy. But I'm not holding my breath.
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photodan

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Re: D810 + fast primes handheld
« Reply #24 on: August 16, 2014, 02:25:13 pm »

That was actually the first thing I did. It's sharp manually focused. I'm not convinced that means the lens is good though. I think that just means the optics are fine. I could be wrong. I don't know how extensive the electronics are on these things.

Since you've confirmed, per SG's suggestion, that the lens appears sharp when manually focused, and therefore the optics are pretty much ok, that leaves shutter shake or the various focus shift/distance potential issues as possible culprits.

Have you tried setting your 70-200mm zoom to 85mm, turning VR off, setting it at say, f/2.8, and handholding it to shoot comparison shots with the 85mm f/1.4 set at f/2.8, using the same shutter speed for both sets of comparison shots, making sure to do tests at a variety of speeds (by varying ISO)?  Or even, f/4?
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photodan

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Re: D810 + fast primes handheld
« Reply #25 on: August 16, 2014, 02:32:02 pm »

Alright, I redid my tests with the 85mm f1.4g and the d810 in slightly more controlled conditions and with more variation. These are the results:
With the target 6' away, af tune +6 is perfect for f1.4 and f2.8. This also holds for the target 4' away.With the target 16' away, af tune is +10 at f1.4 and f2.8 is fine there too.So, I'm not really seeing focus shift for apertures, but distance. Is that still called focus shift?...

Hmm, I'm surprised that your optimal AF setting for 1.4 is the same as for f2.8. I'm not surprised at variance at distance (having encountered that myself). I looked up my old notes when I had a D800 and a rental 85mm 1.4G, and then had bought one. Here are those notes "Copy 1. Has focus shift to about f5.6. Manual focus via Live View shows xnlt sharpness at almost all apertures. Super sharp from 5.6 to about 11. Autofocus on the lens as it came from the factory apparently delivers max focus accuracy at about f5.6.  Copy 2 (purchased) - the correct AF setting is near 0 to minus2 for 1.4, and perhaps -10 for f2.8 and smaller. There is purple fringing or spherochromatism heavy at 1.4 and 2."  Lens Rentals (where I rented the lens from) tests lenses and reject those which aren't within their standards. The one I bought apparently was not as good as the one I rented, but lenses vary so much from copy to copy it's a crapshoot.


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photodan

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Re: D810 + fast primes handheld
« Reply #26 on: August 16, 2014, 02:52:41 pm »

I'd been reading that term "focus shift" all day, but I was having trouble understanding what it was and why it was. Luckily, I stumbled across this article last night during my research: http://photographylife.com/what-is-focus-shift ...
Here's a good resource for how focus shift applies to the Nikon 85mm f/1.4G specifically: http://www.photozone.de/nikon_ff/606-nikkorafs8514ff?start=1
Also, there's a review of the lens including focus shift on a subscription site http://diglloyd.com/prem/prot/DAP/Nikon85f1_4G/CaseStudy-focus-shift-Nikon-85f1_4G-dolls.html

If focus shift is not the problem with your particular lens / camera combination, and if your af finetune adjustment is set optimally for the aperture you are shooting with, then perhaps the problem lies with the use of continuous AF.

I'm not an expert with continuous af, so please keep that in mind. Others on this forum with more experience with continuous AF on the high mp Nikon cameras would probably have a better insight and may have a way of getting better results than I can.  But my experience with the D810 and 70-200mm f/4 is that for close subjects, minor subject movement, or my movement, forwards and back from the subject (whether it be a leaf in the breeze, or a subjects face/eye) can sometimes (or, make that, often) prove to be too much of a challenge.

I feel I can get better results using spot single static AF and then watching in the optical viewfinder with the point I want to be in focus seems to get there, and take a bunch of shots that way. At least few will turn out ok. That's similar to what I think Bernard and others have suggested, although via manual focusing to begin with. I used that manual focus technique when I had a D800E and rented a Zeiss 135mm f/2. A lot less frustrating (and better optical results of course) than my current experience with the continuous AF with my current equipment.

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trevarthan

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Re: D810 + fast primes handheld
« Reply #27 on: August 16, 2014, 05:06:01 pm »

Hmm, I'm surprised that your optimal AF setting for 1.4 is the same as for f2.8. I'm not surprised at variance at distance (having encountered that myself). I looked up my old notes when I had a D800 and a rental 85mm 1.4G, and then had bought one. Here are those notes "Copy 1. Has focus shift to about f5.6. Manual focus via Live View shows xnlt sharpness at almost all apertures. Super sharp from 5.6 to about 11. Autofocus on the lens as it came from the factory apparently delivers max focus accuracy at about f5.6.  Copy 2 (purchased) - the correct AF setting is near 0 to minus2 for 1.4, and perhaps -10 for f2.8 and smaller. There is purple fringing or spherochromatism heavy at 1.4 and 2."  Lens Rentals (where I rented the lens from) tests lenses and reject those which aren't within their standards. The one I bought apparently was not as good as the one I rented, but lenses vary so much from copy to copy it's a crapshoot.

This is an excellent reply because it contains similar data. Thank you for sharing. You don't happen to know if the older 85mm 1.4 AF-D has the distance issue too, do you? I'm wondering if this is a case where newer isn't better. For some of the shooting I do (people), the distance issue is unacceptable. It would probably be fine for landscapes with automatic focus stacking, but I really bought this thing for shooting people. Sometimes it's a pain lugging around a 70-200mm 2.8, you know?
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trevarthan

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Re: D810 + fast primes handheld
« Reply #28 on: August 16, 2014, 07:04:47 pm »

It had been bugging me that your lensrental copy had focus shift, because I remember reading their glowing review of the 85mm f1.4g and I thought they said it didn't have focus shift. I went back and checked. Here's the excerpt:

 
Quote
The autofocus is quick and the lens is sharp corner to corner by f/2.8. It has almost no distortion. Itís flare resistant, it has little aberration, it doesnít have focus shift Ė it really is just about perfect. If you look at my review of the old Nikon 85 f/1.4 D, I said that lens was badly in need of a makeover. Well, it got it. This one is just about perfect.

https://www.lensrentals.com/rent/nikon/lenses/normal-range/nikon-85mm-f1.4g-af-s

So much misinformation and or variation in this lens. Sigh. Real shame.
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photodan

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Re: D810 + fast primes handheld
« Reply #29 on: August 16, 2014, 09:56:24 pm »

(snipped from two different posts: )...You don't happen to know if the older 85mm 1.4 AF-D has the distance issue too, do you...
... So much misinformation and or variation in this lens. Sigh. Real shame....

I don't have personal experience with the 1.4/af-d. If I recall correctly most reviews say that the 1.4G is supposed to focus better.

Re the varying info that is out there on the 1.4g re focus shift or not. I take all the reviews on all equipment with a grain of salt or more because while the particular reviewer's results may be valid for their particular copy of camera body and lens and test equipment, it may not hold up for MY particular equipment. Roger at Lens Rentals usually tests more than one copy, so I have no idea why his results differ from photozone and diglloyd. Both 85 1.4Gs I had, including the rental copy did have focus shift. Focus shift is common for fast 50s and 85s, so I'm inclined to believe the lens really does have focus shift in general.

It seems like one bonus "joy"  of digital photography is that there's seemingly little room for error. We have to deal with (1) higher mp DSRls being very revealing of flaws in technique and imperfections in lens to camera sensor alignment, optical flaws, etc. (2) phase detection autofocus lack of precision/accuracy/consistency (3) variations not only as expected in manufacturing tolerances but quality control that might have been good enough for 12mp DSLRs but not 36mp, (4) various camera body/lens interactions, (5) God knows what else...

I recently went through two copies of the 35mm f/1.4 Sigma lens for my D810. I had them at the same time, and shot a finely detailed subject at near infinity focus, a landscape including some buildings with several different types of fences. Besides showing moire very nicely it's proved to be a very demanding subject for sharpness across the field.  I shot that subject at the same session with the two copies. One copy showed not only a much more highly variable autofocus (on that and other subjects), required the max af adjust of +20, but also was inferior in sharpness to the other copy,even when carefully manually focused with live view. The other copy was obviously sharper, required much less fine tune adjustment, and most importantly was much more consistent in AF results.  

Perhaps if you can't get your particular lens to perform satisfactorily you might take a small gamble and send it in to Nikon as you indicated before. They might do a decent job and solve your problem, and if not, well, you haven't lost that much by trying.
« Last Edit: August 16, 2014, 10:06:48 pm by photodan »
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trevarthan

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Re: D810 + fast primes handheld
« Reply #30 on: August 16, 2014, 10:32:22 pm »

I don't have personal experience with the 1.4/af-d. If I recall correctly most reviews say that the 1.4G is supposed to focus better.

Re the varying info that is out there on the 1.4g re focus shift or not. I take all the reviews on all equipment with a grain of salt or more because while the particular reviewer's results may be valid for their particular copy of camera body and lens and test equipment, it may not hold up for MY particular equipment. Roger at Lens Rentals usually tests more than one copy, so I have no idea why his results differ from photozone and diglloyd. Both 85 1.4Gs I had, including the rental copy did have focus shift. Focus shift is common for fast 50s and 85s, so I'm inclined to believe the lens really does have focus shift in general.

It seems like one bonus "joy"  of digital photography is that there's seemingly little room for error. We have to deal with (1) higher mp DSRls being very revealing of flaws in technique and imperfections in lens to camera sensor alignment, optical flaws, etc. (2) phase detection autofocus lack of precision/accuracy/consistency (3) variations not only as expected in manufacturing tolerances but quality control that might have been good enough for 12mp DSLRs but not 36mp, (4) various camera body/lens interactions, (5) God knows what else...

I recently went through two copies of the 35mm f/1.4 Sigma lens for my D810. I had them at the same time, and shot a finely detailed subject at near infinity focus, a landscape including some buildings with several different types of fences. Besides showing moire very nicely it's proved to be a very demanding subject for sharpness across the field.  I shot that subject at the same session with the two copies. One copy showed not only a much more highly variable autofocus (on that and other subjects), required the max af adjust of +20, but also was inferior in sharpness to the other copy,even when carefully manually focused with live view. The other copy was obviously sharper, required much less fine tune adjustment, and most importantly was much more consistent in AF results.  

Perhaps if you can't get your particular lens to perform satisfactorily you might take a small gamble and send it in to Nikon as you indicated before. They might do a decent job and solve your problem, and if not, well, you haven't lost that much by trying.

I don't know. What you're saying seems to be at complete odds with the review on the Amazon page for this lens. http://www.amazon.com/Nikon-85mm-1-4G-Nikkor-Digital/product-reviews/B003ZSHNE0

Everyone seems to love it, even on the D800, which seemed to be notorious for autofocus problems. Maybe I just have a lemon. Amazon is processing my return, even though I'm way past their normal return mark. I'll re-order another one as soon as that's done and report back. It'll be interesting to see what I find.
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trevarthan

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Re: D810 + fast primes handheld
« Reply #31 on: September 04, 2014, 02:08:58 pm »

Got a new copy of the 85mm 1.4g. It exhibits the exact same problem as the original, but it's more centered. -2 af tune at 6' and +2 af tune at 16'. I suspect that's how it's supposed to perform, so I'll probably keep this one.
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Ajoy Roy

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Re: D810 + fast primes handheld
« Reply #32 on: September 13, 2014, 11:39:16 am »

I have neither the D800 nor the f1.4 lense. What I have is the D3300 and a 35mm F1.8 lense, The DX sensor has smaller pixels, so the effect of vibration or camera shake should be same. If you need razor sharp AF, you use AF-S - Single Servo and not AF-C Continuous Servo. Some how AF-C in Nikon does not focus sharp, even if it is supposed to.

I have shot indoors in a Large Hall at marriage party at F1.8 at ISO 400 and less, with pretty sharp focus. If you feel that your hands shake (as mine do at times), then use a flash, it will "strobe" so that neither the object shake nor camera shake is usually evident.
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John Koerner

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Re: D810 + fast primes handheld
« Reply #33 on: September 13, 2014, 12:19:33 pm »

I've had a D3s since 2010, but recently bought a D810 for images where resolution matters.

One thing that's really knocking my socks off in a bad way is how much my 85mm f1.4g sucks on the D810, handheld. I was taking pictures of my daughter playing with legos this morning, or trying to, and I thought, NAH, I won't use the 70-200mm f2.8 VR II. It's too big and heavy. I'll just snap that little 85mm f1.4g on there and sneak some pictures while her attention is on the legos. Total fail. I set the shutter speed to 1/250s and every frame turned out blurry.

At first I thought I was getting some back or front focus on the body. Eventually, after playing around with different things and focusing manually with live view as a test, I bumped the shutter to 1/400s. That seemed to be ok. I then got my 70-200mm VR II out and tested how low I could go. I was reliably getting sharp photos at 85mm and 1/125s. That's a HUGE difference. I bought that fast prime to assist in shooting low light scenes hand held, but if I have to crank the shutter speed up to 1/400s to eliminate hand shake (I think I have a pretty steady hand too), that means I have to lower my f-stop to f1.8 or f1.4 just to get the shot at the same ISO. That's a worse picture, not a better picture!

Granted, if there was some serious action going on, the 85mm 1.4g could out perform the 70-200mm f2.8 in low light, but that's a really narrow use case.

Why in the heck didn't they ship these fast primes with VR? That would make these lenses so much more useful.

None of this matters on a tripod, of course. I just felt like ranting this morning.  I think the D3s's resolution is low enough that I never noticed this before. Seems like the D810 just magnifies every little flaw in an image. You have to really be precise with it. Kind of a double edged sword.


You basically answered your own question.

All of this excitement isn't really over the D810, nor of VR, it's over your struggle with reality.

Essentially, if you're wanting the absolute highest image-quality you can get, and have the equipment to get it, then you need to use a tripod to produce those uncompromising results.

Bracing yourself, leaning against walls, etc. will never equal the stability of a tripod + mirror lock-up. Never.

If you want the sharpest images possible, use a tripod. That's what they're for.
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trevarthan

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Re: D810 + fast primes handheld
« Reply #34 on: September 13, 2014, 12:52:08 pm »

Sigh. Read the rest of the thread. The problem was focus shift.
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John Koerner

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Re: D810 + fast primes handheld
« Reply #35 on: September 13, 2014, 01:07:22 pm »

Sigh. Read the rest of the thread. The problem was focus shift.

Then why did you say, "None of this matters on a tripod, of course."?

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John Koerner

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Re: D810 + fast primes handheld
« Reply #36 on: September 13, 2014, 01:11:02 pm »

Do you honestly believe that the highest-resolving sensors + finest lenses render their sharpest images when hand-held?
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trevarthan

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Re: D810 + fast primes handheld
« Reply #37 on: September 17, 2014, 01:16:32 pm »

Do you honestly believe that the highest-resolving sensors + finest lenses render their sharpest images when hand-held?

I tested on a tripod. You're not reading.
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melchiorpavone

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Re: D810 + fast primes handheld
« Reply #38 on: September 17, 2014, 05:58:23 pm »

Do you honestly believe that the highest-resolving sensors + finest lenses render their sharpest images when hand-held?

Depends.
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Ajoy Roy

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Re: D810 + fast primes handheld
« Reply #39 on: September 18, 2014, 12:35:48 am »

Do you honestly believe that the highest-resolving sensors + finest lenses render their sharpest images when hand-held?
Steady hands with a good flash can achieve that, but it is easier with a tripod.
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