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Archive 2014 · Nikon 85mm f/1.8G - Sharp Enough?

workerdrone
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p.2 #1 · Nikon 85mm f/1.8G - Sharp Enough?

I have no experience with FoCal, but I think different light sources and distances can produce different AF results, so maybe that's your issue.

I know you want examples with your particular combo, but here's one with the D800 and 70-200 zoom. I'm sure the prime is capable of this too - full photo and a crop.

It would be nice if a fine tune worked 100% from the day you applied it, but it's often not so - I'll tweak a bit after a few test shots in the 'new' conditions all the time. And I keep a little record of lens/body combos and my baseline fine tune to come back to -

Jan 06, 2014 at 04:54 PM

Frode
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p.2 #2 · Nikon 85mm f/1.8G - Sharp Enough?

If you want to know if your lens is sharp: use liveview to manually focus (zoom in) and take an exposure (with fast enough shutterspeed of course :-).

I would think your kombo (either lens, camera or both) must be fine tuned due to frontfocusing (easy to see when examine your pictures).

And yes; they`re NOT sharp!

Jan 06, 2014 at 04:55 PM

fetopher
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p.2 #3 · Nikon 85mm f/1.8G - Sharp Enough?

oiseau0001 wrote:
Looking at the EXIF gallery on here, below are two links to shots taken with the D800 and 85 F/1.8G. Better lighting for sure, but *much* sharper as well:

https://www.fredmiranda.com/forum/topic/1197076/-1#11475514
https://www.fredmiranda.com/forum/topic/1194095/-1#11386381

I had no idea these forums had an EXIF search. Amazing! Thanks for pointing me in that direction.

workerdrone wrote:
I know you want examples with your particular combo, but here's one with the D800 and 70-200 zoom. I'm sure the prime is capable of this too - full photo and a crop.

Thanks for the 100% crop. That's very sharp! I certainly have not seen anything close to this sharpness with my 85mm.

Jan 06, 2014 at 05:16 PM

fetopher
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p.2 #4 · Nikon 85mm f/1.8G - Sharp Enough?

snapsy wrote:
Nah, the honor is mine to help. Right, we can use the default tuning value in place of the lens-specific value since the default yields more tuning range. But before that we can use the defocused method to find how far the range extends beyond +20 (I described this method most recently here).

Okay, I tried the Dot Tune method. I have some odd results, so perhaps I'm doing it incorrectly. First, what is meant by critical focus? Critical in terms of what auto focus sees? Or critical to my eye (using live view)? I tried it both ways, with differing results.

First, using live view, then pressing AF-ON until AF-S beeps at me:
+9 o>
+10 solid/confirmation
+11 o>
+12 o>
+13 o>
+14 solid/confirmation
+15 <o> (alternating arrows, not lit at same time)
+16 <o
+17 <o

Second, using live view, then manually focusing until it looks in focus to my eye:
+9 o>
+10 o>
+11 solid/confirmation
+12 solid/confirmation
+13 <o
+14 <o

So, it seems like in both cases, it's somewhere in the +10 to +14 range. This is in line with what FoCal told me as well (+12 to +18), and not far off from where I had the fine-tune adjust in all the samples I've posted in this thread (+16).

How do you interpret these results? Or, have I messed it up to the point where it's not reliable? What might I be doing wrong?

Thanks!

Jan 06, 2014 at 05:25 PM

snapsy
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p.2 #5 · Nikon 85mm f/1.8G - Sharp Enough?

fetopher wrote:
Okay, I tried the Dot Tune method. I have some odd results, so perhaps I'm doing it incorrectly. First, what is meant by critical focus? Critical in terms of what auto focus sees? Or critical to my eye (using live view)? I tried it both ways, with differing results.

Critical focus just means "in focus", as determined manually by eye at max magnification in LV or via CDAF in LV. What focus distance did you use and what target? For the 1st DotTune results you posted, are you saying you got a solid confirmation at +10 but then not at +11 through +13 and then solid again at +14? The solid confirmation should be a contiguous range without any gaps - if you see gaps then the procedure should be repeated. It takes a while to get a feel for the rangefinder feedback and you'll need to be patient at first, sometimes pressing AF-ON multiple times over extended duration to make sure there's no rangefinder flicker. But on balance it's looking like +12 but I would do it again to be sure. Btw, +12 vs what you had at +16 for the images you posted is a pretty sizeable jump..enough to cause inconsistent results you may have been seeing (I describe why here).

Jan 06, 2014 at 06:03 PM

workerdrone
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p.2 #6 · Nikon 85mm f/1.8G - Sharp Enough?

Also - don't think you mentioned your AF settings, I seem to have best results with AF-C, keeping AF-on held down while holding the single point on one eye of the subject. I strongly prefer AF to be separated from the shutter but folks more skilled than I like it the other way too. But definitely AF-C not AF-S. At this point I'm not sure what I'd use AF-S for really. On a tripod with static subject I use live view focus.

Unless you're really shaky, I'd think 1/250th should get you some very sharp pix at 85mm even on the D800.

BTW, the example above is handheld @ 175mm and 1/200th with flash so the flash does help with the definition. And it's at f2.8 so a bit more leeway than 1.8. But still, shot after shot, probably at least 80% with that kind of detail.

Jan 06, 2014 at 06:21 PM

fetopher
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p.2 #7 · Nikon 85mm f/1.8G - Sharp Enough?

workerdrone wrote:
Also - don't think you mentioned your AF settings, I seem to have best results with AF-C, keeping AF-on held down while holding the single point on one eye of the subject. I strongly prefer AF to be separated from the shutter but folks more skilled than I like it the other way too. But definitely AF-C not AF-S. At this point I'm not sure what I'd use AF-S for really. On a tripod with static subject I use live view focus.

Unless you're really shaky, I'd think 1/250th should get you some very sharp pix at 85mm even on the...Show more →

Ah, indeed, I failed to mention my AF settings. After much research, I've been rolling with AF-C single point. I also decoupled focus and shutter release by moving focus to AF-ON. Finally, I set my shutter to focus priority (vs. release priority). All of these settings ought to give me the best chance to nail focus, especially on a moving target. But alas...

Snapsy, I'm running Dot Tune again to try to get more consistent results. What would be the best course of action if something like +12 is needed when the subject is near (4-8 feet) but +18 when the subject is far (14-20 feet)?

Thanks!
Chris

Jan 06, 2014 at 06:27 PM

fetopher
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p.2 #8 · Nikon 85mm f/1.8G - Sharp Enough?

Snapsy, one more question for you. The only thing that seems consistent with my Dot Tune testing is how inconsistent the dot is. Is it normal to have confirmation for 5 seconds, then immediately try it again without adjusting anything and have it flicker one direction, then immediately try it again and have it flicker the other direction? I don't get these types of results at every fine-tune level, but a good number of them.

I'm going to run through the range once more but only count a fine-tune adjustment a part of the range if I can get confirmation for 5 seconds on three consecutive attempts.

Jan 06, 2014 at 06:36 PM

fetopher
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p.2 #9 · Nikon 85mm f/1.8G - Sharp Enough?

I'm really struggling with getting consistent results using Dot Tune. I'm sure the method is fine, which means something is wrong with the way I'm doing it, or something is really odd in my D800.

I just ran through the test again and could not get three straight confirmations at any fine-tune adjustment. I used LV, then AF-ON to get my initial focus. My chart was about 14 feet from my camera, which should match what's suggested (50x focal length). Here are the results from 0 to +20:

0 >
+1 >
+2 >
+3 >
+4 >
+5 >
+6 >
+7 >
+8 >
+9 <O> (this was a confirmation for 5 seconds the first attempt, a right arrow the second attempt, then a left arrow the third attempt)
+10 >
+11 >
+12 O> (this was a right arrow the first attempt, a confirmation the second attempt and a right arrow again the third attempt)
+13 <
+14 <> (this was a left arrow the first and second attempt and a right arrow the third attempt)
+15 <
+16 <
+17 <
+18 <
+19 <
+20 <

I'm wondering if I'm not doing step 2 correctly (achieving critical focus). It seems that's the step with the most room for error.

Any thoughts on these results?

Jan 06, 2014 at 06:56 PM

snapsy
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p.2 #10 · Nikon 85mm f/1.8G - Sharp Enough?

It might be your target. I'm actually in the middle of testing various targets that give more consistent results than the original Bob Atkins target I linked to in the video. Download and print this one and see if it gives you more consistent results:

Variable cross-hatch target

Also, what lighting setup are you using? You want at least 1/50 f/1.8 ISO 100 or brighter. Also, don't shine the light directly on the target.

Jan 06, 2014 at 07:16 PM

fetopher
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p.2 #11 · Nikon 85mm f/1.8G - Sharp Enough?

Snapsy, my previous tests may have been faulty because my exposure was not good (too dark).

I just printed out your new target and gave it a whirl. I also fixed my exposure. I don't have quite enough light where I'm at, but can get correct exposure at 1/80s f/1.8 ISO 640.

Here are the results with the new target:

0 >
+1 >
+2 >
+3 >
+4 >
+5 >
+6 O
+7 O
+8 O
+9 O
+10 O
+11 O
+12 O
+13 O
+14 O
+15 O
+16 <
+17 <
+18 <
+19 <
+20 <

So, it seems +10.5 is correct at 14 feet. I'll set it at +11 since it seems like it needs more the farther from the target I go.

With all of this in mind, do you think the difference between +16, where I shot the sample images, and +11, where Dot Tune tells me I should be at 14 feet, is enough to throw the focus out as much as the sample images show?

Thanks!

Jan 06, 2014 at 07:33 PM

snapsy
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p.2 #12 · Nikon 85mm f/1.8G - Sharp Enough?

Great, that's progress. Yep, large-aperture primes esp long ones like 85mm are very sensitive to AF mis-tuning and that sensitivity increases as focus distance increases. I would try shooting real-world subjects at the distance you tuned and in the same lighting conditions and see if your results look good. After that you can try varying distances under that same lighting to see if it holds up. Once past that I would try it under balanced spectrum lighting (daylight) next, which may or may not require a different AF tune.

Jan 06, 2014 at 07:47 PM

Gregg Heckler
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p.2 #13 · Nikon 85mm f/1.8G - Sharp Enough?

The images also look overexposed to me so you are losing some contrast also.

Jan 06, 2014 at 08:29 PM

Mikael Risedal
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p.2 #14 · Nikon 85mm f/1.8G - Sharp Enough?

fetopher wrote:
That's what I've read elsewhere, which is why I am a little disappointed at these results. I expected to be wowed. Instead, I'm searching for what went wrong.

The noise is due to ISO 800.

Do you think 1/250 sec. was quick enough? We're not looking at motion blur here, right? This is more of a soft focus/lens blur issue to my eye.

first of all,a good copy of Nikon 85/1,8 is very sharp but together with d800 I also got blurry shots due to long exposure times and that the combo is very light, easy to handshake and micro tremors can be seen very clearly in D800 large files

Jan 06, 2014 at 08:37 PM

jbouchard
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p.2 #15 · Nikon 85mm f/1.8G - Sharp Enough?

As people have eluded to... forget the focus tuning for a moment. See if you can make a sharp image at all using all the basics to your advantage. I apologize if my comments seem condescending, it's hard to know everyone's background and understanding.

- do the 2 fingered reset (press and hold the 2 buttons with green dots).
- Set your rig on a tripod with a detailed flat object several feet away with plenty of light. Maybe a cereal box.
- base ISO, A-mode, f/8, auto white balance, large fine JPG, Neutral picture control, the Shutter speed is whatever it is.
- switch to live view, zoom in with + button as far as it will go, manual focus carefully. With a flat object square to the lens the whole obect should be sharp.
- set to mirror up mode, with remote trigger, press once for mirror to slap
- wait 3 seconds for invisible movement from mirror slap to stop
- don't move, don't breathe, press the trigger.

View the picture on computer, no processing. It should be incredibly sharp! If not, then the lens is sick, and no amount of focus tuning is going to change that. To make sure, let someone else try the live view focus, some people have better eyes and feel than others. If it's good, shoot larger apatures. It may not be just as sharp at 1.8, but it ought to be pretty close.

Jan 06, 2014 at 08:49 PM

fetopher
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p.2 #16 · Nikon 85mm f/1.8G - Sharp Enough?

jbouchard wrote:
As people have eluded to... forget the focus tuning for a moment. See if you can make a sharp image at all using all the basics to your advantage. I apologize if my comments seem condescending, it's hard to know everyone's background and understanding.

- do the 2 fingered reset (press and hold the 2 buttons with green dots).
- Set your rig on a tripod with a detailed flat object several feet away with plenty of light. Maybe a cereal box.
- base ISO, A-mode, f/8, auto white balance, large fine JPG, Neutral picture control, the Shutter speed is whatever it is.
-...Show more →

Your suggestion is not condescending in the least. I appreciate the help! I've done as you suggested, except rather than focus manually I left the camera lock focus in live view. I did this because part of the problem must be tied to the AF system, so focusing manually wouldn't test what's wrong. Correct me if I'm not thinking about things properly.

Here are two samples (untouched 100% crops). One at f/8, one at f/1.8. Both are focused on the hard drive label, specifically over the middle-right side of the label.

At f/8, the text seems reasonably sharp (not sure what to compare it to). I can make out "Product of China" pretty clearly. At f/1.8, it's considerably less sharp. The same "Product of China" text is bordering on illegible. Both shots were taken with fine-tune adjustment set to +11 as Snapsy's Dot Tune method suggested would be correct.

Am I wrong, or does it seem way too soft at f/1.8?

Part of what's making this difficult on me is not having untouched 100% crops to compare it to. Comparing my samples to this pool of photos taken with the same lens doesn't do me much good because all of those shots have been processed, sharpened and not presented as 100% crops. Such is life when pixel peeping, I suppose. Does anyone have unsharpened, unprocessed 100% crops with this lens?

Thanks!

Jan 07, 2014 at 05:58 PM

rbromfield
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p.2 #17 · Nikon 85mm f/1.8G - Sharp Enough?

Full size straight of out camera and f1.8. Just raw conversion. D800e with a sharpness setting of default 3. Exif intact on full sized photo.

http://www.flickr.com/photos/robertbromfield/9762048455/sizes/o/

Jan 07, 2014 at 06:07 PM

fetopher
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p.2 #18 · Nikon 85mm f/1.8G - Sharp Enough?

rbromfield wrote:
http://farm4.staticflickr.com/3783/9762048455_1144124c05_b.jpg

Full size straight of out camera and f1.8. Just raw conversion. D800e with a sharpness setting of default 3. Exif intact on full sized photo.

Fantastic shot! Your photo was one I found before purchasing this lens and I was really wowed by it.

I tried to look at the original size on Flickr, but it looks like all I can get to is the large size (2048px wide). Any chance you could take a screen cap of the focused area at 100% and post here?

Thanks!

Jan 07, 2014 at 06:35 PM

snapsy
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p.2 #19 · Nikon 85mm f/1.8G - Sharp Enough?

fetopher wrote:
Here are two samples (untouched 100% crops). One at f/8, one at f/1.8. Both are focused on the hard drive labe

What was the focus distance? I have a HD I can shoot with my D800+85G as well and can send you the raw.

Jan 07, 2014 at 06:36 PM

fetopher
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p.2 #20 · Nikon 85mm f/1.8G - Sharp Enough?

snapsy wrote:
What was the focus distance? I have a HD I can shoot with my D800+85G as well and can send you the raw.

Focus distance on the hard drive was 9 feet, or thereabouts. Thanks!

Jan 07, 2014 at 06:38 PM

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