Author Topic: nikkor 105mm f/2 DC  (Read 8564 times)

Jack Dahlgren

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Re: nikkor 105mm f/2 DC
« Reply #30 on: June 20, 2021, 17:11:40 »
I don’t think I’d ever count on the DC lenses to autofocus well. Especially as more DC is dialed in. For me, manual focus is the preferred method.

David H. Hartman

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Re: nikkor 105mm f/2 DC
« Reply #31 on: June 20, 2021, 18:48:39 »
You also have to take into account that as a portrait lens, that's a good thing because it softens the details most people don't want to see in an image of themselves.

If you wish to enhance the sharpness of eye and hair and smooth out the skin there are various methods of achieving this using +/- Sharpening, Mid sharpening and Clarity with Nikon software. Here is a link...

Sharpening and Softening Images (NPS Global)

...other software must have similar features or controls for tuning the sharpening while doing RAW development. If the reader's camera is older, set "Latest picture control" as your default in the preferences of Capture NX-D and NX Studio or some features may be grayed or missing in the Picture Control pallet.

One might combine positive sharpening with negative mid sharpening to achieve the look desired.

Dave

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Oh no, must be the season of the witch!

osmosis

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Re: nikkor 105mm f/2 DC
« Reply #32 on: June 22, 2021, 15:44:30 »
I don’t think I’d ever count on the DC lenses to autofocus well. Especially as more DC is dialed in. For me, manual focus is the preferred method.

That's certainly borne out of my own limited findings. In low'ish light indoors, the hit rate for an in-focus shot is pretty low. 1 in 8 or 10 shots perhaps? When the light is pretty good the rate goes up quite a bit. But as you imply, the AF is pretty unreliable in these lenses. The nice and sharp shots I have had looked great so I personally feel it's worth persisting with the lens. Someone mentioned that you shouldn't dismiss this lens until at least 1,000 shots, because it's such a tricky beast to get the hang of.

osmosis

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Re: nikkor 105mm f/2 DC
« Reply #33 on: June 22, 2021, 15:50:25 »
If you wish to enhance the sharpness of eye and hair and smooth out the skin there are various methods of achieving this using +/- Sharpening, Mid sharpening and Clarity with Nikon software. Here is a link...

Sharpening and Softening Images (NPS Global)

...other software must have similar features or controls for tuning the sharpening while doing RAW development. If the reader's camera is older, set "Latest picture control" as your default in the preferences of Capture NX-D and NX Studio or some features may be grayed or missing in the Picture Control pallet.

One might combine positive sharpening with negative mid sharpening to achieve the look desired.

Dave

Thanks for the info, David. Though I use Lightroom instead, your comments have prompted me to spend more time with the sharpening/denoise filters in LR.

Jack Dahlgren

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Re: nikkor 105mm f/2 DC
« Reply #34 on: June 22, 2021, 16:06:12 »
That's certainly borne out of my own limited findings. In low'ish light indoors, the hit rate for an in-focus shot is pretty low. 1 in 8 or 10 shots perhaps? When the light is pretty good the rate goes up quite a bit. But as you imply, the AF is pretty unreliable in these lenses. The nice and sharp shots I have had looked great so I personally feel it's worth persisting with the lens. Someone mentioned that you shouldn't dismiss this lens until at least 1,000 shots, because it's such a tricky beast to get the hang of.

I can't speak about the 105mm but the 135 certainly does reward practice. I can't imagine being happy/proficient with this lens back in the days of film.

Ilkka Nissilä

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Re: nikkor 105mm f/2 DC
« Reply #35 on: June 23, 2021, 10:04:25 »
That's certainly borne out of my own limited findings. In low'ish light indoors, the hit rate for an in-focus shot is pretty low. 1 in 8 or 10 shots perhaps? When the light is pretty good the rate goes up quite a bit. But as you imply, the AF is pretty unreliable in these lenses. The nice and sharp shots I have had looked great so I personally feel it's worth persisting with the lens. Someone mentioned that you shouldn't dismiss this lens until at least 1,000 shots, because it's such a tricky beast to get the hang of.

I haven't noticed such problems with my DC Nikkors and recent camera bodies. When using the 105 DC with studio flash lighting, I get about 90% in focus to the requirements of head and shoulder portraits, for available light I would still consider most shots acceptable though they're not the same kind of sharp as one can get with the 105/1.4.

I've always loved the 105 DC and the 135 DC is somewhat less sharp, but somehow of the shots I've printed and framed on my walls, the 135 DC has taken the lead position, there is a feeling in those images that I really like even though sharpness is not what I'd consider among it's merits.

I will try to perform some experiments on both DC Nikkors and compare them to a reference lens, such as the 70-200/2.8 FL, to get an idea of what kind of autofocus precision and accuracy can be expected in different conditions. I recently acquired Reikan FoCal software which can be used to give some data on the focusing as well.

I think these lenses can be challenging to use, but 1 in 10 shots sharp doesn't sound right and I suspect camera body or calibration to be influencing the outcome.  Of course, it also depends on the definition of what is considered "in focus" as some applications and users are more demanding than others!

osmosis

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Re: nikkor 105mm f/2 DC
« Reply #36 on: June 23, 2021, 20:15:53 »
I haven't noticed such problems with my DC Nikkors and recent camera bodies. When using the 105 DC with studio flash lighting, I get about 90% in focus to the requirements of head and shoulder portraits, for available light I would still consider most shots acceptable though they're not the same kind of sharp as one can get with the 105/1.4.

I've always loved the 105 DC and the 135 DC is somewhat less sharp, but somehow of the shots I've printed and framed on my walls, the 135 DC has taken the lead position, there is a feeling in those images that I really like even though sharpness is not what I'd consider among it's merits.

I will try to perform some experiments on both DC Nikkors and compare them to a reference lens, such as the 70-200/2.8 FL, to get an idea of what kind of autofocus precision and accuracy can be expected in different conditions. I recently acquired Reikan FoCal software which can be used to give some data on the focusing as well.

I think these lenses can be challenging to use, but 1 in 10 shots sharp doesn't sound right and I suspect camera body or calibration to be influencing the outcome.  Of course, it also depends on the definition of what is considered "in focus" as some applications and users are more demanding than others!

I've just run a few tests shots with my son and have discovered that the keeper rate goes up the more the DC setting moves to F.

From 0 toward the R, the eye area blurs again and is too soft. From F2 up to F5.6, the eye gets sharper and sharper. I appreciate it's not a formal test but it is showing that this lens is indeed sharp but having to move the DC control so far away from the actual aperture does pose more questions than answers.


Bern

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Re: nikkor 105mm f/2 DC
« Reply #37 on: June 24, 2021, 06:16:05 »
I've just run a few tests shots with my son and have discovered that the keeper rate goes up the more the DC setting moves to F.

From 0 toward the R, the eye area blurs again and is too soft. From F2 up to F5.6, the eye gets sharper and sharper.

did you re focus each time the DC setting was changed?
Keep shooting,
Bern

Erik Lund

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Re: nikkor 105mm f/2 DC
« Reply #38 on: June 24, 2021, 08:14:38 »
To reliable focus any lens on a DSLR you need to fully understand how the focus system is working, it doesn't know it's focusing on an eye, the iris the eyelashes or the reflected image of the eyeball suface.
Also the sensor has an size so cross-talk is often an issue and what AF mode AF-S or AF-C and so on. Is the model still, is the photographer steady.The later and higher model DSLR the better the focus system is.With the later high resolution DSLR you get AF fine tune to play with as well, your compensation of -12 is a very high value and I fear that is messing with you, I would try to return to 0, no compensation and use AF-C.
The new Z bodies are IMHO just a new way of missing critical focus, sometimes.
Erik Lund

osmosis

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Re: nikkor 105mm f/2 DC
« Reply #39 on: June 24, 2021, 08:41:53 »
did you re focus each time the DC setting was changed?

Yes, I re-focused each time after changing the DC setting.

osmosis

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Re: nikkor 105mm f/2 DC
« Reply #40 on: June 24, 2021, 09:13:34 »
To reliable focus any lens on a DSLR you need to fully understand how the focus system is working, it doesn't know it's focusing on an eye, the iris the eyelashes or the reflected image of the eyeball suface.
Also the sensor has an size so cross-talk is often an issue and what AF mode AF-S or AF-C and so on. Is the model still, is the photographer steady.The later and higher model DSLR the better the focus system is.With the later high resolution DSLR you get AF fine tune to play with as well, your compensation of -12 is a very high value and I fear that is messing with you, I would try to return to 0, no compensation and use AF-C.
The new Z bodies are IMHO just a new way of missing critical focus, sometimes.

Hi, Erik. Thanks for your info. The shots of my son are of course a little unreliable as it was handheld and he doesn't exactly sit still. Focus mode was AFC-S, using the central focus point. On my computer I could clearly see a progression from out-of-focus to in-focus as the DC setting moved from Rear to Front.

The -12 AF fine tune result came after three calibration tests with Reikan FoCal – all with the DC setting on 0. However, today I'm going to re-run the calibration test multiple times with AF fine tune at 0, and on each test use a different DC setting to see which gives the sharpest results. I'm suspecting there's something wrong with this lens but luckily I have a few more days left to send it back for a refund.

It's my understanding that whilst the DC setting will bring a softness to the image, it shouldn't be affecting the in-focus plane. I'm not quite sure what it means if a large DC setting makes the image sharper.

Thanks again.


Erik Lund

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Re: nikkor 105mm f/2 DC
« Reply #41 on: June 24, 2021, 11:56:22 »
The DC setting makes the image softer and softer and shifts or smear out the focus plane more and more as you dial in higher settings.
So,,, you have a higher chance of getting something acceptable sharp as you dial in more DC.
 
I strongly suggest to make a simple setup instead of relying of a live model - Set up good neutral strong light with good contrast for the AF focus system to work reliably on the target(soft light low contrast) (some led light bulbs only emit very limited light spectrum)

Start with: Tripod and a target where you can access the depth of focus as it move back and forth as you dial in the Fine Tune setting, form -20 to +20
 
First at DC 0 - Then dial in more DC and stop down the lens also.
 
Good luck!
Erik Lund

osmosis

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Re: nikkor 105mm f/2 DC
« Reply #42 on: June 24, 2021, 14:56:11 »
The DC setting makes the image softer and softer and shifts or smear out the focus plane more and more as you dial in higher settings.
So,,, you have a higher chance of getting something acceptable sharp as you dial in more DC.
 
I strongly suggest to make a simple setup instead of relying of a live model - Set up good neutral strong light with good contrast for the AF focus system to work reliably on the target(soft light low contrast) (some led light bulbs only emit very limited light spectrum)

Start with: Tripod and a target where you can access the depth of focus as it move back and forth as you dial in the Fine Tune setting, form -20 to +20
 
First at DC 0 - Then dial in more DC and stop down the lens also.
 
Good luck!

I've spoken with the seller, who is a reputable camera/lens retailer. They're taking the lens back to run some tests themselves on their own D750, and if needs be sending it off to the company that serviced the lens back in April.

This is because calibrating the lens again today with FoCal, I found out the following:

DCR2.8 requires AF fine-tune +67
DCR2 requires AF fine-tune +11 (11% improvement)
DC0 requires AF fine-tune -8 (5% improvement)
DCF2 requires AF fine-tune -41
DCF2.8 requires AF fine-tune -43

(D750 on tripod, tethered auto-shooting, AF fine-tune at 0 before each calibration, f/2, ISO100, AFS-S, 3m from FoCal target, indoors)

So you can see how massive those fine-tune numbers are, particularly DCF2, which matches the aperture shot and shouldn't be giving such an out-of-focus image. Conversations with the seller and another service centre confirm that the lens should still be producing a crisp enough image of the target no matter the DC setting used.

I'll report back when I've heard from the seller and let you know their findings.

EDIT (28/06/21):
The seller came back to me today, having tested the lens on a D750 with/without tripod/target/live view. He's not seeing anything out of the ordinary for this lens, having owned one previously and remembering its quirks well. We both agree that the DC setting will be throwing FoCal off and an AF fine-tune on Neutral shouldn't affect normal use even when moving the DC setting to match the aperture. I'll be getting it back tomorrow.

Thanks to you all for your guidance. It seems it's one of those lenses that requires a lot of patience and perseverance to get the best results.

EDIT EDIT (30/06/21):
The lens is back with me and after a few test shots, I've determined that this lens works perfectly no matter the DC setting used so long as you use Live View (contrast-detection autofocus). But if you shoot through the viewfinder, phase-detection autofocus struggles unless the DC setting is at 0.

So, as per other DC users' experiences, for best results...shoot manual focus through the viewfinder when the DC setting is to the front or rear (matching the aperture). And only use autofocus through the viewfinder when DC is at 0.

John Geerts

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Re: nikkor 105mm f/2 DC
« Reply #43 on: June 24, 2021, 19:31:40 »
You can't use AF  Fine tune with  a DC lens because there is a focus shift when using DC.