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Author Topic: Nikon 7-200 w/white BG (high key) - FLARE issues!  (Read 4443 times)

Charles Waugh

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Nikon 7-200 w/white BG (high key) - FLARE issues!
« on: July 31, 2010, 04:54:48 pm »

I'm shooting a D2700 with the 70-200 VR1 lens and I'm getting significant flare in the center of the image.
The flare is quite red and low-contrast.  With a black sweater, for instance, it leaves a large area of red-tinge.

This is at all apertures, and all focal lengths (though shorter seems to make for a bigger-by-area flare).

Background is lit so it just hits 256 on the histogram, so I'm not over-lighting it.
All lights are heavily flagged and the
Also shows up with a 2 foot long kraft-paper lens hood.

My 28-85 shows the same, but just a little bit.

So, my question:

Is this just to be expected, or is my 70-200 having 'special troubles'?


Charles Waugh


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Charles Waugh

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Nikon 7-200 w/white BG (high key) - FLARE issues!
« Reply #1 on: July 31, 2010, 04:55:44 pm »

Er, that should be D700.
:-)
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Steve Weldon

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Nikon 7-200 w/white BG (high key) - FLARE issues!
« Reply #2 on: July 31, 2010, 10:03:49 pm »

Quote from: Charles Waugh
I'm shooting a D2700 with the 70-200 VR1 lens and I'm getting significant flare in the center of the image.
The flare is quite red and low-contrast.  With a black sweater, for instance, it leaves a large area of red-tinge.

This is at all apertures, and all focal lengths (though shorter seems to make for a bigger-by-area flare).

Background is lit so it just hits 256 on the histogram, so I'm not over-lighting it.
All lights are heavily flagged and the
Also shows up with a 2 foot long kraft-paper lens hood.

My 28-85 shows the same, but just a little bit.

So, my question:

Is this just to be expected, or is my 70-200 having 'special troubles'?


Charles Waugh
Are you using a filter?  And if so what kind?   I shot the VR1 for a long time in the studio without such issues.
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Charles Waugh

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Nikon 7-200 w/white BG (high key) - FLARE issues!
« Reply #3 on: July 31, 2010, 11:46:44 pm »

Good thought, but no - no filter.
(I sure did open my bag real fast just now, hoping to find a thin UV on there that I had forgotten, but, no such luck...)

Thanks!
« Last Edit: July 31, 2010, 11:47:05 pm by Charles Waugh »
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Steve Weldon

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Nikon 7-200 w/white BG (high key) - FLARE issues!
« Reply #4 on: August 01, 2010, 12:06:46 am »

Quote from: Charles Waugh
Good thought, but no - no filter.
(I sure did open my bag real fast just now, hoping to find a thin UV on there that I had forgotten, but, no such luck...)

Thanks!

Well damn.. did you check it for water spots too..
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Dustbak

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Nikon 7-200 w/white BG (high key) - FLARE issues!
« Reply #5 on: August 01, 2010, 03:55:49 pm »

I have had this exact same phenomen with several lenses. Apparently an optical issue where something like the last elements of the lens reflect on the sensor. Dependinp on coatings the color of the spot varies.

I have seen this with the:

Nikkor PC85
Zeiss ZF Macro 50/2.0

I borrowed another PC85 from NPS which showed the same thing. I got confirmation about this thing from Zeiss about the 50Macro having this issue. Apparently the 70-200 is prone to it too.
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Michael Bailey

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Nikon 7-200 w/white BG (high key) - FLARE issues!
« Reply #6 on: August 02, 2010, 03:02:43 pm »

Hi Charles,

I'm pretty sure you have the same red spot issue that has bitten many others. I was in a discussion about this very issue a few months ago:
http://luminous-landscape.com/forum/index....c=40262&hl=
I didn't know that the 70-210 had this problem, particularly, but I think strong back light such as yours can bring it out in many otherwise fine lenses. If you read my post you'll see that I've owned a couple of lenses that were simply unusable, even in conditions less extreme than what you describe.

For what it's worth, here are some suggestions.
1.- Buy the new VR-II lens. Likely it's coating and design will prevent the problem in the future. Of course, I don't KNOW this, but, hey, it's not my money! What's a couple of thousand dollars more of less?
2.- Unless you have creative reasons for your set up, I'd turn down the background light a bit, so it registers more in the 250-250-250 range. Reasons?
[blockquote]
a.-The edges of your subject will be cleaner, especially hair. Even though 255 isn't off the tonal scale, it still creates a lot more flair and edge fuzziness. Unfair but true.
b.-The difference between 255 and 250 in terms of f-stops can be surprisingly large. Could be a full stop. Imagine how much better behaved the red spot will be if it's a stop darker. Might disappear altogether.
c.-Granted, this will create work for you in post-production if you want to clean up or erase the white background. As a worst case, though, you can apply a constant adjustment curve that will bring your results back to where you would have been with the brighter background. Then do a rough bit of black painting in the layer mask so your skin highlights don't turn white.[/blockquote]
3.-To repair the pictures you've already shot, you could make a couple of Adjustment Layers. One would be Hue/Saturation, in which you select the reds and turn their saturation down. The other Adjustment Layer would be a Curve. Make a dark curve and use the "Blend If" settings so the curve only applies to the tones of the spot. Then, for both adjustment layers, paint a soft white dot into their black Layers Masks which correspond to the position of the red spot.
4.-If you shot raw, the new Adjustment Brush might be a great help. I used Auto Mask to help define my spot, then fiddled with Brightness, Contrast, Saturation and a bit of Color to get the spot to match the surrounding area. The Adjustment Brush can also be copied from one file to the next if you synchronize "Local Adjustments". Come to think of it, this method can also work for existing Tiff files, provided you tell ACR to open Tiff files, and you haven't made any other adjustments in those Tiff files yet.   MB
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Charles Waugh

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Nikon 7-200 w/white BG (high key) - FLARE issues!
« Reply #7 on: August 02, 2010, 03:54:42 pm »

Michael,
Thank you!
You're so right about the diff betw 250 and 255, and yes, the adj. brush is the bomb (plus sync-ing in Lightroom)
I need to do more tests (always!)

Though, thinking it through, reducing the light will only reduce the light, it won't reduce the percentage of reflection.  
If it were an electronics-stream issue (i.e., sensor, processing algorithms, etc.) reducing the light might help, but if it's physical, the percentage of reflection will be the same throughout.
Though... uh... maybe not.  Hmmm... time for tests!

I fear that it's just a trial-and-error lens search that will fix the issue.

BTW: If you would be so kind as to buy a VR-II lens and loan it to me for a few years, I'd be able to tell you definitively whether that is the right solution.

Cheers!


Quote from: Michael Bailey
Hi Charles,

I'm pretty sure you have the same red spot issue that has bitten many others. I was in a discussion about this very issue a few months ago:
http://luminous-landscape.com/forum/index....c=40262&hl=
I didn't know that the 70-210 had this problem, particularly, but I think strong back light such as yours can bring it out in many otherwise fine lenses. If you read my post you'll see that I've owned a couple of lenses that were simply unusable, even in conditions less extreme than what you describe.

For what it's worth, here are some suggestions.
1.- Buy the new VR-II lens. Likely it's coating and design will prevent the problem in the future. Of course, I don't KNOW this, but, hey, it's not my money! What's a couple of thousand dollars more of less?
2.- Unless you have creative reasons for your set up, I'd turn down the background light a bit, so it registers more in the 250-250-250 range. Reasons?
[blockquote]
a.-The edges of your subject will be cleaner, especially hair. Even though 255 isn't off the tonal scale, it still creates a lot more flair and edge fuzziness. Unfair but true.
b.-The difference between 255 and 250 in terms of f-stops can be surprisingly large. Could be a full stop. Imagine how much better behaved the red spot will be if it's a stop darker. Might disappear altogether.
c.-Granted, this will create work for you in post-production if you want to clean up or erase the white background. As a worst case, though, you can apply a constant adjustment curve that will bring your results back to where you would have been with the brighter background. Then do a rough bit of black painting in the layer mask so your skin highlights don't turn white.[/blockquote]
3.-To repair the pictures you've already shot, you could make a couple of Adjustment Layers. One would be Hue/Saturation, in which you select the reds and turn their saturation down. The other Adjustment Layer would be a Curve. Make a dark curve and use the "Blend If" settings so the curve only applies to the tones of the spot. Then, for both adjustment layers, paint a soft white dot into their black Layers Masks which correspond to the position of the red spot.
4.-If you shot raw, the new Adjustment Brush might be a great help. I used Auto Mask to help define my spot, then fiddled with Brightness, Contrast, Saturation and a bit of Color to get the spot to match the surrounding area. The Adjustment Brush can also be copied from one file to the next if you synchronize "Local Adjustments". Come to think of it, this method can also work for existing Tiff files, provided you tell ACR to open Tiff files, and you haven't made any other adjustments in those Tiff files yet.   MB
« Last Edit: August 02, 2010, 03:55:19 pm by Charles Waugh »
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Dustbak

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Nikon 7-200 w/white BG (high key) - FLARE issues!
« Reply #8 on: August 03, 2010, 03:43:29 am »

Though a very good practice to shoot at 250 (I actually use 240 and have a level action with mask to up the white to above 255) it will lessen the 'hot-spot' issue but not take it away. My best Nikon lenses which I have used for years were old 50/3.5 macro lenses. Dirt cheap, incredibly sharp and no hot-spots. The 70-180micro lens was my other lens of choice but not so cheap
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Michael Bailey

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Nikon 7-200 w/white BG (high key) - FLARE issues!
« Reply #9 on: August 03, 2010, 02:02:58 pm »

Charles,

I'm pretty sure that lowering the background light level will reduce the spot without affecting the rest of the photo. The spot is caused by background light reflecting off the sensor, into the back of the lens, and back onto the sensor. So, reducing the background level will reduce the spot without affecting the subject area of the photo. It might even darken the spot enough that it stops being a problem--if you're lucky.

My grand theory has become this: every lens has this condition, to some degree. There's a line that gets crossed after which this theoretical bit of optical junk becomes a distinct problem. Whether that happens depends on the lens and the lighting. (And the f-stop, according to a poster on that other discussion I mentioned. His 85mm 1.8 D was terrible at f 11 and below. My study has not been that thorough.)

Like all grand theories, 99% of mine is based on guesswork. However, if you wish to submit it to the Nobel Committee, I will be happy to use part of the winnings to buy you a new 70-210 lens.

Now that I've written so often about this subject, it does make me wonder. Shouldn't there be some way for published lens tests to include information about it? I would think it could be quantified, but I've never noticed it mentioned. Just wondering. MB
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Charles Waugh

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Nikon 7-200 w/white BG (high key) - FLARE issues!
« Reply #10 on: August 04, 2010, 09:16:47 pm »

Michael,
Well, here I am in the studio today and I'm doing tests.

Nikon 24-85 ED lens:
   Significant white spot at f22 and background at way over 255
   Reduced the ISO by two stops and the spot is almost gone

   But...
   Now it's the next day and the flare is terrible.
   
So, moved my background lights out from the white seamless another 3 feet or so (they are ceiling mounted and are now 6 feet from the seamless)
That helped a bunch.

My wife suggested trying a polarizing filter...
Hmmm... the 'skip' angle is not s ow that it could add polarization, but I'll try it.  I'LL TRY ANYTHING!

Yeah, I'm getting tired of this flare junk.

L A T E R . . .

I suddenly realized that 'Auto Tone' had been turned on in Lightroom 3.
ARGH!!!

Turning it off go rid f 95% of the flare issues.
Also, I turned off the 'D-lighting' in the camera (D700 and that helped a tiny bit more)
And, I did one more cleaning of the front and rear elements, just for good measure...

Sheesh!
I feel like a newbie with ten filters on his lens complaining that the images are 'soft'.
:-)


Sigh..

It's time to go home.

Charles










 








Quote from: Michael Bailey
Charles,

I'm pretty sure that lowering the background light level will reduce the spot without affecting the rest of the photo. The spot is caused by background light reflecting off the sensor, into the back of the lens, and back onto the sensor. So, reducing the background level will reduce the spot without affecting the subject area of the photo. It might even darken the spot enough that it stops being a problem--if you're lucky.

My grand theory has become this: every lens has this condition, to some degree. There's a line that gets crossed after which this theoretical bit of optical junk becomes a distinct problem. Whether that happens depends on the lens and the lighting. (And the f-stop, according to a poster on that other discussion I mentioned. His 85mm 1.8 D was terrible at f 11 and below. My study has not been that thorough.)

Like all grand theories, 99% of mine is based on guesswork. However, if you wish to submit it to the Nobel Committee, I will be happy to use part of the winnings to buy you a new 70-210 lens.

Now that I've written so often about this subject, it does make me wonder. Shouldn't there be some way for published lens tests to include information about it? I would think it could be quantified, but I've never noticed it mentioned. Just wondering. MB
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Michael Bailey

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Nikon 7-200 w/white BG (high key) - FLARE issues!
« Reply #11 on: August 05, 2010, 09:29:54 pm »

Hi Charles,

I think you're certainly on the right track by turning off D-Lighting and Auto Tone in Lightroom. Both of those features are designed to give you more detail in shadows than you'd likely want in a set you're lighting yourself.

And, as you've seen, blasting the background above 255 makes the spot more prominent.

But when you say you reduced the ISO by two stops, does that mean you opened the lens by two stops, too? If so, that would make your observations fit with what Nashville Mike told me at the end of that other discussion.
http://luminous-landscape.com/forum/index....c=40262&hl=
Can we conclude that smaller f-stops make the problem worse? Has anybody else out there tested that idea? I'd love to read about your results.

As for the polarizer, I'll go out on a limb and say with 99% confidence that a it shouldn't make any difference. Of course, if the polarizer leads you to a larger f-stop...

MB
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Charles Waugh

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Nikon 7-200 w/white BG (high key) - FLARE issues!
« Reply #12 on: August 05, 2010, 09:42:59 pm »

Michael,
I changed the ISO - the D700 is magical at 500, which is where I am now.
The f is at 14, 16 or 18 (I'm not at the studio and one's memory... you know!)

And, yes, smaller apertures (higher f-stop numbers) seemed to exacerbate the problem (with all the electronic junk turned on)

Polarizer made some difference, but only on low-to-the-ground shots where there was more 'skip' off the floor. But, it was minimal. And, more glass in the light path only added more crud to the image (of course).

Moral is:
Be willing to look dumb when asking for advice in a public forum.
:-)

Thanks for listening and responding!

Charles

 



Quote from: Michael Bailey
Hi Charles,

I think you're certainly on the right track by turning off D-Lighting and Auto Tone in Lightroom. Both of those features are designed to give you more detail in shadows than you'd likely want in a set you're lighting yourself.

And, as you've seen, blasting the background above 255 makes the spot more prominent.

But when you say you reduced the ISO by two stops, does that mean you opened the lens by two stops, too? If so, that would make your observations fit with what Nashville Mike told me at the end of that other discussion.
http://luminous-landscape.com/forum/index....c=40262&hl=
Can we conclude that smaller f-stops make the problem worse? Has anybody else out there tested that idea? I'd love to read about your results.

As for the polarizer, I'll go out on a limb and say with 99% confidence that a it shouldn't make any difference. Of course, if the polarizer leads you to a larger f-stop...

MB
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