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I have a Nikon D3300 and Sigma 70-200mm f2.8 OS DG lens. When I use the camera in Aperture priority mode and set the aperture to f/9, the images I am getting are very overexposed. If I underexpose using exposure compensation to between -2.7EV and -3.3EV (depending on the scene) I get properly exposed images. The same problem does not happen at lower f-numbers such as f/2.8, f/4, or f/5.6.

It only starts with f/9 and higher f-numbers, (the higher the f-number the more I need to compensate with negative exposure compensation values to get proper exposure).

The camera meters light correctly in manual mode. I get properly exposed images in manual mode when I use settings so that the camera meter reads no over or underexposure.

What could be the issue? My camera is still under warranty so if it's a camera issue I will send it to Nikon for investigation, but I want to make sure it is really a camera issue.

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    Are you able to test with a different lens? – Philip Kendall Jan 3 '17 at 7:09
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    How old is the Sigma lens? Did you buy it used? Is it a non-CPU lens (i.e., does it have a chip with electronic contacts on the lens mount)? In manual mode vs. A mode, are you changing how you adjust the aperture (i.e., using a ring on the lens vs. dials on the camera)? – inkista Jan 3 '17 at 21:07
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    Please provide some more information about camera settings during this problem. Do you have Auto ISO enabled? If so, what is the Minimum Shutter Speed in ISO Sensitivity Settings? Are you using flash when this happens? What are the ISO & shutter speeds of the actual shots that are overexposed? Finally, what are your shooting conditions (indoors vs. outdoors, well lit, lots of lighting contrast, lots of fast motion, etc.)? – scottbb Jan 3 '17 at 23:24
  • Just to clarify: you get properly exposed images at f/9 (or above) with the camera set to manual mode and showing correct exposure for your iso/shutter settings? So if you shoot at f/9 in Aperture priority mode, get overexposure, note down the iso and shutter settings, switch to manual, shoot with the exact same aperture, iso, shutter settings, then it suddenly becomes correctly exposed? – RoG Jan 5 '17 at 8:13
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    @Snaptastic : yes i did that test, once i got overexposed image in Aperture priority mode, i immediately shifted to manual mode and saw that camera meter reading shows over exposure at the settings where aperture priority mode got over exposed image, then i increased the shutter speed in manual mode till camera meter shows 0 and clicked image, comes out properly exposed :( – maxchirag Jan 24 '17 at 9:39
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This sounds like a lens bias issue, especially since you say it gets worse the higher the f-stop. Many years ago, one of the lenses I had for my first SLR was like this. It shot fine up to f5.6 but if I stepped it down further than that, it would start to have issues until I learned to adjust the EV settings. Of course back then I'd shoot a roll over the weekend, turn it in for processing on Monday and get it back on Friday. My how things have changed...

My experience with that re-branded Pentax SLR and lens is what has me thinking the most likely cause of your trouble is an imperfect calibration between the Nikon and Sigma standards that is just ever so slightly off in the translation at the lens baseline of f2.8 and grows more and distinct as the f/stop increases.

You have stated that you always shoot in RAW. RAW is good for a number of things, but one of things it is known for is the ability to 'fix' exposure in post-production. Have you been able to fix this overexposure in post?

RAW is a format that is seemingly universal but in truth it is universally proprietary. Everyone decided on a name and no one decided to drop their in-house solution and pay someone else for the rights to use theirs. Each manufacturer produces the files in different ways. Nikon can adapt it for their lenses, but the Sigma lenses might not be perfectly matched up like Nikkor ones.

Next time your your setting up a shot with a high f/stop, try shooting in RAW+Fine JPG instead of just RAW. While your at it, after you've gotten the shots you want, try at least a few frames in full automatic. Compare the results before deciding the camera is faulty. Not saying that RAW is the problem or not, but why not see what it does for you in automatic. That will give an indication on if its in the lens or the camera.

I find that sometimes the little imp in my D3300 can beat my eyes, so I give him a chance occasionally to show me up. Mind you he doesn't do it often, and almost always when I'm shooting in conditions that are hard for my eyes to see with perfect clarity.

The Sigma 70-200 lenses like this one I found with a quick google search, seem to all have a slight dark bias, meaning they are engineered for lower-light photography. That's not a bad thing, it means that the lens has more depth in lower light shooting.

In fact letting more light in is the problem your talking about, and it might be just the way the optics in that particular lens work with the sensors in that particular camera body.

The reviews for the lens I linked to are really almost all positive, though a couple did mention some slight differences in performance from the equivalent Nikkor 70-200mm f2.8 AF lens.

While your Sigma 70-200mm is hardly a 'very-large-apature lens' this Wikipedia article explains an effect similar to what your dealing with, and may prove interesting reading.

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Disclaimer: This is not a Perfect answer, but I am just guessing on you camera settings.

Please check the Active Lighting feature of Camera, sometimes it happens available light is enough to have a perfect images, but due to Active D lightning feature is "ON" our images become over exposed. Active D-lightning may be on Extra high or Auto mode. Please check.

P.S: May be I am 200% wrong, but It's complete guess which surely have an impact on your image.If answer is not helpful enough, please don't downgrade it.

  • How would this explain the problem occurring only at f/9 or narrower? – Philip Kendall Jan 4 '17 at 0:25
  • I notice on A mode when F/9 or lower.. default ISO is between 800 to 1200+ along with that if Active D lightening mode on in Camera settings, this will definitely add up exposure as compare to Normal exposure. Correct me If I'm wrong. – Atul Agarawal Jan 4 '17 at 1:08
  • I don't understand your sentence "Add up exposure as compared to normal exposure" when talking about aperture priority mode. If it is in A mode, the shutter speed should compensate for whatever aperture (and ISO) is chosen to give a correct exposure. This should happen regardless of whether Active D Lighting is enabled. If you can provide more info on underexposure while using ADL I would be interested to see it. Also, it sounds like you mean "auto ISO", not "default iso"? – RoG Jan 5 '17 at 11:24
  • @AtulAgarawal : i dont use Active D-Lighting, i keep this function "ALWAYS OFF" reason being i shoot always in raw & do the highlight & shadow correction in post processing as per the need & type of image. – maxchirag Jan 24 '17 at 9:49

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