My camera became "darker" after sensor cleaning

<p>Well, pretty much as the title says.<br>

I have a Nikon D7000 with Sigma 17-50/f2.8 fixed. Recently (about a month ago) i took both camera and lens for service, and on the camera I had sensor cleaned.<br>

The lens had mechanical problem, with zoom stopped working, and I had it repaired. Now, all seem to work fine, but it seems to me that things have become darker. Same kind of photos I took, now seem to be more on the left side of the spectrum. I constantly find myself shooting at high ISOs, which I would normally want to avoid.<br>

Any suggestions? what could have happened? </p>

<p>Winter is coming?</p>

<p>That's an odd one. Do you have another exposure meter or camera to check yours against, in case there is some sort of metering issue? Might also be worth trying a reset. </p>

<p>Are you sure the iris on the lens is working correctly after the repair?</p>

<p>Was the camera (and any exposure compensation previously set) reset during the cleaning?</p>

<p>Is the underexposure consistent all of the time?</p>

<p>Have you tried resetting to original mfr settings?</p>

<p>You can get a histogram on the camera, and some post processing programs can give you a histogram of any older images. Can you compare them to see if one or the other is off?</p>

<p>Have you checked exposure compensation? Maybe it got changed during service?</p>

I agree with Matthew. Check the EXIF data on

current exposures against pictures taken before

the repair. A careful comparison should reveal any

change or inconsistency.

 

That's assuming the difference isn't just down to a

change in weather or lighting.

<p>Since Dima said, "I constantly find myself shooting at high ISOs", that would rule out exposure comp, etc., wouldn't it? Even if you raised the ISO, exposure comp would still be in effect. That sounds like something is reducing light transmission like the aperture stuck at small f/stops.</p>

<p>I, too, would check to see if your exposure compensation changed before and after.</p>

<p>It would help a lot if you could borrow a second lens that is known to work properly, and do some test shots with it. Do you know anyone else with any Nikon AF DSLR? Any lens should work. If you took the camera to a brick and mortar store, I'd take it back there, explain your issue, and see if they could hand you another lens to try. Any lens, even a crummy one, if it's working, should give you a correct exposure. If it does, suspect your lens. If it does not, suspect your camera. </p>

<p>Did you set auto-ISO at a high shutter speed?</p>

<p>Everything that you say makes sense to try, if I could rule out one of the variables - camera or a lens. With just one left, I could go with different camera/lens.<br>

I have 2 other lenses, that I rarely use, will have to go try. Maybe it all is just in my head. I suspect some similar issues I had with the Tamron lens I used before this one - after some time, I thought that it becomes harder to shoot at certain conditions.</p>

 

<p>Dima, a simple sanity check for your camera's meter - the sunny-16 rule says correct exposure is defined as f16 at a shutter speed of 1/ISO. So set your ISO at 200, select Shutter priority and adjust the shutter to 1/200 sec, and point the camera at a sunny day. If it tells you f16, the meter is working pretty good. If you get something else, more tests would be in order.</p>

<p>Thank you, Bob.<br />I will give it a try. I heard a term "sunny-16", but did not know the details.</p>

<p>In reality, you can pretty much forget about how the camera used to perform before. What matters is whether it is metering correctly and exposing correctly, now.</p>

<p>As mentioned before, use "sunny 16" to check whether the metering is correct.</p>

<p>Use depth of field preview to check whether the lens aperture is stopping down correctly. Test exposure with the lens wide open (f2.8) and stopped down. If the exposure is fine wide open but you get overexposed images stopped down, maybe the aperture diaphragm is not closing properly.</p>

<p>Dima, as mentioned before, don't forget to check your exposure compensation. In support of what Shun said, if you were shooting with an exposure compensation adjustment inadvertently set to over expose and it was then reset to zero at the shop then you would expect the camera to now "relatively" under expose compared to what you are used to seeing and the sunny 16 rule to be spot on. If sunny 16 shows your camera is correctly metering then you should go forward with the idea that you’re now getting correct exposure. Also if you can get your hands on an ExpoDisc that is calibrated for 18% light transmission it will help with checking your meter system. If your compensation is set to zero after coming from the shop I would ask the shop if they reset the compensation. Also I would check the before and after histograms in Photoshop/elements and look at the file information as well. The EXIF data may well tell the tale. I looked at the histograms of your images on Photoshop and noticed that your shooting style tends towards darker exposure anyway. This may be well exacerbated if you were inadvertently overexposing by means of exposure compensation and now have it turned off. Good hunting.</p>